hgext/convert/transport.py

import-checker: establish modern import convention

We introduce a new convention for declaring imports and enforce it via
the import checker script.

The new convention is only active when absolute imports are used, which is
currently nowhere. Keying off "from __future__ import absolute_import" to
engage the new import convention seems like the easiest solution. It is
also beneficial for Mercurial to use this mode because it means less work
and ambiguity for the importer and potentially better performance due to
fewer stat() system calls because the importer won't look for modules in
relative paths unless explicitly asked.

Once all files are converted to use absolute import, we can refactor
this code to again only have a single import convention and we can
require use of absolute import in the style checker.

The rules for the new convention are documented in the docstring of the
added function. Tests have been added to test-module-imports.t. Some
tests are sensitive to newlines and source column position, which makes
docstring testing difficult and/or impossible.

# -*- coding: utf-8 -*-

# Copyright (C) 2007 Daniel Holth <[e-mail]>
# This is a stripped-down version of the original bzr-svn transport.py,
# Copyright (C) 2006 Jelmer Vernooij <[e-mail]>

# 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, see <http://www.gnu.org/licenses/>.

from mercurial import util
from svn.core import SubversionException, Pool
import svn.ra
import svn.client
import svn.core

# Some older versions of the Python bindings need to be
# explicitly initialized. But what we want to do probably
# won't work worth a darn against those libraries anyway!
svn.ra.initialize()

svn_config = svn.core.svn_config_get_config(None)


def _create_auth_baton(pool):
    """Create a Subversion authentication baton. """
    import svn.client
    # Give the client context baton a suite of authentication
    # providers.h
    providers = [
        svn.client.get_simple_provider(pool),
        svn.client.get_username_provider(pool),
        svn.client.get_ssl_client_cert_file_provider(pool),
        svn.client.get_ssl_client_cert_pw_file_provider(pool),
        svn.client.get_ssl_server_trust_file_provider(pool),
        ]
    # Platform-dependent authentication methods
    getprovider = getattr(svn.core, 'svn_auth_get_platform_specific_provider',
                          None)
    if getprovider:
        # Available in svn >= 1.6
        for name in ('gnome_keyring', 'keychain', 'kwallet', 'windows'):
            for type in ('simple', 'ssl_client_cert_pw', 'ssl_server_trust'):
                p = getprovider(name, type, pool)
                if p:
                    providers.append(p)
    else:
        if util.safehasattr(svn.client, 'get_windows_simple_provider'):
            providers.append(svn.client.get_windows_simple_provider(pool))

    return svn.core.svn_auth_open(providers, pool)

class NotBranchError(SubversionException):
    pass

class SvnRaTransport(object):
    """
    Open an ra connection to a Subversion repository.
    """
    def __init__(self, url="", ra=None):
        self.pool = Pool()
        self.svn_url = url
        self.username = ''
        self.password = ''

        # Only Subversion 1.4 has reparent()
        if ra is None or not util.safehasattr(svn.ra, 'reparent'):
            self.client = svn.client.create_context(self.pool)
            ab = _create_auth_baton(self.pool)
            if False:
                svn.core.svn_auth_set_parameter(
                    ab, svn.core.SVN_AUTH_PARAM_DEFAULT_USERNAME, self.username)
                svn.core.svn_auth_set_parameter(
                    ab, svn.core.SVN_AUTH_PARAM_DEFAULT_PASSWORD, self.password)
            self.client.auth_baton = ab
            self.client.config = svn_config
            try:
                self.ra = svn.client.open_ra_session(
                    self.svn_url,
                    self.client, self.pool)
            except SubversionException as xxx_todo_changeme:
                (inst, num) = xxx_todo_changeme.args
                if num in (svn.core.SVN_ERR_RA_ILLEGAL_URL,
                           svn.core.SVN_ERR_RA_LOCAL_REPOS_OPEN_FAILED,
                           svn.core.SVN_ERR_BAD_URL):
                    raise NotBranchError(url)
                raise
        else:
            self.ra = ra
            svn.ra.reparent(self.ra, self.svn_url.encode('utf8'))

    class Reporter(object):
        def __init__(self, reporter_data):
            self._reporter, self._baton = reporter_data

        def set_path(self, path, revnum, start_empty, lock_token, pool=None):
            svn.ra.reporter2_invoke_set_path(self._reporter, self._baton,
                        path, revnum, start_empty, lock_token, pool)

        def delete_path(self, path, pool=None):
            svn.ra.reporter2_invoke_delete_path(self._reporter, self._baton,
                    path, pool)

        def link_path(self, path, url, revision, start_empty, lock_token,
                      pool=None):
            svn.ra.reporter2_invoke_link_path(self._reporter, self._baton,
                    path, url, revision, start_empty, lock_token,
                    pool)

        def finish_report(self, pool=None):
            svn.ra.reporter2_invoke_finish_report(self._reporter,
                    self._baton, pool)

        def abort_report(self, pool=None):
            svn.ra.reporter2_invoke_abort_report(self._reporter,
                    self._baton, pool)

    def do_update(self, revnum, path, *args, **kwargs):
        return self.Reporter(svn.ra.do_update(self.ra, revnum, path,
                                              *args, **kwargs))