~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2004, 2005 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""bzr python plugin support

Any python module in $BZR_PLUGIN_PATH will be imported upon initialization of

bzrlib. The module will be imported as 'bzrlib.plugins.$BASENAME(PLUGIN)'.

In the plugin's main body, it should update any bzrlib registries it wants to

extend; for example, to add new commands, import bzrlib.commands and add your

new command to the plugin_cmds variable.

"""

# TODO: Refactor this to make it more testable.  The main problem at the

# moment is that loading plugins affects the global process state -- for bzr

# in general use it's a reasonable assumption that all plugins are loaded at

# startup and then stay loaded, but this is less good for testing.

# 

# Several specific issues:

#  - plugins can't be unloaded and will continue to effect later tests

#  - load_plugins does nothing if called a second time

#  - plugin hooks can't be removed

#

# Our options are either to remove these restrictions, or work around them by

# loading the plugins into a different space than the one running the tests.

# That could be either a separate Python interpreter or perhaps a new

# namespace inside this interpreter.

import os

import sys

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

import imp

import types

from bzrlib import (

    config,

    osutils,

    plugins,

    )

""")

from bzrlib.trace import mutter, warning, log_exception_quietly

DEFAULT_PLUGIN_PATH = None

def get_default_plugin_path():

    """Get the DEFAULT_PLUGIN_PATH"""

    global DEFAULT_PLUGIN_PATH

    if DEFAULT_PLUGIN_PATH is None:

        DEFAULT_PLUGIN_PATH = osutils.pathjoin(config.config_dir(), 'plugins')

    return DEFAULT_PLUGIN_PATH

_loaded = False

def all_plugins():

    """Return a dictionary of the plugins."""

    result = {}

    for name, plugin in plugins.__dict__.items():

        if isinstance(plugin, types.ModuleType):

            result[name] = plugin

    return result

def disable_plugins():

    """Disable loading plugins.

    Future calls to load_plugins() will be ignored.

    """

    # TODO: jam 20060131 This should probably also disable

    #       load_from_dirs()

    global _loaded

    _loaded = True

def load_plugins():

    """Load bzrlib plugins.

    The environment variable BZR_PLUGIN_PATH is considered a delimited

    set of paths to look through. Each entry is searched for *.py

    files (and whatever other extensions are used in the platform,

    such as *.pyd).

    load_from_dirs() provides the underlying mechanism and is called with

    the default directory list to provide the normal behaviour.

    """

    global _loaded

    if _loaded:

        # People can make sure plugins are loaded, they just won't be twice

        return

    _loaded = True

    dirs = os.environ.get('BZR_PLUGIN_PATH',

                          get_default_plugin_path()).split(os.pathsep)

    dirs.insert(0, os.path.dirname(plugins.__file__))

    load_from_dirs(dirs)

def load_from_dirs(dirs):

    """Load bzrlib plugins found in each dir in dirs.

    Loading a plugin means importing it into the python interpreter.

    The plugin is expected to make calls to register commands when

    it's loaded (or perhaps access other hooks in future.)

    Plugins are loaded into bzrlib.plugins.NAME, and can be found there

    for future reference.

    """

    # Get the list of valid python suffixes for __init__.py?

    # this includes .py, .pyc, and .pyo (depending on if we are running -O)

    # but it doesn't include compiled modules (.so, .dll, etc)

    valid_suffixes = [suffix for suffix, mod_type, flags in imp.get_suffixes()

                              if flags in (imp.PY_SOURCE, imp.PY_COMPILED)]

    package_entries = ['__init__'+suffix for suffix in valid_suffixes]

    for d in dirs:

        if not d:

            continue

        mutter('looking for plugins in %s', d)

        plugin_names = set()

        if not os.path.isdir(d):

            continue

        for f in os.listdir(d):

            path = osutils.pathjoin(d, f)

            if os.path.isdir(path):

                for entry in package_entries:

                    # This directory should be a package, and thus added to

                    # the list

                    if os.path.isfile(osutils.pathjoin(path, entry)):

                        break

                else: # This directory is not a package

                    continue

            else:

                for suffix_info in imp.get_suffixes():

                    if f.endswith(suffix_info[0]):

                        f = f[:-len(suffix_info[0])]

                        if suffix_info[2] == imp.C_EXTENSION and f.endswith('module'):

                            f = f[:-len('module')]

                        break

                else:

                    continue

            if getattr(plugins, f, None):

                mutter('Plugin name %s already loaded', f)

            else:

                mutter('add plugin name %s', f)

                plugin_names.add(f)

        plugin_names = list(plugin_names)

        plugin_names.sort()

        for name in plugin_names:

            try:

                plugin_info = imp.find_module(name, [d])

                mutter('load plugin %r', plugin_info)

                try:

                    plugin = imp.load_module('bzrlib.plugins.' + name,

                                             *plugin_info)

                    setattr(plugins, name, plugin)

                finally:

                    if plugin_info[0] is not None:

                        plugin_info[0].close()

                mutter('loaded succesfully')

            except KeyboardInterrupt:

                raise

            except Exception, e:

                ## import pdb; pdb.set_trace()

                warning('Unable to load plugin %r from %r' % (name, d))

                log_exception_quietly()