add u1db code (not as submodule)

1 files changed, 80 insertions, 0 deletions

diff --git a/u1db/commandline/command.py b/u1db/commandline/command.py
new file mode 100644
index 00000000..eace0560
--- /dev/null
+++ b/u1db/commandline/command.py
@@ -0,0 +1,80 @@
+# Copyright 2011 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Command infrastructure for u1db"""
+
+import argparse
+import inspect
+
+
+class CommandGroup(object):
+    """A collection of commands."""
+
+    def __init__(self, description=None):
+        self.commands = {}
+        self.description = description
+
+    def register(self, cmd):
+        """Register a new command to be incorporated with this group."""
+        self.commands[cmd.name] = cmd
+
+    def make_argparser(self):
+        """Create an argparse.ArgumentParser"""
+        parser = argparse.ArgumentParser(description=self.description)
+        subs = parser.add_subparsers(title='commands')
+        for name, cmd in sorted(self.commands.iteritems()):
+            sub = subs.add_parser(name, help=cmd.__doc__)
+            sub.set_defaults(subcommand=cmd)
+            cmd._populate_subparser(sub)
+        return parser
+
+    def run_argv(self, argv, stdin, stdout, stderr):
+        """Run a command, from a sys.argv[1:] style input."""
+        parser = self.make_argparser()
+        args = parser.parse_args(argv)
+        cmd = args.subcommand(stdin, stdout, stderr)
+        params, _, _, _ = inspect.getargspec(cmd.run)
+        vals = []
+        for param in params[1:]:
+            vals.append(getattr(args, param))
+        return cmd.run(*vals)
+
+
+class Command(object):
+    """Definition of a Command that can be run.
+
+    :cvar name: The name of the command, so that you can run
+        'u1db-client <name>'.
+    """
+
+    name = None
+
+    def __init__(self, stdin, stdout, stderr):
+        self.stdin = stdin
+        self.stdout = stdout
+        self.stderr = stderr
+
+    @classmethod
+    def _populate_subparser(cls, parser):
+        """Child classes should override this to provide their arguments."""
+        raise NotImplementedError(cls._populate_subparser)
+
+    def run(self, *args):
+        """This is where the magic happens.
+
+        Subclasses should implement this, requesting their specific arguments.
+        """
+        raise NotImplementedError(self.run)