This file is indexed.

/usr/lib/python2.7/dist-packages/gevent/lock.py is in python-gevent 1.1.0-2.

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
# Copyright (c) 2009-2012 Denis Bilenko. See LICENSE for details.
"""Locking primitives"""
from __future__ import absolute_import

from gevent.hub import getcurrent, PYPY
from gevent._semaphore import Semaphore, BoundedSemaphore


__all__ = ['Semaphore', 'DummySemaphore', 'BoundedSemaphore', 'RLock']

# On PyPy, we don't compile the Semaphore class with Cython. Under
# Cython, each individual method holds the GIL for its entire
# duration, ensuring that no other thread can interrupt us in an
# unsafe state (only when we _do_wait do we call back into Python and
# allow switching threads). Simulate that here through the use of a manual
# lock. (We use a separate lock for each semaphore to allow sys.settrace functions
# to use locks *other* than the one being traced.)
if PYPY:
    # TODO: Need to use monkey.get_original?
    from thread import allocate_lock as _allocate_lock
    from thread import get_ident as _get_ident
    _sem_lock = _allocate_lock()

    class _OwnedLock(object):

        def __init__(self):
            self._owner = None
            self._block = _allocate_lock()
            self._locking = {}
            self._count = 0

        def untraceable(f):
            # Don't allow re-entry to these functions in a single thread, as can
            # happen if a sys.settrace is used
            def wrapper(self):
                me = _get_ident()
                try:
                    count = self._locking[me]
                except KeyError:
                    count = self._locking[me] = 1
                else:
                    count = self._locking[me] = count + 1
                if count:
                    return

                try:
                    return f(self)
                finally:
                    count = count - 1
                    if not count:
                        del self._locking[me]
                    else:
                        self._locking[me] = count
            return wrapper

        @untraceable
        def acquire(self):
            me = _get_ident()
            if self._owner == me:
                self._count += 1
                return

            self._owner = me
            self._block.acquire()
            self._count = 1

        @untraceable
        def release(self):
            self._count = count = self._count - 1
            if not count:
                self._block.release()
                self._owner = None

    # acquire, wait, and release all acquire the lock on entry and release it
    # on exit. acquire and wait can call _do_wait, which must release it on entry
    # and re-acquire it for them on exit.
    class _around(object):
        before = None
        after = None

        def __enter__(self):
            self.before()

        def __exit__(self, t, v, tb):
            self.after()

    def _decorate(func, cmname):
        # functools.wrap?
        def wrapped(self, *args, **kwargs):
            with getattr(self, cmname):
                return func(self, *args, **kwargs)
        return wrapped

    Semaphore._py3k_acquire = Semaphore.acquire = _decorate(Semaphore.acquire, '_lock_locked')
    Semaphore.release = _decorate(Semaphore.release, '_lock_locked')
    Semaphore.wait = _decorate(Semaphore.wait, '_lock_locked')
    Semaphore._do_wait = _decorate(Semaphore._do_wait, '_lock_unlocked')

    _Sem_init = Semaphore.__init__

    def __init__(self, *args, **kwargs):
        l = self._lock_lock = _OwnedLock()
        self._lock_locked = _around()
        self._lock_locked.before = l.acquire
        self._lock_locked.after = l.release
        self._lock_unlocked = _around()
        self._lock_unlocked.before = l.release
        self._lock_unlocked.after = l.acquire
        _Sem_init(self, *args, **kwargs)

    Semaphore.__init__ = __init__

    del _decorate


class DummySemaphore(object):
    """
    DummySemaphore(value=None) -> DummySemaphore

    A Semaphore initialized with "infinite" initial value. None of its
    methods ever block.

    This can be used to parameterize on whether or not to actually
    guard access to a potentially limited resource. If the resource is
    actually limited, such as a fixed-size thread pool, use a real
    :class:`Semaphore`, but if the resource is unbounded, use an
    instance of this class. In that way none of the supporting code
    needs to change.

    Similarly, it can be used to parameterize on whether or not to
    enforce mutual exclusion to some underlying object. If the
    underlying object is known to be thread-safe itself mutual
    exclusion is not needed and a ``DummySemaphore`` can be used, but
    if that's not true, use a real ``Semaphore``.
    """

    # Internally this is used for exactly the purpose described in the
    # documentation. gevent.pool.Pool uses it instead of a Semaphore
    # when the pool size is unlimited, and
    # gevent.fileobject.FileObjectThread takes a parameter that
    # determines whether it should lock around IO to the underlying
    # file object.

    def __init__(self, value=None):
        """
        .. versionchanged:: 1.1rc3
            Accept and ignore a *value* argument for compatibility with Semaphore.
        """
        pass

    def __str__(self):
        return '<%s>' % self.__class__.__name__

    def locked(self):
        """A DummySemaphore is never locked so this always returns False."""
        return False

    def release(self):
        """Releasing a dummy semaphore does nothing."""
        pass

    def rawlink(self, callback):
        # XXX should still work and notify?
        pass

    def unlink(self, callback):
        pass

    def wait(self, timeout=None):
        """Waiting for a DummySemaphore returns immediately."""
        pass

    def acquire(self, blocking=True, timeout=None):
        """
        A DummySemaphore can always be acquired immediately so this always
        returns True and ignores its arguments.

        .. versionchanged:: 1.1a1
           Always return *true*.
        """
        return True

    def __enter__(self):
        pass

    def __exit__(self, typ, val, tb):
        pass


class RLock(object):

    def __init__(self):
        self._block = Semaphore(1)
        self._owner = None
        self._count = 0

    def __repr__(self):
        return "<%s at 0x%x _block=%s _count=%r _owner=%r)>" % (
            self.__class__.__name__,
            id(self),
            self._block,
            self._count,
            self._owner)

    def acquire(self, blocking=1):
        me = getcurrent()
        if self._owner is me:
            self._count = self._count + 1
            return 1
        rc = self._block.acquire(blocking)
        if rc:
            self._owner = me
            self._count = 1
        return rc

    def __enter__(self):
        return self.acquire()

    def release(self):
        if self._owner is not getcurrent():
            raise RuntimeError("cannot release un-aquired lock")
        self._count = count = self._count - 1
        if not count:
            self._owner = None
            self._block.release()

    def __exit__(self, typ, value, tb):
        self.release()

    # Internal methods used by condition variables

    def _acquire_restore(self, count_owner):
        count, owner = count_owner
        self._block.acquire()
        self._count = count
        self._owner = owner

    def _release_save(self):
        count = self._count
        self._count = 0
        owner = self._owner
        self._owner = None
        self._block.release()
        return (count, owner)

    def _is_owned(self):
        return self._owner is getcurrent()