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# Copyright (C) 2007-2011 Canonical Ltd
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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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"""Support for plugin hooking logic."""
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from __future__ import absolute_import
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from .lazy_import import lazy_import
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lazy_import(globals(), """
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_format_version_tuple,
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from breezy.i18n import gettext
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class UnknownHook(errors.BzrError):
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_fmt = "The %(type)s hook '%(hook)s' is unknown in this version of breezy."
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def __init__(self, hook_type, hook_name):
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errors.BzrError.__init__(self)
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class KnownHooksRegistry(registry.Registry):
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# known_hooks registry contains
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# tuple of (module, member name) which is the hook point
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# module where the specific hooks are defined
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# callable to get the empty specific Hooks for that attribute
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def register_lazy_hook(self, hook_module_name, hook_member_name,
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hook_factory_member_name):
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self.register_lazy((hook_module_name, hook_member_name),
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hook_module_name, hook_factory_member_name)
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def iter_parent_objects(self):
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"""Yield (hook_key, (parent_object, attr)) tuples for every registered
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hook, where 'parent_object' is the object that holds the hook
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This is useful for resetting/restoring all the hooks to a known state,
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as is done in breezy.tests.TestCase._clear_hooks.
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for key in self.keys():
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yield key, self.key_to_parent_and_attribute(key)
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def key_to_parent_and_attribute(self, key):
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"""Convert a known_hooks key to a (parent_obj, attr) pair.
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:param key: A tuple (module_name, member_name) as found in the keys of
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the known_hooks registry.
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:return: The parent_object of the hook and the name of the attribute on
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that parent object where the hook is kept.
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parent_mod, parent_member, attr = pyutils.calc_parent_name(*key)
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return pyutils.get_named_object(parent_mod, parent_member), attr
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_builtin_known_hooks = (
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('breezy.branch', 'Branch.hooks', 'BranchHooks'),
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('breezy.controldir', 'ControlDir.hooks', 'ControlDirHooks'),
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('breezy.commands', 'Command.hooks', 'CommandHooks'),
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('breezy.config', 'ConfigHooks', '_ConfigHooks'),
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('breezy.info', 'hooks', 'InfoHooks'),
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('breezy.lock', 'Lock.hooks', 'LockHooks'),
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('breezy.merge', 'Merger.hooks', 'MergeHooks'),
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('breezy.msgeditor', 'hooks', 'MessageEditorHooks'),
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('breezy.mutabletree', 'MutableTree.hooks', 'MutableTreeHooks'),
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('breezy.bzr.smart.client', '_SmartClient.hooks', 'SmartClientHooks'),
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('breezy.bzr.smart.server', 'SmartTCPServer.hooks', 'SmartServerHooks'),
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('breezy.status', 'hooks', 'StatusHooks'),
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('breezy.transport', 'Transport.hooks', 'TransportHooks'),
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('breezy.version_info_formats.format_rio', 'RioVersionInfoBuilder.hooks',
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'RioVersionInfoBuilderHooks'),
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('breezy.merge_directive', 'BaseMergeDirective.hooks',
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'MergeDirectiveHooks'),
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known_hooks = KnownHooksRegistry()
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for (_hook_module, _hook_attribute, _hook_class) in _builtin_known_hooks:
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known_hooks.register_lazy_hook(_hook_module, _hook_attribute, _hook_class)
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del _builtin_known_hooks, _hook_module, _hook_attribute, _hook_class
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def known_hooks_key_to_object(key):
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"""Convert a known_hooks key to a object.
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:param key: A tuple (module_name, member_name) as found in the keys of
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the known_hooks registry.
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:return: The object this specifies.
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return pyutils.get_named_object(*key)
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"""A dictionary mapping hook name to a list of callables.
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e.g. ['FOO'] Is the list of items to be called when the
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FOO hook is triggered.
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def __init__(self, module=None, member_name=None):
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"""Create a new hooks dictionary.
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:param module: The module from which this hooks dictionary should be loaded
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(used for lazy hooks)
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:param member_name: Name under which this hooks dictionary should be loaded.
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(used for lazy hooks)
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self._callable_names = {}
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self._lazy_callable_names = {}
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self._module = module
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self._member_name = member_name
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def add_hook(self, name, doc, introduced, deprecated=None):
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"""Add a hook point to this dictionary.
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:param name: The name of the hook, for clients to use when registering.
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:param doc: The docs for the hook.
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:param introduced: When the hook was introduced (e.g. (0, 15)).
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:param deprecated: When the hook was deprecated, None for
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raise errors.DuplicateKey(name)
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callbacks = _lazy_hooks.setdefault(
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(self._module, self._member_name, name), [])
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hookpoint = HookPoint(name=name, doc=doc, introduced=introduced,
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deprecated=deprecated, callbacks=callbacks)
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self[name] = hookpoint
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"""Generate the documentation for this Hooks instance.
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This introspects all the individual hooks and returns their docs as well.
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hook_names = sorted(self.keys())
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name = self.__class__.__name__
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hook_docs.append(name)
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hook_docs.append("-" * len(name))
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for hook_name in hook_names:
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hook = self[hook_name]
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hook_docs.append(hook.docs())
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except AttributeError:
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strings.append(hook_name)
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strings.append("~" * len(hook_name))
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strings.append("An old-style hook. For documentation see the __init__ "
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"method of '%s'\n" % (name,))
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hook_docs.extend(strings)
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return "\n".join(hook_docs)
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def get_hook_name(self, a_callable):
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"""Get the name for a_callable for UI display.
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If no name has been registered, the string 'No hook name' is returned.
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We use a fixed string rather than repr or the callables module because
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the code names are rarely meaningful for end users and this is not
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intended for debugging.
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name = self._callable_names.get(a_callable, None)
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if name is None and a_callable is not None:
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name = self._lazy_callable_names.get((a_callable.__module__,
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a_callable.__name__),
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return 'No hook name'
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def install_named_hook_lazy(self, hook_name, callable_module,
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callable_member, name):
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"""Install a_callable in to the hook hook_name lazily, and label it.
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:param hook_name: A hook name. See the __init__ method for the complete
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:param callable_module: Name of the module in which the callable is
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:param callable_member: Member name of the callable.
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:param name: A name to associate the callable with, to show users what
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hook = self[hook_name]
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raise UnknownHook(self.__class__.__name__, hook_name)
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hook_lazy = getattr(hook, "hook_lazy")
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except AttributeError:
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raise errors.UnsupportedOperation(self.install_named_hook_lazy,
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hook_lazy(callable_module, callable_member, name)
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self.name_hook_lazy(callable_module, callable_member, name)
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def install_named_hook(self, hook_name, a_callable, name):
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"""Install a_callable in to the hook hook_name, and label it name.
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:param hook_name: A hook name. See the __init__ method for the complete
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:param a_callable: The callable to be invoked when the hook triggers.
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The exact signature will depend on the hook - see the __init__
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method for details on each hook.
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:param name: A name to associate a_callable with, to show users what is
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hook = self[hook_name]
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raise UnknownHook(self.__class__.__name__, hook_name)
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# list hooks, old-style, not yet deprecated but less useful.
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hook.append(a_callable)
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except AttributeError:
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hook.hook(a_callable, name)
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self.name_hook(a_callable, name)
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def uninstall_named_hook(self, hook_name, label):
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"""Uninstall named hooks.
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:param hook_name: Hook point name
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:param label: Label of the callable to uninstall
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hook = self[hook_name]
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raise UnknownHook(self.__class__.__name__, hook_name)
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uninstall = getattr(hook, "uninstall")
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except AttributeError:
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raise errors.UnsupportedOperation(self.uninstall_named_hook, self)
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def name_hook(self, a_callable, name):
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"""Associate name with a_callable to show users what is running."""
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self._callable_names[a_callable] = name
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def name_hook_lazy(self, callable_module, callable_member, callable_name):
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self._lazy_callable_names[(callable_module, callable_member)] = \
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class HookPoint(object):
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"""A single hook that clients can register to be called back when it fires.
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:ivar name: The name of the hook.
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:ivar doc: The docs for using the hook.
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:ivar introduced: A version tuple specifying what version the hook was
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introduced in. None indicates an unknown version.
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:ivar deprecated: A version tuple specifying what version the hook was
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deprecated or superseded in. None indicates that the hook is not
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superseded or deprecated. If the hook is superseded then the doc
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should describe the recommended replacement hook to register for.
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def __init__(self, name, doc, introduced, deprecated=None, callbacks=None):
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"""Create a HookPoint.
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:param name: The name of the hook, for clients to use when registering.
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:param doc: The docs for the hook.
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:param introduced: When the hook was introduced (e.g. (0, 15)).
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:param deprecated: When the hook was deprecated, None for
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self.introduced = introduced
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self.deprecated = deprecated
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if callbacks is None:
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self._callbacks = callbacks
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"""Generate the documentation for this HookPoint.
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:return: A string terminated in \n.
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strings.append(self.name)
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strings.append('~' * len(self.name))
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introduced_string = _format_version_tuple(self.introduced)
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introduced_string = 'unknown'
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strings.append(gettext('Introduced in: %s') % introduced_string)
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deprecated_string = _format_version_tuple(self.deprecated)
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strings.append(gettext('Deprecated in: %s') % deprecated_string)
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strings.extend(textwrap.wrap(self.__doc__,
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break_long_words=False))
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return '\n'.join(strings)
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def __eq__(self, other):
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return (isinstance(other, type(self)) and other.__dict__ == self.__dict__)
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def hook_lazy(self, callback_module, callback_member, callback_label):
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"""Lazily register a callback to be called when this HookPoint fires.
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:param callback_module: Module of the callable to use when this
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:param callback_member: Member name of the callback.
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:param callback_label: A label to show in the UI while this callback is
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obj_getter = registry._LazyObjectGetter(callback_module,
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self._callbacks.append((obj_getter, callback_label))
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def hook(self, callback, callback_label):
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"""Register a callback to be called when this HookPoint fires.
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:param callback: The callable to use when this HookPoint fires.
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:param callback_label: A label to show in the UI while this callback is
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obj_getter = registry._ObjectGetter(callback)
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self._callbacks.append((obj_getter, callback_label))
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def uninstall(self, label):
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"""Uninstall the callback with the specified label.
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:param label: Label of the entry to uninstall
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entries_to_remove = []
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for entry in self._callbacks:
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(entry_callback, entry_label) = entry
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if entry_label == label:
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entries_to_remove.append(entry)
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if entries_to_remove == []:
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raise KeyError("No entry with label %r" % label)
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for entry in entries_to_remove:
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self._callbacks.remove(entry)
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return (callback.get_obj() for callback, name in self._callbacks)
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return len(self._callbacks)
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strings.append("<%s(" % type(self).__name__)
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strings.append(self.name)
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strings.append("), callbacks=[")
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callbacks = self._callbacks
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for (callback, callback_name) in callbacks:
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strings.append(repr(callback.get_obj()))
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strings.append(callback_name)
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if len(callbacks) == 1:
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return ''.join(strings)
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A hook of type *xxx* of class *yyy* needs to be registered using::
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yyy.hooks.install_named_hook("xxx", ...)
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See :doc:`Using hooks<../user-guide/hooks>` in the User Guide for examples.
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The class that contains each hook is given before the hooks it supplies. For
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instance, BranchHooks as the class is the hooks class for
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`breezy.branch.Branch.hooks`.
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Each description also indicates whether the hook runs on the client (the
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machine where bzr was invoked) or the server (the machine addressed by
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the branch URL). These may be, but are not necessarily, the same machine.
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Plugins (including hooks) are run on the server if all of these is true:
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* The connection is via a smart server (accessed with a URL starting with
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"bzr://", "bzr+ssh://" or "bzr+http://", or accessed via a "http://"
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URL when a smart server is available via HTTP).
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* The hook is either server specific or part of general infrastructure rather
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than client specific code (such as commit).
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def hooks_help_text(topic):
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segments = [_help_prefix]
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for hook_key in sorted(known_hooks.keys()):
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hooks = known_hooks_key_to_object(hook_key)
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segments.append(hooks.docs())
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return '\n'.join(segments)
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# Lazily registered hooks. Maps (module, name, hook_name) tuples
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# to lists of tuples with objectgetters and names
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def install_lazy_named_hook(hookpoints_module, hookpoints_name, hook_name,
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"""Install a callable in to a hook lazily, and label it name.
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:param hookpoints_module: Module name of the hook points.
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:param hookpoints_name: Name of the hook points.
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:param hook_name: A hook name.
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:param callable: a callable to call for the hook.
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:param name: A name to associate a_callable with, to show users what is
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key = (hookpoints_module, hookpoints_name, hook_name)
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obj_getter = registry._ObjectGetter(a_callable)
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_lazy_hooks.setdefault(key, []).append((obj_getter, name))
added
removed
breezy/hooks.py
