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"""Support for plugin hooking logic."""
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from bzrlib import registry
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from bzrlib.lazy_import import lazy_import
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from bzrlib.symbol_versioning import deprecated_method
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lazy_import(globals(), """
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from bzrlib import (
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_format_version_tuple,
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_format_version_tuple,
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from bzrlib.help_topics import help_as_plain_text
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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 bzrlib.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, (module_name, member_name)):
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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(module_name,
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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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('bzrlib.branch', 'Branch.hooks', 'BranchHooks'),
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('bzrlib.bzrdir', 'BzrDir.hooks', 'BzrDirHooks'),
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('bzrlib.commands', 'Command.hooks', 'CommandHooks'),
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('bzrlib.config', 'ConfigHooks', '_ConfigHooks'),
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('bzrlib.info', 'hooks', 'InfoHooks'),
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('bzrlib.lock', 'Lock.hooks', 'LockHooks'),
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('bzrlib.merge', 'Merger.hooks', 'MergeHooks'),
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('bzrlib.msgeditor', 'hooks', 'MessageEditorHooks'),
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('bzrlib.mutabletree', 'MutableTree.hooks', 'MutableTreeHooks'),
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('bzrlib.smart.client', '_SmartClient.hooks', 'SmartClientHooks'),
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('bzrlib.smart.server', 'SmartTCPServer.hooks', 'SmartServerHooks'),
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('bzrlib.status', 'hooks', 'StatusHooks'),
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('bzrlib.version_info_formats.format_rio', 'RioVersionInfoBuilder.hooks',
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'RioVersionInfoBuilderHooks'),
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('bzrlib.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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known_hooks = 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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known_hooks.register_lazy(('bzrlib.branch', 'Branch.hooks'), 'bzrlib.branch',
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known_hooks.register_lazy(('bzrlib.bzrdir', 'BzrDir.hooks'), 'bzrlib.bzrdir',
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known_hooks.register_lazy(('bzrlib.commands', 'Command.hooks'),
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'bzrlib.commands', 'CommandHooks')
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known_hooks.register_lazy(('bzrlib.info', 'hooks'),
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'bzrlib.info', 'InfoHooks')
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known_hooks.register_lazy(('bzrlib.lock', 'Lock.hooks'), 'bzrlib.lock',
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known_hooks.register_lazy(('bzrlib.msgeditor', 'hooks'), 'bzrlib.msgeditor',
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known_hooks.register_lazy(('bzrlib.mutabletree', 'MutableTree.hooks'),
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'bzrlib.mutabletree', 'MutableTreeHooks')
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known_hooks.register_lazy(('bzrlib.smart.client', '_SmartClient.hooks'),
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'bzrlib.smart.client', 'SmartClientHooks')
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known_hooks.register_lazy(('bzrlib.smart.server', 'SmartTCPServer.hooks'),
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'bzrlib.smart.server', 'SmartServerHooks')
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known_hooks.register_lazy(
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('bzrlib.version_info_formats.format_rio', 'RioVersionInfoBuilder.hooks'),
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'bzrlib.version_info_formats.format_rio', 'RioVersionInfoBuilderHooks')
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def known_hooks_key_to_object((module_name, member_name)):
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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(module_name, member_name)
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@symbol_versioning.deprecated_function(symbol_versioning.deprecated_in((2, 3)))
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def known_hooks_key_to_parent_and_attribute(key):
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"""See KnownHooksRegistry.key_to_parent_and_attribute."""
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return known_hooks.key_to_parent_and_attribute(key)
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return registry._LazyObjectGetter(module_name, member_name).get_obj()
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def known_hooks_key_to_parent_and_attribute((module_name, member_name)):
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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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member_list = member_name.rsplit('.', 1)
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if len(member_list) == 2:
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parent_name, attribute = member_list
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attribute = member_name
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parent = known_hooks_key_to_object((module_name, parent_name))
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return parent, attribute
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class Hooks(dict):
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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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dict.__init__(self)
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self._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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@symbol_versioning.deprecated_method(symbol_versioning.deprecated_in((2, 4)))
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def create_hook(self, hook):
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"""Create a hook which can have callbacks registered for it.
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return self._callable_names.get(a_callable, "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 errors.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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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 hook_name: A hook name. See the __init__ method of BranchHooks
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for the complete list of hooks.
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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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method of BranchHooks 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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"""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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deprecated or superceded in. None indicates that the hook is not
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superceded or deprecated. If the hook is superceded then the doc
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should describe the recommended replacement hook to register for.
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:ivar doc: The docs for using the hook.
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def __init__(self, name, doc, introduced, deprecated=None, callbacks=None):
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def __init__(self, name, doc, introduced, deprecated):
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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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strings.append('Introduced in: %s' % introduced_string)
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if self.deprecated:
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deprecated_string = _format_version_tuple(self.deprecated)
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strings.append('Deprecated in: %s' % deprecated_string)
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deprecated_string = 'Not deprecated'
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strings.append('Deprecated in: %s' % deprecated_string)
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strings.append('')
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strings.extend(textwrap.wrap(self.__doc__,
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break_long_words=False))
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strings.extend(textwrap.wrap(self.__doc__))
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strings.append('')
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return '\n'.join(strings)
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def __eq__(self, other):
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return (type(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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return (type(other) == type(self) and
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other.__dict__ == self.__dict__)
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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_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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self._callbacks.append(callback)
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if callback_label is not None:
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self._callback_names[callback] = callback_label
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def __iter__(self):
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return (callback.get_obj() for callback, name in self._callbacks)
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return iter(self._callbacks)
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def __len__(self):
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return len(self._callbacks)
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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))