This file is indexed.

/usr/lib/python3/dist-packages/sqlalchemy/event.py is in python3-sqlalchemy 0.7.8-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
# sqlalchemy/event.py
# Copyright (C) 2005-2012 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 event API."""

from sqlalchemy import util, exc

CANCEL = util.symbol('CANCEL')
NO_RETVAL = util.symbol('NO_RETVAL')

def listen(target, identifier, fn, *args, **kw):
    """Register a listener function for the given target.

    e.g.::

        from sqlalchemy import event
        from sqlalchemy.schema import UniqueConstraint

        def unique_constraint_name(const, table):
            const.name = "uq_%s_%s" % (
                table.name,
                list(const.columns)[0].name
            )
        event.listen(
                UniqueConstraint, 
                "after_parent_attach", 
                unique_constraint_name)

    """

    for evt_cls in _registrars[identifier]:
        tgt = evt_cls._accept_with(target)
        if tgt is not None:
            tgt.dispatch._listen(tgt, identifier, fn, *args, **kw)
            return
    raise exc.InvalidRequestError("No such event '%s' for target '%s'" %
                                (identifier,target))

def listens_for(target, identifier, *args, **kw):
    """Decorate a function as a listener for the given target + identifier.

    e.g.::

        from sqlalchemy import event
        from sqlalchemy.schema import UniqueConstraint

        @event.listens_for(UniqueConstraint, "after_parent_attach")
        def unique_constraint_name(const, table):
            const.name = "uq_%s_%s" % (
                table.name,
                list(const.columns)[0].name
            )
    """
    def decorate(fn):
        listen(target, identifier, fn, *args, **kw)
        return fn
    return decorate

def remove(target, identifier, fn):
    """Remove an event listener.

    Note that some event removals, particularly for those event dispatchers
    which create wrapper functions and secondary even listeners, may not yet
    be supported.

    """
    for evt_cls in _registrars[identifier]:
        for tgt in evt_cls._accept_with(target):
            tgt.dispatch._remove(identifier, tgt, fn, *args, **kw)
            return

_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.

    """

    def __init__(self, _parent_cls):
        self._parent_cls = _parent_cls

    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):
            getattr(self, ls.name)._update(ls, only_propagate=only_propagate)

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)
    cls.dispatch = dispatch_cls = type("%sDispatch" % classname, 
                                        (dispatch_base, ), {})
    dispatch_cls._listen = cls._listen
    dispatch_cls._clear = cls._clear

    for k in dict_:
        if _is_event_name(k):
            setattr(dispatch_cls, k, _DispatchDescriptor(dict_[k]))
            _registrars[k].append(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(object, metaclass=_EventMeta):
    """Define event listening functions for a particular target type."""

    @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, target, identifier, fn, propagate=False, insert=False):
        if insert:
            getattr(target.dispatch, identifier).insert(fn, target, propagate)
        else:
            getattr(target.dispatch, identifier).append(fn, target, propagate)

    @classmethod
    def _remove(cls, target, identifier, fn):
        getattr(target.dispatch, identifier).remove(fn, target)

    @classmethod
    def _clear(cls):
        for attr in dir(cls.dispatch):
            if _is_event_name(attr):
                getattr(cls.dispatch, attr).clear()

class _DispatchDescriptor(object):
    """Class-level attributes on :class:`._Dispatch` classes."""

    def __init__(self, fn):
        self.__name__ = fn.__name__
        self.__doc__ = fn.__doc__
        self._clslevel = util.defaultdict(list)

    def insert(self, obj, target, propagate):
        assert isinstance(target, type), \
                "Class-level Event targets must be classes."
        stack = [target]
        while stack:
            cls = stack.pop(0)
            stack.extend(cls.__subclasses__())
            if cls is not target and cls not in self._clslevel:
                self.update_subclass(cls)
            else:
                self._clslevel[cls].insert(0, obj)

    def append(self, obj, target, propagate):
        assert isinstance(target, type), \
                "Class-level Event targets must be classes."

        stack = [target]
        while stack:
            cls = stack.pop(0)
            stack.extend(cls.__subclasses__())
            if cls is not target and cls not in self._clslevel:
                self.update_subclass(cls)
            else:
                self._clslevel[cls].append(obj)

    def update_subclass(self, target):
        clslevel = self._clslevel[target]
        for cls in target.__mro__[1:]:
            if cls in self._clslevel:
                clslevel.extend([
                    fn for fn 
                    in self._clslevel[cls] 
                    if fn not in clslevel
                ])

    def remove(self, obj, target):
        stack = [target]
        while stack:
            cls = stack.pop(0)
            stack.extend(cls.__subclasses__())
            self._clslevel[cls].remove(obj)

    def clear(self):
        """Clear all class level listeners"""

        for dispatcher in list(self._clslevel.values()):
            dispatcher[:] = []

    def __get__(self, obj, cls):
        if obj is None:
            return self
        obj.__dict__[self.__name__] = result = \
                            _ListenerCollection(self, obj._parent_cls)
        return result

class _ListenerCollection(object):
    """Instance-level attributes on instances of :class:`._Dispatch`.

    Represents a collection of listeners.

    """

    _exec_once = False

    def __init__(self, parent, target_cls):
        if target_cls not in parent._clslevel:
            parent.update_subclass(target_cls)
        self.parent_listeners = parent._clslevel[target_cls]
        self.name = parent.__name__
        self.listeners = []
        self.propagate = set()

    def exec_once(self, *args, **kw):
        """Execute this event, but only if it has not been
        executed already for this collection."""

        if not self._exec_once:
            self(*args, **kw)
            self._exec_once = True

    def __call__(self, *args, **kw):
        """Execute this event."""

        for fn in self.parent_listeners:
            fn(*args, **kw)
        for fn in self.listeners:
            fn(*args, **kw)

    # I'm not entirely thrilled about the overhead here,
    # but this allows class-level listeners to be added
    # at any point.
    #
    # alternatively, _DispatchDescriptor could notify
    # all _ListenerCollection objects, but then we move
    # to a higher memory model, i.e.weakrefs to all _ListenerCollection
    # objects, the _DispatchDescriptor collection repeated
    # for all instances.

    def __len__(self):
        return len(self.parent_listeners + self.listeners)

    def __iter__(self):
        return iter(self.parent_listeners + self.listeners)

    def __getitem__(self, index):
        return (self.parent_listeners + self.listeners)[index]

    def __bool__(self):
        return bool(self.listeners or self.parent_listeners)

    def _update(self, other, only_propagate=True):
        """Populate from the listeners in another :class:`_Dispatch`
            object."""

        existing_listeners = self.listeners
        existing_listener_set = set(existing_listeners)
        self.propagate.update(other.propagate)
        existing_listeners.extend([l for l 
                                in other.listeners 
                                if l not in existing_listener_set
                                and not only_propagate or l in self.propagate
                                ])

    def insert(self, obj, target, propagate):
        if obj not in self.listeners:
            self.listeners.insert(0, obj)
            if propagate:
                self.propagate.add(obj)

    def append(self, obj, target, propagate):
        if obj not in self.listeners:
            self.listeners.append(obj)
            if propagate:
                self.propagate.add(obj)

    def remove(self, obj, target):
        if obj in self.listeners:
            self.listeners.remove(obj)
            self.propagate.discard(obj)

    def clear(self):
        self.listeners[:] = []
        self.propagate.clear()

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