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# Copyright (C) 2005-2011 Canonical Ltd, 2017 Breezy developers
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Breezy plugin support.
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Which plugins to load can be configured by setting these environment variables:
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- BRZ_PLUGIN_PATH: Paths to look for plugins in.
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- BRZ_DISABLE_PLUGINS: Plugin names to block from being loaded.
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- BRZ_PLUGINS_AT: Name and paths for plugins to load from specific locations.
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The interfaces this module exports include:
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- disable_plugins: Load no plugins and stop future automatic loading.
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- load_plugins: Load all plugins that can be found in configuration.
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- describe_plugins: Generate text for each loaded (or failed) plugin.
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- extend_path: Mechanism by which the plugins package path is set.
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- plugin_name: Gives unprefixed name of a plugin module.
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See the plugin-api developer documentation for information about writing
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from .lazy_import import lazy_import
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lazy_import(globals(), """
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from importlib import util as importlib_util
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_MODULE_PREFIX = "breezy.plugins."
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def disable_plugins(state=None):
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"""Disable loading plugins.
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Future calls to load_plugins() will be ignored.
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:param state: The library state object that records loaded plugins.
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state = breezy.get_global_state()
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def load_plugins(path=None, state=None):
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"""Load breezy plugins.
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The environment variable BRZ_PLUGIN_PATH is considered a delimited
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set of paths to look through. Each entry is searched for `*.py`
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files (and whatever other extensions are used in the platform,
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:param path: The list of paths to search for plugins. By default,
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it is populated from the __path__ of the breezy.plugins package.
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:param state: The library state object that records loaded plugins.
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state = breezy.get_global_state()
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if getattr(state, 'plugins', None) is not None:
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# People can make sure plugins are loaded, they just won't be twice
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# Calls back into extend_path() here
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from breezy.plugins import __path__ as path
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state.plugin_warnings = {}
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_load_plugins_from_path(state, path)
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if (None, 'entrypoints') in _env_plugin_path():
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_load_plugins_from_entrypoints(state)
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state.plugins = plugins()
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def _load_plugins_from_entrypoints(state):
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# No pkg_resources, no entrypoints.
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for ep in pkg_resources.iter_entry_points('breezy.plugin'):
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fullname = _MODULE_PREFIX + ep.name
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if fullname in sys.modules:
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sys.modules[fullname] = ep.load()
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def plugin_name(module_name):
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"""Gives unprefixed name from module_name or None."""
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if module_name.startswith(_MODULE_PREFIX):
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parts = module_name.split(".")
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def extend_path(path, name):
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"""Helper so breezy.plugins can be a sort of namespace package.
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To be used in similar fashion to pkgutil.extend_path:
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from breezy.plugins import extend_path
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__path__ = extend_path(__path__, __name__)
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Inspects the BRZ_PLUGIN* envvars, sys.path, and the filesystem to find
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plugins. May mutate sys.modules in order to block plugin loading, and may
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append a new meta path finder to sys.meta_path for plugins@ loading.
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Returns a list of paths to import from, as an enhanced object that also
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contains details of the other configuration used.
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blocks = _env_disable_plugins()
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_block_plugins(blocks)
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extra_details = _env_plugins_at()
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_install_importer_if_needed(extra_details)
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paths = _iter_plugin_paths(_env_plugin_path(), path)
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return _Path(name, blocks, extra_details, paths)
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"""List type to use as __path__ but containing additional details.
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Python 3 allows any iterable for __path__ but Python 2 is more fussy.
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def __init__(self, package_name, blocked, extra, paths):
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super(_Path, self).__init__(paths)
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self.package_name = package_name
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self.blocked_names = blocked
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self.extra_details = extra
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return "%s(%r, %r, %r, %s)" % (
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self.__class__.__name__, self.package_name, self.blocked_names,
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self.extra_details, list.__repr__(self))
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def _expect_identifier(name, env_key, env_value):
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"""Validate given name from envvar is usable as a Python identifier.
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Returns the name as a native str, or None if it was invalid.
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Per PEP 3131 this is no longer strictly correct for Python 3, but as MvL
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didn't include a neat way to check except eval, this enforces ascii.
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if re.match(r"^[A-Za-z_][A-Za-z0-9_]*$", name) is None:
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trace.warning("Invalid name '%s' in %s='%s'", name, env_key, env_value)
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def _env_disable_plugins(key='BRZ_DISABLE_PLUGINS'):
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"""Gives list of names for plugins to disable from environ key."""
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env = os.environ.get(key)
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for name in env.split(os.pathsep):
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name = _expect_identifier(name, key, env)
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disabled_names.append(name)
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return disabled_names
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def _env_plugins_at(key='BRZ_PLUGINS_AT'):
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"""Gives list of names and paths of specific plugins from environ key."""
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env = os.environ.get(key)
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for pair in env.split(os.pathsep):
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name, path = pair.split('@', 1)
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name = osutils.basename(path).split('.', 1)[0]
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name = _expect_identifier(name, key, env)
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plugin_details.append((name, path))
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return plugin_details
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def _env_plugin_path(key='BRZ_PLUGIN_PATH'):
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"""Gives list of paths and contexts for plugins from environ key.
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Each entry is either a specific path to load plugins from and the value
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'path', or None and one of the values 'user', 'core', 'entrypoints', 'site'.
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env = os.environ.get(key)
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'entrypoints': False,
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# Add paths specified by user in order
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for p in env.split(os.pathsep):
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flag, name = p[:1], p[1:]
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if flag in ("+", "-") and name in defaults:
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if flag == "+" and defaults[name] is not None:
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path_details.append((None, name))
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defaults[name] = None
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path_details.append((p, 'path'))
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# Add any remaining default paths
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for name in ('user', 'core', 'entrypoints', 'site'):
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path_details.append((None, name))
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def _iter_plugin_paths(paths_from_env, core_paths):
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"""Generate paths using paths_from_env and core_paths."""
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# GZ 2017-06-02: This is kinda horrid, should make better.
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for path, context in paths_from_env:
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if context == 'path':
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elif context == 'user':
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path = get_user_plugin_path()
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if os.path.isdir(path):
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elif context == 'core':
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for path in _get_core_plugin_paths(core_paths):
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elif context == 'site':
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for path in _get_site_plugin_paths(sys.path):
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if os.path.isdir(path):
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def _install_importer_if_needed(plugin_details):
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"""Install a meta path finder to handle plugin_details if any."""
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finder = _PluginsAtFinder(_MODULE_PREFIX, plugin_details)
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# For Python 3, must insert before default PathFinder to override.
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sys.meta_path.insert(2, finder)
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def _load_plugins_from_path(state, paths):
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"""Do the importing all plugins from paths."""
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imported_names = set()
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for name, path in _iter_possible_plugins(paths):
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if name not in imported_names:
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msg = _load_plugin_module(name, path)
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state.plugin_warnings.setdefault(name, []).append(msg)
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imported_names.add(name)
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def _block_plugins(names):
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"""Add names to sys.modules to block future imports."""
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package_name = _MODULE_PREFIX + name
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if sys.modules.get(package_name) is not None:
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trace.mutter("Blocked plugin %s already loaded.", name)
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sys.modules[package_name] = None
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def _get_package_init(package_path):
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"""Get path of __init__ file from package_path or None if not a package."""
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init_path = osutils.pathjoin(package_path, "__init__.py")
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if os.path.exists(init_path):
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init_path = init_path[:-3] + COMPILED_EXT
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if os.path.exists(init_path):
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def _iter_possible_plugins(plugin_paths):
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"""Generate names and paths of possible plugins from plugin_paths."""
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# Inspect any from BRZ_PLUGINS_AT first.
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for name, path in getattr(plugin_paths, "extra_details", ()):
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# Then walk over files and directories in the paths from the package.
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for path in plugin_paths:
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if os.path.isfile(path):
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if path.endswith(".zip"):
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trace.mutter("Don't yet support loading plugins from zip.")
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for name, path in _walk_modules(path):
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def _walk_modules(path):
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"""Generate name and path of modules and packages on path."""
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for root, dirs, files in os.walk(path):
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if f.endswith((".py", COMPILED_EXT)):
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yield f.rsplit(".", 1)[0], root
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package_dir = osutils.pathjoin(root, d)
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fullpath = _get_package_init(package_dir)
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if fullpath is not None:
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# Don't descend into subdirectories
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def describe_plugins(show_paths=False, state=None):
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"""Generate text description of plugins.
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Includes both those that have loaded, and those that failed to load.
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:param show_paths: If true, include the plugin path.
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:param state: The library state object to inspect.
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:returns: Iterator of text lines (including newlines.)
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state = breezy.get_global_state()
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loaded_plugins = getattr(state, 'plugins', {})
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plugin_warnings = set(getattr(state, 'plugin_warnings', []))
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all_names = sorted(set(loaded_plugins.keys()).union(plugin_warnings))
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for name in all_names:
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if name in loaded_plugins:
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plugin = loaded_plugins[name]
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version = plugin.__version__
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if version == 'unknown':
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yield '%s %s\n' % (name, version)
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d = plugin.module.__doc__
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doc = d.split('\n')[0]
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doc = '(no description)'
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yield (" %s\n" % doc)
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yield (" %s\n" % plugin.path())
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yield "%s (failed to load)\n" % name
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if name in state.plugin_warnings:
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for line in state.plugin_warnings[name]:
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yield " ** " + line + '\n'
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def _get_core_plugin_paths(existing_paths):
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"""Generate possible locations for plugins based on existing_paths."""
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if getattr(sys, 'frozen', False):
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# We need to use relative path to system-wide plugin
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# directory because breezy from standalone brz.exe
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# could be imported by another standalone program
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# (e.g. brz-config; or TortoiseBzr/Olive if/when they
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# will become standalone exe). [bialix 20071123]
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# __file__ typically is
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# C:\Program Files\Bazaar\lib\library.zip\breezy\plugin.pyc
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# then plugins directory is
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# C:\Program Files\Bazaar\plugins
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# so relative path is ../../../plugins
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yield osutils.abspath(osutils.pathjoin(
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osutils.dirname(__file__), '../../../plugins'))
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else: # don't look inside library.zip
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for path in existing_paths:
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def _get_site_plugin_paths(sys_paths):
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"""Generate possible locations for plugins from given sys_paths."""
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for path in sys_paths:
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if os.path.basename(path) in ('dist-packages', 'site-packages'):
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yield osutils.pathjoin(path, 'breezy', 'plugins')
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def get_user_plugin_path():
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return osutils.pathjoin(bedding.config_dir(), 'plugins')
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def record_plugin_warning(warning_message):
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trace.mutter(warning_message)
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return warning_message
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def _load_plugin_module(name, dir):
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"""Load plugin by name.
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:param name: The plugin name in the breezy.plugins namespace.
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:param dir: The directory the plugin is loaded from for error messages.
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if _MODULE_PREFIX + name in sys.modules:
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__import__(_MODULE_PREFIX + name)
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except errors.IncompatibleVersion as e:
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"Unable to load plugin %r. It supports %s "
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"versions %r but the current version is %s" %
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(name, e.api.__name__, e.wanted, e.current))
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return record_plugin_warning(warning_message)
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except Exception as e:
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trace.log_exception_quietly()
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if 'error' in debug.debug_flags:
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trace.print_exception(sys.exc_info(), sys.stderr)
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# GZ 2017-06-02: Move this name checking up a level, no point trying
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# to import things with bad names.
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if re.search('\\.|-| ', name):
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sanitised_name = re.sub('[-. ]', '_', name)
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if sanitised_name.startswith('brz_'):
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sanitised_name = sanitised_name[len('brz_'):]
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trace.warning("Unable to load %r in %r as a plugin because the "
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"file path isn't a valid module name; try renaming "
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"it to %r." % (name, dir, sanitised_name))
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return record_plugin_warning(
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'Unable to load plugin %r from %r: %s' % (name, dir, e))
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"""Return a dictionary of the plugins.
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Each item in the dictionary is a PlugIn object.
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for fullname in sys.modules:
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if fullname.startswith(_MODULE_PREFIX):
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name = fullname[len(_MODULE_PREFIX):]
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if "." not in name and sys.modules[fullname] is not None:
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result[name] = PlugIn(name, sys.modules[fullname])
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def get_loaded_plugin(name):
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"""Retrieve an already loaded plugin.
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Returns None if there is no such plugin loaded
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module = sys.modules[_MODULE_PREFIX + name]
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return PlugIn(name, module)
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def format_concise_plugin_list(state=None):
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"""Return a string holding a concise list of plugins and their version.
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state = breezy.get_global_state()
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for name, a_plugin in sorted(getattr(state, 'plugins', {}).items()):
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items.append("%s[%s]" %
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(name, a_plugin.__version__))
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return ', '.join(items)
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class PluginsHelpIndex(object):
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"""A help index that returns help topics for plugins."""
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self.prefix = 'plugins/'
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def get_topics(self, topic):
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"""Search for topic in the loaded plugins.
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This will not trigger loading of new plugins.
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:param topic: A topic to search for.
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:return: A list which is either empty or contains a single
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RegisteredTopic entry.
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if topic.startswith(self.prefix):
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topic = topic[len(self.prefix):]
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plugin_module_name = _MODULE_PREFIX + topic
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module = sys.modules[plugin_module_name]
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return [ModuleHelpTopic(module)]
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class ModuleHelpTopic(object):
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"""A help topic which returns the docstring for a module."""
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def __init__(self, module):
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:param module: The module for which help should be generated.
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def get_help_text(self, additional_see_also=None, verbose=True):
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"""Return a string with the help for this topic.
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:param additional_see_also: Additional help topics to be
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if not self.module.__doc__:
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result = "Plugin '%s' has no docstring.\n" % self.module.__name__
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result = self.module.__doc__
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if result[-1] != '\n':
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result += help_topics._format_see_also(additional_see_also)
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def get_help_topic(self):
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"""Return the module help topic: its basename."""
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return self.module.__name__[len(_MODULE_PREFIX):]
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class PlugIn(object):
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"""The breezy representation of a plugin.
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The PlugIn object provides a way to manipulate a given plugin module.
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def __init__(self, name, module):
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"""Construct a plugin for module."""
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"""Get the path that this plugin was loaded from."""
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if getattr(self.module, '__path__', None) is not None:
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return os.path.abspath(self.module.__path__[0])
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elif getattr(self.module, '__file__', None) is not None:
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path = os.path.abspath(self.module.__file__)
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if path[-4:] == COMPILED_EXT:
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pypath = path[:-4] + '.py'
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if os.path.isfile(pypath):
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return repr(self.module)
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return "<%s.%s name=%s, module=%s>" % (
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self.__class__.__module__, self.__class__.__name__,
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self.name, self.module)
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def test_suite(self):
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"""Return the plugin's test suite."""
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if getattr(self.module, 'test_suite', None) is not None:
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return self.module.test_suite()
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def load_plugin_tests(self, loader):
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"""Return the adapted plugin's test suite.
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:param loader: The custom loader that should be used to load additional
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if getattr(self.module, 'load_tests', None) is not None:
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return loader.loadTestsFromModule(self.module)
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def version_info(self):
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"""Return the plugin's version_tuple or None if unknown."""
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version_info = getattr(self.module, 'version_info', None)
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if version_info is not None:
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if isinstance(version_info, str):
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version_info = version_info.split('.')
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elif len(version_info) == 3:
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version_info = tuple(version_info) + ('final', 0)
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# The given version_info isn't even iteratible
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trace.log_exception_quietly()
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version_info = (version_info,)
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def __version__(self):
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version_info = self.version_info()
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if version_info is None or len(version_info) == 0:
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version_string = breezy._format_version_tuple(version_info)
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except (ValueError, TypeError, IndexError):
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trace.log_exception_quietly()
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# Try to show something for the version anyway
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version_string = '.'.join(map(str, version_info))
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return version_string
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class _PluginsAtFinder(object):
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"""Meta path finder to support BRZ_PLUGINS_AT configuration."""
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def __init__(self, prefix, names_and_paths):
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self.names_to_path = dict((prefix + n, p) for n, p in names_and_paths)
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return "<%s %r>" % (self.__class__.__name__, self.prefix)
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def find_spec(self, fullname, paths, target=None):
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"""New module spec returning find method."""
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if fullname not in self.names_to_path:
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path = self.names_to_path[fullname]
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if os.path.isdir(path):
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path = _get_package_init(path)
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# GZ 2017-06-02: Any reason to block loading of the name from
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# further down the path like this?
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raise ImportError("Not loading namespace package %s as %s" % (
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return importlib_util.spec_from_file_location(fullname, path)
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def find_module(self, fullname, path):
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"""Old PEP 302 import hook find_module method."""
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if fullname not in self.names_to_path:
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return _LegacyLoader(self.names_to_path[fullname])
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class _LegacyLoader(object):
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"""Source loader implementation for Python versions without importlib."""
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def __init__(self, filepath):
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self.filepath = filepath
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return "<%s %r>" % (self.__class__.__name__, self.filepath)
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def load_module(self, fullname):
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"""Load a plugin from a specific directory (or file)."""
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plugin_path = self.filepath
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if os.path.isdir(plugin_path):
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init_path = _get_package_init(plugin_path)
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if init_path is not None:
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loading_path = plugin_path
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kind = imp.PKG_DIRECTORY
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for suffix, mode, kind in imp.get_suffixes():
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if plugin_path.endswith(suffix):
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loading_path = plugin_path
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if loading_path is None:
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raise ImportError('%s cannot be loaded from %s'
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% (fullname, plugin_path))
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if kind is imp.PKG_DIRECTORY:
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f = open(loading_path, mode)
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mod = imp.load_module(fullname, f, loading_path,
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(suffix, mode, kind))
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mod.__package__ = fullname
added
removed
breezy/plugin.py
