~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2008, 2009, 2011 Canonical Ltd

#

# 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 2 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, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Directory service registration and usage.

Directory services are utilities that provide a mapping from URL-like strings

to true URLs.  Examples include lp:urls and per-user location aliases.

"""

from __future__ import absolute_import

from bzrlib import (

    errors,

    registry,

    )

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

from bzrlib import (

    branch as _mod_branch,

    urlutils,

    )

""")

class DirectoryServiceRegistry(registry.Registry):

    """This object maintains and uses a list of directory services.

    Directory services may be registered via the standard Registry methods.

    They will be invoked if their key is a prefix of the supplied URL.

    Each item registered should be a factory of objects that provide a look_up

    method, as invoked by dereference.  Specifically, look_up should accept a

    name and URL, and return a URL.

    """

    def dereference(self, url):

        """Dereference a supplied URL if possible.

        URLs that match a registered directory service prefix are looked up in

        it.  Non-matching urls are returned verbatim.

        This is applied only once; the resulting URL must not be one that

        requires further dereferencing.

        :param url: The URL to dereference

        :return: The dereferenced URL if applicable, the input URL otherwise.

        """

        match = self.get_prefix(url)

        if match is None:

            return url

        service, name = match

        return service().look_up(name, url)

directories = DirectoryServiceRegistry()

class AliasDirectory(object):

    """Directory lookup for locations associated with a branch.

    :parent, :submit, :public, :push, :this, and :bound are currently

    supported.  On error, a subclass of DirectoryLookupFailure will be raised.

    """

    branch_aliases = registry.Registry()

    branch_aliases.register('parent', lambda b: b.get_parent(),

        help="The parent of this branch.")

    branch_aliases.register('submit', lambda b: b.get_submit_branch(),

        help="The submit branch for this branch.")

    branch_aliases.register('public', lambda b: b.get_public_branch(),

        help="The public location of this branch.")

    branch_aliases.register('bound', lambda b: b.get_bound_location(),

        help="The branch this branch is bound to, for bound branches.")

    branch_aliases.register('push', lambda b: b.get_push_location(),

        help="The saved location used for `bzr push` with no arguments.")

    branch_aliases.register('this', lambda b: b.base,

        help="This branch.")

    def look_up(self, name, url):

        branch = _mod_branch.Branch.open_containing('.')[0]

        parts = url.split('/', 1)

        if len(parts) == 2:

            name, extra = parts

        else:

            (name,) = parts

            extra = None

        try:

            method = self.branch_aliases.get(name[1:])

        except KeyError:

            raise errors.InvalidLocationAlias(url)

        else:

            result = method(branch)

        if result is None:

            raise errors.UnsetLocationAlias(url)

        if extra is not None:

            result = urlutils.join(result, extra)

        return result

    @classmethod

    def help_text(cls, topic):

        alias_lines = []

        for key in cls.branch_aliases.keys():

            help = cls.branch_aliases.get_help(key)

            alias_lines.append("  :%-10s%s\n" % (key, help))

        return """\

Location aliases

================

Bazaar defines several aliases for locations associated with a branch.  These

can be used with most commands that expect a location, such as `bzr push`.

The aliases are::

%s

For example, to push to the parent location::

    bzr push :parent

""" % "".join(alias_lines)

directories.register(':', AliasDirectory,

                     'Easy access to remembered branch locations')