mirror of
https://github.com/moparisthebest/SickRage
synced 2024-12-12 11:02:21 -05:00
218 lines
7.1 KiB
Python
218 lines
7.1 KiB
Python
# event/base.py
|
|
# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
|
|
"""Base implementation classes.
|
|
|
|
The public-facing ``Events`` serves as the base class for an event interface;
|
|
it's public attributes represent different kinds of events. These attributes
|
|
are mirrored onto a ``_Dispatch`` class, which serves as a container for
|
|
collections of listener functions. These collections are represented both
|
|
at the class level of a particular ``_Dispatch`` class as well as within
|
|
instances of ``_Dispatch``.
|
|
|
|
"""
|
|
from __future__ import absolute_import
|
|
|
|
from .. import util
|
|
from .attr import _JoinedDispatchDescriptor, _EmptyListener, _DispatchDescriptor
|
|
|
|
_registrars = util.defaultdict(list)
|
|
|
|
|
|
def _is_event_name(name):
|
|
return not name.startswith('_') and name != 'dispatch'
|
|
|
|
|
|
class _UnpickleDispatch(object):
|
|
"""Serializable callable that re-generates an instance of
|
|
:class:`_Dispatch` given a particular :class:`.Events` subclass.
|
|
|
|
"""
|
|
def __call__(self, _parent_cls):
|
|
for cls in _parent_cls.__mro__:
|
|
if 'dispatch' in cls.__dict__:
|
|
return cls.__dict__['dispatch'].dispatch_cls(_parent_cls)
|
|
else:
|
|
raise AttributeError("No class with a 'dispatch' member present.")
|
|
|
|
|
|
class _Dispatch(object):
|
|
"""Mirror the event listening definitions of an Events class with
|
|
listener collections.
|
|
|
|
Classes which define a "dispatch" member will return a
|
|
non-instantiated :class:`._Dispatch` subclass when the member
|
|
is accessed at the class level. When the "dispatch" member is
|
|
accessed at the instance level of its owner, an instance
|
|
of the :class:`._Dispatch` class is returned.
|
|
|
|
A :class:`._Dispatch` class is generated for each :class:`.Events`
|
|
class defined, by the :func:`._create_dispatcher_class` function.
|
|
The original :class:`.Events` classes remain untouched.
|
|
This decouples the construction of :class:`.Events` subclasses from
|
|
the implementation used by the event internals, and allows
|
|
inspecting tools like Sphinx to work in an unsurprising
|
|
way against the public API.
|
|
|
|
"""
|
|
|
|
_events = None
|
|
"""reference the :class:`.Events` class which this
|
|
:class:`._Dispatch` is created for."""
|
|
|
|
def __init__(self, _parent_cls):
|
|
self._parent_cls = _parent_cls
|
|
|
|
@util.classproperty
|
|
def _listen(cls):
|
|
return cls._events._listen
|
|
|
|
def _join(self, other):
|
|
"""Create a 'join' of this :class:`._Dispatch` and another.
|
|
|
|
This new dispatcher will dispatch events to both
|
|
:class:`._Dispatch` objects.
|
|
|
|
"""
|
|
if '_joined_dispatch_cls' not in self.__class__.__dict__:
|
|
cls = type(
|
|
"Joined%s" % self.__class__.__name__,
|
|
(_JoinedDispatcher, self.__class__), {}
|
|
)
|
|
for ls in _event_descriptors(self):
|
|
setattr(cls, ls.name, _JoinedDispatchDescriptor(ls.name))
|
|
|
|
self.__class__._joined_dispatch_cls = cls
|
|
return self._joined_dispatch_cls(self, other)
|
|
|
|
def __reduce__(self):
|
|
return _UnpickleDispatch(), (self._parent_cls, )
|
|
|
|
def _update(self, other, only_propagate=True):
|
|
"""Populate from the listeners in another :class:`_Dispatch`
|
|
object."""
|
|
|
|
for ls in _event_descriptors(other):
|
|
if isinstance(ls, _EmptyListener):
|
|
continue
|
|
getattr(self, ls.name).\
|
|
for_modify(self)._update(ls, only_propagate=only_propagate)
|
|
|
|
@util.hybridmethod
|
|
def _clear(self):
|
|
for attr in dir(self):
|
|
if _is_event_name(attr):
|
|
getattr(self, attr).for_modify(self).clear()
|
|
|
|
|
|
def _event_descriptors(target):
|
|
return [getattr(target, k) for k in dir(target) if _is_event_name(k)]
|
|
|
|
|
|
class _EventMeta(type):
|
|
"""Intercept new Event subclasses and create
|
|
associated _Dispatch classes."""
|
|
|
|
def __init__(cls, classname, bases, dict_):
|
|
_create_dispatcher_class(cls, classname, bases, dict_)
|
|
return type.__init__(cls, classname, bases, dict_)
|
|
|
|
|
|
def _create_dispatcher_class(cls, classname, bases, dict_):
|
|
"""Create a :class:`._Dispatch` class corresponding to an
|
|
:class:`.Events` class."""
|
|
|
|
# there's all kinds of ways to do this,
|
|
# i.e. make a Dispatch class that shares the '_listen' method
|
|
# of the Event class, this is the straight monkeypatch.
|
|
dispatch_base = getattr(cls, 'dispatch', _Dispatch)
|
|
dispatch_cls = type("%sDispatch" % classname,
|
|
(dispatch_base, ), {})
|
|
cls._set_dispatch(cls, dispatch_cls)
|
|
|
|
for k in dict_:
|
|
if _is_event_name(k):
|
|
setattr(dispatch_cls, k, _DispatchDescriptor(cls, dict_[k]))
|
|
_registrars[k].append(cls)
|
|
|
|
if getattr(cls, '_dispatch_target', None):
|
|
cls._dispatch_target.dispatch = dispatcher(cls)
|
|
|
|
|
|
def _remove_dispatcher(cls):
|
|
for k in dir(cls):
|
|
if _is_event_name(k):
|
|
_registrars[k].remove(cls)
|
|
if not _registrars[k]:
|
|
del _registrars[k]
|
|
|
|
class Events(util.with_metaclass(_EventMeta, object)):
|
|
"""Define event listening functions for a particular target type."""
|
|
|
|
@staticmethod
|
|
def _set_dispatch(cls, dispatch_cls):
|
|
# this allows an Events subclass to define additional utility
|
|
# methods made available to the target via
|
|
# "self.dispatch._events.<utilitymethod>"
|
|
# @staticemethod to allow easy "super" calls while in a metaclass
|
|
# constructor.
|
|
cls.dispatch = dispatch_cls
|
|
dispatch_cls._events = cls
|
|
|
|
|
|
@classmethod
|
|
def _accept_with(cls, target):
|
|
# Mapper, ClassManager, Session override this to
|
|
# also accept classes, scoped_sessions, sessionmakers, etc.
|
|
if hasattr(target, 'dispatch') and (
|
|
isinstance(target.dispatch, cls.dispatch) or \
|
|
isinstance(target.dispatch, type) and \
|
|
issubclass(target.dispatch, cls.dispatch)
|
|
):
|
|
return target
|
|
else:
|
|
return None
|
|
|
|
@classmethod
|
|
def _listen(cls, event_key, propagate=False, insert=False, named=False):
|
|
event_key.base_listen(propagate=propagate, insert=insert, named=named)
|
|
|
|
@classmethod
|
|
def _remove(cls, event_key):
|
|
event_key.remove()
|
|
|
|
@classmethod
|
|
def _clear(cls):
|
|
cls.dispatch._clear()
|
|
|
|
|
|
class _JoinedDispatcher(object):
|
|
"""Represent a connection between two _Dispatch objects."""
|
|
|
|
def __init__(self, local, parent):
|
|
self.local = local
|
|
self.parent = parent
|
|
self._parent_cls = local._parent_cls
|
|
|
|
|
|
class dispatcher(object):
|
|
"""Descriptor used by target classes to
|
|
deliver the _Dispatch class at the class level
|
|
and produce new _Dispatch instances for target
|
|
instances.
|
|
|
|
"""
|
|
def __init__(self, events):
|
|
self.dispatch_cls = events.dispatch
|
|
self.events = events
|
|
|
|
def __get__(self, obj, cls):
|
|
if obj is None:
|
|
return self.dispatch_cls
|
|
obj.__dict__['dispatch'] = disp = self.dispatch_cls(cls)
|
|
return disp
|
|
|