Merge tag '0.8.0'

Tag soledad version 0.8.0

26 files changed, 4209 insertions, 2412 deletions

diff --git a/common/MANIFEST.in b/common/MANIFEST.in
index a26a12a6..93f46bbe 100644
--- a/common/MANIFEST.in
+++ b/common/MANIFEST.in
@@ -6,3 +6,4 @@ include CHANGELOG
 # What do we want the ddocs folder in the source package for? -- kali
 # it should be enough with having the compiled stuff.
 recursive-include src/leap/soledad/common/ddocs *
+include src/leap/soledad/common/_version.py
diff --git a/common/changes/create_db_cmd b/common/changes/create_db_cmd
deleted file mode 100644
index 00bbdf71..00000000
--- a/common/changes/create_db_cmd
+++ /dev/null
@@ -1,2 +0,0 @@
-  o Add a sanitized command executor for database creation and re-enable
-  user database creation on CouchServerState via command line.
diff --git a/common/changes/next-changelog.rst b/common/changes/next-changelog.rst
new file mode 100644
index 00000000..c0974384
--- /dev/null
+++ b/common/changes/next-changelog.rst
@@ -0,0 +1,28 @@
+0.8.0 - ...
++++++++++++++++++++++++++++++++
+
+Please add lines to this file, they will be moved to the CHANGELOG.rst during
+the next release.
+
+There are two template lines for each category, use them as reference.
+
+I've added a new category `Misc` so we can track doc/style/packaging stuff.
+
+Features
+~~~~~~~~
+- `#1234 <https://leap.se/code/issues/1234>`_: Description of the new feature corresponding with issue #1234.
+- New feature without related issue number.
+
+Bugfixes
+~~~~~~~~
+- `#1235 <https://leap.se/code/issues/1235>`_: Description for the fixed stuff corresponding with issue #1235.
+- Bugfix without related issue number.
+
+Misc
+~~~~
+- `#1236 <https://leap.se/code/issues/1236>`_: Description of the new feature corresponding with issue #1236.
+- Some change without issue number.
+
+Known Issues
+~~~~~~~~~~~~
+- `#1236 <https://leap.se/code/issues/1236>`_: Description of the known issue corresponding with issue #1236.
diff --git a/common/setup.cfg b/common/setup.cfg
index 3eb110b7..ed06f60d 100644
--- a/common/setup.cfg
+++ b/common/setup.cfg
@@ -8,3 +8,10 @@ ignore = E731
 [flake8]
 exclude = versioneer.py,_version.py,ddocs.py,*.egg,build,docs
 ignore = E731
+
+[versioneer]
+VCS = git
+style = pep440
+versionfile_source = src/leap/soledad/common/_version.py
+versionfile_build = leap/soledad/common/_version.py
+tag_prefix = 
diff --git a/common/setup.py b/common/setup.py
index 383745dc..8d9c4d6e 100644
--- a/common/setup.py
+++ b/common/setup.py
@@ -23,19 +23,15 @@ from os import listdir
 from os.path import realpath, dirname, isdir, join, isfile, basename
 import re
 
+from distutils.command.build import build as _build
 from setuptools import setup
 from setuptools import find_packages
 from setuptools import Command
 from setuptools.command.develop import develop as _cmd_develop
+import versioneer
 
 from pkg import utils
 
-import versioneer
-versioneer.versionfile_source = 'src/leap/soledad/common/_version.py'
-versioneer.versionfile_build = 'leap/soledad/common/_version.py'
-versioneer.tag_prefix = ''  # tags are like 1.2.0
-versioneer.parentdir_prefix = 'leap.soledad.common-'
-
 
 trove_classifiers = (
     "Development Status :: 3 - Alpha",
@@ -51,11 +47,11 @@ trove_classifiers = (
     "Topic :: Software Development :: Libraries :: Python Modules"
 )
 
-DOWNLOAD_BASE = ('https://github.com/leapcode/soledad/'
+DOWNLOAD_BASE = ('https://github.com/leapcode/bitmask_client/'
                  'archive/%s.tar.gz')
 _versions = versioneer.get_versions()
 VERSION = _versions['version']
-VERSION_FULL = _versions['full']
+VERSION_REVISION = _versions['full-revisionid']
 DOWNLOAD_URL = ""
 
 # get the short version for the download url
@@ -64,15 +60,30 @@ if len(_version_short) > 0:
     VERSION_SHORT = _version_short[0]
     DOWNLOAD_URL = DOWNLOAD_BASE % VERSION_SHORT
 
-cmdclass = versioneer.get_cmdclass()
-
 
 class freeze_debianver(Command):
+
     """
     Freezes the version in a debian branch.
     To be used after merging the development branch onto the debian one.
     """
     user_options = []
+    template = r"""
+# This file was generated by the `freeze_debianver` command in setup.py
+# Using 'versioneer.py' (0.16) from
+# revision-control system data, or from the parent directory name of an
+# unpacked source archive. Distribution tarballs contain a pre-generated copy
+# of this file.
+
+version_version = '{version}'
+full_revisionid = '{full_revisionid}'
+"""
+    templatefun = r"""
+
+def get_versions(default={}, verbose=False):
+        return {'version': version_version,
+                'full-revisionid': full_revisionid}
+"""
 
     def initialize_options(self):
         pass
@@ -86,28 +97,16 @@ class freeze_debianver(Command):
         if proceed != "y":
             print("He. You scared. Aborting.")
             return
-        template = r"""
-# This file was generated by the `freeze_debianver` command in setup.py
-# Using 'versioneer.py' (0.7+) from
-# revision-control system data, or from the parent directory name of an
-# unpacked source archive. Distribution tarballs contain a pre-generated copy
-# of this file.
-
-version_version = '{version}'
-version_full = '{version_full}'
-"""
-        templatefun = r"""
-
-def get_versions(default={}, verbose=False):
-        return {'version': version_version, 'full': version_full}
-"""
-        subst_template = template.format(
+        subst_template = self.template.format(
             version=VERSION_SHORT,
-            version_full=VERSION_FULL) + templatefun
-        with open(versioneer.versionfile_source, 'w') as f:
+            full_revisionid=VERSION_REVISION) + self.templatefun
+        versioneer_cfg = versioneer.get_config_from_root('.')
+        with open(versioneer_cfg.versionfile_source, 'w') as f:
             f.write(subst_template)
 
 
+cmdclass = versioneer.get_cmdclass()
+
 #
 # Couch backend design docs file generation.
 #
@@ -229,13 +228,9 @@ class cmd_develop(_cmd_develop):
         build_ddocs_py()
 
 
-# versioneer powered
-old_cmd_build = cmdclass["build"]
-
-
-class cmd_build(old_cmd_build):
+class cmd_build(_build):
     def run(self):
-        old_cmd_build.run(self)
+        _build.run(self)
         build_ddocs_py(basedir=self.build_lib, with_src=False)
 
 
diff --git a/common/src/leap/soledad/common/__init__.py b/common/src/leap/soledad/common/__init__.py
index 1ba6ab89..d7f6929c 100644
--- a/common/src/leap/soledad/common/__init__.py
+++ b/common/src/leap/soledad/common/__init__.py
@@ -47,3 +47,7 @@ __all__ = [
     "soledad_assert_type",
     "__version__",
 ]
+
+from ._version import get_versions
+__version__ = get_versions()['version']
+del get_versions
diff --git a/common/src/leap/soledad/common/_version.py b/common/src/leap/soledad/common/_version.py
index a58af503..1168a88d 100644
--- a/common/src/leap/soledad/common/_version.py
+++ b/common/src/leap/soledad/common/_version.py
@@ -1,73 +1,157 @@
+
 # This file helps to compute a version number in source trees obtained from
 # git-archive tarball (such as those provided by githubs download-from-tag
-# feature). Distribution tarballs (build by setup.py sdist) and build
+# feature). Distribution tarballs (built by setup.py sdist) and build
 # directories (produced by setup.py build) will contain a much shorter file
 # that just contains the computed version number.
 
 # This file is released into the public domain. Generated by
-# versioneer-0.7+ (https://github.com/warner/python-versioneer)
+# versioneer-0.16 (https://github.com/warner/python-versioneer)
+
+"""Git implementation of _version.py."""
 
-# these strings will be replaced by git during git-archive
+import errno
+import os
+import re
 import subprocess
 import sys
-import re
-import os.path
 
-IN_LONG_VERSION_PY = True
 
-git_refnames = "$Format:%d$"
-git_full = "$Format:%H$"
+def get_keywords():
+    """Get the keywords needed to look up the version information."""
+    # these strings will be replaced by git during git-archive.
+    # setup.py/versioneer.py will grep for the variable names, so they must
+    # each be defined on a line of their own. _version.py will just call
+    # get_keywords().
+    git_refnames = "$Format:%d$"
+    git_full = "$Format:%H$"
+    keywords = {"refnames": git_refnames, "full": git_full}
+    return keywords
 
 
-def run_command(args, cwd=None, verbose=False):
-    try:
-        # remember shell=False, so use git.cmd on windows, not just git
-        p = subprocess.Popen(args, stdout=subprocess.PIPE, cwd=cwd)
-    except EnvironmentError:
-        e = sys.exc_info()[1]
+class VersioneerConfig:
+    """Container for Versioneer configuration parameters."""
+
+
+def get_config():
+    """Create, populate and return the VersioneerConfig() object."""
+    # these strings are filled in when 'setup.py versioneer' creates
+    # _version.py
+    cfg = VersioneerConfig()
+    cfg.VCS = "git"
+    cfg.style = "pep440"
+    cfg.tag_prefix = ""
+    cfg.parentdir_prefix = "None"
+    cfg.versionfile_source = "src/leap/soledad/common/_version.py"
+    cfg.verbose = False
+    return cfg
+
+
+class NotThisMethod(Exception):
+    """Exception raised if a method is not valid for the current scenario."""
+
+
+LONG_VERSION_PY = {}
+HANDLERS = {}
+
+
+def register_vcs_handler(vcs, method):  # decorator
+    """Decorator to mark a method as the handler for a particular VCS."""
+    def decorate(f):
+        """Store f in HANDLERS[vcs][method]."""
+        if vcs not in HANDLERS:
+            HANDLERS[vcs] = {}
+        HANDLERS[vcs][method] = f
+        return f
+    return decorate
+
+
+def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False):
+    """Call the given command(s)."""
+    assert isinstance(commands, list)
+    p = None
+    for c in commands:
+        try:
+            dispcmd = str([c] + args)
+            # remember shell=False, so use git.cmd on windows, not just git
+            p = subprocess.Popen([c] + args, cwd=cwd, stdout=subprocess.PIPE,
+                                 stderr=(subprocess.PIPE if hide_stderr
+                                         else None))
+            break
+        except EnvironmentError:
+            e = sys.exc_info()[1]
+            if e.errno == errno.ENOENT:
+                continue
+            if verbose:
+                print("unable to run %s" % dispcmd)
+                print(e)
+            return None
+    else:
         if verbose:
-            print("unable to run %s" % args[0])
-            print(e)
+            print("unable to find command, tried %s" % (commands,))
         return None
     stdout = p.communicate()[0].strip()
-    if sys.version >= '3':
+    if sys.version_info[0] >= 3:
         stdout = stdout.decode()
     if p.returncode != 0:
         if verbose:
-            print("unable to run %s (error)" % args[0])
+            print("unable to run %s (error)" % dispcmd)
         return None
     return stdout
 
 
-def get_expanded_variables(versionfile_source):
+def versions_from_parentdir(parentdir_prefix, root, verbose):
+    """Try to determine the version from the parent directory name.
+
+    Source tarballs conventionally unpack into a directory that includes
+    both the project name and a version string.
+    """
+    dirname = os.path.basename(root)
+    if not dirname.startswith(parentdir_prefix):
+        if verbose:
+            print("guessing rootdir is '%s', but '%s' doesn't start with "
+                  "prefix '%s'" % (root, dirname, parentdir_prefix))
+        raise NotThisMethod("rootdir doesn't start with parentdir_prefix")
+    return {"version": dirname[len(parentdir_prefix):],
+            "full-revisionid": None,
+            "dirty": False, "error": None}
+
+
+@register_vcs_handler("git", "get_keywords")
+def git_get_keywords(versionfile_abs):
+    """Extract version information from the given file."""
     # the code embedded in _version.py can just fetch the value of these
-    # variables. When used from setup.py, we don't want to import
-    # _version.py, so we do it with a regexp instead. This function is not
-    # used from _version.py.
-    variables = {}
+    # keywords. When used from setup.py, we don't want to import _version.py,
+    # so we do it with a regexp instead. This function is not used from
+    # _version.py.
+    keywords = {}
     try:
-        f = open(versionfile_source, "r")
+        f = open(versionfile_abs, "r")
         for line in f.readlines():
             if line.strip().startswith("git_refnames ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["refnames"] = mo.group(1)
+                    keywords["refnames"] = mo.group(1)
             if line.strip().startswith("git_full ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["full"] = mo.group(1)
+                    keywords["full"] = mo.group(1)
         f.close()
     except EnvironmentError:
         pass
-    return variables
+    return keywords
 
 
-def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
-    refnames = variables["refnames"].strip()
+@register_vcs_handler("git", "keywords")
+def git_versions_from_keywords(keywords, tag_prefix, verbose):
+    """Get version information from git keywords."""
+    if not keywords:
+        raise NotThisMethod("no keywords at all, weird")
+    refnames = keywords["refnames"].strip()
     if refnames.startswith("$Format"):
         if verbose:
-            print("variables are unexpanded, not using")
-        return {}  # unexpanded, so not in an unpacked git-archive tarball
+            print("keywords are unexpanded, not using")
+        raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
     refs = set([r.strip() for r in refnames.strip("()").split(",")])
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
@@ -83,7 +167,7 @@ def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
         # "stabilization", as well as "HEAD" and "master".
         tags = set([r for r in refs if re.search(r'\d', r)])
         if verbose:
-            print("discarding '%s', no digits" % ",".join(refs - tags))
+            print("discarding '%s', no digits" % ",".join(refs-tags))
     if verbose:
         print("likely tags: %s" % ",".join(sorted(tags)))
     for ref in sorted(tags):
@@ -93,123 +177,308 @@ def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
             if verbose:
                 print("picking %s" % r)
             return {"version": r,
-                    "full": variables["full"].strip()}
-    # no suitable tags, so we use the full revision id
+                    "full-revisionid": keywords["full"].strip(),
+                    "dirty": False, "error": None
+                    }
+    # no suitable tags, so version is "0+unknown", but full hex is still there
     if verbose:
-        print("no suitable tags, using full revision id")
-    return {"version": variables["full"].strip(),
-            "full": variables["full"].strip()}
-
-
-def versions_from_vcs(tag_prefix, versionfile_source, verbose=False):
-    # this runs 'git' from the root of the source tree. That either means
-    # someone ran a setup.py command (and this code is in versioneer.py, so
-    # IN_LONG_VERSION_PY=False, thus the containing directory is the root of
-    # the source tree), or someone ran a project-specific entry point (and
-    # this code is in _version.py, so IN_LONG_VERSION_PY=True, thus the
-    # containing directory is somewhere deeper in the source tree). This only
-    # gets called if the git-archive 'subst' variables were *not* expanded,
-    # and _version.py hasn't already been rewritten with a short version
-    # string, meaning we're inside a checked out source tree.
+        print("no suitable tags, using unknown + full revision id")
+    return {"version": "0+unknown",
+            "full-revisionid": keywords["full"].strip(),
+            "dirty": False, "error": "no suitable tags"}
 
-    try:
-        here = os.path.abspath(__file__)
-    except NameError:
-        # some py2exe/bbfreeze/non-CPython implementations don't do __file__
-        return {}  # not always correct
-
-    # versionfile_source is the relative path from the top of the source tree
-    # (where the .git directory might live) to this file. Invert this to find
-    # the root from __file__.
-    root = here
-    if IN_LONG_VERSION_PY:
-        for i in range(len(versionfile_source.split("/"))):
-            root = os.path.dirname(root)
-    else:
-        root = os.path.dirname(
-            os.path.join('..', here))
 
-    #
-    # XXX patch for our specific configuration with
-    # the three projects leap.soledad.{common, client, server}
-    # inside the same repo.
-    #
-    root = os.path.dirname(os.path.join('..', root))
+@register_vcs_handler("git", "pieces_from_vcs")
+def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+    """Get version from 'git describe' in the root of the source tree.
 
+    This only gets called if the git-archive 'subst' keywords were *not*
+    expanded, and _version.py hasn't already been rewritten with a short
+    version string, meaning we're inside a checked out source tree.
+    """
     if not os.path.exists(os.path.join(root, ".git")):
         if verbose:
             print("no .git in %s" % root)
-        return {}
+        raise NotThisMethod("no .git directory")
 
-    GIT = "git"
+    GITS = ["git"]
     if sys.platform == "win32":
-        GIT = "git.cmd"
-    stdout = run_command([GIT, "describe", "--tags", "--dirty", "--always"],
-                         cwd=root)
-    if stdout is None:
-        return {}
-    if not stdout.startswith(tag_prefix):
-        if verbose:
-            print("tag '%s' doesn't start with prefix '%s'" % (
-                stdout, tag_prefix))
-        return {}
-    tag = stdout[len(tag_prefix):]
-    stdout = run_command([GIT, "rev-parse", "HEAD"], cwd=root)
-    if stdout is None:
-        return {}
-    full = stdout.strip()
-    if tag.endswith("-dirty"):
-        full += "-dirty"
-    return {"version": tag, "full": full}
-
-
-def versions_from_parentdir(parentdir_prefix, versionfile_source,
-                            verbose=False):
-    if IN_LONG_VERSION_PY:
-        # We're running from _version.py. If it's from a source tree
-        # (execute-in-place), we can work upwards to find the root of the
-        # tree, and then check the parent directory for a version string. If
-        # it's in an installed application, there's no hope.
-        try:
-            here = os.path.abspath(__file__)
-        except NameError:
-            # py2exe/bbfreeze/non-CPython don't have __file__
-            return {}  # without __file__, we have no hope
+        GITS = ["git.cmd", "git.exe"]
+    # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
+    # if there isn't one, this yields HEX[-dirty] (no NUM)
+    describe_out = run_command(GITS, ["describe", "--tags", "--dirty",
+                                      "--always", "--long",
+                                      "--match", "%s*" % tag_prefix],
+                               cwd=root)
+    # --long was added in git-1.5.5
+    if describe_out is None:
+        raise NotThisMethod("'git describe' failed")
+    describe_out = describe_out.strip()
+    full_out = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    if full_out is None:
+        raise NotThisMethod("'git rev-parse' failed")
+    full_out = full_out.strip()
+
+    pieces = {}
+    pieces["long"] = full_out
+    pieces["short"] = full_out[:7]  # maybe improved later
+    pieces["error"] = None
+
+    # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
+    # TAG might have hyphens.
+    git_describe = describe_out
+
+    # look for -dirty suffix
+    dirty = git_describe.endswith("-dirty")
+    pieces["dirty"] = dirty
+    if dirty:
+        git_describe = git_describe[:git_describe.rindex("-dirty")]
+
+    # now we have TAG-NUM-gHEX or HEX
+
+    if "-" in git_describe:
+        # TAG-NUM-gHEX
+        mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
+        if not mo:
+            # unparseable. Maybe git-describe is misbehaving?
+            pieces["error"] = ("unable to parse git-describe output: '%s'"
+                               % describe_out)
+            return pieces
+
+        # tag
+        full_tag = mo.group(1)
+        if not full_tag.startswith(tag_prefix):
+            if verbose:
+                fmt = "tag '%s' doesn't start with prefix '%s'"
+                print(fmt % (full_tag, tag_prefix))
+            pieces["error"] = ("tag '%s' doesn't start with prefix '%s'"
+                               % (full_tag, tag_prefix))
+            return pieces
+        pieces["closest-tag"] = full_tag[len(tag_prefix):]
+
+        # distance: number of commits since tag
+        pieces["distance"] = int(mo.group(2))
+
+        # commit: short hex revision ID
+        pieces["short"] = mo.group(3)
+
+    else:
+        # HEX: no tags
+        pieces["closest-tag"] = None
+        count_out = run_command(GITS, ["rev-list", "HEAD", "--count"],
+                                cwd=root)
+        pieces["distance"] = int(count_out)  # total number of commits
+
+    return pieces
+
+
+def plus_or_dot(pieces):
+    """Return a + if we don't already have one, else return a ."""
+    if "+" in pieces.get("closest-tag", ""):
+        return "."
+    return "+"
+
+
+def render_pep440(pieces):
+    """Build up version string, with post-release "local version identifier".
+
+    Our goal: TAG[+DISTANCE.gHEX[.dirty]] . Note that if you
+    get a tagged build and then dirty it, you'll get TAG+0.gHEX.dirty
+
+    Exceptions:
+    1: no tags. git_describe was just HEX. 0+untagged.DISTANCE.gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += plus_or_dot(pieces)
+            rendered += "%d.g%s" % (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0+untagged.%d.g%s" % (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def render_pep440_pre(pieces):
+    """TAG[.post.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post.devDISTANCE
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += ".post.dev%d" % pieces["distance"]
+    else:
+        # exception #1
+        rendered = "0.post.dev%d" % pieces["distance"]
+    return rendered
+
+
+def render_pep440_post(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX] .
+
+    The ".dev0" means dirty. Note that .dev0 sorts backwards
+    (a dirty tree will appear "older" than the corresponding clean one),
+    but you shouldn't be releasing software with -dirty anyways.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%s" % pieces["short"]
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+        rendered += "+g%s" % pieces["short"]
+    return rendered
+
+
+def render_pep440_old(pieces):
+    """TAG[.postDISTANCE[.dev0]] .
+
+    The ".dev0" means dirty.
+
+    Eexceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+    return rendered
+
+
+def render_git_describe(pieces):
+    """TAG[-DISTANCE-gHEX][-dirty].
+
+    Like 'git describe --tags --dirty --always'.
+
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += "-%d-g%s" % (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render_git_describe_long(pieces):
+    """TAG-DISTANCE-gHEX[-dirty].
+
+    Like 'git describe --tags --dirty --always -long'.
+    The distance/hash is unconditional.
+
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        rendered += "-%d-g%s" % (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render(pieces, style):
+    """Render the given version pieces into the requested style."""
+    if pieces["error"]:
+        return {"version": "unknown",
+                "full-revisionid": pieces.get("long"),
+                "dirty": None,
+                "error": pieces["error"]}
+
+    if not style or style == "default":
+        style = "pep440"  # the default
+
+    if style == "pep440":
+        rendered = render_pep440(pieces)
+    elif style == "pep440-pre":
+        rendered = render_pep440_pre(pieces)
+    elif style == "pep440-post":
+        rendered = render_pep440_post(pieces)
+    elif style == "pep440-old":
+        rendered = render_pep440_old(pieces)
+    elif style == "git-describe":
+        rendered = render_git_describe(pieces)
+    elif style == "git-describe-long":
+        rendered = render_git_describe_long(pieces)
+    else:
+        raise ValueError("unknown style '%s'" % style)
+
+    return {"version": rendered, "full-revisionid": pieces["long"],
+            "dirty": pieces["dirty"], "error": None}
+
+
+def get_versions():
+    """Get version information or return default if unable to do so."""
+    # I am in _version.py, which lives at ROOT/VERSIONFILE_SOURCE. If we have
+    # __file__, we can work backwards from there to the root. Some
+    # py2exe/bbfreeze/non-CPython implementations don't do __file__, in which
+    # case we can only use expanded keywords.
+
+    cfg = get_config()
+    verbose = cfg.verbose
+
+    try:
+        return git_versions_from_keywords(get_keywords(), cfg.tag_prefix,
+                                          verbose)
+    except NotThisMethod:
+        pass
+
+    try:
+        root = os.path.realpath(__file__)
         # versionfile_source is the relative path from the top of the source
-        # tree to _version.py. Invert this to find the root from __file__.
-        root = here
-        for i in range(len(versionfile_source.split("/"))):
+        # tree (where the .git directory might live) to this file. Invert
+        # this to find the root from __file__.
+        for i in cfg.versionfile_source.split('/'):
             root = os.path.dirname(root)
-    else:
-        # we're running from versioneer.py, which means we're running from
-        # the setup.py in a source tree. sys.argv[0] is setup.py in the root.
-        here = os.path.abspath(sys.argv[0])
-        root = os.path.dirname(here)
+    except NameError:
+        return {"version": "0+unknown", "full-revisionid": None,
+                "dirty": None,
+                "error": "unable to find root of source tree"}
 
-    # Source tarballs conventionally unpack into a directory that includes
-    # both the project name and a version string.
-    dirname = os.path.basename(root)
-    if not dirname.startswith(parentdir_prefix):
-        if verbose:
-            print("guessing rootdir is '%s', but '%s' doesn't start with "
-                  "prefix '%s'" %
-                  (root, dirname, parentdir_prefix))
-        return None
-    return {"version": dirname[len(parentdir_prefix):], "full": ""}
-
-tag_prefix = ""
-parentdir_prefix = "leap.soledad.common-"
-versionfile_source = "src/leap/soledad/common/_version.py"
-
-
-def get_versions(default={"version": "unknown", "full": ""}, verbose=False):
-    variables = {"refnames": git_refnames, "full": git_full}
-    ver = versions_from_expanded_variables(variables, tag_prefix, verbose)
-    if not ver:
-        ver = versions_from_vcs(tag_prefix, versionfile_source, verbose)
-    if not ver:
-        ver = versions_from_parentdir(parentdir_prefix, versionfile_source,
-                                      verbose)
-    if not ver:
-        ver = default
-    return ver
+    try:
+        pieces = git_pieces_from_vcs(cfg.tag_prefix, root, verbose)
+        return render(pieces, cfg.style)
+    except NotThisMethod:
+        pass
+
+    try:
+        if cfg.parentdir_prefix:
+            return versions_from_parentdir(cfg.parentdir_prefix, root, verbose)
+    except NotThisMethod:
+        pass
+
+    return {"version": "0+unknown", "full-revisionid": None,
+            "dirty": None,
+            "error": "unable to compute version"}
diff --git a/common/src/leap/soledad/common/backend.py b/common/src/leap/soledad/common/backend.py
new file mode 100644
index 00000000..53426fb5
--- /dev/null
+++ b/common/src/leap/soledad/common/backend.py
@@ -0,0 +1,642 @@
+# -*- coding: utf-8 -*-
+# backend.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+"""A U1DB generic backend."""
+
+
+from u1db import vectorclock
+from u1db.errors import (
+    RevisionConflict,
+    InvalidDocId,
+    ConflictedDoc,
+    DocumentDoesNotExist,
+    DocumentAlreadyDeleted,
+)
+from u1db.backends import CommonBackend
+from u1db.backends import CommonSyncTarget
+from leap.soledad.common.document import ServerDocument
+
+
+class SoledadBackend(CommonBackend):
+    BATCH_SUPPORT = False
+
+    """
+    A U1DB backend implementation.
+    """
+
+    def __init__(self, database, replica_uid=None):
+        """
+        Create a new backend.
+
+        :param database: the database implementation
+        :type database: Database
+        :param replica_uid: an optional unique replica identifier
+        :type replica_uid: str
+        """
+        # save params
+        self._factory = ServerDocument
+        self._real_replica_uid = None
+        self._cache = None
+        self._dbname = database._dbname
+        self._database = database
+        self.batching = False
+        if replica_uid is not None:
+            self._set_replica_uid(replica_uid)
+
+    def batch_start(self):
+        if not self.BATCH_SUPPORT:
+            return
+        self.batching = True
+        self.after_batch_callbacks = {}
+        self._database.batch_start()
+        if not self._cache:
+            # batching needs cache
+            self._cache = {}
+        self._get_generation()  # warm up gen info
+
+    def batch_end(self):
+        if not self.BATCH_SUPPORT:
+            return
+        self.batching = False
+        self._database.batch_end()
+        for name in self.after_batch_callbacks:
+            self.after_batch_callbacks[name]()
+        self.after_batch_callbacks = None
+
+    @property
+    def cache(self):
+        if self._cache is not None:
+            return self._cache
+        else:
+            return {}
+
+    def init_caching(self, cache):
+        """
+        Start using cache by setting internal _cache attribute.
+
+        :param cache: the cache instance, anything that behaves like a dict
+        :type cache: dict
+        """
+        self._cache = cache
+
+    def get_sync_target(self):
+        """
+        Return a SyncTarget object, for another u1db to synchronize with.
+
+        :return: The sync target.
+        :rtype: SoledadSyncTarget
+        """
+        return SoledadSyncTarget(self)
+
+    def delete_database(self):
+        """
+        Delete a U1DB database.
+        """
+        self._database.delete_database()
+
+    def close(self):
+        """
+        Release any resources associated with this database.
+
+        :return: True if db was succesfully closed.
+        :rtype: bool
+        """
+        self._database.close()
+        return True
+
+    def __del__(self):
+        """
+        Close the database upon garbage collection.
+        """
+        self.close()
+
+    def _set_replica_uid(self, replica_uid):
+        """
+        Force the replica uid to be set.
+
+        :param replica_uid: The new replica uid.
+        :type replica_uid: str
+        """
+        self._database.set_replica_uid(replica_uid)
+        self._real_replica_uid = replica_uid
+        self.cache['replica_uid'] = self._real_replica_uid
+
+    def _get_replica_uid(self):
+        """
+        Get the replica uid.
+
+        :return: The replica uid.
+        :rtype: str
+        """
+        if self._real_replica_uid is not None:
+            self.cache['replica_uid'] = self._real_replica_uid
+            return self._real_replica_uid
+        if 'replica_uid' in self.cache:
+            return self.cache['replica_uid']
+        self._real_replica_uid = self._database.get_replica_uid()
+        self._set_replica_uid(self._real_replica_uid)
+        return self._real_replica_uid
+
+    _replica_uid = property(_get_replica_uid, _set_replica_uid)
+
+    replica_uid = property(_get_replica_uid)
+
+    def _get_generation(self):
+        """
+        Return the current generation.
+
+        :return: The current generation.
+        :rtype: int
+
+        :raise SoledadError: Raised by database on operation failure
+        """
+        return self._get_generation_info()[0]
+
+    def _get_generation_info(self):
+        """
+        Return the current generation.
+
+        :return: A tuple containing the current generation and transaction id.
+        :rtype: (int, str)
+
+        :raise SoledadError: Raised by database on operation failure
+        """
+        cur_gen, newest_trans_id = self._database.get_generation_info()
+        return (cur_gen, newest_trans_id)
+
+    def _get_trans_id_for_gen(self, generation):
+        """
+        Get the transaction id corresponding to a particular generation.
+
+        :param generation: The generation for which to get the transaction id.
+        :type generation: int
+
+        :return: The transaction id for C{generation}.
+        :rtype: str
+
+        :raise InvalidGeneration: Raised when the generation does not exist.
+
+        """
+        return self._database.get_trans_id_for_gen(generation)
+
+    def _get_transaction_log(self):
+        """
+        This is only for the test suite, it is not part of the api.
+
+        :return: The complete transaction log.
+        :rtype: [(str, str)]
+
+        """
+        return self._database.get_transaction_log()
+
+    def _get_doc(self, doc_id, check_for_conflicts=False):
+        """
+        Extract the document from storage.
+
+        This can return None if the document doesn't exist.
+
+        :param doc_id: The unique document identifier
+        :type doc_id: str
+        :param check_for_conflicts: If set to False, then the conflict check
+                                    will be skipped.
+        :type check_for_conflicts: bool
+
+        :return: The document.
+        :rtype: ServerDocument
+        """
+        return self._database.get_doc(doc_id, check_for_conflicts)
+
+    def get_doc(self, doc_id, include_deleted=False):
+        """
+        Get the JSON string for the given document.
+
+        :param doc_id: The unique document identifier
+        :type doc_id: str
+        :param include_deleted: If set to True, deleted documents will be
+            returned with empty content. Otherwise asking for a deleted
+            document will return None.
+        :type include_deleted: bool
+
+        :return: A document object.
+        :rtype: ServerDocument.
+        """
+        doc = self._get_doc(doc_id, check_for_conflicts=True)
+        if doc is None:
+            return None
+        if doc.is_tombstone() and not include_deleted:
+            return None
+        return doc
+
+    def get_all_docs(self, include_deleted=False):
+        """
+        Get the JSON content for all documents in the database.
+
+        :param include_deleted: If set to True, deleted documents will be
+                                returned with empty content. Otherwise deleted
+                                documents will not be included in the results.
+        :type include_deleted: bool
+
+        :return: (generation, [ServerDocument])
+            The current generation of the database, followed by a list of all
+            the documents in the database.
+        :rtype: (int, [ServerDocument])
+        """
+        return self._database.get_all_docs(include_deleted)
+
+    def _put_doc(self, old_doc, doc):
+        """
+        Put the document in the backend database.
+
+        Note that C{old_doc} must have been fetched with the parameter
+        C{check_for_conflicts} equal to True, so we can properly update the
+        new document using the conflict information from the old one.
+
+        :param old_doc: The old document version.
+        :type old_doc: ServerDocument
+        :param doc: The document to be put.
+        :type doc: ServerDocument
+        """
+        self._database.save_document(old_doc, doc,
+                                     self._allocate_transaction_id())
+
+    def put_doc(self, doc):
+        """
+        Update a document.
+
+        If the document currently has conflicts, put will fail.
+        If the database specifies a maximum document size and the document
+        exceeds it, put will fail and raise a DocumentTooBig exception.
+
+        :param doc: A Document with new content.
+        :return: new_doc_rev - The new revision identifier for the document.
+            The Document object will also be updated.
+
+        :raise InvalidDocId: Raised if the document's id is invalid.
+        :raise DocumentTooBig: Raised if the document size is too big.
+        :raise ConflictedDoc: Raised if the document has conflicts.
+        """
+        if doc.doc_id is None:
+            raise InvalidDocId()
+        self._check_doc_id(doc.doc_id)
+        self._check_doc_size(doc)
+        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
+        if old_doc and old_doc.has_conflicts:
+            raise ConflictedDoc()
+        if old_doc and doc.rev is None and old_doc.is_tombstone():
+            new_rev = self._allocate_doc_rev(old_doc.rev)
+        else:
+            if old_doc is not None:
+                    if old_doc.rev != doc.rev:
+                        raise RevisionConflict()
+            else:
+                if doc.rev is not None:
+                    raise RevisionConflict()
+            new_rev = self._allocate_doc_rev(doc.rev)
+        doc.rev = new_rev
+        self._put_doc(old_doc, doc)
+        return new_rev
+
+    def whats_changed(self, old_generation=0):
+        """
+        Return a list of documents that have changed since old_generation.
+
+        :param old_generation: The generation of the database in the old
+                               state.
+        :type old_generation: int
+
+        :return: (generation, trans_id, [(doc_id, generation, trans_id),...])
+                 The current generation of the database, its associated
+                 transaction id, and a list of of changed documents since
+                 old_generation, represented by tuples with for each document
+                 its doc_id and the generation and transaction id corresponding
+                 to the last intervening change and sorted by generation (old
+                 changes first)
+        :rtype: (int, str, [(str, int, str)])
+        """
+        return self._database.whats_changed(old_generation)
+
+    def delete_doc(self, doc):
+        """
+        Mark a document as deleted.
+
+        Will abort if the current revision doesn't match doc.rev.
+        This will also set doc.content to None.
+
+        :param doc: The document to mark as deleted.
+        :type doc: ServerDocument.
+
+        :raise DocumentDoesNotExist: Raised if the document does not
+                                            exist.
+        :raise RevisionConflict: Raised if the revisions do not match.
+        :raise DocumentAlreadyDeleted: Raised if the document is
+                                              already deleted.
+        :raise ConflictedDoc: Raised if the doc has conflicts.
+        """
+        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
+        if old_doc is None:
+            raise DocumentDoesNotExist
+        if old_doc.rev != doc.rev:
+            raise RevisionConflict()
+        if old_doc.is_tombstone():
+            raise DocumentAlreadyDeleted
+        if old_doc.has_conflicts:
+            raise ConflictedDoc()
+        new_rev = self._allocate_doc_rev(doc.rev)
+        doc.rev = new_rev
+        doc.make_tombstone()
+        self._put_doc(old_doc, doc)
+        return new_rev
+
+    def get_doc_conflicts(self, doc_id):
+        """
+        Get the conflicted versions of a document.
+
+        :param doc_id: The document id.
+        :type doc_id: str
+
+        :return: A list of conflicted versions of the document.
+        :rtype: list
+        """
+        return self._database.get_doc_conflicts(doc_id)
+
+    def _get_replica_gen_and_trans_id(self, other_replica_uid):
+        """
+        Return the last known generation and transaction id for the other db
+        replica.
+
+        When you do a synchronization with another replica, the Database keeps
+        track of what generation the other database replica was at, and what
+        the associated transaction id was.  This is used to determine what data
+        needs to be sent, and if two databases are claiming to be the same
+        replica.
+
+        :param other_replica_uid: The identifier for the other replica.
+        :type other_replica_uid: str
+
+        :return: A tuple containing the generation and transaction id we
+                 encountered during synchronization. If we've never
+                 synchronized with the replica, this is (0, '').
+        :rtype: (int, str)
+        """
+        if other_replica_uid in self.cache:
+            return self.cache[other_replica_uid]
+        gen, trans_id = \
+            self._database.get_replica_gen_and_trans_id(other_replica_uid)
+        self.cache[other_replica_uid] = (gen, trans_id)
+        return (gen, trans_id)
+
+    def _set_replica_gen_and_trans_id(self, other_replica_uid,
+                                      other_generation, other_transaction_id):
+        """
+        Set the last-known generation and transaction id for the other
+        database replica.
+
+        We have just performed some synchronization, and we want to track what
+        generation the other replica was at. See also
+        _get_replica_gen_and_trans_id.
+
+        :param other_replica_uid: The U1DB identifier for the other replica.
+        :type other_replica_uid: str
+        :param other_generation: The generation number for the other replica.
+        :type other_generation: int
+        :param other_transaction_id: The transaction id associated with the
+            generation.
+        :type other_transaction_id: str
+        """
+        if other_replica_uid is not None and other_generation is not None:
+            self.cache[other_replica_uid] = (other_generation,
+                                             other_transaction_id)
+            self._database.set_replica_gen_and_trans_id(other_replica_uid,
+                                                        other_generation,
+                                                        other_transaction_id)
+
+    def _do_set_replica_gen_and_trans_id(
+            self, other_replica_uid, other_generation, other_transaction_id):
+        """
+        _put_doc_if_newer from super class is calling it. So we declare this.
+
+        :param other_replica_uid: The U1DB identifier for the other replica.
+        :type other_replica_uid: str
+        :param other_generation: The generation number for the other replica.
+        :type other_generation: int
+        :param other_transaction_id: The transaction id associated with the
+                                     generation.
+        :type other_transaction_id: str
+        """
+        function = self._set_replica_gen_and_trans_id
+        args = [other_replica_uid, other_generation, other_transaction_id]
+        callback = lambda: function(*args)
+        if self.batching:
+            self.after_batch_callbacks['set_source_info'] = callback
+        else:
+            callback()
+
+    def _force_doc_sync_conflict(self, doc):
+        """
+        Add a conflict and force a document put.
+
+        :param doc: The document to be put.
+        :type doc: ServerDocument
+        """
+        my_doc = self._get_doc(doc.doc_id)
+        self._prune_conflicts(doc, vectorclock.VectorClockRev(doc.rev))
+        doc.add_conflict(self._factory(doc.doc_id, my_doc.rev,
+                                       my_doc.get_json()))
+        doc.has_conflicts = True
+        self._put_doc(my_doc, doc)
+
+    def resolve_doc(self, doc, conflicted_doc_revs):
+        """
+        Mark a document as no longer conflicted.
+
+        We take the list of revisions that the client knows about that it is
+        superseding. This may be a different list from the actual current
+        conflicts, in which case only those are removed as conflicted.  This
+        may fail if the conflict list is significantly different from the
+        supplied information. (sync could have happened in the background from
+        the time you GET_DOC_CONFLICTS until the point where you RESOLVE)
+
+        :param doc: A Document with the new content to be inserted.
+        :type doc: ServerDocument
+        :param conflicted_doc_revs: A list of revisions that the new content
+                                    supersedes.
+        :type conflicted_doc_revs: [str]
+
+        :raise SoledadError: Raised by database on operation failure
+        """
+        cur_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
+        new_rev = self._ensure_maximal_rev(cur_doc.rev,
+                                           conflicted_doc_revs)
+        superseded_revs = set(conflicted_doc_revs)
+        doc.rev = new_rev
+        # this backend stores conflicts as properties of the documents, so we
+        # have to copy these conflicts over to the document being updated.
+        if cur_doc.rev in superseded_revs:
+            # the newer doc version will supersede the one in the database, so
+            # we copy conflicts before updating the backend.
+            doc.set_conflicts(cur_doc.get_conflicts())  # copy conflicts over.
+            doc.delete_conflicts(superseded_revs)
+            self._put_doc(cur_doc, doc)
+        else:
+            # the newer doc version does not supersede the one in the
+            # database, so we will add a conflict to the database and copy
+            # those over to the document the user has in her hands.
+            cur_doc.add_conflict(doc)
+            cur_doc.delete_conflicts(superseded_revs)
+            self._put_doc(cur_doc, cur_doc)  # just update conflicts
+            # backend has been updated with current conflicts, now copy them
+            # to the current document.
+            doc.set_conflicts(cur_doc.get_conflicts())
+
+    def _put_doc_if_newer(self, doc, save_conflict, replica_uid, replica_gen,
+                          replica_trans_id='', number_of_docs=None,
+                          doc_idx=None, sync_id=None):
+        """
+        Insert/update document into the database with a given revision.
+
+        This api is used during synchronization operations.
+
+        If a document would conflict and save_conflict is set to True, the
+        content will be selected as the 'current' content for doc.doc_id,
+        even though doc.rev doesn't supersede the currently stored revision.
+        The currently stored document will be added to the list of conflict
+        alternatives for the given doc_id.
+
+        This forces the new content to be 'current' so that we get convergence
+        after synchronizing, even if people don't resolve conflicts. Users can
+        then notice that their content is out of date, update it, and
+        synchronize again. (The alternative is that users could synchronize and
+        think the data has propagated, but their local copy looks fine, and the
+        remote copy is never updated again.)
+
+        :param doc: A document object
+        :type doc: ServerDocument
+        :param save_conflict: If this document is a conflict, do you want to
+                              save it as a conflict, or just ignore it.
+        :type save_conflict: bool
+        :param replica_uid: A unique replica identifier.
+        :type replica_uid: str
+        :param replica_gen: The generation of the replica corresponding to the
+                            this document. The replica arguments are optional,
+                            but are used during synchronization.
+        :type replica_gen: int
+        :param replica_trans_id: The transaction_id associated with the
+                                 generation.
+        :type replica_trans_id: str
+        :param number_of_docs: The total amount of documents sent on this sync
+                               session.
+        :type number_of_docs: int
+        :param doc_idx: The index of the current document being sent.
+        :type doc_idx: int
+        :param sync_id: The id of the current sync session.
+        :type sync_id: str
+
+        :return: (state, at_gen) -  If we don't have doc_id already, or if
+                 doc_rev supersedes the existing document revision, then the
+                 content will be inserted, and state is 'inserted'.  If
+                 doc_rev is less than or equal to the existing revision, then
+                 the put is ignored and state is respecitvely 'superseded' or
+                 'converged'.  If doc_rev is not strictly superseded or
+                 supersedes, then state is 'conflicted'. The document will not
+                 be inserted if save_conflict is False.  For 'inserted' or
+                 'converged', at_gen is the insertion/current generation.
+        :rtype: (str, int)
+        """
+        if not isinstance(doc, ServerDocument):
+            doc = self._factory(doc.doc_id, doc.rev, doc.get_json())
+        my_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
+        if my_doc:
+            doc.set_conflicts(my_doc.get_conflicts())
+        return CommonBackend._put_doc_if_newer(self, doc, save_conflict,
+                                               replica_uid, replica_gen,
+                                               replica_trans_id)
+
+    def _put_and_update_indexes(self, cur_doc, doc):
+        self._put_doc(cur_doc, doc)
+
+    def get_docs(self, doc_ids, check_for_conflicts=True,
+                 include_deleted=False):
+        """
+        Get the JSON content for many documents.
+
+        :param doc_ids: A list of document identifiers or None for all.
+        :type doc_ids: list
+        :param check_for_conflicts: If set to False, then the conflict check
+                                    will be skipped, and 'None' will be
+                                    returned instead of True/False.
+        :type check_for_conflicts: bool
+        :param include_deleted: If set to True, deleted documents will be
+                                returned with empty content. Otherwise deleted
+                                documents will not be included in the results.
+        :return: iterable giving the Document object for each document id
+                 in matching doc_ids order.
+        :rtype: iterable
+        """
+        return self._database.get_docs(doc_ids, check_for_conflicts,
+                                       include_deleted)
+
+    def _prune_conflicts(self, doc, doc_vcr):
+        """
+        Prune conflicts that are older then the current document's revision, or
+        whose content match to the current document's content.
+        Originally in u1db.CommonBackend
+
+        :param doc: The document to have conflicts pruned.
+        :type doc: ServerDocument
+        :param doc_vcr: A vector clock representing the current document's
+                        revision.
+        :type doc_vcr: u1db.vectorclock.VectorClock
+        """
+        if doc.has_conflicts:
+            autoresolved = False
+            c_revs_to_prune = []
+            for c_doc in doc._conflicts:
+                c_vcr = vectorclock.VectorClockRev(c_doc.rev)
+                if doc_vcr.is_newer(c_vcr):
+                    c_revs_to_prune.append(c_doc.rev)
+                elif doc.same_content_as(c_doc):
+                    c_revs_to_prune.append(c_doc.rev)
+                    doc_vcr.maximize(c_vcr)
+                    autoresolved = True
+            if autoresolved:
+                doc_vcr.increment(self._replica_uid)
+                doc.rev = doc_vcr.as_str()
+            doc.delete_conflicts(c_revs_to_prune)
+
+
+class SoledadSyncTarget(CommonSyncTarget):
+
+    """
+    Functionality for using a SoledadBackend as a synchronization target.
+    """
+
+    def get_sync_info(self, source_replica_uid):
+        source_gen, source_trans_id = self._db._get_replica_gen_and_trans_id(
+            source_replica_uid)
+        my_gen, my_trans_id = self._db._get_generation_info()
+        return (
+            self._db._replica_uid, my_gen, my_trans_id, source_gen,
+            source_trans_id)
+
+    def record_sync_info(self, source_replica_uid, source_replica_generation,
+                         source_replica_transaction_id):
+        if self._trace_hook:
+            self._trace_hook('record_sync_info')
+        self._db._set_replica_gen_and_trans_id(
+            source_replica_uid, source_replica_generation,
+            source_replica_transaction_id)
diff --git a/common/src/leap/soledad/common/couch.py b/common/src/leap/soledad/common/couch.py
deleted file mode 100644
index 3dee1473..00000000
--- a/common/src/leap/soledad/common/couch.py
+++ /dev/null
@@ -1,1489 +0,0 @@
-# -*- coding: utf-8 -*-
-# couch.py
-# Copyright (C) 2013 LEAP
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-
-"""A U1DB backend that uses CouchDB as its persistence layer."""
-
-
-import json
-import re
-import uuid
-import logging
-import binascii
-import time
-import sys
-
-
-from StringIO import StringIO
-from urlparse import urljoin
-from contextlib import contextmanager
-from multiprocessing.pool import ThreadPool
-
-
-from couchdb.client import Server, Database
-from couchdb.http import (
-    ResourceConflict,
-    ResourceNotFound,
-    ServerError,
-    Session,
-    urljoin as couch_urljoin,
-    Resource,
-)
-from u1db import vectorclock
-from u1db.errors import (
-    DatabaseDoesNotExist,
-    InvalidGeneration,
-    RevisionConflict,
-    InvalidDocId,
-    ConflictedDoc,
-    DocumentDoesNotExist,
-    DocumentAlreadyDeleted,
-    Unauthorized,
-)
-from u1db.backends import CommonBackend, CommonSyncTarget
-from u1db.remote import http_app
-from u1db.remote.server_state import ServerState
-
-
-from leap.soledad.common import ddocs, errors
-from leap.soledad.common.command import exec_validated_cmd
-from leap.soledad.common.document import SoledadDocument
-
-
-logger = logging.getLogger(__name__)
-
-
-COUCH_TIMEOUT = 120  # timeout for transfers between Soledad server and Couch
-
-
-class InvalidURLError(Exception):
-
-    """
-    Exception raised when Soledad encounters a malformed URL.
-    """
-
-
-class CouchDocument(SoledadDocument):
-
-    """
-    This is the document used for maintaining the Couch backend.
-
-    A CouchDocument can fetch and manipulate conflicts and also holds a
-    reference to the couch document revision. This data is used to ensure an
-    atomic and consistent update of the database.
-    """
-
-    def __init__(self, doc_id=None, rev=None, json='{}', has_conflicts=False):
-        """
-        Container for handling a document that is stored in couch backend.
-
-        :param doc_id: The unique document identifier.
-        :type doc_id: str
-        :param rev: The revision identifier of the document.
-        :type rev: str
-        :param json: The JSON string for this document.
-        :type json: str
-        :param has_conflicts: Boolean indicating if this document has conflicts
-        :type has_conflicts: bool
-        """
-        SoledadDocument.__init__(self, doc_id, rev, json, has_conflicts)
-        self.couch_rev = None
-        self.transactions = None
-        self._conflicts = None
-
-    def get_conflicts(self):
-        """
-        Get the conflicted versions of the document.
-
-        :return: The conflicted versions of the document.
-        :rtype: [CouchDocument]
-        """
-        return self._conflicts or []
-
-    def set_conflicts(self, conflicts):
-        """
-        Set the conflicted versions of the document.
-
-        :param conflicts: The conflicted versions of the document.
-        :type conflicts: list
-        """
-        self._conflicts = conflicts
-        self.has_conflicts = len(self._conflicts) > 0
-
-    def add_conflict(self, doc):
-        """
-        Add a conflict to this document.
-
-        :param doc: The conflicted version to be added.
-        :type doc: CouchDocument
-        """
-        if self._conflicts is None:
-            raise Exception("Fetch conflicts first!")
-        self._conflicts.append(doc)
-        self.has_conflicts = len(self._conflicts) > 0
-
-    def delete_conflicts(self, conflict_revs):
-        """
-        Delete conflicted versions of this document.
-
-        :param conflict_revs: The conflicted revisions to be deleted.
-        :type conflict_revs: [str]
-        """
-        if self._conflicts is None:
-            raise Exception("Fetch conflicts first!")
-        self._conflicts = filter(
-            lambda doc: doc.rev not in conflict_revs,
-            self._conflicts)
-        self.has_conflicts = len(self._conflicts) > 0
-
-    def update(self, new_doc):
-        # update info
-        self.rev = new_doc.rev
-        if new_doc.is_tombstone():
-            self.is_tombstone()
-        else:
-            self.content = new_doc.content
-        self.has_conflicts = new_doc.has_conflicts
-
-    def prune_conflicts(self, doc_vcr, autoresolved_increment):
-        """
-        Prune conflicts that are older then the current document's revision, or
-        whose content match to the current document's content.
-        Originally in u1db.CommonBackend
-
-        :param doc: The document to have conflicts pruned.
-        :type doc: CouchDocument
-        :param doc_vcr: A vector clock representing the current document's
-                        revision.
-        :type doc_vcr: u1db.vectorclock.VectorClock
-        """
-        if self.has_conflicts:
-            autoresolved = False
-            c_revs_to_prune = []
-            for c_doc in self._conflicts:
-                c_vcr = vectorclock.VectorClockRev(c_doc.rev)
-                if doc_vcr.is_newer(c_vcr):
-                    c_revs_to_prune.append(c_doc.rev)
-                elif self.same_content_as(c_doc):
-                    c_revs_to_prune.append(c_doc.rev)
-                    doc_vcr.maximize(c_vcr)
-                    autoresolved = True
-            if autoresolved:
-                doc_vcr.increment(autoresolved_increment)
-                self.rev = doc_vcr.as_str()
-            self.delete_conflicts(c_revs_to_prune)
-
-
-# monkey-patch the u1db http app to use CouchDocument
-http_app.Document = CouchDocument
-
-
-def raise_missing_design_doc_error(exc, ddoc_path):
-    """
-    Raise an appropriate exception when catching a ResourceNotFound when
-    accessing a design document.
-
-    :param exc: The exception cought.
-    :type exc: ResourceNotFound
-    :param ddoc_path: A list representing the requested path.
-    :type ddoc_path: list
-
-    :raise MissingDesignDocError: Raised when tried to access a missing design
-                                  document.
-    :raise MissingDesignDocListFunctionError: Raised when trying to access a
-                                              missing list function on a
-                                              design document.
-    :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                           missing named view on a design
-                                           document.
-    :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                         deleted design document.
-    :raise MissingDesignDocUnknownError: Raised when failed to access a design
-                                         document for an yet unknown reason.
-    """
-    path = "".join(ddoc_path)
-    if exc.message[1] == 'missing':
-        raise errors.MissingDesignDocError(path)
-    elif exc.message[1] == 'missing function' or \
-            exc.message[1].startswith('missing lists function'):
-        raise errors.MissingDesignDocListFunctionError(path)
-    elif exc.message[1] == 'missing_named_view':
-        raise errors.MissingDesignDocNamedViewError(path)
-    elif exc.message[1] == 'deleted':
-        raise errors.MissingDesignDocDeletedError(path)
-    # other errors are unknown for now
-    raise errors.DesignDocUnknownError("%s: %s" % (path, str(exc.message)))
-
-
-def raise_server_error(exc, ddoc_path):
-    """
-    Raise an appropriate exception when catching a ServerError when
-    accessing a design document.
-
-    :param exc: The exception cought.
-    :type exc: ResourceNotFound
-    :param ddoc_path: A list representing the requested path.
-    :type ddoc_path: list
-
-    :raise MissingDesignDocListFunctionError: Raised when trying to access a
-                                              missing list function on a
-                                              design document.
-    :raise MissingDesignDocUnknownError: Raised when failed to access a design
-                                         document for an yet unknown reason.
-    """
-    path = "".join(ddoc_path)
-    msg = exc.message[1][0]
-    if msg == 'unnamed_error':
-        raise errors.MissingDesignDocListFunctionError(path)
-    elif msg == 'TypeError':
-        if 'point is undefined' in exc.message[1][1]:
-            raise errors.MissingDesignDocListFunctionError
-    # other errors are unknown for now
-    raise errors.DesignDocUnknownError(path)
-
-
-class MultipartWriter(object):
-
-    """
-    A multipart writer adapted from python-couchdb's one so we can PUT
-    documents using couch's multipart PUT.
-
-    This stripped down version does not allow for nested structures, and
-    contains only the essential things we need to PUT SoledadDocuments to the
-    couch backend.
-    """
-
-    CRLF = '\r\n'
-
-    def __init__(self, fileobj, headers=None, boundary=None):
-        """
-        Initialize the multipart writer.
-        """
-        self.fileobj = fileobj
-        if boundary is None:
-            boundary = self._make_boundary()
-        self._boundary = boundary
-        self._build_headers('related', headers)
-
-    def add(self, mimetype, content, headers={}):
-        """
-        Add a part to the multipart stream.
-        """
-        self.fileobj.write('--')
-        self.fileobj.write(self._boundary)
-        self.fileobj.write(self.CRLF)
-        headers['Content-Type'] = mimetype
-        self._write_headers(headers)
-        if content:
-            # XXX: throw an exception if a boundary appears in the content??
-            self.fileobj.write(content)
-            self.fileobj.write(self.CRLF)
-
-    def close(self):
-        """
-        Close the multipart stream.
-        """
-        self.fileobj.write('--')
-        self.fileobj.write(self._boundary)
-        # be careful not to have anything after '--', otherwise old couch
-        # versions (including bigcouch) will fail.
-        self.fileobj.write('--')
-
-    def _make_boundary(self):
-        """
-        Create a boundary to discern multi parts.
-        """
-        try:
-            from uuid import uuid4
-            return '==' + uuid4().hex + '=='
-        except ImportError:
-            from random import randrange
-            token = randrange(sys.maxint)
-            format = '%%0%dd' % len(repr(sys.maxint - 1))
-            return '===============' + (format % token) + '=='
-
-    def _write_headers(self, headers):
-        """
-        Write a part header in the buffer stream.
-        """
-        if headers:
-            for name in sorted(headers.keys()):
-                value = headers[name]
-                self.fileobj.write(name)
-                self.fileobj.write(': ')
-                self.fileobj.write(value)
-                self.fileobj.write(self.CRLF)
-        self.fileobj.write(self.CRLF)
-
-    def _build_headers(self, subtype, headers):
-        """
-        Build the main headers of the multipart stream.
-
-        This is here so we can send headers separete from content using
-        python-couchdb API.
-        """
-        self.headers = {}
-        self.headers['Content-Type'] = 'multipart/%s; boundary="%s"' % \
-                                       (subtype, self._boundary)
-        if headers:
-            for name in sorted(headers.keys()):
-                value = headers[name]
-                self.headers[name] = value
-
-
-@contextmanager
-def couch_server(url):
-    """
-    Provide a connection to a couch server and cleanup after use.
-
-    For database creation and deletion we use an ephemeral connection to the
-    couch server. That connection has to be properly closed, so we provide it
-    as a context manager.
-
-    :param url: The URL of the Couch server.
-    :type url: str
-    """
-    session = Session(timeout=COUCH_TIMEOUT)
-    server = Server(url=url, full_commit=False, session=session)
-    yield server
-
-
-THREAD_POOL = ThreadPool(20)
-
-
-class CouchDatabase(CommonBackend):
-
-    """
-    A U1DB implementation that uses CouchDB as its persistence layer.
-    """
-
-    @classmethod
-    def open_database(cls, url, create, replica_uid=None, ensure_ddocs=False):
-        """
-        Open a U1DB database using CouchDB as backend.
-
-        :param url: the url of the database replica
-        :type url: str
-        :param create: should the replica be created if it does not exist?
-        :type create: bool
-        :param replica_uid: an optional unique replica identifier
-        :type replica_uid: str
-        :param ensure_ddocs: Ensure that the design docs exist on server.
-        :type ensure_ddocs: bool
-
-        :return: the database instance
-        :rtype: CouchDatabase
-        """
-        # get database from url
-        m = re.match('(^https?://[^/]+)/(.+)$', url)
-        if not m:
-            raise InvalidURLError
-        url = m.group(1)
-        dbname = m.group(2)
-        with couch_server(url) as server:
-            try:
-                server[dbname]
-            except ResourceNotFound:
-                if not create:
-                    raise DatabaseDoesNotExist()
-                server.create(dbname)
-        return cls(
-            url, dbname, replica_uid=replica_uid, ensure_ddocs=ensure_ddocs)
-
-    def __init__(self, url, dbname, replica_uid=None, ensure_ddocs=False):
-        """
-        Create a new Couch data container.
-
-        :param url: the url of the couch database
-        :type url: str
-        :param dbname: the database name
-        :type dbname: str
-        :param replica_uid: an optional unique replica identifier
-        :type replica_uid: str
-        :param ensure_ddocs: Ensure that the design docs exist on server.
-        :type ensure_ddocs: bool
-        """
-        # save params
-        self._url = url
-        self._session = Session(timeout=COUCH_TIMEOUT)
-        self._factory = CouchDocument
-        self._real_replica_uid = None
-        # configure couch
-        self._dbname = dbname
-        self._database = Database(
-            urljoin(self._url, self._dbname),
-            self._session)
-        try:
-            self._database.info()
-        except ResourceNotFound:
-            raise DatabaseDoesNotExist()
-        if replica_uid is not None:
-            self._set_replica_uid(replica_uid)
-        if ensure_ddocs:
-            self.ensure_ddocs_on_db()
-            self.ensure_security_ddoc()
-        self._cache = None
-
-    @property
-    def cache(self):
-        if self._cache is not None:
-            return self._cache
-        else:
-            return {}
-
-    def init_caching(self, cache):
-        """
-        Start using cache by setting internal _cache attribute.
-
-        :param cache: the cache instance, anything that behaves like a dict
-        :type cache: dict
-        """
-        self._cache = cache
-
-    def ensure_ddocs_on_db(self):
-        """
-        Ensure that the design documents used by the backend exist on the
-        couch database.
-        """
-        for ddoc_name in ['docs', 'syncs', 'transactions']:
-            try:
-                self._database.resource('_design',
-                                        ddoc_name, '_info').get_json()
-            except ResourceNotFound:
-                ddoc = json.loads(
-                    binascii.a2b_base64(
-                        getattr(ddocs, ddoc_name)))
-                self._database.save(ddoc)
-
-    def ensure_security_ddoc(self):
-        """
-        Make sure that only soledad user is able to access this database as
-        an unprivileged member, meaning that administration access will
-        be forbidden even inside an user database.
-        The goal is to make sure that only the lowest access level is given
-        to the unprivileged CouchDB user set on the server process.
-        This is achieved by creating a _security design document, see:
-        http://docs.couchdb.org/en/latest/api/database/security.html
-        """
-        security = self._database.resource.get_json('_security')[2]
-        security['members'] = {'names': ['soledad'], 'roles': []}
-        security['admins'] = {'names': [], 'roles': []}
-        self._database.resource.put_json('_security', body=security)
-
-    def get_sync_target(self):
-        """
-        Return a SyncTarget object, for another u1db to synchronize with.
-
-        :return: The sync target.
-        :rtype: CouchSyncTarget
-        """
-        return CouchSyncTarget(self)
-
-    def delete_database(self):
-        """
-        Delete a U1DB CouchDB database.
-        """
-        with couch_server(self._url) as server:
-            del(server[self._dbname])
-
-    def close(self):
-        """
-        Release any resources associated with this database.
-
-        :return: True if db was succesfully closed.
-        :rtype: bool
-        """
-        self._url = None
-        self._full_commit = None
-        self._session = None
-        self._database = None
-        return True
-
-    def __del__(self):
-        """
-        Close the database upon garbage collection.
-        """
-        self.close()
-
-    def _set_replica_uid(self, replica_uid):
-        """
-        Force the replica uid to be set.
-
-        :param replica_uid: The new replica uid.
-        :type replica_uid: str
-        """
-        try:
-            # set on existent config document
-            doc = self._database['u1db_config']
-            doc['replica_uid'] = replica_uid
-        except ResourceNotFound:
-            # or create the config document
-            doc = {
-                '_id': 'u1db_config',
-                'replica_uid': replica_uid,
-            }
-        self._database.save(doc)
-        self._real_replica_uid = replica_uid
-
-    def _get_replica_uid(self):
-        """
-        Get the replica uid.
-
-        :return: The replica uid.
-        :rtype: str
-        """
-        if self._real_replica_uid is not None:
-            self.cache[self._url] = {'replica_uid': self._real_replica_uid}
-            return self._real_replica_uid
-        if self._url in self.cache:
-            return self.cache[self._url]['replica_uid']
-        try:
-            # grab replica_uid from server
-            doc = self._database['u1db_config']
-            self.cache[self._url] = doc
-            self._real_replica_uid = doc['replica_uid']
-            return self._real_replica_uid
-        except ResourceNotFound:
-            # create a unique replica_uid
-            self._real_replica_uid = uuid.uuid4().hex
-            self._set_replica_uid(self._real_replica_uid)
-            return self._real_replica_uid
-
-    _replica_uid = property(_get_replica_uid, _set_replica_uid)
-
-    replica_uid = property(_get_replica_uid)
-
-    def _get_generation(self):
-        """
-        Return the current generation.
-
-        :return: The current generation.
-        :rtype: int
-
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        # query a couch list function
-        if self.replica_uid + '_gen' in self.cache:
-            return self.cache[self.replica_uid + '_gen']['generation']
-        ddoc_path = ['_design', 'transactions', '_list', 'generation', 'log']
-        res = self._database.resource(*ddoc_path)
-        try:
-            response = res.get_json()
-            self.cache[self.replica_uid + '_gen'] = response[2]
-            return response[2]['generation']
-        except ResourceNotFound as e:
-            raise_missing_design_doc_error(e, ddoc_path)
-        except ServerError as e:
-            raise_server_error(e, ddoc_path)
-
-    def _get_generation_info(self):
-        """
-        Return the current generation.
-
-        :return: A tuple containing the current generation and transaction id.
-        :rtype: (int, str)
-
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        if self.replica_uid + '_gen' in self.cache:
-            response = self.cache[self.replica_uid + '_gen']
-            return (response['generation'], response['transaction_id'])
-        # query a couch list function
-        ddoc_path = ['_design', 'transactions', '_list', 'generation', 'log']
-        res = self._database.resource(*ddoc_path)
-        try:
-            response = res.get_json()
-            self.cache[self.replica_uid + '_gen'] = response[2]
-            return (response[2]['generation'], response[2]['transaction_id'])
-        except ResourceNotFound as e:
-            raise_missing_design_doc_error(e, ddoc_path)
-        except ServerError as e:
-            raise_server_error(e, ddoc_path)
-
-    def _get_trans_id_for_gen(self, generation):
-        """
-        Get the transaction id corresponding to a particular generation.
-
-        :param generation: The generation for which to get the transaction id.
-        :type generation: int
-
-        :return: The transaction id for C{generation}.
-        :rtype: str
-
-        :raise InvalidGeneration: Raised when the generation does not exist.
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        if generation == 0:
-            return ''
-        # query a couch list function
-        ddoc_path = [
-            '_design', 'transactions', '_list', 'trans_id_for_gen', 'log'
-        ]
-        res = self._database.resource(*ddoc_path)
-        try:
-            response = res.get_json(gen=generation)
-            if response[2] == {}:
-                raise InvalidGeneration
-            return response[2]['transaction_id']
-        except ResourceNotFound as e:
-            raise_missing_design_doc_error(e, ddoc_path)
-        except ServerError as e:
-            raise_server_error(e, ddoc_path)
-
-    def _get_transaction_log(self):
-        """
-        This is only for the test suite, it is not part of the api.
-
-        :return: The complete transaction log.
-        :rtype: [(str, str)]
-
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        # query a couch view
-        ddoc_path = ['_design', 'transactions', '_view', 'log']
-        res = self._database.resource(*ddoc_path)
-        try:
-            response = res.get_json()
-            return map(
-                lambda row: (row['id'], row['value']),
-                response[2]['rows'])
-        except ResourceNotFound as e:
-            raise_missing_design_doc_error(e, ddoc_path)
-
-    def _get_doc(self, doc_id, check_for_conflicts=False):
-        """
-        Extract the document from storage.
-
-        This can return None if the document doesn't exist.
-
-        :param doc_id: The unique document identifier
-        :type doc_id: str
-        :param check_for_conflicts: If set to False, then the conflict check
-                                    will be skipped.
-        :type check_for_conflicts: bool
-
-        :return: The document.
-        :rtype: CouchDocument
-        """
-        # get document with all attachments (u1db content and eventual
-        # conflicts)
-        try:
-            result = \
-                self._database.resource(doc_id).get_json(
-                    attachments=True)[2]
-        except ResourceNotFound:
-            return None
-        return self.__parse_doc_from_couch(result, doc_id, check_for_conflicts)
-
-    def __parse_doc_from_couch(self, result, doc_id,
-                               check_for_conflicts=False):
-        # restrict to u1db documents
-        if 'u1db_rev' not in result:
-            return None
-        doc = self._factory(doc_id, result['u1db_rev'])
-        # set contents or make tombstone
-        if '_attachments' not in result \
-                or 'u1db_content' not in result['_attachments']:
-            doc.make_tombstone()
-        else:
-            doc.content = json.loads(
-                binascii.a2b_base64(
-                    result['_attachments']['u1db_content']['data']))
-        # determine if there are conflicts
-        if check_for_conflicts \
-                and '_attachments' in result \
-                and 'u1db_conflicts' in result['_attachments']:
-            doc.set_conflicts(
-                self._build_conflicts(
-                    doc.doc_id,
-                    json.loads(binascii.a2b_base64(
-                        result['_attachments']['u1db_conflicts']['data']))))
-        # store couch revision
-        doc.couch_rev = result['_rev']
-        # store transactions
-        doc.transactions = result['u1db_transactions']
-        return doc
-
-    def get_doc(self, doc_id, include_deleted=False):
-        """
-        Get the JSON string for the given document.
-
-        :param doc_id: The unique document identifier
-        :type doc_id: str
-        :param include_deleted: If set to True, deleted documents will be
-            returned with empty content. Otherwise asking for a deleted
-            document will return None.
-        :type include_deleted: bool
-
-        :return: A document object.
-        :rtype: CouchDocument.
-        """
-        doc = self._get_doc(doc_id, check_for_conflicts=True)
-        if doc is None:
-            return None
-        if doc.is_tombstone() and not include_deleted:
-            return None
-        return doc
-
-    def get_all_docs(self, include_deleted=False):
-        """
-        Get the JSON content for all documents in the database.
-
-        :param include_deleted: If set to True, deleted documents will be
-                                returned with empty content. Otherwise deleted
-                                documents will not be included in the results.
-        :type include_deleted: bool
-
-        :return: (generation, [CouchDocument])
-            The current generation of the database, followed by a list of all
-            the documents in the database.
-        :rtype: (int, [CouchDocument])
-        """
-
-        generation = self._get_generation()
-        results = list(self.get_docs(self._database,
-                                     include_deleted=include_deleted))
-        return (generation, results)
-
-    def _put_doc(self, old_doc, doc):
-        """
-        Put the document in the Couch backend database.
-
-        Note that C{old_doc} must have been fetched with the parameter
-        C{check_for_conflicts} equal to True, so we can properly update the
-        new document using the conflict information from the old one.
-
-        :param old_doc: The old document version.
-        :type old_doc: CouchDocument
-        :param doc: The document to be put.
-        :type doc: CouchDocument
-
-        :raise RevisionConflict: Raised when trying to update a document but
-                                 couch revisions mismatch.
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        attachments = {}  # we save content and conflicts as attachments
-        parts = []  # and we put it using couch's multipart PUT
-        # save content as attachment
-        if doc.is_tombstone() is False:
-            content = doc.get_json()
-            attachments['u1db_content'] = {
-                'follows': True,
-                'content_type': 'application/octet-stream',
-                'length': len(content),
-            }
-            parts.append(content)
-        # save conflicts as attachment
-        if doc.has_conflicts is True:
-            conflicts = json.dumps(
-                map(lambda cdoc: (cdoc.rev, cdoc.content),
-                    doc.get_conflicts()))
-            attachments['u1db_conflicts'] = {
-                'follows': True,
-                'content_type': 'application/octet-stream',
-                'length': len(conflicts),
-            }
-            parts.append(conflicts)
-        # store old transactions, if any
-        transactions = old_doc.transactions[:] if old_doc is not None else []
-        # create a new transaction id and timestamp it so the transaction log
-        # is consistent when querying the database.
-        transactions.append(
-            # here we store milliseconds to keep consistent with javascript
-            # Date.prototype.getTime() which was used before inside a couchdb
-            # update handler.
-            (int(time.time() * 1000),
-             self._allocate_transaction_id()))
-        # build the couch document
-        couch_doc = {
-            '_id': doc.doc_id,
-            'u1db_rev': doc.rev,
-            'u1db_transactions': transactions,
-            '_attachments': attachments,
-        }
-        # if we are updating a doc we have to add the couch doc revision
-        if old_doc is not None:
-            couch_doc['_rev'] = old_doc.couch_rev
-        # prepare the multipart PUT
-        buf = StringIO()
-        envelope = MultipartWriter(buf)
-        envelope.add('application/json', json.dumps(couch_doc))
-        for part in parts:
-            envelope.add('application/octet-stream', part)
-        envelope.close()
-        # try to save and fail if there's a revision conflict
-        try:
-            resource = self._new_resource()
-            resource.put_json(
-                doc.doc_id, body=str(buf.getvalue()), headers=envelope.headers)
-        except ResourceConflict:
-            raise RevisionConflict()
-        if self.replica_uid + '_gen' in self.cache:
-            gen_info = self.cache[self.replica_uid + '_gen']
-            gen_info['generation'] += 1
-            gen_info['transaction_id'] = transactions[-1][1]
-
-    def put_doc(self, doc):
-        """
-        Update a document.
-
-        If the document currently has conflicts, put will fail.
-        If the database specifies a maximum document size and the document
-        exceeds it, put will fail and raise a DocumentTooBig exception.
-
-        :param doc: A Document with new content.
-        :return: new_doc_rev - The new revision identifier for the document.
-            The Document object will also be updated.
-
-        :raise InvalidDocId: Raised if the document's id is invalid.
-        :raise DocumentTooBig: Raised if the document size is too big.
-        :raise ConflictedDoc: Raised if the document has conflicts.
-        """
-        if doc.doc_id is None:
-            raise InvalidDocId()
-        self._check_doc_id(doc.doc_id)
-        self._check_doc_size(doc)
-        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
-        if old_doc and old_doc.has_conflicts:
-            raise ConflictedDoc()
-        if old_doc and doc.rev is None and old_doc.is_tombstone():
-            new_rev = self._allocate_doc_rev(old_doc.rev)
-        else:
-            if old_doc is not None:
-                    if old_doc.rev != doc.rev:
-                        raise RevisionConflict()
-            else:
-                if doc.rev is not None:
-                    raise RevisionConflict()
-            new_rev = self._allocate_doc_rev(doc.rev)
-        doc.rev = new_rev
-        self._put_doc(old_doc, doc)
-        return new_rev
-
-    def whats_changed(self, old_generation=0):
-        """
-        Return a list of documents that have changed since old_generation.
-
-        :param old_generation: The generation of the database in the old
-                               state.
-        :type old_generation: int
-
-        :return: (generation, trans_id, [(doc_id, generation, trans_id),...])
-                 The current generation of the database, its associated
-                 transaction id, and a list of of changed documents since
-                 old_generation, represented by tuples with for each document
-                 its doc_id and the generation and transaction id corresponding
-                 to the last intervening change and sorted by generation (old
-                 changes first)
-        :rtype: (int, str, [(str, int, str)])
-
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        # query a couch list function
-        ddoc_path = [
-            '_design', 'transactions', '_list', 'whats_changed', 'log'
-        ]
-        res = self._database.resource(*ddoc_path)
-        try:
-            response = res.get_json(old_gen=old_generation)
-            results = map(
-                lambda row:
-                    (row['generation'], row['doc_id'], row['transaction_id']),
-                response[2]['transactions'])
-            results.reverse()
-            cur_gen = old_generation
-            seen = set()
-            changes = []
-            newest_trans_id = ''
-            for generation, doc_id, trans_id in results:
-                if doc_id not in seen:
-                    changes.append((doc_id, generation, trans_id))
-                    seen.add(doc_id)
-            if changes:
-                cur_gen = changes[0][1]  # max generation
-                newest_trans_id = changes[0][2]
-                changes.reverse()
-            else:
-                cur_gen, newest_trans_id = self._get_generation_info()
-
-            return cur_gen, newest_trans_id, changes
-        except ResourceNotFound as e:
-            raise_missing_design_doc_error(e, ddoc_path)
-        except ServerError as e:
-            raise_server_error(e, ddoc_path)
-
-    def delete_doc(self, doc):
-        """
-        Mark a document as deleted.
-
-        Will abort if the current revision doesn't match doc.rev.
-        This will also set doc.content to None.
-
-        :param doc: The document to mark as deleted.
-        :type doc: CouchDocument.
-
-        :raise DocumentDoesNotExist: Raised if the document does not
-                                            exist.
-        :raise RevisionConflict: Raised if the revisions do not match.
-        :raise DocumentAlreadyDeleted: Raised if the document is
-                                              already deleted.
-        :raise ConflictedDoc: Raised if the doc has conflicts.
-        """
-        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
-        if old_doc is None:
-            raise DocumentDoesNotExist
-        if old_doc.rev != doc.rev:
-            raise RevisionConflict()
-        if old_doc.is_tombstone():
-            raise DocumentAlreadyDeleted
-        if old_doc.has_conflicts:
-            raise ConflictedDoc()
-        new_rev = self._allocate_doc_rev(doc.rev)
-        doc.rev = new_rev
-        doc.make_tombstone()
-        self._put_doc(old_doc, doc)
-        return new_rev
-
-    def _build_conflicts(self, doc_id, attached_conflicts):
-        """
-        Build the conflicted documents list from the conflicts attachment
-        fetched from a couch document.
-
-        :param attached_conflicts: The document's conflicts as fetched from a
-                                   couch document attachment.
-        :type attached_conflicts: dict
-        """
-        conflicts = []
-        for doc_rev, content in attached_conflicts:
-            doc = self._factory(doc_id, doc_rev)
-            if content is None:
-                doc.make_tombstone()
-            else:
-                doc.content = content
-            conflicts.append(doc)
-        return conflicts
-
-    def get_doc_conflicts(self, doc_id, couch_rev=None):
-        """
-        Get the conflicted versions of a document.
-
-        If the C{couch_rev} parameter is not None, conflicts for a specific
-        document's couch revision are returned.
-
-        :param couch_rev: The couch document revision.
-        :type couch_rev: str
-
-        :return: A list of conflicted versions of the document.
-        :rtype: list
-        """
-        # request conflicts attachment from server
-        params = {}
-        conflicts = []
-        if couch_rev is not None:
-            params['rev'] = couch_rev  # restric document's couch revision
-        else:
-            # TODO: move into resource logic!
-            first_entry = self._get_doc(doc_id, check_for_conflicts=True)
-            conflicts.append(first_entry)
-        resource = self._database.resource(doc_id, 'u1db_conflicts')
-        try:
-            response = resource.get_json(**params)
-            return conflicts + self._build_conflicts(
-                doc_id, json.loads(response[2].read()))
-        except ResourceNotFound:
-            return []
-
-    def _get_replica_gen_and_trans_id(self, other_replica_uid):
-        """
-        Return the last known generation and transaction id for the other db
-        replica.
-
-        When you do a synchronization with another replica, the Database keeps
-        track of what generation the other database replica was at, and what
-        the associated transaction id was.  This is used to determine what data
-        needs to be sent, and if two databases are claiming to be the same
-        replica.
-
-        :param other_replica_uid: The identifier for the other replica.
-        :type other_replica_uid: str
-
-        :return: A tuple containing the generation and transaction id we
-                 encountered during synchronization. If we've never
-                 synchronized with the replica, this is (0, '').
-        :rtype: (int, str)
-        """
-        if other_replica_uid in self.cache:
-            return self.cache[other_replica_uid]
-
-        doc_id = 'u1db_sync_%s' % other_replica_uid
-        try:
-            doc = self._database[doc_id]
-        except ResourceNotFound:
-            doc = {
-                '_id': doc_id,
-                'generation': 0,
-                'transaction_id': '',
-            }
-            self._database.save(doc)
-        result = doc['generation'], doc['transaction_id']
-        self.cache[other_replica_uid] = result
-        return result
-
-    def _set_replica_gen_and_trans_id(self, other_replica_uid,
-                                      other_generation, other_transaction_id,
-                                      number_of_docs=None, doc_idx=None,
-                                      sync_id=None):
-        """
-        Set the last-known generation and transaction id for the other
-        database replica.
-
-        We have just performed some synchronization, and we want to track what
-        generation the other replica was at. See also
-        _get_replica_gen_and_trans_id.
-
-        :param other_replica_uid: The U1DB identifier for the other replica.
-        :type other_replica_uid: str
-        :param other_generation: The generation number for the other replica.
-        :type other_generation: int
-        :param other_transaction_id: The transaction id associated with the
-            generation.
-        :type other_transaction_id: str
-        :param number_of_docs: The total amount of documents sent on this sync
-                               session.
-        :type number_of_docs: int
-        :param doc_idx: The index of the current document being sent.
-        :type doc_idx: int
-        :param sync_id: The id of the current sync session.
-        :type sync_id: str
-        """
-        if other_replica_uid is not None and other_generation is not None:
-            self._do_set_replica_gen_and_trans_id(
-                other_replica_uid, other_generation, other_transaction_id,
-                number_of_docs=number_of_docs, doc_idx=doc_idx,
-                sync_id=sync_id)
-
-    def _do_set_replica_gen_and_trans_id(
-            self, other_replica_uid, other_generation, other_transaction_id,
-            number_of_docs=None, doc_idx=None, sync_id=None):
-        """
-        Set the last-known generation and transaction id for the other
-        database replica.
-
-        We have just performed some synchronization, and we want to track what
-        generation the other replica was at. See also
-        _get_replica_gen_and_trans_id.
-
-        :param other_replica_uid: The U1DB identifier for the other replica.
-        :type other_replica_uid: str
-        :param other_generation: The generation number for the other replica.
-        :type other_generation: int
-        :param other_transaction_id: The transaction id associated with the
-                                     generation.
-        :type other_transaction_id: str
-        :param number_of_docs: The total amount of documents sent on this sync
-                               session.
-        :type number_of_docs: int
-        :param doc_idx: The index of the current document being sent.
-        :type doc_idx: int
-        :param sync_id: The id of the current sync session.
-        :type sync_id: str
-        """
-        self.cache[other_replica_uid] = (other_generation,
-                                         other_transaction_id)
-        doc_id = 'u1db_sync_%s' % other_replica_uid
-        try:
-            doc = self._database[doc_id]
-        except ResourceNotFound:
-            doc = {'_id': doc_id}
-        doc['generation'] = other_generation
-        doc['transaction_id'] = other_transaction_id
-        self._database.save(doc)
-
-    def _force_doc_sync_conflict(self, doc):
-        """
-        Add a conflict and force a document put.
-
-        :param doc: The document to be put.
-        :type doc: CouchDocument
-        """
-        my_doc = self._get_doc(doc.doc_id)
-        self._prune_conflicts(doc, vectorclock.VectorClockRev(doc.rev))
-        doc.add_conflict(self._factory(doc.doc_id, my_doc.rev,
-                                       my_doc.get_json()))
-        doc.has_conflicts = True
-        self._put_doc(my_doc, doc)
-
-    def resolve_doc(self, doc, conflicted_doc_revs):
-        """
-        Mark a document as no longer conflicted.
-
-        We take the list of revisions that the client knows about that it is
-        superseding. This may be a different list from the actual current
-        conflicts, in which case only those are removed as conflicted.  This
-        may fail if the conflict list is significantly different from the
-        supplied information. (sync could have happened in the background from
-        the time you GET_DOC_CONFLICTS until the point where you RESOLVE)
-
-        :param doc: A Document with the new content to be inserted.
-        :type doc: CouchDocument
-        :param conflicted_doc_revs: A list of revisions that the new content
-                                    supersedes.
-        :type conflicted_doc_revs: [str]
-
-        :raise MissingDesignDocError: Raised when tried to access a missing
-                                      design document.
-        :raise MissingDesignDocListFunctionError: Raised when trying to access
-                                                  a missing list function on a
-                                                  design document.
-        :raise MissingDesignDocNamedViewError: Raised when trying to access a
-                                               missing named view on a design
-                                               document.
-        :raise MissingDesignDocDeletedError: Raised when trying to access a
-                                             deleted design document.
-        :raise MissingDesignDocUnknownError: Raised when failed to access a
-                                             design document for an yet
-                                             unknown reason.
-        """
-        cur_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
-        new_rev = self._ensure_maximal_rev(cur_doc.rev,
-                                           conflicted_doc_revs)
-        superseded_revs = set(conflicted_doc_revs)
-        doc.rev = new_rev
-        # this backend stores conflicts as properties of the documents, so we
-        # have to copy these conflicts over to the document being updated.
-        if cur_doc.rev in superseded_revs:
-            # the newer doc version will supersede the one in the database, so
-            # we copy conflicts before updating the backend.
-            doc.set_conflicts(cur_doc.get_conflicts())  # copy conflicts over.
-            doc.delete_conflicts(superseded_revs)
-            self._put_doc(cur_doc, doc)
-        else:
-            # the newer doc version does not supersede the one in the
-            # database, so we will add a conflict to the database and copy
-            # those over to the document the user has in her hands.
-            cur_doc.add_conflict(doc)
-            cur_doc.delete_conflicts(superseded_revs)
-            self._put_doc(cur_doc, cur_doc)  # just update conflicts
-            # backend has been updated with current conflicts, now copy them
-            # to the current document.
-            doc.set_conflicts(cur_doc.get_conflicts())
-
-    def _put_doc_if_newer(self, doc, save_conflict, replica_uid, replica_gen,
-                          replica_trans_id='', number_of_docs=None,
-                          doc_idx=None, sync_id=None):
-        """
-        Insert/update document into the database with a given revision.
-
-        This api is used during synchronization operations.
-
-        If a document would conflict and save_conflict is set to True, the
-        content will be selected as the 'current' content for doc.doc_id,
-        even though doc.rev doesn't supersede the currently stored revision.
-        The currently stored document will be added to the list of conflict
-        alternatives for the given doc_id.
-
-        This forces the new content to be 'current' so that we get convergence
-        after synchronizing, even if people don't resolve conflicts. Users can
-        then notice that their content is out of date, update it, and
-        synchronize again. (The alternative is that users could synchronize and
-        think the data has propagated, but their local copy looks fine, and the
-        remote copy is never updated again.)
-
-        :param doc: A document object
-        :type doc: CouchDocument
-        :param save_conflict: If this document is a conflict, do you want to
-                              save it as a conflict, or just ignore it.
-        :type save_conflict: bool
-        :param replica_uid: A unique replica identifier.
-        :type replica_uid: str
-        :param replica_gen: The generation of the replica corresponding to the
-                            this document. The replica arguments are optional,
-                            but are used during synchronization.
-        :type replica_gen: int
-        :param replica_trans_id: The transaction_id associated with the
-                                 generation.
-        :type replica_trans_id: str
-        :param number_of_docs: The total amount of documents sent on this sync
-                               session.
-        :type number_of_docs: int
-        :param doc_idx: The index of the current document being sent.
-        :type doc_idx: int
-        :param sync_id: The id of the current sync session.
-        :type sync_id: str
-
-        :return: (state, at_gen) -  If we don't have doc_id already, or if
-                 doc_rev supersedes the existing document revision, then the
-                 content will be inserted, and state is 'inserted'.  If
-                 doc_rev is less than or equal to the existing revision, then
-                 the put is ignored and state is respecitvely 'superseded' or
-                 'converged'.  If doc_rev is not strictly superseded or
-                 supersedes, then state is 'conflicted'. The document will not
-                 be inserted if save_conflict is False.  For 'inserted' or
-                 'converged', at_gen is the insertion/current generation.
-        :rtype: (str, int)
-        """
-        if not isinstance(doc, CouchDocument):
-            doc = self._factory(doc.doc_id, doc.rev, doc.get_json())
-        my_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
-        if my_doc:
-            doc.set_conflicts(my_doc.get_conflicts())
-        return CommonBackend._put_doc_if_newer(self, doc, save_conflict,
-                                               replica_uid, replica_gen,
-                                               replica_trans_id)
-
-    def _put_and_update_indexes(self, cur_doc, doc):
-        self._put_doc(cur_doc, doc)
-
-    def get_docs(self, doc_ids, check_for_conflicts=True,
-                 include_deleted=False):
-        """
-        Get the JSON content for many documents.
-
-        :param doc_ids: A list of document identifiers or None for all.
-        :type doc_ids: list
-        :param check_for_conflicts: If set to False, then the conflict check
-                                    will be skipped, and 'None' will be
-                                    returned instead of True/False.
-        :type check_for_conflicts: bool
-        :param include_deleted: If set to True, deleted documents will be
-                                returned with empty content. Otherwise deleted
-                                documents will not be included in the results.
-        :return: iterable giving the Document object for each document id
-                 in matching doc_ids order.
-        :rtype: iterable
-        """
-        # Workaround for:
-        #
-        #   http://bugs.python.org/issue7980
-        #   https://leap.se/code/issues/5449
-        #
-        # python-couchdb uses time.strptime, which is not thread safe. In
-        # order to avoid the problem described on the issues above, we preload
-        # strptime here by evaluating the conversion of an arbitrary date.
-        # This will not be needed when/if we switch from python-couchdb to
-        # paisley.
-        time.strptime('Mar 8 1917', '%b %d %Y')
-        get_one = lambda doc_id: self._get_doc(doc_id, check_for_conflicts)
-        docs = [THREAD_POOL.apply_async(get_one, [doc_id])
-                for doc_id in doc_ids]
-        for doc in docs:
-            doc = doc.get()
-            if not doc or not include_deleted and doc.is_tombstone():
-                continue
-            yield doc
-
-    def _prune_conflicts(self, doc, doc_vcr):
-        """
-        Overrides original method, but it is implemented elsewhere for
-        simplicity.
-        """
-        doc.prune_conflicts(doc_vcr, self._replica_uid)
-
-    def _new_resource(self, *path):
-        """
-        Return a new resource for accessing a couch database.
-
-        :return: A resource for accessing a couch database.
-        :rtype: couchdb.http.Resource
-        """
-        # Workaround for: https://leap.se/code/issues/5448
-        url = couch_urljoin(self._database.resource.url, *path)
-        resource = Resource(url, Session(timeout=COUCH_TIMEOUT))
-        resource.credentials = self._database.resource.credentials
-        resource.headers = self._database.resource.headers.copy()
-        return resource
-
-
-class CouchSyncTarget(CommonSyncTarget):
-
-    """
-    Functionality for using a CouchDatabase as a synchronization target.
-    """
-
-    def get_sync_info(self, source_replica_uid):
-        source_gen, source_trans_id = self._db._get_replica_gen_and_trans_id(
-            source_replica_uid)
-        my_gen, my_trans_id = self._db._get_generation_info()
-        return (
-            self._db._replica_uid, my_gen, my_trans_id, source_gen,
-            source_trans_id)
-
-    def record_sync_info(self, source_replica_uid, source_replica_generation,
-                         source_replica_transaction_id):
-        if self._trace_hook:
-            self._trace_hook('record_sync_info')
-        self._db._set_replica_gen_and_trans_id(
-            source_replica_uid, source_replica_generation,
-            source_replica_transaction_id)
-
-
-def is_db_name_valid(name):
-    """
-    Validate a user database using a regular expression.
-
-    :param name: database name.
-    :type name: str
-
-    :return: boolean for name vailidity
-    :rtype: bool
-    """
-    db_name_regex = "^user-[a-f0-9]+$"
-    return re.match(db_name_regex, name) is not None
-
-
-class CouchServerState(ServerState):
-
-    """
-    Inteface of the WSGI server with the CouchDB backend.
-    """
-
-    def __init__(self, couch_url, create_cmd=None):
-        """
-        Initialize the couch server state.
-
-        :param couch_url: The URL for the couch database.
-        :type couch_url: str
-        """
-        self.couch_url = couch_url
-        self.create_cmd = create_cmd
-
-    def open_database(self, dbname):
-        """
-        Open a couch database.
-
-        :param dbname: The name of the database to open.
-        :type dbname: str
-
-        :return: The CouchDatabase object.
-        :rtype: CouchDatabase
-        """
-        db = CouchDatabase(
-            self.couch_url,
-            dbname,
-            ensure_ddocs=False)
-        return db
-
-    def ensure_database(self, dbname):
-        """
-        Ensure couch database exists.
-
-        :param dbname: The name of the database to ensure.
-        :type dbname: str
-
-        :raise Unauthorized: If disabled or other error was raised.
-
-        :return: The CouchDatabase object and its replica_uid.
-        :rtype: (CouchDatabase, str)
-        """
-        if not self.create_cmd:
-            raise Unauthorized()
-        else:
-            code, out = exec_validated_cmd(self.create_cmd, dbname,
-                                           validator=is_db_name_valid)
-            if code is not 0:
-                logger.error("""
-                    Error while creating database (%s) with (%s) command.
-                    Output: %s
-                    Exit code: %d
-                    """ % (dbname, self.create_cmd, out, code))
-                raise Unauthorized()
-        db = self.open_database(dbname)
-        return db, db.replica_uid
-
-    def delete_database(self, dbname):
-        """
-        Delete couch database.
-
-        :param dbname: The name of the database to delete.
-        :type dbname: str
-
-        :raise Unauthorized: Always, because Soledad server is not allowed to
-                             delete databases.
-        """
-        raise Unauthorized()
diff --git a/common/src/leap/soledad/common/couch/__init__.py b/common/src/leap/soledad/common/couch/__init__.py
new file mode 100644
index 00000000..18ed8a19
--- /dev/null
+++ b/common/src/leap/soledad/common/couch/__init__.py
@@ -0,0 +1,798 @@
+# -*- coding: utf-8 -*-
+# __init__.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+"""A U1DB backend that uses CouchDB as its persistence layer."""
+
+
+import json
+import re
+import uuid
+import binascii
+import time
+
+
+from StringIO import StringIO
+from urlparse import urljoin
+from contextlib import contextmanager
+from multiprocessing.pool import ThreadPool
+
+
+from couchdb.client import Server, Database
+from couchdb.http import (
+    ResourceConflict,
+    ResourceNotFound,
+    ServerError,
+    Session,
+    urljoin as couch_urljoin,
+    Resource,
+)
+from u1db.errors import (
+    DatabaseDoesNotExist,
+    InvalidGeneration,
+    RevisionConflict,
+)
+from u1db.remote import http_app
+
+
+from leap.soledad.common import ddocs
+from .errors import raise_server_error
+from .errors import raise_missing_design_doc_error
+from .support import MultipartWriter
+from leap.soledad.common.errors import InvalidURLError
+from leap.soledad.common.document import ServerDocument
+from leap.soledad.common.backend import SoledadBackend
+
+
+COUCH_TIMEOUT = 120  # timeout for transfers between Soledad server and Couch
+
+
+def list_users_dbs(couch_url):
+    """
+    Retrieves a list with all databases that starts with 'user-' on CouchDB.
+    Those databases belongs to users. So, the list will contain all the
+    database names in the form of 'user-{uuid4}'.
+
+    :param couch_url: The couch url with needed credentials
+    :type couch_url: str
+
+    :return: The list of all database names from users.
+    :rtype: [str]
+    """
+    with couch_server(couch_url) as server:
+        users = [dbname for dbname in server if dbname.startswith('user-')]
+    return users
+
+
+# monkey-patch the u1db http app to use ServerDocument
+http_app.Document = ServerDocument
+
+
+@contextmanager
+def couch_server(url):
+    """
+    Provide a connection to a couch server and cleanup after use.
+
+    For database creation and deletion we use an ephemeral connection to the
+    couch server. That connection has to be properly closed, so we provide it
+    as a context manager.
+
+    :param url: The URL of the Couch server.
+    :type url: str
+    """
+    session = Session(timeout=COUCH_TIMEOUT)
+    server = Server(url=url, full_commit=False, session=session)
+    yield server
+
+
+THREAD_POOL = ThreadPool(20)
+
+
+class CouchDatabase(object):
+    """
+    Holds CouchDB related code.
+    This class gives methods to encapsulate database operations and hide
+    CouchDB details from backend code.
+    """
+
+    @classmethod
+    def open_database(cls, url, create, ensure_ddocs=False, replica_uid=None,
+                      database_security=None):
+        """
+        Open a U1DB database using CouchDB as backend.
+
+        :param url: the url of the database replica
+        :type url: str
+        :param create: should the replica be created if it does not exist?
+        :type create: bool
+        :param replica_uid: an optional unique replica identifier
+        :type replica_uid: str
+        :param ensure_ddocs: Ensure that the design docs exist on server.
+        :type ensure_ddocs: bool
+        :param database_security: security rules as CouchDB security doc
+        :type database_security: dict
+
+        :return: the database instance
+        :rtype: SoledadBackend
+
+        :raise DatabaseDoesNotExist: Raised if database does not exist.
+        """
+        # get database from url
+        m = re.match('(^https?://[^/]+)/(.+)$', url)
+        if not m:
+            raise InvalidURLError
+        url = m.group(1)
+        dbname = m.group(2)
+        with couch_server(url) as server:
+            if dbname not in server:
+                if create:
+                    server.create(dbname)
+                else:
+                    raise DatabaseDoesNotExist()
+        db = cls(url,
+                 dbname, ensure_ddocs=ensure_ddocs,
+                 database_security=database_security)
+        return SoledadBackend(
+            db, replica_uid=replica_uid)
+
+    def __init__(self, url, dbname, ensure_ddocs=True,
+                 database_security=None):
+        """
+        :param url: Couch server URL with necessary credentials
+        :type url: string
+        :param dbname: Couch database name
+        :type dbname: string
+        :param ensure_ddocs: Ensure that the design docs exist on server.
+        :type ensure_ddocs: bool
+        :param database_security: security rules as CouchDB security doc
+        :type database_security: dict
+        """
+        self._session = Session(timeout=COUCH_TIMEOUT)
+        self._url = url
+        self._dbname = dbname
+        self._database = self.get_couch_database(url, dbname)
+        self.batching = False
+        self.batch_generation = None
+        self.batch_docs = {}
+        if ensure_ddocs:
+            self.ensure_ddocs_on_db()
+            self.ensure_security_ddoc(database_security)
+
+    def batch_start(self):
+        self.batching = True
+        self.batch_generation = self.get_generation_info()
+        ids = set(row.id for row in self._database.view('_all_docs'))
+        self.batched_ids = ids
+
+    def batch_end(self):
+        self.batching = False
+        self.batch_generation = None
+        self.__perform_batch()
+
+    def get_couch_database(self, url, dbname):
+        """
+        Generate a couchdb.Database instance given a url and dbname.
+
+        :param url: CouchDB's server url with credentials
+        :type url: str
+        :param dbname: Database name
+        :type dbname: str
+
+        :return: couch library database instance
+        :rtype: couchdb.Database
+
+        :raise DatabaseDoesNotExist: Raised if database does not exist.
+        """
+        try:
+            return Database(
+                urljoin(url, dbname),
+                self._session)
+        except ResourceNotFound:
+            raise DatabaseDoesNotExist()
+
+    def ensure_ddocs_on_db(self):
+        """
+        Ensure that the design documents used by the backend exist on the
+        couch database.
+        """
+        for ddoc_name in ['docs', 'syncs', 'transactions']:
+            try:
+                self.json_from_resource(['_design'] +
+                                        ddoc_name.split('/') + ['_info'],
+                                        check_missing_ddoc=False)
+            except ResourceNotFound:
+                ddoc = json.loads(
+                    binascii.a2b_base64(
+                        getattr(ddocs, ddoc_name)))
+                self._database.save(ddoc)
+
+    def ensure_security_ddoc(self, security_config=None):
+        """
+        Make sure that only soledad user is able to access this database as
+        an unprivileged member, meaning that administration access will
+        be forbidden even inside an user database.
+        The goal is to make sure that only the lowest access level is given
+        to the unprivileged CouchDB user set on the server process.
+        This is achieved by creating a _security design document, see:
+        http://docs.couchdb.org/en/latest/api/database/security.html
+
+        :param security_config: security configuration parsed from conf file
+        :type security_config: dict
+        """
+        security_config = security_config or {}
+        security = self._database.resource.get_json('_security')[2]
+        security['members'] = {'names': [], 'roles': []}
+        security['members']['names'] = security_config.get('members',
+                                                           ['soledad'])
+        security['members']['roles'] = security_config.get('members_roles', [])
+        security['admins'] = {'names': [], 'roles': []}
+        security['admins']['names'] = security_config.get('admins', [])
+        security['admins']['roles'] = security_config.get('admins_roles', [])
+        self._database.resource.put_json('_security', body=security)
+
+    def delete_database(self):
+        """
+        Delete a U1DB CouchDB database.
+        """
+        with couch_server(self._url) as server:
+            del(server[self._dbname])
+
+    def set_replica_uid(self, replica_uid):
+        """
+        Force the replica uid to be set.
+
+        :param replica_uid: The new replica uid.
+        :type replica_uid: str
+        """
+        try:
+            # set on existent config document
+            doc = self._database['u1db_config']
+            doc['replica_uid'] = replica_uid
+        except ResourceNotFound:
+            # or create the config document
+            doc = {
+                '_id': 'u1db_config',
+                'replica_uid': replica_uid,
+            }
+        self._database.save(doc)
+
+    def get_replica_uid(self):
+        """
+        Get the replica uid.
+
+        :return: The replica uid.
+        :rtype: str
+        """
+        try:
+            # grab replica_uid from server
+            doc = self._database['u1db_config']
+            replica_uid = doc['replica_uid']
+            return replica_uid
+        except ResourceNotFound:
+            # create a unique replica_uid
+            replica_uid = uuid.uuid4().hex
+            self.set_replica_uid(replica_uid)
+            return replica_uid
+
+    def close(self):
+        self._database = None
+
+    def get_all_docs(self, include_deleted=False):
+        """
+        Get the JSON content for all documents in the database.
+
+        :param include_deleted: If set to True, deleted documents will be
+                                returned with empty content. Otherwise deleted
+                                documents will not be included in the results.
+        :type include_deleted: bool
+
+        :return: (generation, [ServerDocument])
+            The current generation of the database, followed by a list of all
+            the documents in the database.
+        :rtype: (int, [ServerDocument])
+        """
+
+        generation, _ = self.get_generation_info()
+        results = list(self.get_docs(self._database,
+                                     include_deleted=include_deleted))
+        return (generation, results)
+
+    def get_docs(self, doc_ids, check_for_conflicts=True,
+                 include_deleted=False):
+        """
+        Get the JSON content for many documents.
+
+        :param doc_ids: A list of document identifiers or None for all.
+        :type doc_ids: list
+        :param check_for_conflicts: If set to False, then the conflict check
+                                    will be skipped, and 'None' will be
+                                    returned instead of True/False.
+        :type check_for_conflicts: bool
+        :param include_deleted: If set to True, deleted documents will be
+                                returned with empty content. Otherwise deleted
+                                documents will not be included in the results.
+        :return: iterable giving the Document object for each document id
+                 in matching doc_ids order.
+        :rtype: iterable
+        """
+        # Workaround for:
+        #
+        #   http://bugs.python.org/issue7980
+        #   https://leap.se/code/issues/5449
+        #
+        # python-couchdb uses time.strptime, which is not thread safe. In
+        # order to avoid the problem described on the issues above, we preload
+        # strptime here by evaluating the conversion of an arbitrary date.
+        # This will not be needed when/if we switch from python-couchdb to
+        # paisley.
+        time.strptime('Mar 8 1917', '%b %d %Y')
+        get_one = lambda doc_id: self.get_doc(doc_id, check_for_conflicts)
+        docs = [THREAD_POOL.apply_async(get_one, [doc_id])
+                for doc_id in doc_ids]
+        for doc in docs:
+            doc = doc.get()
+            if not doc or not include_deleted and doc.is_tombstone():
+                continue
+            yield doc
+
+    def get_doc(self, doc_id, check_for_conflicts=False):
+        """
+        Extract the document from storage.
+
+        This can return None if the document doesn't exist.
+
+        :param doc_id: The unique document identifier
+        :type doc_id: str
+        :param check_for_conflicts: If set to False, then the conflict check
+                                    will be skipped.
+        :type check_for_conflicts: bool
+
+        :return: The document.
+        :rtype: ServerDocument
+        """
+        doc_from_batch = self.__check_batch_before_get(doc_id)
+        if doc_from_batch:
+            return doc_from_batch
+        if self.batching and doc_id not in self.batched_ids:
+            return None
+        if doc_id not in self._database:
+            return None
+        # get document with all attachments (u1db content and eventual
+        # conflicts)
+        result = self.json_from_resource([doc_id], attachments=True)
+        return self.__parse_doc_from_couch(result, doc_id, check_for_conflicts)
+
+    def __check_batch_before_get(self, doc_id):
+        """
+        If doc_id is staged for batching, then we need to commit the batch
+        before going ahead. This avoids consistency problems, like trying to
+        get a document that isn't persisted and processing like it is missing.
+
+        :param doc_id: The unique document identifier
+        :type doc_id: str
+        """
+        if doc_id in self.batch_docs:
+            couch_doc = self.batch_docs[doc_id]
+            rev = self.__perform_batch(doc_id)
+            couch_doc['_rev'] = rev
+            self.batched_ids.add(doc_id)
+            return self.__parse_doc_from_couch(couch_doc, doc_id, True)
+        return None
+
+    def __perform_batch(self, doc_id=None):
+        status = self._database.update(self.batch_docs.values())
+        rev = None
+        for ok, stored_doc_id, rev_or_error in status:
+            if not ok:
+                error = rev_or_error
+                if type(error) is ResourceConflict:
+                    raise RevisionConflict
+                raise error
+            elif doc_id == stored_doc_id:
+                rev = rev_or_error
+        self.batch_docs.clear()
+        return rev
+
+    def __parse_doc_from_couch(self, result, doc_id,
+                               check_for_conflicts=False):
+        # restrict to u1db documents
+        if 'u1db_rev' not in result:
+            return None
+        doc = ServerDocument(doc_id, result['u1db_rev'])
+        # set contents or make tombstone
+        if '_attachments' not in result \
+                or 'u1db_content' not in result['_attachments']:
+            doc.make_tombstone()
+        else:
+            doc.content = json.loads(
+                binascii.a2b_base64(
+                    result['_attachments']['u1db_content']['data']))
+        # determine if there are conflicts
+        if check_for_conflicts \
+                and '_attachments' in result \
+                and 'u1db_conflicts' in result['_attachments']:
+            doc.set_conflicts(
+                self._build_conflicts(
+                    doc.doc_id,
+                    json.loads(binascii.a2b_base64(
+                        result['_attachments']['u1db_conflicts']['data']))))
+        # store couch revision
+        doc.couch_rev = result['_rev']
+        # store transactions
+        doc.transactions = result['u1db_transactions']
+        return doc
+
+    def _build_conflicts(self, doc_id, attached_conflicts):
+        """
+        Build the conflicted documents list from the conflicts attachment
+        fetched from a couch document.
+
+        :param attached_conflicts: The document's conflicts as fetched from a
+                                   couch document attachment.
+        :type attached_conflicts: dict
+        """
+        conflicts = []
+        for doc_rev, content in attached_conflicts:
+            doc = ServerDocument(doc_id, doc_rev)
+            if content is None:
+                doc.make_tombstone()
+            else:
+                doc.content = content
+            conflicts.append(doc)
+        return conflicts
+
+    def get_trans_id_for_gen(self, generation):
+        """
+        Get the transaction id corresponding to a particular generation.
+
+        :param generation: The generation for which to get the transaction id.
+        :type generation: int
+
+        :return: The transaction id for C{generation}.
+        :rtype: str
+
+        :raise InvalidGeneration: Raised when the generation does not exist.
+        """
+        if generation == 0:
+            return ''
+        # query a couch list function
+        ddoc_path = [
+            '_design', 'transactions', '_list', 'trans_id_for_gen', 'log'
+        ]
+        response = self.json_from_resource(ddoc_path, gen=generation)
+        if response == {}:
+            raise InvalidGeneration
+        return response['transaction_id']
+
+    def get_replica_gen_and_trans_id(self, other_replica_uid):
+        """
+        Return the last known generation and transaction id for the other db
+        replica.
+
+        When you do a synchronization with another replica, the Database keeps
+        track of what generation the other database replica was at, and what
+        the associated transaction id was.  This is used to determine what data
+        needs to be sent, and if two databases are claiming to be the same
+        replica.
+
+        :param other_replica_uid: The identifier for the other replica.
+        :type other_replica_uid: str
+
+        :return: A tuple containing the generation and transaction id we
+                 encountered during synchronization. If we've never
+                 synchronized with the replica, this is (0, '').
+        :rtype: (int, str)
+        """
+        doc_id = 'u1db_sync_%s' % other_replica_uid
+        try:
+            doc = self._database[doc_id]
+        except ResourceNotFound:
+            doc = {
+                '_id': doc_id,
+                'generation': 0,
+                'transaction_id': '',
+            }
+            self._database.save(doc)
+        result = doc['generation'], doc['transaction_id']
+        return result
+
+    def get_doc_conflicts(self, doc_id, couch_rev=None):
+        """
+        Get the conflicted versions of a document.
+
+        If the C{couch_rev} parameter is not None, conflicts for a specific
+        document's couch revision are returned.
+
+        :param couch_rev: The couch document revision.
+        :type couch_rev: str
+
+        :return: A list of conflicted versions of the document.
+        :rtype: list
+        """
+        # request conflicts attachment from server
+        params = {}
+        conflicts = []
+        if couch_rev is not None:
+            params['rev'] = couch_rev  # restric document's couch revision
+        else:
+            # TODO: move into resource logic!
+            first_entry = self.get_doc(doc_id, check_for_conflicts=True)
+            conflicts.append(first_entry)
+
+        try:
+            response = self.json_from_resource([doc_id, 'u1db_conflicts'],
+                                               check_missing_ddoc=False,
+                                               **params)
+            return conflicts + self._build_conflicts(
+                doc_id, json.loads(response.read()))
+        except ResourceNotFound:
+            return []
+
+    def set_replica_gen_and_trans_id(
+            self, other_replica_uid, other_generation, other_transaction_id):
+        """
+        Set the last-known generation and transaction id for the other
+        database replica.
+
+        We have just performed some synchronization, and we want to track what
+        generation the other replica was at. See also
+        get_replica_gen_and_trans_id.
+
+        :param other_replica_uid: The U1DB identifier for the other replica.
+        :type other_replica_uid: str
+        :param other_generation: The generation number for the other replica.
+        :type other_generation: int
+        :param other_transaction_id: The transaction id associated with the
+                                     generation.
+        :type other_transaction_id: str
+        """
+        doc_id = 'u1db_sync_%s' % other_replica_uid
+        try:
+            doc = self._database[doc_id]
+        except ResourceNotFound:
+            doc = {'_id': doc_id}
+        doc['generation'] = other_generation
+        doc['transaction_id'] = other_transaction_id
+        self._database.save(doc)
+
+    def get_transaction_log(self):
+        """
+        This is only for the test suite, it is not part of the api.
+
+        :return: The complete transaction log.
+        :rtype: [(str, str)]
+        """
+        # query a couch view
+        ddoc_path = ['_design', 'transactions', '_view', 'log']
+        response = self.json_from_resource(ddoc_path)
+        return map(
+            lambda row: (row['id'], row['value']),
+            response['rows'])
+
+    def whats_changed(self, old_generation=0):
+        """
+        Return a list of documents that have changed since old_generation.
+
+        :param old_generation: The generation of the database in the old
+                               state.
+        :type old_generation: int
+
+        :return: (generation, trans_id, [(doc_id, generation, trans_id),...])
+                 The current generation of the database, its associated
+                 transaction id, and a list of of changed documents since
+                 old_generation, represented by tuples with for each document
+                 its doc_id and the generation and transaction id corresponding
+                 to the last intervening change and sorted by generation (old
+                 changes first)
+        :rtype: (int, str, [(str, int, str)])
+        """
+        # query a couch list function
+        ddoc_path = [
+            '_design', 'transactions', '_list', 'whats_changed', 'log'
+        ]
+        response = self.json_from_resource(ddoc_path, old_gen=old_generation)
+        results = map(
+            lambda row:
+                (row['generation'], row['doc_id'], row['transaction_id']),
+            response['transactions'])
+        results.reverse()
+        cur_gen = old_generation
+        seen = set()
+        changes = []
+        newest_trans_id = ''
+        for generation, doc_id, trans_id in results:
+            if doc_id not in seen:
+                changes.append((doc_id, generation, trans_id))
+                seen.add(doc_id)
+        if changes:
+            cur_gen = changes[0][1]  # max generation
+            newest_trans_id = changes[0][2]
+            changes.reverse()
+        else:
+            cur_gen, newest_trans_id = self.get_generation_info()
+
+        return cur_gen, newest_trans_id, changes
+
+    def get_generation_info(self):
+        """
+        Return the current generation.
+
+        :return: A tuple containing the current generation and transaction id.
+        :rtype: (int, str)
+        """
+        if self.batching and self.batch_generation:
+            return self.batch_generation
+        # query a couch list function
+        ddoc_path = ['_design', 'transactions', '_list', 'generation', 'log']
+        info = self.json_from_resource(ddoc_path)
+        return (info['generation'], info['transaction_id'])
+
+    def json_from_resource(self, ddoc_path, check_missing_ddoc=True,
+                           **kwargs):
+        """
+        Get a resource from it's path and gets a doc's JSON using provided
+        parameters, also checking for missing design docs by default.
+
+        :param ddoc_path: The path to resource.
+        :type ddoc_path: [str]
+        :param check_missing_ddoc: Raises info on what design doc is missing.
+        :type check_missin_ddoc: bool
+
+        :return: The request's data parsed from JSON to a dict.
+        :rtype: dict
+
+        :raise MissingDesignDocError: Raised when tried to access a missing
+                                      design document.
+        :raise MissingDesignDocListFunctionError: Raised when trying to access
+                                                  a missing list function on a
+                                                  design document.
+        :raise MissingDesignDocNamedViewError: Raised when trying to access a
+                                               missing named view on a design
+                                               document.
+        :raise MissingDesignDocDeletedError: Raised when trying to access a
+                                             deleted design document.
+        :raise MissingDesignDocUnknownError: Raised when failed to access a
+                                             design document for an yet
+                                             unknown reason.
+        """
+        if ddoc_path is not None:
+            resource = self._database.resource(*ddoc_path)
+        else:
+            resource = self._database.resource()
+        try:
+            _, _, data = resource.get_json(**kwargs)
+            return data
+        except ResourceNotFound as e:
+            if check_missing_ddoc:
+                raise_missing_design_doc_error(e, ddoc_path)
+            else:
+                raise e
+        except ServerError as e:
+            raise_server_error(e, ddoc_path)
+
+    def save_document(self, old_doc, doc, transaction_id):
+        """
+        Put the document in the Couch backend database.
+
+        Note that C{old_doc} must have been fetched with the parameter
+        C{check_for_conflicts} equal to True, so we can properly update the
+        new document using the conflict information from the old one.
+
+        :param old_doc: The old document version.
+        :type old_doc: ServerDocument
+        :param doc: The document to be put.
+        :type doc: ServerDocument
+
+        :raise RevisionConflict: Raised when trying to update a document but
+                                 couch revisions mismatch.
+        :raise MissingDesignDocError: Raised when tried to access a missing
+                                      design document.
+        :raise MissingDesignDocListFunctionError: Raised when trying to access
+                                                  a missing list function on a
+                                                  design document.
+        :raise MissingDesignDocNamedViewError: Raised when trying to access a
+                                               missing named view on a design
+                                               document.
+        :raise MissingDesignDocDeletedError: Raised when trying to access a
+                                             deleted design document.
+        :raise MissingDesignDocUnknownError: Raised when failed to access a
+                                             design document for an yet
+                                             unknown reason.
+        """
+        attachments = {}  # we save content and conflicts as attachments
+        parts = []  # and we put it using couch's multipart PUT
+        # save content as attachment
+        if doc.is_tombstone() is False:
+            content = doc.get_json()
+            attachments['u1db_content'] = {
+                'follows': True,
+                'content_type': 'application/octet-stream',
+                'length': len(content),
+            }
+            parts.append(content)
+        # save conflicts as attachment
+        if doc.has_conflicts is True:
+            conflicts = json.dumps(
+                map(lambda cdoc: (cdoc.rev, cdoc.content),
+                    doc.get_conflicts()))
+            attachments['u1db_conflicts'] = {
+                'follows': True,
+                'content_type': 'application/octet-stream',
+                'length': len(conflicts),
+            }
+            parts.append(conflicts)
+        # store old transactions, if any
+        transactions = old_doc.transactions[:] if old_doc is not None else []
+        # create a new transaction id and timestamp it so the transaction log
+        # is consistent when querying the database.
+        transactions.append(
+            # here we store milliseconds to keep consistent with javascript
+            # Date.prototype.getTime() which was used before inside a couchdb
+            # update handler.
+            (int(time.time() * 1000),
+             transaction_id))
+        # build the couch document
+        couch_doc = {
+            '_id': doc.doc_id,
+            'u1db_rev': doc.rev,
+            'u1db_transactions': transactions,
+            '_attachments': attachments,
+        }
+        # if we are updating a doc we have to add the couch doc revision
+        if old_doc is not None and hasattr(old_doc, 'couch_rev'):
+            couch_doc['_rev'] = old_doc.couch_rev
+        # prepare the multipart PUT
+        if not self.batching:
+            buf = StringIO()
+            envelope = MultipartWriter(buf)
+            envelope.add('application/json', json.dumps(couch_doc))
+            for part in parts:
+                envelope.add('application/octet-stream', part)
+            envelope.close()
+            # try to save and fail if there's a revision conflict
+            try:
+                resource = self._new_resource()
+                resource.put_json(
+                    doc.doc_id, body=str(buf.getvalue()),
+                    headers=envelope.headers)
+            except ResourceConflict:
+                raise RevisionConflict()
+        else:
+            for name, attachment in attachments.items():
+                del attachment['follows']
+                del attachment['length']
+                index = 0 if name is 'u1db_content' else 1
+                attachment['data'] = binascii.b2a_base64(parts[index]).strip()
+            couch_doc['_attachments'] = attachments
+            self.batch_docs[doc.doc_id] = couch_doc
+            last_gen, last_trans_id = self.batch_generation
+            self.batch_generation = (last_gen + 1, transaction_id)
+        return transactions[-1][1]
+
+    def _new_resource(self, *path):
+        """
+        Return a new resource for accessing a couch database.
+
+        :return: A resource for accessing a couch database.
+        :rtype: couchdb.http.Resource
+        """
+        # Workaround for: https://leap.se/code/issues/5448
+        url = couch_urljoin(self._database.resource.url, *path)
+        resource = Resource(url, Session(timeout=COUCH_TIMEOUT))
+        resource.credentials = self._database.resource.credentials
+        resource.headers = self._database.resource.headers.copy()
+        return resource
diff --git a/common/src/leap/soledad/common/couch/errors.py b/common/src/leap/soledad/common/couch/errors.py
new file mode 100644
index 00000000..9b287c76
--- /dev/null
+++ b/common/src/leap/soledad/common/couch/errors.py
@@ -0,0 +1,144 @@
+# -*- coding: utf-8 -*-
+# errors.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+from leap.soledad.common.errors import SoledadError, BackendNotReadyError
+from leap.soledad.common.errors import register_exception
+
+"""
+Specific errors that can be raised by CouchDatabase.
+"""
+
+
+@register_exception
+class MissingDesignDocError(BackendNotReadyError):
+
+    """
+    Raised when trying to access a missing couch design document.
+    """
+
+    wire_description = "missing design document"
+    status = 500
+
+
+@register_exception
+class MissingDesignDocNamedViewError(SoledadError):
+
+    """
+    Raised when trying to access a missing named view on a couch design
+    document.
+    """
+
+    wire_description = "missing design document named function"
+    status = 500
+
+
+@register_exception
+class MissingDesignDocListFunctionError(SoledadError):
+
+    """
+    Raised when trying to access a missing list function on a couch design
+    document.
+    """
+
+    wire_description = "missing design document list function"
+    status = 500
+
+
+@register_exception
+class MissingDesignDocDeletedError(SoledadError):
+
+    """
+    Raised when trying to access a deleted couch design document.
+    """
+
+    wire_description = "design document was deleted"
+    status = 500
+
+
+@register_exception
+class DesignDocUnknownError(SoledadError):
+
+    """
+    Raised when trying to access a couch design document and getting an
+    unknown error.
+    """
+
+    wire_description = "missing design document unknown error"
+    status = 500
+
+
+def raise_missing_design_doc_error(exc, ddoc_path):
+    """
+    Raise an appropriate exception when catching a ResourceNotFound when
+    accessing a design document.
+
+    :param exc: The exception cought.
+    :type exc: ResourceNotFound
+    :param ddoc_path: A list representing the requested path.
+    :type ddoc_path: list
+
+    :raise MissingDesignDocError: Raised when tried to access a missing design
+                                  document.
+    :raise MissingDesignDocListFunctionError: Raised when trying to access a
+                                              missing list function on a
+                                              design document.
+    :raise MissingDesignDocNamedViewError: Raised when trying to access a
+                                           missing named view on a design
+                                           document.
+    :raise MissingDesignDocDeletedError: Raised when trying to access a
+                                         deleted design document.
+    :raise MissingDesignDocUnknownError: Raised when failed to access a design
+                                         document for an yet unknown reason.
+    """
+    path = "".join(ddoc_path)
+    if exc.message[1] == 'missing':
+        raise MissingDesignDocError(path)
+    elif exc.message[1] == 'missing function' or \
+            exc.message[1].startswith('missing lists function'):
+        raise MissingDesignDocListFunctionError(path)
+    elif exc.message[1] == 'missing_named_view':
+        raise MissingDesignDocNamedViewError(path)
+    elif exc.message[1] == 'deleted':
+        raise MissingDesignDocDeletedError(path)
+    # other errors are unknown for now
+    raise DesignDocUnknownError("%s: %s" % (path, str(exc.message)))
+
+
+def raise_server_error(exc, ddoc_path):
+    """
+    Raise an appropriate exception when catching a ServerError when
+    accessing a design document.
+
+    :param exc: The exception cought.
+    :type exc: ResourceNotFound
+    :param ddoc_path: A list representing the requested path.
+    :type ddoc_path: list
+
+    :raise MissingDesignDocListFunctionError: Raised when trying to access a
+                                              missing list function on a
+                                              design document.
+    :raise MissingDesignDocUnknownError: Raised when failed to access a design
+                                         document for an yet unknown reason.
+    """
+    path = "".join(ddoc_path)
+    msg = exc.message[1][0]
+    if msg == 'unnamed_error':
+        raise MissingDesignDocListFunctionError(path)
+    elif msg == 'TypeError':
+        if 'point is undefined' in exc.message[1][1]:
+            raise MissingDesignDocListFunctionError
+    # other errors are unknown for now
+    raise DesignDocUnknownError("%s: %s" % (path, str(exc.message)))
diff --git a/common/src/leap/soledad/common/couch/state.py b/common/src/leap/soledad/common/couch/state.py
new file mode 100644
index 00000000..4f07c105
--- /dev/null
+++ b/common/src/leap/soledad/common/couch/state.py
@@ -0,0 +1,160 @@
+# -*- coding: utf-8 -*-
+# state.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+"""
+Server state using CouchDatabase as backend.
+"""
+import re
+import logging
+import time
+from urlparse import urljoin
+from hashlib import sha512
+
+from u1db.remote.server_state import ServerState
+from leap.soledad.common.command import exec_validated_cmd
+from leap.soledad.common.couch import CouchDatabase
+from leap.soledad.common.couch import couch_server
+from u1db.errors import Unauthorized
+
+
+logger = logging.getLogger(__name__)
+
+
+def is_db_name_valid(name):
+    """
+    Validate a user database using a regular expression.
+
+    :param name: database name.
+    :type name: str
+
+    :return: boolean for name vailidity
+    :rtype: bool
+    """
+    db_name_regex = "^user-[a-f0-9]+$"
+    return re.match(db_name_regex, name) is not None
+
+
+class CouchServerState(ServerState):
+
+    """
+    Inteface of the WSGI server with the CouchDB backend.
+    """
+
+    TOKENS_DB_PREFIX = "tokens_"
+    TOKENS_DB_EXPIRE = 30 * 24 * 3600  # 30 days in seconds
+    TOKENS_TYPE_KEY = "type"
+    TOKENS_TYPE_DEF = "Token"
+    TOKENS_USER_ID_KEY = "user_id"
+
+    def __init__(self, couch_url, create_cmd=None):
+        """
+        Initialize the couch server state.
+
+        :param couch_url: The URL for the couch database.
+        :type couch_url: str
+        """
+        self.couch_url = couch_url
+        self.create_cmd = create_cmd
+
+    def open_database(self, dbname):
+        """
+        Open a couch database.
+
+        :param dbname: The name of the database to open.
+        :type dbname: str
+
+        :return: The SoledadBackend object.
+        :rtype: SoledadBackend
+        """
+        url = urljoin(self.couch_url, dbname)
+        db = CouchDatabase.open_database(url, create=False, ensure_ddocs=False)
+        return db
+
+    def ensure_database(self, dbname):
+        """
+        Ensure couch database exists.
+
+        :param dbname: The name of the database to ensure.
+        :type dbname: str
+
+        :raise Unauthorized: If disabled or other error was raised.
+
+        :return: The SoledadBackend object and its replica_uid.
+        :rtype: (SoledadBackend, str)
+        """
+        if not self.create_cmd:
+            raise Unauthorized()
+        else:
+            code, out = exec_validated_cmd(self.create_cmd, dbname,
+                                           validator=is_db_name_valid)
+            if code is not 0:
+                logger.error("""
+                    Error while creating database (%s) with (%s) command.
+                    Output: %s
+                    Exit code: %d
+                    """ % (dbname, self.create_cmd, out, code))
+                raise Unauthorized()
+        db = self.open_database(dbname)
+        return db, db.replica_uid
+
+    def delete_database(self, dbname):
+        """
+        Delete couch database.
+
+        :param dbname: The name of the database to delete.
+        :type dbname: str
+
+        :raise Unauthorized: Always, because Soledad server is not allowed to
+                             delete databases.
+        """
+        raise Unauthorized()
+
+    def verify_token(self, uuid, token):
+        """
+        Query couchdb to decide if C{token} is valid for C{uuid}.
+
+        @param uuid: The user uuid.
+        @type uuid: str
+        @param token: The token.
+        @type token: str
+        """
+        with couch_server(self.couch_url) as server:
+            # the tokens db rotates every 30 days, and the current db name is
+            # "tokens_NNN", where NNN is the number of seconds since epoch
+            # divide dby the rotate period in seconds. When rotating, old and
+            # new tokens db coexist during a certain window of time and valid
+            # tokens are replicated from the old db to the new one. See:
+            # https://leap.se/code/issues/6785
+            dbname = self._tokens_dbname()
+            db = server[dbname]
+        # lookup key is a hash of the token to prevent timing attacks.
+        token = db.get(sha512(token).hexdigest())
+        if token is None:
+            return False
+        # we compare uuid hashes to avoid possible timing attacks that
+        # might exploit python's builtin comparison operator behaviour,
+        # which fails immediatelly when non-matching bytes are found.
+        couch_uuid_hash = sha512(token[self.TOKENS_USER_ID_KEY]).digest()
+        req_uuid_hash = sha512(uuid).digest()
+        if token[self.TOKENS_TYPE_KEY] != self.TOKENS_TYPE_DEF \
+                or couch_uuid_hash != req_uuid_hash:
+            return False
+        return True
+
+    def _tokens_dbname(self):
+        dbname = self.TOKENS_DB_PREFIX + \
+            str(int(time.time() / self.TOKENS_DB_EXPIRE))
+        return dbname
diff --git a/common/src/leap/soledad/common/couch/support.py b/common/src/leap/soledad/common/couch/support.py
new file mode 100644
index 00000000..bfc4fef6
--- /dev/null
+++ b/common/src/leap/soledad/common/couch/support.py
@@ -0,0 +1,115 @@
+# -*- coding: utf-8 -*-
+# support.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+import sys
+
+
+"""
+Monkey patches and temporary code that may be removed with version changes.
+"""
+
+
+# for bigcouch
+# TODO: Remove if bigcouch support is dropped
+class MultipartWriter(object):
+
+    """
+    A multipart writer adapted from python-couchdb's one so we can PUT
+    documents using couch's multipart PUT.
+
+    This stripped down version does not allow for nested structures, and
+    contains only the essential things we need to PUT SoledadDocuments to the
+    couch backend. Also, please note that this is a patch. The couchdb lib has
+    another implementation that works fine with CouchDB 1.6, but removing this
+    now will break compatibility with bigcouch.
+    """
+
+    CRLF = '\r\n'
+
+    def __init__(self, fileobj, headers=None, boundary=None):
+        """
+        Initialize the multipart writer.
+        """
+        self.fileobj = fileobj
+        if boundary is None:
+            boundary = self._make_boundary()
+        self._boundary = boundary
+        self._build_headers('related', headers)
+
+    def add(self, mimetype, content, headers={}):
+        """
+        Add a part to the multipart stream.
+        """
+        self.fileobj.write('--')
+        self.fileobj.write(self._boundary)
+        self.fileobj.write(self.CRLF)
+        headers['Content-Type'] = mimetype
+        self._write_headers(headers)
+        if content:
+            # XXX: throw an exception if a boundary appears in the content??
+            self.fileobj.write(content)
+            self.fileobj.write(self.CRLF)
+
+    def close(self):
+        """
+        Close the multipart stream.
+        """
+        self.fileobj.write('--')
+        self.fileobj.write(self._boundary)
+        # be careful not to have anything after '--', otherwise old couch
+        # versions (including bigcouch) will fail.
+        self.fileobj.write('--')
+
+    def _make_boundary(self):
+        """
+        Create a boundary to discern multi parts.
+        """
+        try:
+            from uuid import uuid4
+            return '==' + uuid4().hex + '=='
+        except ImportError:
+            from random import randrange
+            token = randrange(sys.maxint)
+            format = '%%0%dd' % len(repr(sys.maxint - 1))
+            return '===============' + (format % token) + '=='
+
+    def _write_headers(self, headers):
+        """
+        Write a part header in the buffer stream.
+        """
+        if headers:
+            for name in sorted(headers.keys()):
+                value = headers[name]
+                self.fileobj.write(name)
+                self.fileobj.write(': ')
+                self.fileobj.write(value)
+                self.fileobj.write(self.CRLF)
+        self.fileobj.write(self.CRLF)
+
+    def _build_headers(self, subtype, headers):
+        """
+        Build the main headers of the multipart stream.
+
+        This is here so we can send headers separete from content using
+        python-couchdb API.
+        """
+        self.headers = {}
+        self.headers['Content-Type'] = 'multipart/%s; boundary="%s"' % \
+                                       (subtype, self._boundary)
+        if headers:
+            for name in sorted(headers.keys()):
+                value = headers[name]
+                self.headers[name] = value
diff --git a/common/src/leap/soledad/common/document.py b/common/src/leap/soledad/common/document.py
index 919ade12..9e0c0976 100644
--- a/common/src/leap/soledad/common/document.py
+++ b/common/src/leap/soledad/common/document.py
@@ -108,3 +108,73 @@ class SoledadDocument(Document):
         _get_rev,
         _set_rev,
         doc="Wrapper to ensure `doc.rev` is always returned as bytes.")
+
+
+class ServerDocument(SoledadDocument):
+    """
+    This is the document used by server to hold conflicts and transactions
+    on a database.
+
+    The goal is to ensure an atomic and consistent update of the database.
+    """
+
+    def __init__(self, doc_id=None, rev=None, json='{}', has_conflicts=False):
+        """
+        Container for handling a document that stored on server.
+
+        :param doc_id: The unique document identifier.
+        :type doc_id: str
+        :param rev: The revision identifier of the document.
+        :type rev: str
+        :param json: The JSON string for this document.
+        :type json: str
+        :param has_conflicts: Boolean indicating if this document has conflicts
+        :type has_conflicts: bool
+        """
+        SoledadDocument.__init__(self, doc_id, rev, json, has_conflicts)
+        self._conflicts = None
+
+    def get_conflicts(self):
+        """
+        Get the conflicted versions of the document.
+
+        :return: The conflicted versions of the document.
+        :rtype: [ServerDocument]
+        """
+        return self._conflicts or []
+
+    def set_conflicts(self, conflicts):
+        """
+        Set the conflicted versions of the document.
+
+        :param conflicts: The conflicted versions of the document.
+        :type conflicts: list
+        """
+        self._conflicts = conflicts
+        self.has_conflicts = len(self._conflicts) > 0
+
+    def add_conflict(self, doc):
+        """
+        Add a conflict to this document.
+
+        :param doc: The conflicted version to be added.
+        :type doc: Document
+        """
+        if self._conflicts is None:
+            raise Exception("Fetch conflicts first!")
+        self._conflicts.append(doc)
+        self.has_conflicts = len(self._conflicts) > 0
+
+    def delete_conflicts(self, conflict_revs):
+        """
+        Delete conflicted versions of this document.
+
+        :param conflict_revs: The conflicted revisions to be deleted.
+        :type conflict_revs: [str]
+        """
+        if self._conflicts is None:
+            raise Exception("Fetch conflicts first!")
+        self._conflicts = filter(
+            lambda doc: doc.rev not in conflict_revs,
+            self._conflicts)
+        self.has_conflicts = len(self._conflicts) > 0
diff --git a/common/src/leap/soledad/common/errors.py b/common/src/leap/soledad/common/errors.py
index 5798770b..0b6bb4e6 100644
--- a/common/src/leap/soledad/common/errors.py
+++ b/common/src/leap/soledad/common/errors.py
@@ -132,67 +132,23 @@ class CouldNotObtainLockError(SoledadError):
 
 
 #
-# CouchDatabase errors
-#
-
-@register_exception
-class MissingDesignDocError(SoledadError):
-
-    """
-    Raised when trying to access a missing couch design document.
-    """
-
-    wire_description = "missing design document"
-    status = 500
-
-
-@register_exception
-class MissingDesignDocNamedViewError(SoledadError):
-
-    """
-    Raised when trying to access a missing named view on a couch design
-    document.
-    """
-
-    wire_description = "missing design document named function"
-    status = 500
-
-
-@register_exception
-class MissingDesignDocListFunctionError(SoledadError):
-
-    """
-    Raised when trying to access a missing list function on a couch design
-    document.
-    """
-
-    wire_description = "missing design document list function"
-    status = 500
+# SoledadBackend errors
+# u1db error statuses also have to be updated
+http_errors.ERROR_STATUSES = set(
+    http_errors.wire_description_to_status.values())
 
 
-@register_exception
-class MissingDesignDocDeletedError(SoledadError):
+class InvalidURLError(Exception):
 
     """
-    Raised when trying to access a deleted couch design document.
+    Exception raised when Soledad encounters a malformed URL.
     """
 
-    wire_description = "design document was deleted"
-    status = 500
-
-
-@register_exception
-class DesignDocUnknownError(SoledadError):
 
+class BackendNotReadyError(SoledadError):
     """
-    Raised when trying to access a couch design document and getting an
-    unknown error.
+    Generic exception raised when the backend is not ready to dispatch a client
+    request.
     """
-
-    wire_description = "missing design document unknown error"
+    wire_description = "backend not ready"
     status = 500
-
-
-# u1db error statuses also have to be updated
-http_errors.ERROR_STATUSES = set(
-    http_errors.wire_description_to_status.values())
diff --git a/common/src/leap/soledad/common/tests/fixture_soledad.conf b/common/src/leap/soledad/common/tests/fixture_soledad.conf
new file mode 100644
index 00000000..8d8161c3
--- /dev/null
+++ b/common/src/leap/soledad/common/tests/fixture_soledad.conf
@@ -0,0 +1,11 @@
+[soledad-server]
+couch_url   = http://soledad:passwd@localhost:5984
+create_cmd  = sudo -u soledad-admin /usr/bin/create-user-db
+admin_netrc = /etc/couchdb/couchdb-soledad-admin.netrc
+batching    = 0
+
+[database-security]
+members       = user1, user2
+members_roles = role1, role2
+admins        = user3, user4
+admins_roles  = role3, role3
diff --git a/common/src/leap/soledad/common/tests/test_couch.py b/common/src/leap/soledad/common/tests/test_couch.py
index b4797f5e..7ba50e11 100644
--- a/common/src/leap/soledad/common/tests/test_couch.py
+++ b/common/src/leap/soledad/common/tests/test_couch.py
@@ -36,7 +36,8 @@ from u1db import SyncTarget
 from u1db import vectorclock
 
 from leap.soledad.common import couch
-from leap.soledad.common import errors
+from leap.soledad.common.document import ServerDocument
+from leap.soledad.common.couch import errors
 
 from leap.soledad.common.tests import u1db_tests as tests
 from leap.soledad.common.tests.util import CouchDBTestCase
@@ -46,8 +47,6 @@ from leap.soledad.common.tests.util import sync_via_synchronizer
 from leap.soledad.common.tests.u1db_tests import test_backends
 from leap.soledad.common.tests.u1db_tests import DatabaseBaseTests
 
-from u1db.backends.inmemory import InMemoryIndex
-
 
 # -----------------------------------------------------------------------------
 # The following tests come from `u1db.tests.test_common_backend`.
@@ -133,7 +132,7 @@ def copy_couch_database_for_test(test, db):
 
 
 def make_document_for_test(test, doc_id, rev, content, has_conflicts=False):
-    return couch.CouchDocument(
+    return ServerDocument(
         doc_id, rev, content, has_conflicts=has_conflicts)
 
 
@@ -150,7 +149,7 @@ class CouchTests(
     scenarios = COUCH_SCENARIOS
 
 
-class CouchDatabaseTests(
+class SoledadBackendTests(
         TestWithScenarios,
         test_backends.LocalDatabaseTests,
         CouchDBTestCase):
@@ -206,7 +205,7 @@ simple_doc = tests.simple_doc
 nested_doc = tests.nested_doc
 
 
-class CouchDatabaseSyncTargetTests(
+class SoledadBackendSyncTargetTests(
         TestWithScenarios,
         DatabaseBaseTests,
         CouchDBTestCase):
@@ -529,90 +528,6 @@ class CouchDatabaseSyncTargetTests(
         self.st.record_sync_info('replica', 0, 'T-sid')
         self.assertEqual(expected, called)
 
-
-# The following tests need that the database have an index, so we fake one.
-
-class IndexedCouchDatabase(couch.CouchDatabase):
-
-    def __init__(self, url, dbname, replica_uid=None, ensure_ddocs=True):
-        old_class.__init__(self, url, dbname, replica_uid=replica_uid,
-                           ensure_ddocs=ensure_ddocs)
-        self._indexes = {}
-
-    def _put_doc(self, old_doc, doc):
-        for index in self._indexes.itervalues():
-            if old_doc is not None and not old_doc.is_tombstone():
-                index.remove_json(old_doc.doc_id, old_doc.get_json())
-            if not doc.is_tombstone():
-                index.add_json(doc.doc_id, doc.get_json())
-        old_class._put_doc(self, old_doc, doc)
-
-    def create_index(self, index_name, *index_expressions):
-        if index_name in self._indexes:
-            if self._indexes[index_name]._definition == list(
-                    index_expressions):
-                return
-            raise u1db_errors.IndexNameTakenError
-        index = InMemoryIndex(index_name, list(index_expressions))
-        _, all_docs = self.get_all_docs()
-        for doc in all_docs:
-            index.add_json(doc.doc_id, doc.get_json())
-        self._indexes[index_name] = index
-
-    def delete_index(self, index_name):
-        del self._indexes[index_name]
-
-    def list_indexes(self):
-        definitions = []
-        for idx in self._indexes.itervalues():
-            definitions.append((idx._name, idx._definition))
-        return definitions
-
-    def get_from_index(self, index_name, *key_values):
-        try:
-            index = self._indexes[index_name]
-        except KeyError:
-            raise u1db_errors.IndexDoesNotExist
-        doc_ids = index.lookup(key_values)
-        result = []
-        for doc_id in doc_ids:
-            result.append(self._get_doc(doc_id, check_for_conflicts=True))
-        return result
-
-    def get_range_from_index(self, index_name, start_value=None,
-                             end_value=None):
-        """Return all documents with key values in the specified range."""
-        try:
-            index = self._indexes[index_name]
-        except KeyError:
-            raise u1db_errors.IndexDoesNotExist
-        if isinstance(start_value, basestring):
-            start_value = (start_value,)
-        if isinstance(end_value, basestring):
-            end_value = (end_value,)
-        doc_ids = index.lookup_range(start_value, end_value)
-        result = []
-        for doc_id in doc_ids:
-            result.append(self._get_doc(doc_id, check_for_conflicts=True))
-        return result
-
-    def get_index_keys(self, index_name):
-        try:
-            index = self._indexes[index_name]
-        except KeyError:
-            raise u1db_errors.IndexDoesNotExist
-        keys = index.keys()
-        # XXX inefficiency warning
-        return list(set([tuple(key.split('\x01')) for key in keys]))
-
-
-# monkey patch CouchDatabase (once) to include virtual indexes
-if getattr(couch.CouchDatabase, '_old_class', None) is None:
-    old_class = couch.CouchDatabase
-    IndexedCouchDatabase._old_class = old_class
-    couch.CouchDatabase = IndexedCouchDatabase
-
-
 sync_scenarios = []
 for name, scenario in COUCH_SCENARIOS:
     scenario = dict(scenario)
@@ -621,7 +536,7 @@ for name, scenario in COUCH_SCENARIOS:
     scenario = dict(scenario)
 
 
-class CouchDatabaseSyncTests(
+class SoledadBackendSyncTests(
         TestWithScenarios,
         DatabaseBaseTests,
         CouchDBTestCase):
@@ -922,7 +837,6 @@ class CouchDatabaseSyncTests(
         self.db1 = self.create_database('test1', 'source')
         self.db2 = self.create_database('test2', 'target')
         doc = self.db2.create_doc_from_json(simple_doc)
-        self.db1.create_index('test-idx', 'key')
         self.assertEqual(0, self.sync(self.db1, self.db2))
         self.assertGetDoc(self.db1, doc.doc_id, doc.rev, simple_doc, False)
         self.assertEqual(1, self.db1._get_replica_gen_and_trans_id('test2')[0])
@@ -932,7 +846,7 @@ class CouchDatabaseSyncTests(
             {'receive': {'docs': [], 'last_known_gen': 0},
              'return': {'docs': [(doc.doc_id, doc.rev)],
                         'last_gen': 1}})
-        self.assertEqual([doc], self.db1.get_from_index('test-idx', 'value'))
+        self.assertGetDoc(self.db2, doc.doc_id, doc.rev, simple_doc, False)
 
     def test_sync_pulling_doesnt_update_other_if_changed(self):
         self.db1 = self.create_database('test1', 'source')
@@ -1021,7 +935,6 @@ class CouchDatabaseSyncTests(
         doc1 = self.db1.create_doc_from_json(simple_doc)
         doc_id = doc1.doc_id
         doc1_rev = doc1.rev
-        self.db1.create_index('test-idx', 'key')
         new_doc = '{"key": "altval"}'
         doc2 = self.db2.create_doc_from_json(new_doc, doc_id=doc_id)
         doc2_rev = doc2.rev
@@ -1037,18 +950,12 @@ class CouchDatabaseSyncTests(
         self.assertTransactionLog([doc_id, doc_id], self.db1)
         self.assertGetDoc(self.db1, doc_id, doc2_rev, new_doc, True)
         self.assertGetDoc(self.db2, doc_id, doc2_rev, new_doc, False)
-        from_idx = self.db1.get_from_index('test-idx', 'altval')[0]
-        self.assertEqual(doc2.doc_id, from_idx.doc_id)
-        self.assertEqual(doc2.rev, from_idx.rev)
-        self.assertTrue(from_idx.has_conflicts)
-        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
 
     def test_sync_sees_remote_delete_conflicted(self):
         self.db1 = self.create_database('test1', 'source')
         self.db2 = self.create_database('test2', 'target')
         doc1 = self.db1.create_doc_from_json(simple_doc)
         doc_id = doc1.doc_id
-        self.db1.create_index('test-idx', 'key')
         self.sync(self.db1, self.db2)
         doc2 = self.make_document(doc1.doc_id, doc1.rev, doc1.get_json())
         new_doc = '{"key": "altval"}'
@@ -1068,7 +975,6 @@ class CouchDatabaseSyncTests(
         self.assertGetDocIncludeDeleted(self.db1, doc_id, doc2.rev, None, True)
         self.assertGetDocIncludeDeleted(
             self.db2, doc_id, doc2.rev, None, False)
-        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
 
     def test_sync_local_race_conflicted(self):
         self.db1 = self.create_database('test1', 'source')
@@ -1076,7 +982,6 @@ class CouchDatabaseSyncTests(
         doc = self.db1.create_doc_from_json(simple_doc)
         doc_id = doc.doc_id
         doc1_rev = doc.rev
-        self.db1.create_index('test-idx', 'key')
         self.sync(self.db1, self.db2)
         content1 = '{"key": "localval"}'
         content2 = '{"key": "altval"}'
@@ -1095,21 +1000,13 @@ class CouchDatabaseSyncTests(
         self.sync(self.db1, self.db2, trace_hook=after_whatschanged)
         self.assertEqual([True], triggered)
         self.assertGetDoc(self.db1, doc_id, doc2_rev2, content2, True)
-        from_idx = self.db1.get_from_index('test-idx', 'altval')[0]
-        self.assertEqual(doc.doc_id, from_idx.doc_id)
-        self.assertEqual(doc.rev, from_idx.rev)
-        self.assertTrue(from_idx.has_conflicts)
-        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
-        self.assertEqual([], self.db1.get_from_index('test-idx', 'localval'))
 
     def test_sync_propagates_deletes(self):
         self.db1 = self.create_database('test1', 'source')
         self.db2 = self.create_database('test2', 'both')
         doc1 = self.db1.create_doc_from_json(simple_doc)
         doc_id = doc1.doc_id
-        self.db1.create_index('test-idx', 'key')
         self.sync(self.db1, self.db2)
-        self.db2.create_index('test-idx', 'key')
         self.db3 = self.create_database('test3', 'target')
         self.sync(self.db1, self.db3)
         self.db1.delete_doc(doc1)
@@ -1125,8 +1022,6 @@ class CouchDatabaseSyncTests(
             self.db1, doc_id, deleted_rev, None, False)
         self.assertGetDocIncludeDeleted(
             self.db2, doc_id, deleted_rev, None, False)
-        self.assertEqual([], self.db1.get_from_index('test-idx', 'value'))
-        self.assertEqual([], self.db2.get_from_index('test-idx', 'value'))
         self.sync(self.db2, self.db3)
         self.assertLastExchangeLog(
             self.db3,
@@ -1317,7 +1212,7 @@ class CouchDatabaseSyncTests(
         self.assertEqual(cont2, self.db1.get_doc("2").get_json())
 
 
-class CouchDatabaseExceptionsTests(CouchDBTestCase):
+class SoledadBackendExceptionsTests(CouchDBTestCase):
 
     def setUp(self):
         CouchDBTestCase.setUp(self)
@@ -1325,9 +1220,11 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
     def create_db(self, ensure=True, dbname=None):
         if not dbname:
             dbname = ('test-%s' % uuid4().hex)
-        self.db = couch.CouchDatabase.open_database(
-            urljoin('http://127.0.0.1:%d' % self.couch_port, dbname),
-            create=True,
+        if dbname not in self.couch_server:
+            self.couch_server.create(dbname)
+        self.db = couch.CouchDatabase(
+            ('http://127.0.0.1:%d' % self.couch_port),
+            dbname,
             ensure_ddocs=ensure)
 
     def tearDown(self):
@@ -1341,22 +1238,18 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         design docs are not present.
         """
         self.create_db(ensure=False)
-        # _get_generation()
+        # get_generation_info()
         self.assertRaises(
             errors.MissingDesignDocError,
-            self.db._get_generation)
-        # _get_generation_info()
+            self.db.get_generation_info)
+        # get_trans_id_for_gen()
         self.assertRaises(
             errors.MissingDesignDocError,
-            self.db._get_generation_info)
-        # _get_trans_id_for_gen()
+            self.db.get_trans_id_for_gen, 1)
+        # get_transaction_log()
         self.assertRaises(
             errors.MissingDesignDocError,
-            self.db._get_trans_id_for_gen, 1)
-        # _get_transaction_log()
-        self.assertRaises(
-            errors.MissingDesignDocError,
-            self.db._get_transaction_log)
+            self.db.get_transaction_log)
         # whats_changed()
         self.assertRaises(
             errors.MissingDesignDocError,
@@ -1372,18 +1265,14 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         transactions = self.db._database['_design/transactions']
         transactions['lists'] = {}
         self.db._database.save(transactions)
-        # _get_generation()
+        # get_generation_info()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
-            self.db._get_generation)
-        # _get_generation_info()
+            self.db.get_generation_info)
+        # get_trans_id_for_gen()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
-            self.db._get_generation_info)
-        # _get_trans_id_for_gen()
-        self.assertRaises(
-            errors.MissingDesignDocListFunctionError,
-            self.db._get_trans_id_for_gen, 1)
+            self.db.get_trans_id_for_gen, 1)
         # whats_changed()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
@@ -1399,18 +1288,14 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         transactions = self.db._database['_design/transactions']
         del transactions['lists']
         self.db._database.save(transactions)
-        # _get_generation()
+        # get_generation_info()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
-            self.db._get_generation)
-        # _get_generation_info()
-        self.assertRaises(
-            errors.MissingDesignDocListFunctionError,
-            self.db._get_generation_info)
+            self.db.get_generation_info)
         # _get_trans_id_for_gen()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
-            self.db._get_trans_id_for_gen, 1)
+            self.db.get_trans_id_for_gen, 1)
         # whats_changed()
         self.assertRaises(
             errors.MissingDesignDocListFunctionError,
@@ -1434,22 +1319,18 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         transactions = self.db._database['_design/transactions']
         del transactions['views']
         self.db._database.save(transactions)
-        # _get_generation()
-        self.assertRaises(
-            errors.MissingDesignDocNamedViewError,
-            self.db._get_generation)
-        # _get_generation_info()
+        # get_generation_info()
         self.assertRaises(
             errors.MissingDesignDocNamedViewError,
-            self.db._get_generation_info)
+            self.db.get_generation_info)
         # _get_trans_id_for_gen()
         self.assertRaises(
             errors.MissingDesignDocNamedViewError,
-            self.db._get_trans_id_for_gen, 1)
+            self.db.get_trans_id_for_gen, 1)
         # _get_transaction_log()
         self.assertRaises(
             errors.MissingDesignDocNamedViewError,
-            self.db._get_transaction_log)
+            self.db.get_transaction_log)
         # whats_changed()
         self.assertRaises(
             errors.MissingDesignDocNamedViewError,
@@ -1467,22 +1348,18 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         del self.db._database['_design/syncs']
         # delete _design/transactions
         del self.db._database['_design/transactions']
-        # _get_generation()
-        self.assertRaises(
-            errors.MissingDesignDocDeletedError,
-            self.db._get_generation)
-        # _get_generation_info()
+        # get_generation_info()
         self.assertRaises(
             errors.MissingDesignDocDeletedError,
-            self.db._get_generation_info)
-        # _get_trans_id_for_gen()
+            self.db.get_generation_info)
+        # get_trans_id_for_gen()
         self.assertRaises(
             errors.MissingDesignDocDeletedError,
-            self.db._get_trans_id_for_gen, 1)
-        # _get_transaction_log()
+            self.db.get_trans_id_for_gen, 1)
+        # get_transaction_log()
         self.assertRaises(
             errors.MissingDesignDocDeletedError,
-            self.db._get_transaction_log)
+            self.db.get_transaction_log)
         # whats_changed()
         self.assertRaises(
             errors.MissingDesignDocDeletedError,
@@ -1497,9 +1374,9 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         del self.db._database['_design/transactions']
         self.assertRaises(
             errors.MissingDesignDocDeletedError,
-            self.db._get_transaction_log)
+            self.db.get_transaction_log)
         self.create_db(ensure=True, dbname=self.db._dbname)
-        self.db._get_transaction_log()
+        self.db.get_transaction_log()
 
     def test_ensure_security_doc(self):
         """
@@ -1515,18 +1392,41 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase):
         self.assertIn('members', security_ddoc)
         self.assertIn('soledad', security_ddoc['members']['names'])
 
+    def test_ensure_security_from_configuration(self):
+        """
+        Given a configuration, follow it to create the security document
+        """
+        self.create_db(ensure=False)
+        configuration = {'members': ['user1', 'user2'],
+                         'members_roles': ['role1', 'role2'],
+                         'admins': ['admin'],
+                         'admins_roles': ['administrators']
+                         }
+        self.db.ensure_security_ddoc(configuration)
+
+        security_ddoc = self.db._database.resource.get_json('_security')[2]
+        self.assertEquals(configuration['admins'],
+                          security_ddoc['admins']['names'])
+        self.assertEquals(configuration['admins_roles'],
+                          security_ddoc['admins']['roles'])
+        self.assertEquals(configuration['members'],
+                          security_ddoc['members']['names'])
+        self.assertEquals(configuration['members_roles'],
+                          security_ddoc['members']['roles'])
+
 
 class DatabaseNameValidationTest(unittest.TestCase):
 
     def test_database_name_validation(self):
-        self.assertFalse(couch.is_db_name_valid("user-deadbeef | cat /secret"))
-        self.assertTrue(couch.is_db_name_valid("user-cafe1337"))
+        inject = couch.state.is_db_name_valid("user-deadbeef | cat /secret")
+        self.assertFalse(inject)
+        self.assertTrue(couch.state.is_db_name_valid("user-cafe1337"))
 
 
 class CommandBasedDBCreationTest(unittest.TestCase):
 
     def test_ensure_db_using_custom_command(self):
-        state = couch.CouchServerState("url", create_cmd="echo")
+        state = couch.state.CouchServerState("url", create_cmd="echo")
         mock_db = Mock()
         mock_db.replica_uid = 'replica_uid'
         state.open_database = Mock(return_value=mock_db)
@@ -1535,11 +1435,11 @@ class CommandBasedDBCreationTest(unittest.TestCase):
         self.assertEquals(mock_db.replica_uid, replica_uid)
 
     def test_raises_unauthorized_on_failure(self):
-        state = couch.CouchServerState("url", create_cmd="inexistent")
+        state = couch.state.CouchServerState("url", create_cmd="inexistent")
         self.assertRaises(u1db_errors.Unauthorized,
                           state.ensure_database, "user-1337")
 
     def test_raises_unauthorized_by_default(self):
-        state = couch.CouchServerState("url")
+        state = couch.state.CouchServerState("url")
         self.assertRaises(u1db_errors.Unauthorized,
                           state.ensure_database, "user-1337")
diff --git a/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py b/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py
index 507f2984..8cd3ae08 100644
--- a/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py
+++ b/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py
@@ -26,7 +26,8 @@ from twisted.internet import defer
 from uuid import uuid4
 
 from leap.soledad.client import Soledad
-from leap.soledad.common.couch import CouchDatabase, CouchServerState
+from leap.soledad.common.couch.state import CouchServerState
+from leap.soledad.common.couch import CouchDatabase
 
 from leap.soledad.common.tests.util import (
     make_token_soledad_app,
diff --git a/common/src/leap/soledad/common/tests/test_encdecpool.py b/common/src/leap/soledad/common/tests/test_encdecpool.py
index 793bfa1a..694eb7ad 100644
--- a/common/src/leap/soledad/common/tests/test_encdecpool.py
+++ b/common/src/leap/soledad/common/tests/test_encdecpool.py
@@ -18,6 +18,7 @@
 Tests for encryption and decryption pool.
 """
 import json
+from random import shuffle
 
 from twisted.internet.defer import inlineCallbacks
 
@@ -171,20 +172,21 @@ class TestSyncDecrypterPool(BaseSoledadTest):
             DOC_ID, DOC_REV, encrypted_content, 1, "trans_id", 1)
 
         def _assert_doc_was_decrypted_and_inserted(_):
+            self.assertEqual(1, len(self._inserted_docs))
             self.assertEqual(self._inserted_docs, [(doc, 1, u"trans_id")])
 
         self._pool.deferred.addCallback(
             _assert_doc_was_decrypted_and_inserted)
         return self._pool.deferred
 
-    def test_insert_encrypted_received_doc_many(self):
+    def test_insert_encrypted_received_doc_many(self, many=100):
         """
         Test that many encrypted documents added to the pool are decrypted and
         inserted using the callback.
         """
         crypto = self._soledad._crypto
-        many = 100
         self._pool.start(many)
+        docs = []
 
         # insert many encrypted docs in the pool
         for i in xrange(many):
@@ -198,9 +200,12 @@ class TestSyncDecrypterPool(BaseSoledadTest):
                 doc_id=doc_id, rev=rev, json=json.dumps(content))
 
             encrypted_content = json.loads(crypto.encrypt_doc(doc))
+            docs.append((doc_id, rev, encrypted_content, gen,
+                         trans_id, idx))
+        shuffle(docs)
 
-            self._pool.insert_encrypted_received_doc(
-                doc_id, rev, encrypted_content, gen, trans_id, idx)
+        for doc in docs:
+            self._pool.insert_encrypted_received_doc(*doc)
 
         def _assert_docs_were_decrypted_and_inserted(_):
             self.assertEqual(many, len(self._inserted_docs))
@@ -223,3 +228,16 @@ class TestSyncDecrypterPool(BaseSoledadTest):
         self._pool.deferred.addCallback(
             _assert_docs_were_decrypted_and_inserted)
         return self._pool.deferred
+
+    @inlineCallbacks
+    def test_pool_reuse(self):
+        """
+        The pool is reused between syncs, this test verifies that
+        reusing is fine.
+        """
+        for i in xrange(3):
+            yield self.test_insert_encrypted_received_doc_many(5)
+            self._inserted_docs = []
+            decrypted_docs = yield self._pool._get_docs(encrypted=False)
+            # check that decrypted docs staging is clean
+            self.assertEquals([], decrypted_docs)
diff --git a/common/src/leap/soledad/common/tests/test_server.py b/common/src/leap/soledad/common/tests/test_server.py
index 19d2907d..20fe8579 100644
--- a/common/src/leap/soledad/common/tests/test_server.py
+++ b/common/src/leap/soledad/common/tests/test_server.py
@@ -22,15 +22,16 @@ import tempfile
 import mock
 import time
 import binascii
+from pkg_resources import resource_filename
 from uuid import uuid4
+from hashlib import sha512
 
 from urlparse import urljoin
 from twisted.internet import defer
+from twisted.trial import unittest
 
-from leap.soledad.common.couch import (
-    CouchServerState,
-    CouchDatabase,
-)
+from leap.soledad.common.couch.state import CouchServerState
+from leap.soledad.common.couch import CouchDatabase
 from leap.soledad.common.tests.u1db_tests import TestCaseWithServer
 from leap.soledad.common.tests.test_couch import CouchDBTestCase
 from leap.soledad.common.tests.util import (
@@ -43,7 +44,39 @@ from leap.soledad.common.tests.util import (
 from leap.soledad.common import crypto
 from leap.soledad.client import Soledad
 from leap.soledad.server import LockResource
+from leap.soledad.server import load_configuration
+from leap.soledad.server import CONFIG_DEFAULTS
 from leap.soledad.server.auth import URLToAuthorization
+from leap.soledad.server.auth import SoledadTokenAuthMiddleware
+
+
+class ServerAuthenticationMiddlewareTestCase(CouchDBTestCase):
+
+    def setUp(self):
+        super(ServerAuthenticationMiddlewareTestCase, self).setUp()
+        app = mock.Mock()
+        self._state = CouchServerState(self.couch_url)
+        app.state = self._state
+        self.auth_middleware = SoledadTokenAuthMiddleware(app)
+        self._authorize('valid-uuid', 'valid-token')
+
+    def _authorize(self, uuid, token):
+        token_doc = {}
+        token_doc['_id'] = sha512(token).hexdigest()
+        token_doc[self._state.TOKENS_USER_ID_KEY] = uuid
+        token_doc[self._state.TOKENS_TYPE_KEY] = \
+            self._state.TOKENS_TYPE_DEF
+        dbname = self._state._tokens_dbname()
+        db = self.couch_server.create(dbname)
+        db.save(token_doc)
+        self.addCleanup(self.delete_db, db.name)
+
+    def test_authorized_user(self):
+        is_authorized = self.auth_middleware._verify_authentication_data
+        self.assertTrue(is_authorized('valid-uuid', 'valid-token'))
+        self.assertFalse(is_authorized('valid-uuid', 'invalid-token'))
+        self.assertFalse(is_authorized('invalid-uuid', 'valid-token'))
+        self.assertFalse(is_authorized('eve', 'invalid-token'))
 
 
 class ServerAuthorizationTestCase(BaseSoledadTest):
@@ -587,3 +620,45 @@ class LockResourceTestCase(
         self.assertIsNotNone(lr._shared_db.get_doc('lock-' + lock_uuid))
         responder.send_response_json.assert_called_with(
             401, error='unlock unauthorized')
+
+
+class ConfigurationParsingTest(unittest.TestCase):
+
+    def setUp(self):
+        self.maxDiff = None
+
+    def test_use_defaults_on_failure(self):
+        config = load_configuration('this file will never exist')
+        expected = CONFIG_DEFAULTS
+        self.assertEquals(expected, config)
+
+    def test_security_values_configuration(self):
+        # given
+        config_path = resource_filename('leap.soledad.common.tests',
+                                        'fixture_soledad.conf')
+        # when
+        config = load_configuration(config_path)
+
+        # then
+        expected = {'members': ['user1', 'user2'],
+                    'members_roles': ['role1', 'role2'],
+                    'admins': ['user3', 'user4'],
+                    'admins_roles': ['role3', 'role3']}
+        self.assertDictEqual(expected, config['database-security'])
+
+    def test_server_values_configuration(self):
+        # given
+        config_path = resource_filename('leap.soledad.common.tests',
+                                        'fixture_soledad.conf')
+        # when
+        config = load_configuration(config_path)
+
+        # then
+        expected = {'couch_url':
+                    'http://soledad:passwd@localhost:5984',
+                    'create_cmd':
+                    'sudo -u soledad-admin /usr/bin/create-user-db',
+                    'admin_netrc':
+                    '/etc/couchdb/couchdb-soledad-admin.netrc',
+                    'batching': False}
+        self.assertDictEqual(expected, config['soledad-server'])
diff --git a/common/src/leap/soledad/common/tests/test_soledad.py b/common/src/leap/soledad/common/tests/test_soledad.py
index 85d6734e..36c4003c 100644
--- a/common/src/leap/soledad/common/tests/test_soledad.py
+++ b/common/src/leap/soledad/common/tests/test_soledad.py
@@ -249,55 +249,51 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         # get a fresh instance so it emits all bootstrap signals
         sol = self._soledad_instance(
             secrets_path='alternative_stage3.json',
-            local_db_path='alternative_stage3.u1db')
+            local_db_path='alternative_stage3.u1db',
+            userid=ADDRESS)
         # reverse call order so we can verify in the order the signals were
         # expected
         soledad.client.secrets.events.emit_async.mock_calls.reverse()
         soledad.client.secrets.events.emit_async.call_args = \
             soledad.client.secrets.events.emit_async.call_args_list[0]
         soledad.client.secrets.events.emit_async.call_args_list.reverse()
+
+        user_data = {'userid': ADDRESS, 'uuid': ADDRESS}
+
         # downloading keys signals
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DOWNLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DOWNLOADING_KEYS, user_data
         )
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DONE_DOWNLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DONE_DOWNLOADING_KEYS, user_data
         )
         # creating keys signals
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_CREATING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_CREATING_KEYS, user_data
         )
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DONE_CREATING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DONE_CREATING_KEYS, user_data
         )
         # downloading once more (inside _put_keys_in_shared_db)
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DOWNLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DOWNLOADING_KEYS, user_data
         )
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DONE_DOWNLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DONE_DOWNLOADING_KEYS, user_data
         )
         # uploading keys signals
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_UPLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_UPLOADING_KEYS, user_data
         )
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
-            catalog.SOLEDAD_DONE_UPLOADING_KEYS,
-            ADDRESS,
+            catalog.SOLEDAD_DONE_UPLOADING_KEYS, user_data
         )
         # assert db was locked and unlocked
         sol.shared_db.lock.assert_called_with()
@@ -332,12 +328,12 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         # assert download keys signals
         soledad.client.secrets.events.emit_async.assert_called_with(
             catalog.SOLEDAD_DOWNLOADING_KEYS,
-            ADDRESS,
+            {'userid': ADDRESS, 'uuid': ADDRESS}
         )
         self._pop_mock_call(soledad.client.secrets.events.emit_async)
         soledad.client.secrets.events.emit_async.assert_called_with(
             catalog.SOLEDAD_DONE_DOWNLOADING_KEYS,
-            ADDRESS,
+            {'userid': ADDRESS, 'uuid': ADDRESS},
         )
         sol.close()
 
@@ -371,6 +367,6 @@ class SoledadSignalingTestCase(BaseSoledadTest):
         # assert the signal has been emitted
         soledad.client.events.emit_async.assert_called_with(
             catalog.SOLEDAD_DONE_DATA_SYNC,
-            ADDRESS,
+            {'userid': ADDRESS, 'uuid': ADDRESS},
         )
         sol.close()
diff --git a/common/src/leap/soledad/common/tests/test_sync_deferred.py b/common/src/leap/soledad/common/tests/test_sync_deferred.py
index 90b00670..c62bd156 100644
--- a/common/src/leap/soledad/common/tests/test_sync_deferred.py
+++ b/common/src/leap/soledad/common/tests/test_sync_deferred.py
@@ -148,6 +148,8 @@ class TestSoledadDbSyncDeferredEncDecr(
         replica_uid = self._soledad._dbpool.replica_uid
         sync_db = self._soledad._sync_db
         sync_enc_pool = self._soledad._sync_enc_pool
+        dbsyncer = self._soledad._dbsyncer  # Soledad.sync uses the dbsyncer
+
         target = soledad_sync_target(
             self, self.db2._dbname,
             source_replica_uid=replica_uid,
@@ -155,7 +157,7 @@ class TestSoledadDbSyncDeferredEncDecr(
             sync_enc_pool=sync_enc_pool)
         self.addCleanup(target.close)
         return sync.SoledadSynchronizer(
-            self.db1,
+            dbsyncer,
             target).sync(defer_decryption=True)
 
     def wait_for_sync(self):
diff --git a/common/src/leap/soledad/common/tests/test_sync_mutex.py b/common/src/leap/soledad/common/tests/test_sync_mutex.py
index 2e2123a7..973a8587 100644
--- a/common/src/leap/soledad/common/tests/test_sync_mutex.py
+++ b/common/src/leap/soledad/common/tests/test_sync_mutex.py
@@ -33,7 +33,8 @@ from twisted.internet import defer
 
 from leap.soledad.client.sync import SoledadSynchronizer
 
-from leap.soledad.common import couch
+from leap.soledad.common.couch.state import CouchServerState
+from leap.soledad.common.couch import CouchDatabase
 from leap.soledad.common.tests.u1db_tests import TestCaseWithServer
 from leap.soledad.common.tests.test_couch import CouchDBTestCase
 
@@ -84,7 +85,7 @@ class TestSyncMutex(
     sync_target = soledad_sync_target
 
     def make_app(self):
-        self.request_state = couch.CouchServerState(self.couch_url)
+        self.request_state = CouchServerState(self.couch_url)
         return self.make_app_with_state(self.request_state)
 
     def setUp(self):
@@ -102,7 +103,7 @@ class TestSyncMutex(
         self.startServer()
 
         # ensure remote db exists before syncing
-        db = couch.CouchDatabase.open_database(
+        db = CouchDatabase.open_database(
             urljoin(self.couch_url, 'user-' + self.user),
             create=True,
             ensure_ddocs=True)
diff --git a/common/src/leap/soledad/common/tests/test_sync_target.py b/common/src/leap/soledad/common/tests/test_sync_target.py
index c0987e90..f25e84dd 100644
--- a/common/src/leap/soledad/common/tests/test_sync_target.py
+++ b/common/src/leap/soledad/common/tests/test_sync_target.py
@@ -29,7 +29,6 @@ from uuid import uuid4
 
 from testscenarios import TestWithScenarios
 from twisted.internet import defer
-from urlparse import urljoin
 
 from leap.soledad.client import http_target as target
 from leap.soledad.client import crypto
@@ -37,7 +36,6 @@ from leap.soledad.client.sqlcipher import SQLCipherU1DBSync
 from leap.soledad.client.sqlcipher import SQLCipherOptions
 from leap.soledad.client.sqlcipher import SQLCipherDatabase
 
-from leap.soledad.common import couch
 from leap.soledad.common.document import SoledadDocument
 
 from leap.soledad.common.tests import u1db_tests as tests
@@ -265,9 +263,9 @@ class TestSoledadSyncTarget(
                                      replica_trans_id=replica_trans_id,
                                      number_of_docs=number_of_docs,
                                      doc_idx=doc_idx, sync_id=sync_id)
-        from leap.soledad.common.tests.test_couch import IndexedCouchDatabase
+        from leap.soledad.common.backend import SoledadBackend
         self.patch(
-            IndexedCouchDatabase, '_put_doc_if_newer', bomb_put_doc_if_newer)
+            SoledadBackend, '_put_doc_if_newer', bomb_put_doc_if_newer)
         remote_target = self.getSyncTarget(
             source_replica_uid='replica')
         other_changes = []
diff --git a/common/src/leap/soledad/common/tests/util.py b/common/src/leap/soledad/common/tests/util.py
index 1c7adb91..d4510686 100644
--- a/common/src/leap/soledad/common/tests/util.py
+++ b/common/src/leap/soledad/common/tests/util.py
@@ -27,7 +27,6 @@ import shutil
 import random
 import string
 import u1db
-import traceback
 import couchdb
 
 from uuid import uuid4
@@ -37,17 +36,17 @@ from StringIO import StringIO
 from pysqlcipher import dbapi2
 
 from u1db import sync
-from u1db.errors import DatabaseDoesNotExist
 from u1db.remote import http_database
 
 from twisted.trial import unittest
 
-from leap.common.files import mkdir_p
 from leap.common.testing.basetest import BaseLeapTest
 
 from leap.soledad.common import soledad_assert
 from leap.soledad.common.document import SoledadDocument
-from leap.soledad.common.couch import CouchDatabase, CouchServerState
+from leap.soledad.common.couch import CouchDatabase
+from leap.soledad.common.couch.state import CouchServerState
+
 from leap.soledad.common.crypto import ENC_SCHEME_KEY
 
 from leap.soledad.client import Soledad
@@ -246,6 +245,7 @@ class BaseSoledadTest(BaseLeapTest, MockedSharedDBTest):
         # each local db.
         self.rand_prefix = ''.join(
             map(lambda x: random.choice(string.ascii_letters), range(6)))
+
         # initialize soledad by hand so we can control keys
         # XXX check if this soledad is actually used
         self._soledad = self._soledad_instance(
@@ -286,7 +286,8 @@ class BaseSoledadTest(BaseLeapTest, MockedSharedDBTest):
                           server_url='https://127.0.0.1/',
                           cert_file=None,
                           shared_db_class=None,
-                          auth_token='auth-token'):
+                          auth_token='auth-token',
+                          userid=ADDRESS):
 
         def _put_doc_side_effect(doc):
             self._doc_put = doc
@@ -308,7 +309,8 @@ class BaseSoledadTest(BaseLeapTest, MockedSharedDBTest):
             cert_file=cert_file,
             defer_encryption=self.defer_sync_encryption,
             shared_db=MockSharedDB(),
-            auth_token=auth_token)
+            auth_token=auth_token,
+            userid=userid)
         self.addCleanup(soledad.close)
         return soledad
 
diff --git a/common/versioneer.py b/common/versioneer.py
index 18dfd923..58339251 100644
--- a/common/versioneer.py
+++ b/common/versioneer.py
@@ -1,170 +1,641 @@
-#! /usr/bin/python
 
-"""versioneer.py
+# Version: 0.16
 
-(like a rocketeer, but for versions)
+"""The Versioneer - like a rocketeer, but for versions.
 
+The Versioneer
+==============
+
+* like a rocketeer, but for versions!
 * https://github.com/warner/python-versioneer
 * Brian Warner
 * License: Public Domain
-* Version: 0.7+
-
-This file helps distutils-based projects manage their version number by just
-creating version-control tags.
-
-For developers who work from a VCS-generated tree (e.g. 'git clone' etc),
-each 'setup.py version', 'setup.py build', 'setup.py sdist' will compute a
-version number by asking your version-control tool about the current
-checkout. The version number will be written into a generated _version.py
-file of your choosing, where it can be included by your __init__.py
-
-For users who work from a VCS-generated tarball (e.g. 'git archive'), it will
-compute a version number by looking at the name of the directory created when
-te tarball is unpacked. This conventionally includes both the name of the
-project and a version number.
-
-For users who work from a tarball built by 'setup.py sdist', it will get a
-version number from a previously-generated _version.py file.
-
-As a result, loading code directly from the source tree will not result in a
-real version. If you want real versions from VCS trees (where you frequently
-update from the upstream repository, or do new development), you will need to
-do a 'setup.py version' after each update, and load code from the build/
-directory.
-
-You need to provide this code with a few configuration values:
-
- versionfile_source:
-    A project-relative pathname into which the generated version strings
-    should be written. This is usually a _version.py next to your project's
-    main __init__.py file. If your project uses src/myproject/__init__.py,
-    this should be 'src/myproject/_version.py'. This file should be checked
-    in to your VCS as usual: the copy created below by 'setup.py
-    update_files' will include code that parses expanded VCS keywords in
-    generated tarballs. The 'build' and 'sdist' commands will replace it with
-    a copy that has just the calculated version string.
-
- versionfile_build:
-    Like versionfile_source, but relative to the build directory instead of
-    the source directory. These will differ when your setup.py uses
-    'package_dir='. If you have package_dir={'myproject': 'src/myproject'},
-    then you will probably have versionfile_build='myproject/_version.py' and
-    versionfile_source='src/myproject/_version.py'.
-
- tag_prefix: a string, like 'PROJECTNAME-', which appears at the start of all
-             VCS tags. If your tags look like 'myproject-1.2.0', then you
-             should use tag_prefix='myproject-'. If you use unprefixed tags
-             like '1.2.0', this should be an empty string.
-
- parentdir_prefix: a string, frequently the same as tag_prefix, which
-                   appears at the start of all unpacked tarball filenames. If
-                   your tarball unpacks into 'myproject-1.2.0', this should
-                   be 'myproject-'.
-
-To use it:
-
- 1: include this file in the top level of your project
- 2: make the following changes to the top of your setup.py:
-     import versioneer
-     versioneer.versionfile_source = 'src/myproject/_version.py'
-     versioneer.versionfile_build = 'myproject/_version.py'
-     versioneer.tag_prefix = '' # tags are like 1.2.0
-     versioneer.parentdir_prefix = 'myproject-' # dirname like 'myproject-1.2.0'
- 3: add the following arguments to the setup() call in your setup.py:
-     version=versioneer.get_version(),
-     cmdclass=versioneer.get_cmdclass(),
- 4: run 'setup.py update_files', which will create _version.py, and will
-    modify your __init__.py to define __version__ (by calling a function
-    from _version.py)
- 5: modify your MANIFEST.in to include versioneer.py
- 6: add both versioneer.py and the generated _version.py to your VCS
-"""
+* Compatible With: python2.6, 2.7, 3.3, 3.4, 3.5, and pypy
+* [![Latest Version]
+(https://pypip.in/version/versioneer/badge.svg?style=flat)
+](https://pypi.python.org/pypi/versioneer/)
+* [![Build Status]
+(https://travis-ci.org/warner/python-versioneer.png?branch=master)
+](https://travis-ci.org/warner/python-versioneer)
+
+This is a tool for managing a recorded version number in distutils-based
+python projects. The goal is to remove the tedious and error-prone "update
+the embedded version string" step from your release process. Making a new
+release should be as easy as recording a new tag in your version-control
+system, and maybe making new tarballs.
+
+
+## Quick Install
+
+* `pip install versioneer` to somewhere to your $PATH
+* add a `[versioneer]` section to your setup.cfg (see below)
+* run `versioneer install` in your source tree, commit the results
+
+## Version Identifiers
+
+Source trees come from a variety of places:
+
+* a version-control system checkout (mostly used by developers)
+* a nightly tarball, produced by build automation
+* a snapshot tarball, produced by a web-based VCS browser, like github's
+  "tarball from tag" feature
+* a release tarball, produced by "setup.py sdist", distributed through PyPI
+
+Within each source tree, the version identifier (either a string or a number,
+this tool is format-agnostic) can come from a variety of places:
+
+* ask the VCS tool itself, e.g. "git describe" (for checkouts), which knows
+  about recent "tags" and an absolute revision-id
+* the name of the directory into which the tarball was unpacked
+* an expanded VCS keyword ($Id$, etc)
+* a `_version.py` created by some earlier build step
+
+For released software, the version identifier is closely related to a VCS
+tag. Some projects use tag names that include more than just the version
+string (e.g. "myproject-1.2" instead of just "1.2"), in which case the tool
+needs to strip the tag prefix to extract the version identifier. For
+unreleased software (between tags), the version identifier should provide
+enough information to help developers recreate the same tree, while also
+giving them an idea of roughly how old the tree is (after version 1.2, before
+version 1.3). Many VCS systems can report a description that captures this,
+for example `git describe --tags --dirty --always` reports things like
+"0.7-1-g574ab98-dirty" to indicate that the checkout is one revision past the
+0.7 tag, has a unique revision id of "574ab98", and is "dirty" (it has
+uncommitted changes.
+
+The version identifier is used for multiple purposes:
+
+* to allow the module to self-identify its version: `myproject.__version__`
+* to choose a name and prefix for a 'setup.py sdist' tarball
+
+## Theory of Operation
+
+Versioneer works by adding a special `_version.py` file into your source
+tree, where your `__init__.py` can import it. This `_version.py` knows how to
+dynamically ask the VCS tool for version information at import time.
+
+`_version.py` also contains `$Revision$` markers, and the installation
+process marks `_version.py` to have this marker rewritten with a tag name
+during the `git archive` command. As a result, generated tarballs will
+contain enough information to get the proper version.
+
+To allow `setup.py` to compute a version too, a `versioneer.py` is added to
+the top level of your source tree, next to `setup.py` and the `setup.cfg`
+that configures it. This overrides several distutils/setuptools commands to
+compute the version when invoked, and changes `setup.py build` and `setup.py
+sdist` to replace `_version.py` with a small static file that contains just
+the generated version data.
+
+## Installation
+
+First, decide on values for the following configuration variables:
+
+* `VCS`: the version control system you use. Currently accepts "git".
+
+* `style`: the style of version string to be produced. See "Styles" below for
+  details. Defaults to "pep440", which looks like
+  `TAG[+DISTANCE.gSHORTHASH[.dirty]]`.
+
+* `versionfile_source`:
+
+  A project-relative pathname into which the generated version strings should
+  be written. This is usually a `_version.py` next to your project's main
+  `__init__.py` file, so it can be imported at runtime. If your project uses
+  `src/myproject/__init__.py`, this should be `src/myproject/_version.py`.
+  This file should be checked in to your VCS as usual: the copy created below
+  by `setup.py setup_versioneer` will include code that parses expanded VCS
+  keywords in generated tarballs. The 'build' and 'sdist' commands will
+  replace it with a copy that has just the calculated version string.
+
+  This must be set even if your project does not have any modules (and will
+  therefore never import `_version.py`), since "setup.py sdist" -based trees
+  still need somewhere to record the pre-calculated version strings. Anywhere
+  in the source tree should do. If there is a `__init__.py` next to your
+  `_version.py`, the `setup.py setup_versioneer` command (described below)
+  will append some `__version__`-setting assignments, if they aren't already
+  present.
+
+* `versionfile_build`:
+
+  Like `versionfile_source`, but relative to the build directory instead of
+  the source directory. These will differ when your setup.py uses
+  'package_dir='. If you have `package_dir={'myproject': 'src/myproject'}`,
+  then you will probably have `versionfile_build='myproject/_version.py'` and
+  `versionfile_source='src/myproject/_version.py'`.
+
+  If this is set to None, then `setup.py build` will not attempt to rewrite
+  any `_version.py` in the built tree. If your project does not have any
+  libraries (e.g. if it only builds a script), then you should use
+  `versionfile_build = None`. To actually use the computed version string,
+  your `setup.py` will need to override `distutils.command.build_scripts`
+  with a subclass that explicitly inserts a copy of
+  `versioneer.get_version()` into your script file. See
+  `test/demoapp-script-only/setup.py` for an example.
+
+* `tag_prefix`:
+
+  a string, like 'PROJECTNAME-', which appears at the start of all VCS tags.
+  If your tags look like 'myproject-1.2.0', then you should use
+  tag_prefix='myproject-'. If you use unprefixed tags like '1.2.0', this
+  should be an empty string, using either `tag_prefix=` or `tag_prefix=''`.
+
+* `parentdir_prefix`:
+
+  a optional string, frequently the same as tag_prefix, which appears at the
+  start of all unpacked tarball filenames. If your tarball unpacks into
+  'myproject-1.2.0', this should be 'myproject-'. To disable this feature,
+  just omit the field from your `setup.cfg`.
+
+This tool provides one script, named `versioneer`. That script has one mode,
+"install", which writes a copy of `versioneer.py` into the current directory
+and runs `versioneer.py setup` to finish the installation.
+
+To versioneer-enable your project:
+
+* 1: Modify your `setup.cfg`, adding a section named `[versioneer]` and
+  populating it with the configuration values you decided earlier (note that
+  the option names are not case-sensitive):
+
+  ````
+  [versioneer]
+  VCS = git
+  style = pep440
+  versionfile_source = src/myproject/_version.py
+  versionfile_build = myproject/_version.py
+  tag_prefix =
+  parentdir_prefix = myproject-
+  ````
+
+* 2: Run `versioneer install`. This will do the following:
+
+  * copy `versioneer.py` into the top of your source tree
+  * create `_version.py` in the right place (`versionfile_source`)
+  * modify your `__init__.py` (if one exists next to `_version.py`) to define
+    `__version__` (by calling a function from `_version.py`)
+  * modify your `MANIFEST.in` to include both `versioneer.py` and the
+    generated `_version.py` in sdist tarballs
+
+  `versioneer install` will complain about any problems it finds with your
+  `setup.py` or `setup.cfg`. Run it multiple times until you have fixed all
+  the problems.
+
+* 3: add a `import versioneer` to your setup.py, and add the following
+  arguments to the setup() call:
+
+        version=versioneer.get_version(),
+        cmdclass=versioneer.get_cmdclass(),
+
+* 4: commit these changes to your VCS. To make sure you won't forget,
+  `versioneer install` will mark everything it touched for addition using
+  `git add`. Don't forget to add `setup.py` and `setup.cfg` too.
+
+## Post-Installation Usage
+
+Once established, all uses of your tree from a VCS checkout should get the
+current version string. All generated tarballs should include an embedded
+version string (so users who unpack them will not need a VCS tool installed).
+
+If you distribute your project through PyPI, then the release process should
+boil down to two steps:
+
+* 1: git tag 1.0
+* 2: python setup.py register sdist upload
+
+If you distribute it through github (i.e. users use github to generate
+tarballs with `git archive`), the process is:
+
+* 1: git tag 1.0
+* 2: git push; git push --tags
+
+Versioneer will report "0+untagged.NUMCOMMITS.gHASH" until your tree has at
+least one tag in its history.
+
+## Version-String Flavors
+
+Code which uses Versioneer can learn about its version string at runtime by
+importing `_version` from your main `__init__.py` file and running the
+`get_versions()` function. From the "outside" (e.g. in `setup.py`), you can
+import the top-level `versioneer.py` and run `get_versions()`.
+
+Both functions return a dictionary with different flavors of version
+information:
+
+* `['version']`: A condensed version string, rendered using the selected
+  style. This is the most commonly used value for the project's version
+  string. The default "pep440" style yields strings like `0.11`,
+  `0.11+2.g1076c97`, or `0.11+2.g1076c97.dirty`. See the "Styles" section
+  below for alternative styles.
+
+* `['full-revisionid']`: detailed revision identifier. For Git, this is the
+  full SHA1 commit id, e.g. "1076c978a8d3cfc70f408fe5974aa6c092c949ac".
+
+* `['dirty']`: a boolean, True if the tree has uncommitted changes. Note that
+  this is only accurate if run in a VCS checkout, otherwise it is likely to
+  be False or None
+
+* `['error']`: if the version string could not be computed, this will be set
+  to a string describing the problem, otherwise it will be None. It may be
+  useful to throw an exception in setup.py if this is set, to avoid e.g.
+  creating tarballs with a version string of "unknown".
+
+Some variants are more useful than others. Including `full-revisionid` in a
+bug report should allow developers to reconstruct the exact code being tested
+(or indicate the presence of local changes that should be shared with the
+developers). `version` is suitable for display in an "about" box or a CLI
+`--version` output: it can be easily compared against release notes and lists
+of bugs fixed in various releases.
+
+The installer adds the following text to your `__init__.py` to place a basic
+version in `YOURPROJECT.__version__`:
+
+    from ._version import get_versions
+    __version__ = get_versions()['version']
+    del get_versions
+
+## Styles
+
+The setup.cfg `style=` configuration controls how the VCS information is
+rendered into a version string.
+
+The default style, "pep440", produces a PEP440-compliant string, equal to the
+un-prefixed tag name for actual releases, and containing an additional "local
+version" section with more detail for in-between builds. For Git, this is
+TAG[+DISTANCE.gHEX[.dirty]] , using information from `git describe --tags
+--dirty --always`. For example "0.11+2.g1076c97.dirty" indicates that the
+tree is like the "1076c97" commit but has uncommitted changes (".dirty"), and
+that this commit is two revisions ("+2") beyond the "0.11" tag. For released
+software (exactly equal to a known tag), the identifier will only contain the
+stripped tag, e.g. "0.11".
+
+Other styles are available. See details.md in the Versioneer source tree for
+descriptions.
+
+## Debugging
+
+Versioneer tries to avoid fatal errors: if something goes wrong, it will tend
+to return a version of "0+unknown". To investigate the problem, run `setup.py
+version`, which will run the version-lookup code in a verbose mode, and will
+display the full contents of `get_versions()` (including the `error` string,
+which may help identify what went wrong).
+
+## Updating Versioneer
+
+To upgrade your project to a new release of Versioneer, do the following:
+
+* install the new Versioneer (`pip install -U versioneer` or equivalent)
+* edit `setup.cfg`, if necessary, to include any new configuration settings
+  indicated by the release notes
+* re-run `versioneer install` in your source tree, to replace
+  `SRC/_version.py`
+* commit any changed files
+
+### Upgrading to 0.16
+
+Nothing special.
+
+### Upgrading to 0.15
+
+Starting with this version, Versioneer is configured with a `[versioneer]`
+section in your `setup.cfg` file. Earlier versions required the `setup.py` to
+set attributes on the `versioneer` module immediately after import. The new
+version will refuse to run (raising an exception during import) until you
+have provided the necessary `setup.cfg` section.
+
+In addition, the Versioneer package provides an executable named
+`versioneer`, and the installation process is driven by running `versioneer
+install`. In 0.14 and earlier, the executable was named
+`versioneer-installer` and was run without an argument.
+
+### Upgrading to 0.14
 
-import os, sys, re
-from distutils.core import Command
-from distutils.command.sdist import sdist as _sdist
-from distutils.command.build import build as _build
+0.14 changes the format of the version string. 0.13 and earlier used
+hyphen-separated strings like "0.11-2-g1076c97-dirty". 0.14 and beyond use a
+plus-separated "local version" section strings, with dot-separated
+components, like "0.11+2.g1076c97". PEP440-strict tools did not like the old
+format, but should be ok with the new one.
 
-versionfile_source = None
-versionfile_build = None
-tag_prefix = None
-parentdir_prefix = None
+### Upgrading from 0.11 to 0.12
 
-VCS = "git"
-IN_LONG_VERSION_PY = False
+Nothing special.
 
+### Upgrading from 0.10 to 0.11
 
-LONG_VERSION_PY = '''
-IN_LONG_VERSION_PY = True
+You must add a `versioneer.VCS = "git"` to your `setup.py` before re-running
+`setup.py setup_versioneer`. This will enable the use of additional
+version-control systems (SVN, etc) in the future.
+
+## Future Directions
+
+This tool is designed to make it easily extended to other version-control
+systems: all VCS-specific components are in separate directories like
+src/git/ . The top-level `versioneer.py` script is assembled from these
+components by running make-versioneer.py . In the future, make-versioneer.py
+will take a VCS name as an argument, and will construct a version of
+`versioneer.py` that is specific to the given VCS. It might also take the
+configuration arguments that are currently provided manually during
+installation by editing setup.py . Alternatively, it might go the other
+direction and include code from all supported VCS systems, reducing the
+number of intermediate scripts.
+
+
+## License
+
+To make Versioneer easier to embed, all its code is dedicated to the public
+domain. The `_version.py` that it creates is also in the public domain.
+Specifically, both are released under the Creative Commons "Public Domain
+Dedication" license (CC0-1.0), as described in
+https://creativecommons.org/publicdomain/zero/1.0/ .
+
+"""
+
+from __future__ import print_function
+try:
+    import configparser
+except ImportError:
+    import ConfigParser as configparser
+import errno
+import json
+import os
+import re
+import subprocess
+import sys
+
+
+class VersioneerConfig:
+    """Container for Versioneer configuration parameters."""
+
+
+def get_root():
+    """Get the project root directory.
+
+    We require that all commands are run from the project root, i.e. the
+    directory that contains setup.py, setup.cfg, and versioneer.py .
+    """
+    root = os.path.realpath(os.path.abspath(os.getcwd()))
+    setup_py = os.path.join(root, "setup.py")
+    versioneer_py = os.path.join(root, "versioneer.py")
+    if not (os.path.exists(setup_py) or os.path.exists(versioneer_py)):
+        # allow 'python path/to/setup.py COMMAND'
+        root = os.path.dirname(os.path.realpath(os.path.abspath(sys.argv[0])))
+        setup_py = os.path.join(root, "setup.py")
+        versioneer_py = os.path.join(root, "versioneer.py")
+    if not (os.path.exists(setup_py) or os.path.exists(versioneer_py)):
+        err = ("Versioneer was unable to run the project root directory. "
+               "Versioneer requires setup.py to be executed from "
+               "its immediate directory (like 'python setup.py COMMAND'), "
+               "or in a way that lets it use sys.argv[0] to find the root "
+               "(like 'python path/to/setup.py COMMAND').")
+        raise VersioneerBadRootError(err)
+    try:
+        # Certain runtime workflows (setup.py install/develop in a setuptools
+        # tree) execute all dependencies in a single python process, so
+        # "versioneer" may be imported multiple times, and python's shared
+        # module-import table will cache the first one. So we can't use
+        # os.path.dirname(__file__), as that will find whichever
+        # versioneer.py was first imported, even in later projects.
+        me = os.path.realpath(os.path.abspath(__file__))
+        if os.path.splitext(me)[0] != os.path.splitext(versioneer_py)[0]:
+            print("Warning: build in %s is using versioneer.py from %s"
+                  % (os.path.dirname(me), versioneer_py))
+    except NameError:
+        pass
+    return root
+
+
+def get_config_from_root(root):
+    """Read the project setup.cfg file to determine Versioneer config."""
+    # This might raise EnvironmentError (if setup.cfg is missing), or
+    # configparser.NoSectionError (if it lacks a [versioneer] section), or
+    # configparser.NoOptionError (if it lacks "VCS="). See the docstring at
+    # the top of versioneer.py for instructions on writing your setup.cfg .
+    setup_cfg = os.path.join(root, "setup.cfg")
+    parser = configparser.SafeConfigParser()
+    with open(setup_cfg, "r") as f:
+        parser.readfp(f)
+    VCS = parser.get("versioneer", "VCS")  # mandatory
+
+    def get(parser, name):
+        if parser.has_option("versioneer", name):
+            return parser.get("versioneer", name)
+        return None
+    cfg = VersioneerConfig()
+    cfg.VCS = VCS
+    cfg.style = get(parser, "style") or ""
+    cfg.versionfile_source = get(parser, "versionfile_source")
+    cfg.versionfile_build = get(parser, "versionfile_build")
+    cfg.tag_prefix = get(parser, "tag_prefix")
+    if cfg.tag_prefix in ("''", '""'):
+        cfg.tag_prefix = ""
+    cfg.parentdir_prefix = get(parser, "parentdir_prefix")
+    cfg.verbose = get(parser, "verbose")
+    return cfg
+
+
+class NotThisMethod(Exception):
+    """Exception raised if a method is not valid for the current scenario."""
+
+# these dictionaries contain VCS-specific tools
+LONG_VERSION_PY = {}
+HANDLERS = {}
+
+
+def register_vcs_handler(vcs, method):  # decorator
+    """Decorator to mark a method as the handler for a particular VCS."""
+    def decorate(f):
+        """Store f in HANDLERS[vcs][method]."""
+        if vcs not in HANDLERS:
+            HANDLERS[vcs] = {}
+        HANDLERS[vcs][method] = f
+        return f
+    return decorate
+
+
+def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False):
+    """Call the given command(s)."""
+    assert isinstance(commands, list)
+    p = None
+    for c in commands:
+        try:
+            dispcmd = str([c] + args)
+            # remember shell=False, so use git.cmd on windows, not just git
+            p = subprocess.Popen([c] + args, cwd=cwd, stdout=subprocess.PIPE,
+                                 stderr=(subprocess.PIPE if hide_stderr
+                                         else None))
+            break
+        except EnvironmentError:
+            e = sys.exc_info()[1]
+            if e.errno == errno.ENOENT:
+                continue
+            if verbose:
+                print("unable to run %s" % dispcmd)
+                print(e)
+            return None
+    else:
+        if verbose:
+            print("unable to find command, tried %s" % (commands,))
+        return None
+    stdout = p.communicate()[0].strip()
+    if sys.version_info[0] >= 3:
+        stdout = stdout.decode()
+    if p.returncode != 0:
+        if verbose:
+            print("unable to run %s (error)" % dispcmd)
+        return None
+    return stdout
+LONG_VERSION_PY['git'] = '''
 # This file helps to compute a version number in source trees obtained from
 # git-archive tarball (such as those provided by githubs download-from-tag
-# feature). Distribution tarballs (build by setup.py sdist) and build
+# feature). Distribution tarballs (built by setup.py sdist) and build
 # directories (produced by setup.py build) will contain a much shorter file
 # that just contains the computed version number.
 
 # This file is released into the public domain. Generated by
-# versioneer-0.7+ (https://github.com/warner/python-versioneer)
-
-# these strings will be replaced by git during git-archive
-git_refnames = "%(DOLLAR)sFormat:%%d%(DOLLAR)s"
-git_full = "%(DOLLAR)sFormat:%%H%(DOLLAR)s"
+# versioneer-0.16 (https://github.com/warner/python-versioneer)
 
+"""Git implementation of _version.py."""
 
+import errno
+import os
+import re
 import subprocess
 import sys
 
-def run_command(args, cwd=None, verbose=False):
-    try:
-        # remember shell=False, so use git.exe on windows, not just git
-        p = subprocess.Popen(args, stdout=subprocess.PIPE, cwd=cwd)
-    except EnvironmentError:
-        e = sys.exc_info()[1]
+
+def get_keywords():
+    """Get the keywords needed to look up the version information."""
+    # these strings will be replaced by git during git-archive.
+    # setup.py/versioneer.py will grep for the variable names, so they must
+    # each be defined on a line of their own. _version.py will just call
+    # get_keywords().
+    git_refnames = "%(DOLLAR)sFormat:%%d%(DOLLAR)s"
+    git_full = "%(DOLLAR)sFormat:%%H%(DOLLAR)s"
+    keywords = {"refnames": git_refnames, "full": git_full}
+    return keywords
+
+
+class VersioneerConfig:
+    """Container for Versioneer configuration parameters."""
+
+
+def get_config():
+    """Create, populate and return the VersioneerConfig() object."""
+    # these strings are filled in when 'setup.py versioneer' creates
+    # _version.py
+    cfg = VersioneerConfig()
+    cfg.VCS = "git"
+    cfg.style = "%(STYLE)s"
+    cfg.tag_prefix = "%(TAG_PREFIX)s"
+    cfg.parentdir_prefix = "%(PARENTDIR_PREFIX)s"
+    cfg.versionfile_source = "%(VERSIONFILE_SOURCE)s"
+    cfg.verbose = False
+    return cfg
+
+
+class NotThisMethod(Exception):
+    """Exception raised if a method is not valid for the current scenario."""
+
+
+LONG_VERSION_PY = {}
+HANDLERS = {}
+
+
+def register_vcs_handler(vcs, method):  # decorator
+    """Decorator to mark a method as the handler for a particular VCS."""
+    def decorate(f):
+        """Store f in HANDLERS[vcs][method]."""
+        if vcs not in HANDLERS:
+            HANDLERS[vcs] = {}
+        HANDLERS[vcs][method] = f
+        return f
+    return decorate
+
+
+def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False):
+    """Call the given command(s)."""
+    assert isinstance(commands, list)
+    p = None
+    for c in commands:
+        try:
+            dispcmd = str([c] + args)
+            # remember shell=False, so use git.cmd on windows, not just git
+            p = subprocess.Popen([c] + args, cwd=cwd, stdout=subprocess.PIPE,
+                                 stderr=(subprocess.PIPE if hide_stderr
+                                         else None))
+            break
+        except EnvironmentError:
+            e = sys.exc_info()[1]
+            if e.errno == errno.ENOENT:
+                continue
+            if verbose:
+                print("unable to run %%s" %% dispcmd)
+                print(e)
+            return None
+    else:
         if verbose:
-            print("unable to run %%s" %% args[0])
-            print(e)
+            print("unable to find command, tried %%s" %% (commands,))
         return None
     stdout = p.communicate()[0].strip()
-    if sys.version >= '3':
+    if sys.version_info[0] >= 3:
         stdout = stdout.decode()
     if p.returncode != 0:
         if verbose:
-            print("unable to run %%s (error)" %% args[0])
+            print("unable to run %%s (error)" %% dispcmd)
         return None
     return stdout
 
 
-import sys
-import re
-import os.path
+def versions_from_parentdir(parentdir_prefix, root, verbose):
+    """Try to determine the version from the parent directory name.
+
+    Source tarballs conventionally unpack into a directory that includes
+    both the project name and a version string.
+    """
+    dirname = os.path.basename(root)
+    if not dirname.startswith(parentdir_prefix):
+        if verbose:
+            print("guessing rootdir is '%%s', but '%%s' doesn't start with "
+                  "prefix '%%s'" %% (root, dirname, parentdir_prefix))
+        raise NotThisMethod("rootdir doesn't start with parentdir_prefix")
+    return {"version": dirname[len(parentdir_prefix):],
+            "full-revisionid": None,
+            "dirty": False, "error": None}
+
 
-def get_expanded_variables(versionfile_source):
+@register_vcs_handler("git", "get_keywords")
+def git_get_keywords(versionfile_abs):
+    """Extract version information from the given file."""
     # the code embedded in _version.py can just fetch the value of these
-    # variables. When used from setup.py, we don't want to import
-    # _version.py, so we do it with a regexp instead. This function is not
-    # used from _version.py.
-    variables = {}
+    # keywords. When used from setup.py, we don't want to import _version.py,
+    # so we do it with a regexp instead. This function is not used from
+    # _version.py.
+    keywords = {}
     try:
-        f = open(versionfile_source,"r")
+        f = open(versionfile_abs, "r")
         for line in f.readlines():
             if line.strip().startswith("git_refnames ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["refnames"] = mo.group(1)
+                    keywords["refnames"] = mo.group(1)
             if line.strip().startswith("git_full ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["full"] = mo.group(1)
+                    keywords["full"] = mo.group(1)
         f.close()
     except EnvironmentError:
         pass
-    return variables
+    return keywords
 
-def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
-    refnames = variables["refnames"].strip()
+
+@register_vcs_handler("git", "keywords")
+def git_versions_from_keywords(keywords, tag_prefix, verbose):
+    """Get version information from git keywords."""
+    if not keywords:
+        raise NotThisMethod("no keywords at all, weird")
+    refnames = keywords["refnames"].strip()
     if refnames.startswith("$Format"):
         if verbose:
-            print("variables are unexpanded, not using")
-        return {} # unexpanded, so not in an unpacked git-archive tarball
+            print("keywords are unexpanded, not using")
+        raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
     refs = set([r.strip() for r in refnames.strip("()").split(",")])
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
@@ -189,172 +660,350 @@ def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
             r = ref[len(tag_prefix):]
             if verbose:
                 print("picking %%s" %% r)
-            return { "version": r,
-                     "full": variables["full"].strip() }
-    # no suitable tags, so we use the full revision id
+            return {"version": r,
+                    "full-revisionid": keywords["full"].strip(),
+                    "dirty": False, "error": None
+                    }
+    # no suitable tags, so version is "0+unknown", but full hex is still there
     if verbose:
-        print("no suitable tags, using full revision id")
-    return { "version": variables["full"].strip(),
-             "full": variables["full"].strip() }
-
-def versions_from_vcs(tag_prefix, versionfile_source, verbose=False):
-    # this runs 'git' from the root of the source tree. That either means
-    # someone ran a setup.py command (and this code is in versioneer.py, so
-    # IN_LONG_VERSION_PY=False, thus the containing directory is the root of
-    # the source tree), or someone ran a project-specific entry point (and
-    # this code is in _version.py, so IN_LONG_VERSION_PY=True, thus the
-    # containing directory is somewhere deeper in the source tree). This only
-    # gets called if the git-archive 'subst' variables were *not* expanded,
-    # and _version.py hasn't already been rewritten with a short version
-    # string, meaning we're inside a checked out source tree.
+        print("no suitable tags, using unknown + full revision id")
+    return {"version": "0+unknown",
+            "full-revisionid": keywords["full"].strip(),
+            "dirty": False, "error": "no suitable tags"}
 
-    try:
-        here = os.path.abspath(__file__)
-    except NameError:
-        # some py2exe/bbfreeze/non-CPython implementations don't do __file__
-        return {} # not always correct
-
-    # versionfile_source is the relative path from the top of the source tree
-    # (where the .git directory might live) to this file. Invert this to find
-    # the root from __file__.
-    root = here
-    if IN_LONG_VERSION_PY:
-        for i in range(len(versionfile_source.split("/"))):
-            root = os.path.dirname(root)
-    else:
-        root = os.path.dirname(here)
-    if not os.path.exists(os.path.join(root, ".git")):
+
+@register_vcs_handler("git", "pieces_from_vcs")
+def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+    """Get version from 'git describe' in the root of the source tree.
+
+    This only gets called if the git-archive 'subst' keywords were *not*
+    expanded, and _version.py hasn't already been rewritten with a short
+    version string, meaning we're inside a checked out source tree.
+    """
+    if not os.path.exists(os.path.join(root, "..", ".git")):
         if verbose:
             print("no .git in %%s" %% root)
-        return {}
+        raise NotThisMethod("no .git directory")
 
-    GIT = "git"
+    GITS = ["git"]
     if sys.platform == "win32":
-        GIT = "git.exe"
-    stdout = run_command([GIT, "describe", "--tags", "--dirty", "--always"],
-                         cwd=root)
-    if stdout is None:
-        return {}
-    if not stdout.startswith(tag_prefix):
-        if verbose:
-            print("tag '%%s' doesn't start with prefix '%%s'" %% (stdout, tag_prefix))
-        return {}
-    tag = stdout[len(tag_prefix):]
-    stdout = run_command([GIT, "rev-parse", "HEAD"], cwd=root)
-    if stdout is None:
-        return {}
-    full = stdout.strip()
-    if tag.endswith("-dirty"):
-        full += "-dirty"
-    return {"version": tag, "full": full}
-
-
-def versions_from_parentdir(parentdir_prefix, versionfile_source, verbose=False):
-    if IN_LONG_VERSION_PY:
-        # We're running from _version.py. If it's from a source tree
-        # (execute-in-place), we can work upwards to find the root of the
-        # tree, and then check the parent directory for a version string. If
-        # it's in an installed application, there's no hope.
-        try:
-            here = os.path.abspath(__file__)
-        except NameError:
-            # py2exe/bbfreeze/non-CPython don't have __file__
-            return {} # without __file__, we have no hope
-        # versionfile_source is the relative path from the top of the source
-        # tree to _version.py. Invert this to find the root from __file__.
-        root = here
-        for i in range(len(versionfile_source.split("/"))):
-            root = os.path.dirname(root)
+        GITS = ["git.cmd", "git.exe"]
+    # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
+    # if there isn't one, this yields HEX[-dirty] (no NUM)
+    describe_out = run_command(GITS, ["describe", "--tags", "--dirty",
+                                      "--always", "--long",
+                                      "--match", "%%s*" %% tag_prefix],
+                               cwd=root)
+    # --long was added in git-1.5.5
+    if describe_out is None:
+        raise NotThisMethod("'git describe' failed")
+    describe_out = describe_out.strip()
+    full_out = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    if full_out is None:
+        raise NotThisMethod("'git rev-parse' failed")
+    full_out = full_out.strip()
+
+    pieces = {}
+    pieces["long"] = full_out
+    pieces["short"] = full_out[:7]  # maybe improved later
+    pieces["error"] = None
+
+    # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
+    # TAG might have hyphens.
+    git_describe = describe_out
+
+    # look for -dirty suffix
+    dirty = git_describe.endswith("-dirty")
+    pieces["dirty"] = dirty
+    if dirty:
+        git_describe = git_describe[:git_describe.rindex("-dirty")]
+
+    # now we have TAG-NUM-gHEX or HEX
+
+    if "-" in git_describe:
+        # TAG-NUM-gHEX
+        mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
+        if not mo:
+            # unparseable. Maybe git-describe is misbehaving?
+            pieces["error"] = ("unable to parse git-describe output: '%%s'"
+                               %% describe_out)
+            return pieces
+
+        # tag
+        full_tag = mo.group(1)
+        if not full_tag.startswith(tag_prefix):
+            if verbose:
+                fmt = "tag '%%s' doesn't start with prefix '%%s'"
+                print(fmt %% (full_tag, tag_prefix))
+            pieces["error"] = ("tag '%%s' doesn't start with prefix '%%s'"
+                               %% (full_tag, tag_prefix))
+            return pieces
+        pieces["closest-tag"] = full_tag[len(tag_prefix):]
+
+        # distance: number of commits since tag
+        pieces["distance"] = int(mo.group(2))
+
+        # commit: short hex revision ID
+        pieces["short"] = mo.group(3)
+
+    else:
+        # HEX: no tags
+        pieces["closest-tag"] = None
+        count_out = run_command(GITS, ["rev-list", "HEAD", "--count"],
+                                cwd=root)
+        pieces["distance"] = int(count_out)  # total number of commits
+
+    return pieces
+
+
+def plus_or_dot(pieces):
+    """Return a + if we don't already have one, else return a ."""
+    if "+" in pieces.get("closest-tag", ""):
+        return "."
+    return "+"
+
+
+def render_pep440(pieces):
+    """Build up version string, with post-release "local version identifier".
+
+    Our goal: TAG[+DISTANCE.gHEX[.dirty]] . Note that if you
+    get a tagged build and then dirty it, you'll get TAG+0.gHEX.dirty
+
+    Exceptions:
+    1: no tags. git_describe was just HEX. 0+untagged.DISTANCE.gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += plus_or_dot(pieces)
+            rendered += "%%d.g%%s" %% (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
     else:
-        # we're running from versioneer.py, which means we're running from
-        # the setup.py in a source tree. sys.argv[0] is setup.py in the root.
-        here = os.path.abspath(sys.argv[0])
-        root = os.path.dirname(here)
+        # exception #1
+        rendered = "0+untagged.%%d.g%%s" %% (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def render_pep440_pre(pieces):
+    """TAG[.post.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post.devDISTANCE
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += ".post.dev%%d" %% pieces["distance"]
+    else:
+        # exception #1
+        rendered = "0.post.dev%%d" %% pieces["distance"]
+    return rendered
+
+
+def render_pep440_post(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX] .
+
+    The ".dev0" means dirty. Note that .dev0 sorts backwards
+    (a dirty tree will appear "older" than the corresponding clean one),
+    but you shouldn't be releasing software with -dirty anyways.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%%d" %% pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%%s" %% pieces["short"]
+    else:
+        # exception #1
+        rendered = "0.post%%d" %% pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+        rendered += "+g%%s" %% pieces["short"]
+    return rendered
+
+
+def render_pep440_old(pieces):
+    """TAG[.postDISTANCE[.dev0]] .
+
+    The ".dev0" means dirty.
+
+    Eexceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%%d" %% pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+    else:
+        # exception #1
+        rendered = "0.post%%d" %% pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+    return rendered
 
-    # Source tarballs conventionally unpack into a directory that includes
-    # both the project name and a version string.
-    dirname = os.path.basename(root)
-    if not dirname.startswith(parentdir_prefix):
-        if verbose:
-            print("guessing rootdir is '%%s', but '%%s' doesn't start with prefix '%%s'" %%
-                  (root, dirname, parentdir_prefix))
-        return None
-    return {"version": dirname[len(parentdir_prefix):], "full": ""}
-
-tag_prefix = "%(TAG_PREFIX)s"
-parentdir_prefix = "%(PARENTDIR_PREFIX)s"
-versionfile_source = "%(VERSIONFILE_SOURCE)s"
-
-def get_versions(default={"version": "unknown", "full": ""}, verbose=False):
-    variables = { "refnames": git_refnames, "full": git_full }
-    ver = versions_from_expanded_variables(variables, tag_prefix, verbose)
-    if not ver:
-        ver = versions_from_vcs(tag_prefix, versionfile_source, verbose)
-    if not ver:
-        ver = versions_from_parentdir(parentdir_prefix, versionfile_source,
-                                      verbose)
-    if not ver:
-        ver = default
-    return ver
 
-'''
+def render_git_describe(pieces):
+    """TAG[-DISTANCE-gHEX][-dirty].
 
+    Like 'git describe --tags --dirty --always'.
 
-import subprocess
-import sys
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += "-%%d-g%%s" %% (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render_git_describe_long(pieces):
+    """TAG-DISTANCE-gHEX[-dirty].
+
+    Like 'git describe --tags --dirty --always -long'.
+    The distance/hash is unconditional.
+
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        rendered += "-%%d-g%%s" %% (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render(pieces, style):
+    """Render the given version pieces into the requested style."""
+    if pieces["error"]:
+        return {"version": "unknown",
+                "full-revisionid": pieces.get("long"),
+                "dirty": None,
+                "error": pieces["error"]}
+
+    if not style or style == "default":
+        style = "pep440"  # the default
+
+    if style == "pep440":
+        rendered = render_pep440(pieces)
+    elif style == "pep440-pre":
+        rendered = render_pep440_pre(pieces)
+    elif style == "pep440-post":
+        rendered = render_pep440_post(pieces)
+    elif style == "pep440-old":
+        rendered = render_pep440_old(pieces)
+    elif style == "git-describe":
+        rendered = render_git_describe(pieces)
+    elif style == "git-describe-long":
+        rendered = render_git_describe_long(pieces)
+    else:
+        raise ValueError("unknown style '%%s'" %% style)
+
+    return {"version": rendered, "full-revisionid": pieces["long"],
+            "dirty": pieces["dirty"], "error": None}
+
+
+def get_versions():
+    """Get version information or return default if unable to do so."""
+    # I am in _version.py, which lives at ROOT/VERSIONFILE_SOURCE. If we have
+    # __file__, we can work backwards from there to the root. Some
+    # py2exe/bbfreeze/non-CPython implementations don't do __file__, in which
+    # case we can only use expanded keywords.
+
+    cfg = get_config()
+    verbose = cfg.verbose
 
-def run_command(args, cwd=None, verbose=False):
     try:
-        # remember shell=False, so use git.exe on windows, not just git
-        p = subprocess.Popen(args, stdout=subprocess.PIPE, cwd=cwd)
-    except EnvironmentError:
-        e = sys.exc_info()[1]
-        if verbose:
-            print("unable to run %s" % args[0])
-            print(e)
-        return None
-    stdout = p.communicate()[0].strip()
-    if sys.version >= '3':
-        stdout = stdout.decode()
-    if p.returncode != 0:
-        if verbose:
-            print("unable to run %s (error)" % args[0])
-        return None
-    return stdout
+        return git_versions_from_keywords(get_keywords(), cfg.tag_prefix,
+                                          verbose)
+    except NotThisMethod:
+        pass
 
+    try:
+        root = os.path.realpath(__file__)
+        # versionfile_source is the relative path from the top of the source
+        # tree (where the .git directory might live) to this file. Invert
+        # this to find the root from __file__.
+        for i in cfg.versionfile_source.split('/'):
+            root = os.path.dirname(root)
+    except NameError:
+        return {"version": "0+unknown", "full-revisionid": None,
+                "dirty": None,
+                "error": "unable to find root of source tree"}
 
-import sys
-import re
-import os.path
+    try:
+        pieces = git_pieces_from_vcs(cfg.tag_prefix, root, verbose)
+        return render(pieces, cfg.style)
+    except NotThisMethod:
+        pass
 
-def get_expanded_variables(versionfile_source):
+    try:
+        if cfg.parentdir_prefix:
+            return versions_from_parentdir(cfg.parentdir_prefix, root, verbose)
+    except NotThisMethod:
+        pass
+
+    return {"version": "0+unknown", "full-revisionid": None,
+            "dirty": None,
+            "error": "unable to compute version"}
+'''
+
+
+@register_vcs_handler("git", "get_keywords")
+def git_get_keywords(versionfile_abs):
+    """Extract version information from the given file."""
     # the code embedded in _version.py can just fetch the value of these
-    # variables. When used from setup.py, we don't want to import
-    # _version.py, so we do it with a regexp instead. This function is not
-    # used from _version.py.
-    variables = {}
+    # keywords. When used from setup.py, we don't want to import _version.py,
+    # so we do it with a regexp instead. This function is not used from
+    # _version.py.
+    keywords = {}
     try:
-        f = open(versionfile_source,"r")
+        f = open(versionfile_abs, "r")
         for line in f.readlines():
             if line.strip().startswith("git_refnames ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["refnames"] = mo.group(1)
+                    keywords["refnames"] = mo.group(1)
             if line.strip().startswith("git_full ="):
                 mo = re.search(r'=\s*"(.*)"', line)
                 if mo:
-                    variables["full"] = mo.group(1)
+                    keywords["full"] = mo.group(1)
         f.close()
     except EnvironmentError:
         pass
-    return variables
+    return keywords
 
-def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
-    refnames = variables["refnames"].strip()
+
+@register_vcs_handler("git", "keywords")
+def git_versions_from_keywords(keywords, tag_prefix, verbose):
+    """Get version information from git keywords."""
+    if not keywords:
+        raise NotThisMethod("no keywords at all, weird")
+    refnames = keywords["refnames"].strip()
     if refnames.startswith("$Format"):
         if verbose:
-            print("variables are unexpanded, not using")
-        return {} # unexpanded, so not in an unpacked git-archive tarball
+            print("keywords are unexpanded, not using")
+        raise NotThisMethod("unexpanded keywords, not a git-archive tarball")
     refs = set([r.strip() for r in refnames.strip("()").split(",")])
     # starting in git-1.8.3, tags are listed as "tag: foo-1.0" instead of
     # just "foo-1.0". If we see a "tag: " prefix, prefer those.
@@ -379,117 +1028,122 @@ def versions_from_expanded_variables(variables, tag_prefix, verbose=False):
             r = ref[len(tag_prefix):]
             if verbose:
                 print("picking %s" % r)
-            return { "version": r,
-                     "full": variables["full"].strip() }
-    # no suitable tags, so we use the full revision id
+            return {"version": r,
+                    "full-revisionid": keywords["full"].strip(),
+                    "dirty": False, "error": None
+                    }
+    # no suitable tags, so version is "0+unknown", but full hex is still there
     if verbose:
-        print("no suitable tags, using full revision id")
-    return { "version": variables["full"].strip(),
-             "full": variables["full"].strip() }
-
-def versions_from_vcs(tag_prefix, versionfile_source, verbose=False):
-    # this runs 'git' from the root of the source tree. That either means
-    # someone ran a setup.py command (and this code is in versioneer.py, so
-    # IN_LONG_VERSION_PY=False, thus the containing directory is the root of
-    # the source tree), or someone ran a project-specific entry point (and
-    # this code is in _version.py, so IN_LONG_VERSION_PY=True, thus the
-    # containing directory is somewhere deeper in the source tree). This only
-    # gets called if the git-archive 'subst' variables were *not* expanded,
-    # and _version.py hasn't already been rewritten with a short version
-    # string, meaning we're inside a checked out source tree.
+        print("no suitable tags, using unknown + full revision id")
+    return {"version": "0+unknown",
+            "full-revisionid": keywords["full"].strip(),
+            "dirty": False, "error": "no suitable tags"}
 
-    try:
-        here = os.path.abspath(__file__)
-    except NameError:
-        # some py2exe/bbfreeze/non-CPython implementations don't do __file__
-        return {} # not always correct
-
-    # versionfile_source is the relative path from the top of the source tree
-    # (where the .git directory might live) to this file. Invert this to find
-    # the root from __file__.
-    root = os.path.dirname(
-        os.path.join('..', here))
-    if IN_LONG_VERSION_PY:
-        for i in range(len(versionfile_source.split("/"))):
-            root = os.path.dirname(root)
-    else:
-        root = os.path.dirname(
-            os.path.join('..', here))
 
-    ######################################################
-    # XXX patch for our specific configuration with
-    # the three projects leap.soledad.{common, client, server}
-    # inside the same repo.
-    ######################################################
-    root = os.path.dirname(os.path.join('..', root))
+@register_vcs_handler("git", "pieces_from_vcs")
+def git_pieces_from_vcs(tag_prefix, root, verbose, run_command=run_command):
+    """Get version from 'git describe' in the root of the source tree.
 
-    if not os.path.exists(os.path.join(root, ".git")):
+    This only gets called if the git-archive 'subst' keywords were *not*
+    expanded, and _version.py hasn't already been rewritten with a short
+    version string, meaning we're inside a checked out source tree.
+    """
+    if not os.path.exists(os.path.join(root, "..", ".git")):
         if verbose:
             print("no .git in %s" % root)
-        return {}
+        raise NotThisMethod("no .git directory")
 
-    GIT = "git"
+    GITS = ["git"]
     if sys.platform == "win32":
-        GIT = "git.exe"
-    stdout = run_command([GIT, "describe", "--tags", "--dirty", "--always"],
-                         cwd=root)
-    if stdout is None:
-        return {}
-    if not stdout.startswith(tag_prefix):
-        if verbose:
-            print("tag '%s' doesn't start with prefix '%s'" % (stdout, tag_prefix))
-        return {}
-    tag = stdout[len(tag_prefix):]
-    stdout = run_command([GIT, "rev-parse", "HEAD"], cwd=root)
-    if stdout is None:
-        return {}
-    full = stdout.strip()
-    if tag.endswith("-dirty"):
-        full += "-dirty"
-    return {"version": tag, "full": full}
-
-
-def versions_from_parentdir(parentdir_prefix, versionfile_source, verbose=False):
-    if IN_LONG_VERSION_PY:
-        # We're running from _version.py. If it's from a source tree
-        # (execute-in-place), we can work upwards to find the root of the
-        # tree, and then check the parent directory for a version string. If
-        # it's in an installed application, there's no hope.
-        try:
-            here = os.path.abspath(os.path.join('..', __file__))
-        except NameError:
-            # py2exe/bbfreeze/non-CPython don't have __file__
-            return {} # without __file__, we have no hope
-        # versionfile_source is the relative path from the top of the source
-        # tree to _version.py. Invert this to find the root from __file__.
-        root = here
-        for i in range(len(versionfile_source.split("/"))):
-            root = os.path.dirname(root)
+        GITS = ["git.cmd", "git.exe"]
+    # if there is a tag matching tag_prefix, this yields TAG-NUM-gHEX[-dirty]
+    # if there isn't one, this yields HEX[-dirty] (no NUM)
+    describe_out = run_command(GITS, ["describe", "--tags", "--dirty",
+                                      "--always", "--long",
+                                      "--match", "%s*" % tag_prefix],
+                               cwd=root)
+    # --long was added in git-1.5.5
+    if describe_out is None:
+        raise NotThisMethod("'git describe' failed")
+    describe_out = describe_out.strip()
+    full_out = run_command(GITS, ["rev-parse", "HEAD"], cwd=root)
+    if full_out is None:
+        raise NotThisMethod("'git rev-parse' failed")
+    full_out = full_out.strip()
+
+    pieces = {}
+    pieces["long"] = full_out
+    pieces["short"] = full_out[:7]  # maybe improved later
+    pieces["error"] = None
+
+    # parse describe_out. It will be like TAG-NUM-gHEX[-dirty] or HEX[-dirty]
+    # TAG might have hyphens.
+    git_describe = describe_out
+
+    # look for -dirty suffix
+    dirty = git_describe.endswith("-dirty")
+    pieces["dirty"] = dirty
+    if dirty:
+        git_describe = git_describe[:git_describe.rindex("-dirty")]
+
+    # now we have TAG-NUM-gHEX or HEX
+
+    if "-" in git_describe:
+        # TAG-NUM-gHEX
+        mo = re.search(r'^(.+)-(\d+)-g([0-9a-f]+)$', git_describe)
+        if not mo:
+            # unparseable. Maybe git-describe is misbehaving?
+            pieces["error"] = ("unable to parse git-describe output: '%s'"
+                               % describe_out)
+            return pieces
+
+        # tag
+        full_tag = mo.group(1)
+        if not full_tag.startswith(tag_prefix):
+            if verbose:
+                fmt = "tag '%s' doesn't start with prefix '%s'"
+                print(fmt % (full_tag, tag_prefix))
+            pieces["error"] = ("tag '%s' doesn't start with prefix '%s'"
+                               % (full_tag, tag_prefix))
+            return pieces
+        pieces["closest-tag"] = full_tag[len(tag_prefix):]
+
+        # distance: number of commits since tag
+        pieces["distance"] = int(mo.group(2))
+
+        # commit: short hex revision ID
+        pieces["short"] = mo.group(3)
+
     else:
-        # we're running from versioneer.py, which means we're running from
-        # the setup.py in a source tree. sys.argv[0] is setup.py in the root.
-        here = os.path.abspath(sys.argv[0])
-        root = os.path.dirname(here)
+        # HEX: no tags
+        pieces["closest-tag"] = None
+        count_out = run_command(GITS, ["rev-list", "HEAD", "--count"],
+                                cwd=root)
+        pieces["distance"] = int(count_out)  # total number of commits
 
-    # Source tarballs conventionally unpack into a directory that includes
-    # both the project name and a version string.
-    dirname = os.path.basename(root)
-    if not dirname.startswith(parentdir_prefix):
-        if verbose:
-            print("guessing rootdir is '%s', but '%s' doesn't start with prefix '%s'" %
-                  (root, dirname, parentdir_prefix))
-        return None
-    return {"version": dirname[len(parentdir_prefix):], "full": ""}
+    return pieces
 
-import sys
 
-def do_vcs_install(versionfile_source, ipy):
-    GIT = "git"
+def do_vcs_install(manifest_in, versionfile_source, ipy):
+    """Git-specific installation logic for Versioneer.
+
+    For Git, this means creating/changing .gitattributes to mark _version.py
+    for export-time keyword substitution.
+    """
+    GITS = ["git"]
     if sys.platform == "win32":
-        GIT = "git.exe"
-    run_command([GIT, "add", "versioneer.py"])
-    run_command([GIT, "add", versionfile_source])
-    run_command([GIT, "add", ipy])
+        GITS = ["git.cmd", "git.exe"]
+    files = [manifest_in, versionfile_source]
+    if ipy:
+        files.append(ipy)
+    try:
+        me = __file__
+        if me.endswith(".pyc") or me.endswith(".pyo"):
+            me = os.path.splitext(me)[0] + ".py"
+        versioneer_file = os.path.relpath(me)
+    except NameError:
+        versioneer_file = "versioneer.py"
+    files.append(versioneer_file)
     present = False
     try:
         f = open(".gitattributes", "r")
@@ -504,135 +1158,487 @@ def do_vcs_install(versionfile_source, ipy):
         f = open(".gitattributes", "a+")
         f.write("%s export-subst\n" % versionfile_source)
         f.close()
-        run_command([GIT, "add", ".gitattributes"])
+        files.append(".gitattributes")
+    run_command(GITS, ["add", "--"] + files)
+
 
+def versions_from_parentdir(parentdir_prefix, root, verbose):
+    """Try to determine the version from the parent directory name.
+
+    Source tarballs conventionally unpack into a directory that includes
+    both the project name and a version string.
+    """
+    dirname = os.path.basename(root)
+    if not dirname.startswith(parentdir_prefix):
+        if verbose:
+            print("guessing rootdir is '%s', but '%s' doesn't start with "
+                  "prefix '%s'" % (root, dirname, parentdir_prefix))
+        raise NotThisMethod("rootdir doesn't start with parentdir_prefix")
+    return {"version": dirname[len(parentdir_prefix):],
+            "full-revisionid": None,
+            "dirty": False, "error": None}
 
 SHORT_VERSION_PY = """
-# This file was generated by 'versioneer.py' (0.7+) from
+# This file was generated by 'versioneer.py' (0.16) from
 # revision-control system data, or from the parent directory name of an
 # unpacked source archive. Distribution tarballs contain a pre-generated copy
 # of this file.
 
-version_version = '%(version)s'
-version_full = '%(full)s'
-def get_versions(default={}, verbose=False):
-    return {'version': version_version, 'full': version_full}
+import json
+import sys
+
+version_json = '''
+%s
+'''  # END VERSION_JSON
 
+
+def get_versions():
+    return json.loads(version_json)
 """
 
-DEFAULT = {"version": "unknown", "full": "unknown"}
 
 def versions_from_file(filename):
-    versions = {}
+    """Try to determine the version from _version.py if present."""
     try:
-        f = open(filename)
+        with open(filename) as f:
+            contents = f.read()
     except EnvironmentError:
-        return versions
-    for line in f.readlines():
-        mo = re.match("version_version = '([^']+)'", line)
-        if mo:
-            versions["version"] = mo.group(1)
-        mo = re.match("version_full = '([^']+)'", line)
-        if mo:
-            versions["full"] = mo.group(1)
-    f.close()
-    return versions
+        raise NotThisMethod("unable to read _version.py")
+    mo = re.search(r"version_json = '''\n(.*)'''  # END VERSION_JSON",
+                   contents, re.M | re.S)
+    if not mo:
+        raise NotThisMethod("no version_json in _version.py")
+    return json.loads(mo.group(1))
+
 
 def write_to_version_file(filename, versions):
-    f = open(filename, "w")
-    f.write(SHORT_VERSION_PY % versions)
-    f.close()
+    """Write the given version number to the given _version.py file."""
+    os.unlink(filename)
+    contents = json.dumps(versions, sort_keys=True,
+                          indent=1, separators=(",", ": "))
+    with open(filename, "w") as f:
+        f.write(SHORT_VERSION_PY % contents)
+
     print("set %s to '%s'" % (filename, versions["version"]))
 
 
-def get_best_versions(versionfile, tag_prefix, parentdir_prefix,
-                      default=DEFAULT, verbose=False):
-    # returns dict with two keys: 'version' and 'full'
-    #
-    # extract version from first of _version.py, 'git describe', parentdir.
-    # This is meant to work for developers using a source checkout, for users
-    # of a tarball created by 'setup.py sdist', and for users of a
-    # tarball/zipball created by 'git archive' or github's download-from-tag
-    # feature.
-
-    variables = get_expanded_variables(versionfile_source)
-    if variables:
-        ver = versions_from_expanded_variables(variables, tag_prefix)
-        if ver:
-            if verbose: print("got version from expanded variable %s" % ver)
-            return ver
+def plus_or_dot(pieces):
+    """Return a + if we don't already have one, else return a ."""
+    if "+" in pieces.get("closest-tag", ""):
+        return "."
+    return "+"
 
-    ver = versions_from_file(versionfile)
-    if ver:
-        if verbose: print("got version from file %s %s" % (versionfile, ver))
-        return ver
 
-    ver = versions_from_vcs(tag_prefix, versionfile_source, verbose)
-    if ver:
-        if verbose: print("got version from git %s" % ver)
-        return ver
+def render_pep440(pieces):
+    """Build up version string, with post-release "local version identifier".
 
-    ver = versions_from_parentdir(parentdir_prefix, versionfile_source, verbose)
-    if ver:
-        if verbose: print("got version from parentdir %s" % ver)
-        return ver
+    Our goal: TAG[+DISTANCE.gHEX[.dirty]] . Note that if you
+    get a tagged build and then dirty it, you'll get TAG+0.gHEX.dirty
+
+    Exceptions:
+    1: no tags. git_describe was just HEX. 0+untagged.DISTANCE.gHEX[.dirty]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += plus_or_dot(pieces)
+            rendered += "%d.g%s" % (pieces["distance"], pieces["short"])
+            if pieces["dirty"]:
+                rendered += ".dirty"
+    else:
+        # exception #1
+        rendered = "0+untagged.%d.g%s" % (pieces["distance"],
+                                          pieces["short"])
+        if pieces["dirty"]:
+            rendered += ".dirty"
+    return rendered
+
+
+def render_pep440_pre(pieces):
+    """TAG[.post.devDISTANCE] -- No -dirty.
+
+    Exceptions:
+    1: no tags. 0.post.devDISTANCE
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += ".post.dev%d" % pieces["distance"]
+    else:
+        # exception #1
+        rendered = "0.post.dev%d" % pieces["distance"]
+    return rendered
+
+
+def render_pep440_post(pieces):
+    """TAG[.postDISTANCE[.dev0]+gHEX] .
+
+    The ".dev0" means dirty. Note that .dev0 sorts backwards
+    (a dirty tree will appear "older" than the corresponding clean one),
+    but you shouldn't be releasing software with -dirty anyways.
+
+    Exceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+            rendered += plus_or_dot(pieces)
+            rendered += "g%s" % pieces["short"]
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+        rendered += "+g%s" % pieces["short"]
+    return rendered
+
+
+def render_pep440_old(pieces):
+    """TAG[.postDISTANCE[.dev0]] .
+
+    The ".dev0" means dirty.
+
+    Eexceptions:
+    1: no tags. 0.postDISTANCE[.dev0]
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"] or pieces["dirty"]:
+            rendered += ".post%d" % pieces["distance"]
+            if pieces["dirty"]:
+                rendered += ".dev0"
+    else:
+        # exception #1
+        rendered = "0.post%d" % pieces["distance"]
+        if pieces["dirty"]:
+            rendered += ".dev0"
+    return rendered
+
+
+def render_git_describe(pieces):
+    """TAG[-DISTANCE-gHEX][-dirty].
+
+    Like 'git describe --tags --dirty --always'.
 
-    if verbose: print("got version from default %s" % ver)
-    return default
-
-def get_versions(default=DEFAULT, verbose=False):
-    assert versionfile_source is not None, "please set versioneer.versionfile_source"
-    assert tag_prefix is not None, "please set versioneer.tag_prefix"
-    assert parentdir_prefix is not None, "please set versioneer.parentdir_prefix"
-    return get_best_versions(versionfile_source, tag_prefix, parentdir_prefix,
-                             default=default, verbose=verbose)
-def get_version(verbose=False):
-    return get_versions(verbose=verbose)["version"]
-
-class cmd_version(Command):
-    description = "report generated version string"
-    user_options = []
-    boolean_options = []
-    def initialize_options(self):
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        if pieces["distance"]:
+            rendered += "-%d-g%s" % (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render_git_describe_long(pieces):
+    """TAG-DISTANCE-gHEX[-dirty].
+
+    Like 'git describe --tags --dirty --always -long'.
+    The distance/hash is unconditional.
+
+    Exceptions:
+    1: no tags. HEX[-dirty]  (note: no 'g' prefix)
+    """
+    if pieces["closest-tag"]:
+        rendered = pieces["closest-tag"]
+        rendered += "-%d-g%s" % (pieces["distance"], pieces["short"])
+    else:
+        # exception #1
+        rendered = pieces["short"]
+    if pieces["dirty"]:
+        rendered += "-dirty"
+    return rendered
+
+
+def render(pieces, style):
+    """Render the given version pieces into the requested style."""
+    if pieces["error"]:
+        return {"version": "unknown",
+                "full-revisionid": pieces.get("long"),
+                "dirty": None,
+                "error": pieces["error"]}
+
+    if not style or style == "default":
+        style = "pep440"  # the default
+
+    if style == "pep440":
+        rendered = render_pep440(pieces)
+    elif style == "pep440-pre":
+        rendered = render_pep440_pre(pieces)
+    elif style == "pep440-post":
+        rendered = render_pep440_post(pieces)
+    elif style == "pep440-old":
+        rendered = render_pep440_old(pieces)
+    elif style == "git-describe":
+        rendered = render_git_describe(pieces)
+    elif style == "git-describe-long":
+        rendered = render_git_describe_long(pieces)
+    else:
+        raise ValueError("unknown style '%s'" % style)
+
+    return {"version": rendered, "full-revisionid": pieces["long"],
+            "dirty": pieces["dirty"], "error": None}
+
+
+class VersioneerBadRootError(Exception):
+    """The project root directory is unknown or missing key files."""
+
+
+def get_versions(verbose=False):
+    """Get the project version from whatever source is available.
+
+    Returns dict with two keys: 'version' and 'full'.
+    """
+    if "versioneer" in sys.modules:
+        # see the discussion in cmdclass.py:get_cmdclass()
+        del sys.modules["versioneer"]
+
+    root = get_root()
+    cfg = get_config_from_root(root)
+
+    assert cfg.VCS is not None, "please set [versioneer]VCS= in setup.cfg"
+    handlers = HANDLERS.get(cfg.VCS)
+    assert handlers, "unrecognized VCS '%s'" % cfg.VCS
+    verbose = verbose or cfg.verbose
+    assert cfg.versionfile_source is not None, \
+        "please set versioneer.versionfile_source"
+    assert cfg.tag_prefix is not None, "please set versioneer.tag_prefix"
+
+    versionfile_abs = os.path.join(root, cfg.versionfile_source)
+
+    # extract version from first of: _version.py, VCS command (e.g. 'git
+    # describe'), parentdir. This is meant to work for developers using a
+    # source checkout, for users of a tarball created by 'setup.py sdist',
+    # and for users of a tarball/zipball created by 'git archive' or github's
+    # download-from-tag feature or the equivalent in other VCSes.
+
+    get_keywords_f = handlers.get("get_keywords")
+    from_keywords_f = handlers.get("keywords")
+    if get_keywords_f and from_keywords_f:
+        try:
+            keywords = get_keywords_f(versionfile_abs)
+            ver = from_keywords_f(keywords, cfg.tag_prefix, verbose)
+            if verbose:
+                print("got version from expanded keyword %s" % ver)
+            return ver
+        except NotThisMethod:
+            pass
+
+    try:
+        ver = versions_from_file(versionfile_abs)
+        if verbose:
+            print("got version from file %s %s" % (versionfile_abs, ver))
+        return ver
+    except NotThisMethod:
         pass
-    def finalize_options(self):
+
+    from_vcs_f = handlers.get("pieces_from_vcs")
+    if from_vcs_f:
+        try:
+            pieces = from_vcs_f(cfg.tag_prefix, root, verbose)
+            ver = render(pieces, cfg.style)
+            if verbose:
+                print("got version from VCS %s" % ver)
+            return ver
+        except NotThisMethod:
+            pass
+
+    try:
+        if cfg.parentdir_prefix:
+            ver = versions_from_parentdir(cfg.parentdir_prefix, root, verbose)
+            if verbose:
+                print("got version from parentdir %s" % ver)
+            return ver
+    except NotThisMethod:
         pass
-    def run(self):
-        ver = get_version(verbose=True)
-        print("Version is currently: %s" % ver)
-
-
-class cmd_build(_build):
-    def run(self):
-        versions = get_versions(verbose=True)
-        _build.run(self)
-        # now locate _version.py in the new build/ directory and replace it
-        # with an updated value
-        target_versionfile = os.path.join(self.build_lib, versionfile_build)
-        print("UPDATING %s" % target_versionfile)
-        os.unlink(target_versionfile)
-        f = open(target_versionfile, "w")
-        f.write(SHORT_VERSION_PY % versions)
-        f.close()
 
-class cmd_sdist(_sdist):
-    def run(self):
-        versions = get_versions(verbose=True)
-        self._versioneer_generated_versions = versions
-        # unless we update this, the command will keep using the old version
-        self.distribution.metadata.version = versions["version"]
-        return _sdist.run(self)
-
-    def make_release_tree(self, base_dir, files):
-        _sdist.make_release_tree(self, base_dir, files)
-        # now locate _version.py in the new base_dir directory (remembering
-        # that it may be a hardlink) and replace it with an updated value
-        target_versionfile = os.path.join(base_dir, versionfile_source)
-        print("UPDATING %s" % target_versionfile)
-        os.unlink(target_versionfile)
-        f = open(target_versionfile, "w")
-        f.write(SHORT_VERSION_PY % self._versioneer_generated_versions)
-        f.close()
+    if verbose:
+        print("unable to compute version")
+
+    return {"version": "0+unknown", "full-revisionid": None,
+            "dirty": None, "error": "unable to compute version"}
+
+
+def get_version():
+    """Get the short version string for this project."""
+    return get_versions()["version"]
+
+
+def get_cmdclass():
+    """Get the custom setuptools/distutils subclasses used by Versioneer."""
+    if "versioneer" in sys.modules:
+        del sys.modules["versioneer"]
+        # this fixes the "python setup.py develop" case (also 'install' and
+        # 'easy_install .'), in which subdependencies of the main project are
+        # built (using setup.py bdist_egg) in the same python process. Assume
+        # a main project A and a dependency B, which use different versions
+        # of Versioneer. A's setup.py imports A's Versioneer, leaving it in
+        # sys.modules by the time B's setup.py is executed, causing B to run
+        # with the wrong versioneer. Setuptools wraps the sub-dep builds in a
+        # sandbox that restores sys.modules to it's pre-build state, so the
+        # parent is protected against the child's "import versioneer". By
+        # removing ourselves from sys.modules here, before the child build
+        # happens, we protect the child from the parent's versioneer too.
+        # Also see https://github.com/warner/python-versioneer/issues/52
+
+    cmds = {}
+
+    # we add "version" to both distutils and setuptools
+    from distutils.core import Command
+
+    class cmd_version(Command):
+        description = "report generated version string"
+        user_options = []
+        boolean_options = []
+
+        def initialize_options(self):
+            pass
+
+        def finalize_options(self):
+            pass
+
+        def run(self):
+            vers = get_versions(verbose=True)
+            print("Version: %s" % vers["version"])
+            print(" full-revisionid: %s" % vers.get("full-revisionid"))
+            print(" dirty: %s" % vers.get("dirty"))
+            if vers["error"]:
+                print(" error: %s" % vers["error"])
+    cmds["version"] = cmd_version
+
+    # we override "build_py" in both distutils and setuptools
+    #
+    # most invocation pathways end up running build_py:
+    #  distutils/build -> build_py
+    #  distutils/install -> distutils/build ->..
+    #  setuptools/bdist_wheel -> distutils/install ->..
+    #  setuptools/bdist_egg -> distutils/install_lib -> build_py
+    #  setuptools/install -> bdist_egg ->..
+    #  setuptools/develop -> ?
+
+    # we override different "build_py" commands for both environments
+    if "setuptools" in sys.modules:
+        from setuptools.command.build_py import build_py as _build_py
+    else:
+        from distutils.command.build_py import build_py as _build_py
+
+    class cmd_build_py(_build_py):
+        def run(self):
+            root = get_root()
+            cfg = get_config_from_root(root)
+            versions = get_versions()
+            _build_py.run(self)
+            # now locate _version.py in the new build/ directory and replace
+            # it with an updated value
+            if cfg.versionfile_build:
+                target_versionfile = os.path.join(self.build_lib,
+                                                  cfg.versionfile_build)
+                print("UPDATING %s" % target_versionfile)
+                write_to_version_file(target_versionfile, versions)
+    cmds["build_py"] = cmd_build_py
+
+    if "cx_Freeze" in sys.modules:  # cx_freeze enabled?
+        from cx_Freeze.dist import build_exe as _build_exe
+
+        class cmd_build_exe(_build_exe):
+            def run(self):
+                root = get_root()
+                cfg = get_config_from_root(root)
+                versions = get_versions()
+                target_versionfile = cfg.versionfile_source
+                print("UPDATING %s" % target_versionfile)
+                write_to_version_file(target_versionfile, versions)
+
+                _build_exe.run(self)
+                os.unlink(target_versionfile)
+                with open(cfg.versionfile_source, "w") as f:
+                    LONG = LONG_VERSION_PY[cfg.VCS]
+                    f.write(LONG %
+                            {"DOLLAR": "$",
+                             "STYLE": cfg.style,
+                             "TAG_PREFIX": cfg.tag_prefix,
+                             "PARENTDIR_PREFIX": cfg.parentdir_prefix,
+                             "VERSIONFILE_SOURCE": cfg.versionfile_source,
+                             })
+        cmds["build_exe"] = cmd_build_exe
+        del cmds["build_py"]
+
+    # we override different "sdist" commands for both environments
+    if "setuptools" in sys.modules:
+        from setuptools.command.sdist import sdist as _sdist
+    else:
+        from distutils.command.sdist import sdist as _sdist
+
+    class cmd_sdist(_sdist):
+        def run(self):
+            versions = get_versions()
+            self._versioneer_generated_versions = versions
+            # unless we update this, the command will keep using the old
+            # version
+            self.distribution.metadata.version = versions["version"]
+            return _sdist.run(self)
+
+        def make_release_tree(self, base_dir, files):
+            root = get_root()
+            cfg = get_config_from_root(root)
+            _sdist.make_release_tree(self, base_dir, files)
+            # now locate _version.py in the new base_dir directory
+            # (remembering that it may be a hardlink) and replace it with an
+            # updated value
+            target_versionfile = os.path.join(base_dir, cfg.versionfile_source)
+            print("UPDATING %s" % target_versionfile)
+            write_to_version_file(target_versionfile,
+                                  self._versioneer_generated_versions)
+    cmds["sdist"] = cmd_sdist
+
+    return cmds
+
+
+CONFIG_ERROR = """
+setup.cfg is missing the necessary Versioneer configuration. You need
+a section like:
+
+ [versioneer]
+ VCS = git
+ style = pep440
+ versionfile_source = src/myproject/_version.py
+ versionfile_build = myproject/_version.py
+ tag_prefix =
+ parentdir_prefix = myproject-
+
+You will also need to edit your setup.py to use the results:
+
+ import versioneer
+ setup(version=versioneer.get_version(),
+       cmdclass=versioneer.get_cmdclass(), ...)
+
+Please read the docstring in ./versioneer.py for configuration instructions,
+edit setup.cfg, and re-run the installer or 'python versioneer.py setup'.
+"""
+
+SAMPLE_CONFIG = """
+# See the docstring in versioneer.py for instructions. Note that you must
+# re-run 'versioneer.py setup' after changing this section, and commit the
+# resulting files.
+
+[versioneer]
+#VCS = git
+#style = pep440
+#versionfile_source =
+#versionfile_build =
+#tag_prefix =
+#parentdir_prefix =
+
+"""
 
 INIT_PY_SNIPPET = """
 from ._version import get_versions
@@ -640,40 +1646,129 @@ __version__ = get_versions()['version']
 del get_versions
 """
 
-class cmd_update_files(Command):
-    description = "modify __init__.py and create _version.py"
-    user_options = []
-    boolean_options = []
-    def initialize_options(self):
-        pass
-    def finalize_options(self):
-        pass
-    def run(self):
-        ipy = os.path.join(os.path.dirname(versionfile_source), "__init__.py")
-        print(" creating %s" % versionfile_source)
-        f = open(versionfile_source, "w")
-        f.write(LONG_VERSION_PY % {"DOLLAR": "$",
-                                   "TAG_PREFIX": tag_prefix,
-                                   "PARENTDIR_PREFIX": parentdir_prefix,
-                                   "VERSIONFILE_SOURCE": versionfile_source,
-                                   })
-        f.close()
+
+def do_setup():
+    """Main VCS-independent setup function for installing Versioneer."""
+    root = get_root()
+    try:
+        cfg = get_config_from_root(root)
+    except (EnvironmentError, configparser.NoSectionError,
+            configparser.NoOptionError) as e:
+        if isinstance(e, (EnvironmentError, configparser.NoSectionError)):
+            print("Adding sample versioneer config to setup.cfg",
+                  file=sys.stderr)
+            with open(os.path.join(root, "setup.cfg"), "a") as f:
+                f.write(SAMPLE_CONFIG)
+        print(CONFIG_ERROR, file=sys.stderr)
+        return 1
+
+    print(" creating %s" % cfg.versionfile_source)
+    with open(cfg.versionfile_source, "w") as f:
+        LONG = LONG_VERSION_PY[cfg.VCS]
+        f.write(LONG % {"DOLLAR": "$",
+                        "STYLE": cfg.style,
+                        "TAG_PREFIX": cfg.tag_prefix,
+                        "PARENTDIR_PREFIX": cfg.parentdir_prefix,
+                        "VERSIONFILE_SOURCE": cfg.versionfile_source,
+                        })
+
+    ipy = os.path.join(os.path.dirname(cfg.versionfile_source),
+                       "__init__.py")
+    if os.path.exists(ipy):
         try:
-            old = open(ipy, "r").read()
+            with open(ipy, "r") as f:
+                old = f.read()
         except EnvironmentError:
             old = ""
         if INIT_PY_SNIPPET not in old:
             print(" appending to %s" % ipy)
-            f = open(ipy, "a")
-            f.write(INIT_PY_SNIPPET)
-            f.close()
+            with open(ipy, "a") as f:
+                f.write(INIT_PY_SNIPPET)
         else:
             print(" %s unmodified" % ipy)
-        do_vcs_install(versionfile_source, ipy)
+    else:
+        print(" %s doesn't exist, ok" % ipy)
+        ipy = None
+
+    # Make sure both the top-level "versioneer.py" and versionfile_source
+    # (PKG/_version.py, used by runtime code) are in MANIFEST.in, so
+    # they'll be copied into source distributions. Pip won't be able to
+    # install the package without this.
+    manifest_in = os.path.join(root, "MANIFEST.in")
+    simple_includes = set()
+    try:
+        with open(manifest_in, "r") as f:
+            for line in f:
+                if line.startswith("include "):
+                    for include in line.split()[1:]:
+                        simple_includes.add(include)
+    except EnvironmentError:
+        pass
+    # That doesn't cover everything MANIFEST.in can do
+    # (http://docs.python.org/2/distutils/sourcedist.html#commands), so
+    # it might give some false negatives. Appending redundant 'include'
+    # lines is safe, though.
+    if "versioneer.py" not in simple_includes:
+        print(" appending 'versioneer.py' to MANIFEST.in")
+        with open(manifest_in, "a") as f:
+            f.write("include versioneer.py\n")
+    else:
+        print(" 'versioneer.py' already in MANIFEST.in")
+    if cfg.versionfile_source not in simple_includes:
+        print(" appending versionfile_source ('%s') to MANIFEST.in" %
+              cfg.versionfile_source)
+        with open(manifest_in, "a") as f:
+            f.write("include %s\n" % cfg.versionfile_source)
+    else:
+        print(" versionfile_source already in MANIFEST.in")
 
-def get_cmdclass():
-    return {'version': cmd_version,
-            'update_files': cmd_update_files,
-            'build': cmd_build,
-            'sdist': cmd_sdist,
-            }
+    # Make VCS-specific changes. For git, this means creating/changing
+    # .gitattributes to mark _version.py for export-time keyword
+    # substitution.
+    do_vcs_install(manifest_in, cfg.versionfile_source, ipy)
+    return 0
+
+
+def scan_setup_py():
+    """Validate the contents of setup.py against Versioneer's expectations."""
+    found = set()
+    setters = False
+    errors = 0
+    with open("setup.py", "r") as f:
+        for line in f.readlines():
+            if "import versioneer" in line:
+                found.add("import")
+            if "versioneer.get_cmdclass()" in line:
+                found.add("cmdclass")
+            if "versioneer.get_version()" in line:
+                found.add("get_version")
+            if "versioneer.VCS" in line:
+                setters = True
+            if "versioneer.versionfile_source" in line:
+                setters = True
+    if len(found) != 3:
+        print("")
+        print("Your setup.py appears to be missing some important items")
+        print("(but I might be wrong). Please make sure it has something")
+        print("roughly like the following:")
+        print("")
+        print(" import versioneer")
+        print(" setup( version=versioneer.get_version(),")
+        print("        cmdclass=versioneer.get_cmdclass(),  ...)")
+        print("")
+        errors += 1
+    if setters:
+        print("You should remove lines like 'versioneer.VCS = ' and")
+        print("'versioneer.versionfile_source = ' . This configuration")
+        print("now lives in setup.cfg, and should be removed from setup.py")
+        print("")
+        errors += 1
+    return errors
+
+if __name__ == "__main__":
+    cmd = sys.argv[1]
+    if cmd == "setup":
+        errors = do_setup()
+        errors += scan_setup_py()
+        if errors:
+            sys.exit(1)