[refactor] [bug] simplify and bugfix walk module

some tests added too

- Related: #7999

5 files changed, 298 insertions, 231 deletions

diff --git a/mail/src/leap/mail/adaptors/soledad.py b/mail/src/leap/mail/adaptors/soledad.py
index 298d0172..46c5a2c5 100644
--- a/mail/src/leap/mail/adaptors/soledad.py
+++ b/mail/src/leap/mail/adaptors/soledad.py
@@ -1185,14 +1185,13 @@ def _split_into_parts(raw):
     # TODO populate Default FLAGS/TAGS (unseen?)
     # TODO seed propely the content_docs with defaults??
 
-    msg, parts, chash, multi = _parse_msg(raw)
+    msg, chash, multi = _parse_msg(raw)
     size = len(msg.as_string())
 
-    body_phash = walk.get_body_phash(msg)
-
-    parts_map = walk.walk_msg_tree(parts, body_phash=body_phash)
-    cdocs_list = list(walk.get_raw_docs(msg, parts))
+    parts_map = walk.get_tree(msg)
+    cdocs_list = list(walk.get_raw_docs(msg))
     cdocs_phashes = [c['phash'] for c in cdocs_list]
+    body_phash = walk.get_body_phash(msg)
 
     mdoc = _build_meta_doc(chash, cdocs_phashes)
     fdoc = _build_flags_doc(chash, size, multi)
@@ -1206,10 +1205,9 @@ def _split_into_parts(raw):
 
 def _parse_msg(raw):
     msg = message_from_string(raw)
-    parts = walk.get_parts(msg)
     chash = walk.get_hash(raw)
     multi = msg.is_multipart()
-    return msg, parts, chash, multi
+    return msg, chash, multi
 
 
 def _build_meta_doc(chash, cdocs_phashes):
@@ -1220,6 +1218,7 @@ def _build_meta_doc(chash, cdocs_phashes):
     _mdoc.fdoc = constants.FDOCID.format(mbox_uuid=INBOX_NAME, chash=chash)
     _mdoc.hdoc = constants.HDOCID.format(chash=chash)
     _mdoc.cdocs = [constants.CDOCID.format(phash=p) for p in cdocs_phashes]
+
     return _mdoc.serialize()
 
 
@@ -1259,8 +1258,8 @@ def _build_headers_doc(msg, chash, body_phash, parts_map):
     copy_attr(lower_headers, "date", _hdoc)
 
     hdoc = _hdoc.serialize()
-    # add parts map to header doc
-    # (body, multi, part_map)
+    # add some of the attr from the parts map to header doc
     for key in parts_map:
-        hdoc[key] = parts_map[key]
+        if key in ('body', 'multi', 'part_map'):
+            hdoc[key] = parts_map[key]
     return stringify_parts_map(hdoc)
diff --git a/mail/src/leap/mail/mail.py b/mail/src/leap/mail/mail.py
index d3659de8..2fde3a1b 100644
--- a/mail/src/leap/mail/mail.py
+++ b/mail/src/leap/mail/mail.py
@@ -36,7 +36,6 @@ from twisted.python import log
 
 from leap.common.check import leap_assert_type
 from leap.common.events import emit_async, catalog
-from leap.common.mail import get_email_charset
 
 from leap.mail.adaptors.soledad import SoledadMailAdaptor
 from leap.mail.constants import INBOX_NAME
@@ -124,33 +123,6 @@ def _unpack_headers(headers_dict):
     return headers_l
 
 
-def _get_index_for_cdoc(part_map, cdocs_dict):
-    """
-    Get, if possible, the index for a given content-document matching the phash
-    of the passed part_map.
-
-    This is used when we are initializing a MessagePart, because we just pass a
-    reference to the parent message cdocs container and we need to iterate
-    through the cdocs to figure out which content-doc matches the phash of the
-    part we're currently rendering.
-
-    It is also used when recursing through a nested multipart message, because
-    in the initialization of the child MessagePart we pass a dictionary only
-    for the referenced cdoc.
-
-    :param part_map: a dict describing the mapping of the parts for the current
-                     message-part.
-    :param cdocs: a dict of content-documents, 0-indexed.
-    :rtype: int
-    """
-    phash = part_map.get('phash', None)
-    if phash:
-        for i, cdoc_wrapper in cdocs_dict.items():
-            if cdoc_wrapper.phash == phash:
-                return i
-    return None
-
-
 class MessagePart(object):
     # TODO This class should be better abstracted from the data model.
     # TODO support arbitrarily nested multiparts (right now we only support
@@ -159,7 +131,7 @@ class MessagePart(object):
     Represents a part of a multipart MIME Message.
     """
 
-    def __init__(self, part_map, cdocs={}, nested=False):
+    def __init__(self, part_map, cdocs=None, nested=False):
         """
         :param part_map: a dictionary mapping the subparts for
                          this MessagePart (1-indexed).
@@ -178,13 +150,12 @@ class MessagePart(object):
         :param cdocs: optional, a reference to the top-level dict of wrappers
                       for content-docs (1-indexed).
         """
+        if cdocs is None:
+            cdocs = {}
         self._pmap = part_map
         self._cdocs = cdocs
         self._nested = nested
 
-        index = _get_index_for_cdoc(part_map, self._cdocs) or 1
-        self._index = index
-
     def get_size(self):
         """
         Size of the body, in octets.
@@ -199,13 +170,10 @@ class MessagePart(object):
     def get_body_file(self):
         payload = ""
         pmap = self._pmap
+
         multi = pmap.get('multi')
         if not multi:
-            payload = self._get_payload(self._index)
-        else:
-            # XXX uh, multi also...  should recurse.
-            # This needs to be implemented in a more general and elegant way.
-            raise NotImplementedError
+            payload = self._get_payload(pmap.get('phash'))
         if payload:
             payload = _encode_payload(payload)
 
@@ -220,33 +188,19 @@ class MessagePart(object):
     def get_subpart(self, part):
         if not self.is_multipart():
             raise TypeError
-
         sub_pmap = self._pmap.get("part_map", {})
 
-        # XXX BUG --- workaround. Subparts with more than 1 subparts
-        # need to get the requested index for the subpart decremented.
-        # Off-by-one error, should investigate which is the real reason and
-        # fix it, this is only a quick workaround.
-        num_parts = self._pmap.get("parts", 0)
-        if num_parts > 1:
-            part = part - 1
-        # -------------------------------------------------------------
-
         try:
             part_map = sub_pmap[str(part)]
         except KeyError:
             log.msg("getSubpart for %s: KeyError" % (part,))
             raise IndexError
+        return MessagePart(part_map, cdocs=self._cdocs, nested=True)
 
-        cdoc_index = _get_index_for_cdoc(part_map, self._cdocs)
-        cdoc = self._cdocs.get(cdoc_index, {})
-
-        return MessagePart(part_map, cdocs={1: cdoc}, nested=True)
-
-    def _get_payload(self, index):
-        cdoc_wrapper = self._cdocs.get(index, None)
-        if cdoc_wrapper:
-            return cdoc_wrapper.raw
+    def _get_payload(self, phash):
+        for cdocw in self._cdocs.values():
+            if cdocw.phash == phash:
+                return cdocw.raw
         return ""
 
 
diff --git a/mail/src/leap/mail/tests/rfc822.bounce.message b/mail/src/leap/mail/tests/rfc822.bounce.message
new file mode 100644
index 00000000..7a51ac04
--- /dev/null
+++ b/mail/src/leap/mail/tests/rfc822.bounce.message
@@ -0,0 +1,152 @@
+Return-Path: <>
+X-Original-To: yoyo@dev.pixelated-project.org
+Delivered-To: a6973ec1af0a6d1e2a1e4db4ff85f6c2@deliver.local
+Received: by dev1.dev.pixelated-project.org (Postfix)
+    id 92CEA83164; Thu, 16 Jun 2016 14:53:34 +0200 (CEST)
+Date: Thu, 16 Jun 2016 14:53:34 +0200 (CEST)
+From: MAILER-DAEMON@dev1.dev.pixelated-project.org (Mail Delivery System)
+Subject: Undelivered Mail Returned to Sender
+To: yoyo@dev.pixelated-project.org
+Auto-Submitted: auto-replied
+MIME-Version: 1.0
+Content-Type: multipart/report; report-type=delivery-status;
+    boundary="8F60183010.1466081614/dev1.dev.pixelated-project.org"
+Message-Id: <20160616125334.92CEA83164@dev1.dev.pixelated-project.org>
+
+This is a MIME-encapsulated message.
+
+--8F60183010.1466081614/dev1.dev.pixelated-project.org
+Content-Description: Notification
+Content-Type: text/plain; charset=us-ascii
+
+This is the mail system at host dev1.dev.pixelated-project.org.
+
+I'm sorry to have to inform you that your message could not
+be delivered to one or more recipients. It's attached below.
+
+For further assistance, please send mail to postmaster.
+
+If you do so, please include this problem report. You can
+delete your own text from the attached returned message.
+
+                   The mail system
+
+<nobody@leap.se>: host caribou.leap.se[176.53.69.122] said: 550 5.1.1
+    <nobody@leap.se>: Recipient address rejected: User unknown in virtual alias
+    table (in reply to RCPT TO command)
+
+--8F60183010.1466081614/dev1.dev.pixelated-project.org
+Content-Description: Delivery report
+Content-Type: message/delivery-status
+
+Reporting-MTA: dns; dev1.dev.pixelated-project.org
+X-Postfix-Queue-ID: 8F60183010
+X-Postfix-Sender: rfc822; yoyo@dev.pixelated-project.org
+Arrival-Date: Thu, 16 Jun 2016 14:53:33 +0200 (CEST)
+
+Final-Recipient: rfc822; nobody@leap.se
+Original-Recipient: rfc822;nobody@leap.se
+Action: failed
+Status: 5.1.1
+Remote-MTA: dns; caribou.leap.se
+Diagnostic-Code: smtp; 550 5.1.1 <nobody@leap.se>: Recipient address rejected:
+    User unknown in virtual alias table
+
+--8F60183010.1466081614/dev1.dev.pixelated-project.org
+Content-Description: Undelivered Message
+Content-Type: message/rfc822
+
+Return-Path: <yoyo@dev.pixelated-project.org>
+Received: from leap.mail-0.4.0rc1+111.g736ea86 (localhost [127.0.0.1])
+    (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits))
+    (Client CN "yoyo@dev.pixelated-project.org", Issuer "Pixelated Project Root CA (client certificates only!)" (verified OK))
+    by dev1.dev.pixelated-project.org (Postfix) with ESMTPS id 8F60183010
+    for <nobody@leap.se>; Thu, 16 Jun 2016 14:53:33 +0200 (CEST)
+MIME-Version: 1.0
+Content-Type: multipart/signed; protocol="application/pgp-signature";
+ micalg="pgp-sha512"; boundary="===============7598747164910592838=="
+To: nobody@leap.se
+Subject: vrgg
+From: yoyo@dev.pixelated-project.org
+Date: Thu, 16 Jun 2016 13:53:32 -0000
+Message-Id: <20160616125332.16961.677041909.5@dev1.dev.pixelated-project.org>
+OpenPGP: id=CB546109E857BC34DFF2BCB3288870B39C400C24;
+ url="https://dev.pixelated-project.org/key/yoyo"; preference="signencrypt"
+
+--===============7598747164910592838==
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+MIME-Version: 1.0
+To: nobody@leap.se
+Subject: vrgg
+From: yoyo@dev.pixelated-project.org
+Date: Thu, 16 Jun 2016 13:53:32 -0000
+
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diff --git a/mail/src/leap/mail/tests/test_walk.py b/mail/src/leap/mail/tests/test_walk.py
new file mode 100644
index 00000000..826ec10c
--- /dev/null
+++ b/mail/src/leap/mail/tests/test_walk.py
@@ -0,0 +1,81 @@
+"""
+Tests for leap.mail.walk module
+"""
+import os.path
+from email.parser import Parser
+
+from leap.mail import walk
+
+CORPUS = {
+    'simple': 'rfc822.message',
+    'multimin': 'rfc822.multi-minimal.message',
+    'multisigned': 'rfc822.multi-signed.message',
+    'bounced': 'rfc822.bounce.message',
+}
+
+_here = os.path.dirname(__file__)
+_parser = Parser()
+
+
+# tests
+
+
+def test_simple_mail():
+    msg = _parse('simple')
+    tree = walk.get_tree(msg)
+    assert len(tree['part_map']) == 0
+    assert tree['ctype'] == 'text/plain'
+    assert tree['multi'] is False
+
+
+def test_multipart_minimal():
+    msg = _parse('multimin')
+    tree = walk.get_tree(msg)
+
+    assert tree['multi'] is True
+    assert len(tree['part_map']) == 1
+    first = tree['part_map'][1]
+    assert first['multi'] is False
+    assert first['ctype'] == 'text/plain'
+
+
+def test_multi_signed():
+    msg = _parse('multisigned')
+    tree = walk.get_tree(msg)
+    assert tree['multi'] is True
+    assert len(tree['part_map']) == 2
+
+    _first = tree['part_map'][1]
+    _second = tree['part_map'][2]
+    assert len(_first['part_map']) == 3
+    assert(_second['multi'] is False)
+
+
+def test_bounce_mime():
+    msg = _parse('bounced')
+    tree = walk.get_tree(msg)
+
+    ctypes = [tree['part_map'][index]['ctype']
+              for index in sorted(tree['part_map'].keys())]
+    third = tree['part_map'][3]
+    three_one_ctype = third['part_map'][1]['ctype']
+    assert three_one_ctype == 'multipart/signed'
+
+    assert ctypes == [
+        'text/plain',
+        'message/delivery-status',
+        'message/rfc822']
+
+
+# utils
+
+def _parse(name):
+    _str = _get_string_for_message(name)
+    return _parser.parsestr(_str)
+
+
+def _get_string_for_message(name):
+    filename = os.path.join(_here, CORPUS[name])
+    with open(filename) as f:
+        msgstr = f.read()
+    return msgstr
diff --git a/mail/src/leap/mail/walk.py b/mail/src/leap/mail/walk.py
index c1166014..d143d61e 100644
--- a/mail/src/leap/mail/walk.py
+++ b/mail/src/leap/mail/walk.py
@@ -15,8 +15,11 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
-Utilities for walking along a message tree.
+Walk a message tree and generate documents that can be inserted in the backend
+store.
 """
+from email.parser import Parser
+
 from cryptography.hazmat.backends.multibackend import MultiBackend
 from cryptography.hazmat.backends.openssl.backend import (
     Backend as OpenSSLBackend)
@@ -26,49 +29,32 @@ from leap.mail.utils import first
 
 crypto_backend = MultiBackend([OpenSSLBackend()])
 
+_parser = Parser()
 
-def get_hash(s):
-    digest = hashes.Hash(hashes.SHA256(), crypto_backend)
-    digest.update(s)
-    return digest.finalize().encode("hex").upper()
-
-
-"""
-Get interesting message parts
-"""
-
-
-def get_parts(msg):
-    return [
-        {
-            'multi': part.is_multipart(),
-            'ctype': part.get_content_type(),
-            'size': len(part.as_string()),
-            'parts':
-                len(part.get_payload())
-                if isinstance(part.get_payload(), list)
-                else 1,
-            'headers': part.items(),
-            'phash':
-                get_hash(part.get_payload())
-                if not part.is_multipart()
-                else None
-        } for part in msg.walk()]
-
-"""
-Utility lambda functions for getting the parts vector and the
-payloads from the original message.
-"""
 
+def get_tree(msg):
+    p = {}
+    p['ctype'] = msg.get_content_type()
+    p['headers'] = msg.items()
 
-def get_parts_vector(parts):
-    return (x.get('parts', 1) for x in parts)
+    payload = msg.get_payload()
+    is_multi = msg.is_multipart()
+    if is_multi:
+        p['part_map'] = dict(
+            [(idx, get_tree(part)) for idx, part in enumerate(payload, 1)])
+        p['parts'] = len(payload)
+        p['phash'] = None
+    else:
+        p['parts'] = 0
+        p['size'] = len(payload)
+        p['phash'] = get_hash(payload)
+        p['part_map'] = {}
+    p['multi'] = is_multi
+    return p
 
 
-def get_payloads(msg):
-    return ((x.get_payload(),
-            dict(((str.lower(k), v) for k, v in (x.items()))))
-            for x in msg.walk())
+def get_tree_from_string(messagestr):
+    return get_tree(_parser.parsestr(messagestr))
 
 
 def get_body_phash(msg):
@@ -81,27 +67,29 @@ def get_body_phash(msg):
             # XXX avoid hashing again
             return get_hash(part.get_payload())
 
-"""
-On getting the raw docs, we get also some of the headers to be able to
-index the content. Here we remove any mutable part, as the the filename
-in the content disposition.
-"""
-
 
-def get_raw_docs(msg, parts):
+def get_raw_docs(msg):
+    """
+    We get also some of the headers to be able to
+    index the content. Here we remove any mutable part, as the the filename
+    in the content disposition.
+    """
     return (
-        {
-            "type": "cnt",  # type content they'll be
-            "raw": payload,
-            "phash": get_hash(payload),
-            "content-disposition": first(headers.get(
-                'content-disposition', '').split(';')),
-            "content-type": headers.get(
-                'content-type', ''),
-            "content-transfer-encoding": headers.get(
-                'content-transfer-encoding', '')
-        } for payload, headers in get_payloads(msg)
-        if not isinstance(payload, list))
+        {'type': 'cnt',
+         'raw': part.get_payload(),
+         'phash': get_hash(part.get_payload()),
+         'content-type': part.get_content_type(),
+         'content-disposition': first(part.get(
+             'content-disposition', '').split(';')),
+         'content-transfer-encoding': part.get(
+             'content-transfer-encoding', '')
+         } for part in msg.walk() if not isinstance(part.get_payload(), list))
+
+
+def get_hash(s):
+    digest = hashes.Hash(hashes.SHA256(), crypto_backend)
+    digest.update(s)
+    return digest.finalize().encode("hex").upper()
 
 
 """
@@ -116,111 +104,4 @@ Groucho Marx: What's the matter with it?
 Chico Marx: I don't know, let's hear it again.
 Groucho Marx: So the party of the first part shall be known in this contract as
               the party of the first part.
-
-Chico Marx: Well it sounds a little better this time.
-Groucho Marx: Well, it grows on you. Would you like to hear it once more?
-
-Chico Marx: Just the first part.
-Groucho Marx: All right. It says the first part of the party of the first part
-              shall be known in this contract as the first part of the party of
-              the first part, shall be known in this contract - look, why
-              should we quarrel about a thing like this, we'll take it right
-              out, eh?
-
-Chico Marx: Yes, it's too long anyhow. Now what have we got left?
-Groucho Marx: Well I've got about a foot and a half. Now what's the matter?
-
-Chico Marx: I don't like the second party either.
 """
-
-
-def walk_msg_tree(parts, body_phash=None):
-    """
-    Take a list of interesting items of a message subparts structure,
-    and return a dict of dicts almost ready to be written to the content
-    documents that will be stored in Soledad.
-
-    It walks down the subparts in the parsed message tree, and collapses
-    the leaf documents into a wrapper document until no multipart submessages
-    are left. To achieve this, it iteratively calculates a wrapper vector of
-    all documents in the sequence that have more than one part and have unitary
-    documents to their right. To collapse a multipart, take as many
-    unitary documents as parts the submessage contains, and replace the object
-    in the sequence with the new wrapper document.
-
-    :param parts: A list of dicts containing the interesting properties for
-                  the message structure. Normally this has been generated by
-                  doing a message walk.
-    :type parts: list of dicts.
-    :param body_phash: the payload hash of the body part, to be included
-                       in the outer content doc for convenience.
-    :type body_phash: basestring or None
-    """
-    PART_MAP = "part_map"
-    MULTI = "multi"
-    HEADERS = "headers"
-    PHASH = "phash"
-    BODY = "body"
-
-    # parts vector
-    pv = list(get_parts_vector(parts))
-
-    inner_headers = parts[1].get(HEADERS, None) if (
-        len(parts) == 2) else None
-
-    # wrappers vector
-    def getwv(pv):
-        return [
-            True if pv[i] != 1 and pv[i + 1] == 1
-            else False
-            for i in range(len(pv) - 1)
-        ]
-    wv = getwv(pv)
-
-    # do until no wrapper document is left
-    while any(wv):
-        wind = wv.index(True)  # wrapper index
-        nsub = pv[wind]  # number of subparts to pick
-        slic = parts[wind + 1:wind + 1 + nsub]  # slice with subparts
-
-        cwra = {
-            MULTI: True,
-            PART_MAP: dict((index + 1, part)  # content wrapper
-                           for index, part in enumerate(slic)),
-            HEADERS: dict(parts[wind][HEADERS])
-        }
-
-        # remove subparts and substitute wrapper
-        map(lambda i: parts.remove(i), slic)
-        parts[wind] = cwra
-
-        # refresh vectors for this iteration
-        pv = list(get_parts_vector(parts))
-        wv = getwv(pv)
-
-    if all(x == 1 for x in pv):
-        # special case in the rightmost element
-        main_pmap = parts[0].get(PART_MAP, None)
-        if main_pmap is not None:
-            last_part = max(main_pmap.keys())
-            main_pmap[last_part][PART_MAP] = {}
-            for partind in range(len(pv) - 1):
-                main_pmap[last_part][PART_MAP][partind] = parts[partind + 1]
-
-    outer = parts[0]
-    outer.pop(HEADERS)
-    if PART_MAP not in outer:
-        # we have a multipart with 1 part only, so kind of fix it
-        # although it would be prettier if I take this special case at
-        # the beginning of the walk.
-        pdoc = {MULTI: True,
-                PART_MAP: {1: outer}}
-        pdoc[PART_MAP][1][MULTI] = False
-        if not pdoc[PART_MAP][1].get(PHASH, None):
-            pdoc[PART_MAP][1][PHASH] = body_phash
-        if inner_headers:
-            pdoc[PART_MAP][1][HEADERS] = inner_headers
-    else:
-        pdoc = outer
-    pdoc[BODY] = body_phash
-    return pdoc