This file is indexed.

/usr/lib/python2.7/dist-packages/gevent/queue.py is in python-gevent 1.1.2-1.

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
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
# Copyright (c) 2009-2012 Denis Bilenko. See LICENSE for details.
"""Synchronized queues.

The :mod:`gevent.queue` module implements multi-producer, multi-consumer queues
that work across greenlets, with the API similar to the classes found in the
standard :mod:`Queue` and :class:`multiprocessing <multiprocessing.Queue>` modules.

The classes in this module implement iterator protocol. Iterating over queue
means repeatedly calling :meth:`get <Queue.get>` until :meth:`get <Queue.get>` returns ``StopIteration``.

    >>> queue = gevent.queue.Queue()
    >>> queue.put(1)
    >>> queue.put(2)
    >>> queue.put(StopIteration)
    >>> for item in queue:
    ...    print(item)
    1
    2

.. versionchanged:: 1.0
       ``Queue(0)`` now means queue of infinite size, not a channel. A :exc:`DeprecationWarning`
       will be issued with this argument.
"""

from __future__ import absolute_import
import sys
import heapq
import collections

if sys.version_info[0] == 2:
    import Queue as __queue__
else:
    import queue as __queue__
Full = __queue__.Full
Empty = __queue__.Empty

from gevent.timeout import Timeout
from gevent.hub import get_hub, Waiter, getcurrent, PY3
from gevent.hub import InvalidSwitchError


__all__ = ['Queue', 'PriorityQueue', 'LifoQueue', 'JoinableQueue', 'Channel']


def _safe_remove(deq, item):
    # For when the item may have been removed by
    # Queue._unlock
    try:
        deq.remove(item)
    except ValueError:
        pass


class Queue(object):
    """
    Create a queue object with a given maximum size.

    If *maxsize* is less than or equal to zero or ``None``, the queue
    size is infinite.

    .. versionchanged:: 1.1b3
       Queues now support :func:`len`; it behaves the same as :meth:`qsize`.
    .. versionchanged:: 1.1b3
       Multiple greenlets that block on a call to :meth:`put` for a full queue
       will now be woken up to put their items into the queue in the order in which
       they arrived. Likewise, multiple greenlets that block on a call to :meth:`get` for
       an empty queue will now receive items in the order in which they blocked. An
       implementation quirk under CPython *usually* ensured this was roughly the case
       previously anyway, but that wasn't the case for PyPy.
    """

    def __init__(self, maxsize=None, items=None):
        if maxsize is not None and maxsize <= 0:
            self.maxsize = None
            if maxsize == 0:
                import warnings
                warnings.warn('Queue(0) now equivalent to Queue(None); if you want a channel, use Channel',
                              DeprecationWarning, stacklevel=2)
        else:
            self.maxsize = maxsize
        # Explicitly maintain order for getters and putters that block
        # so that callers can consistently rely on getting things out
        # in the apparent order they went in. This was once required by
        # imap_unordered. Previously these were set() objects, and the
        # items put in the set have default hash() and eq() methods;
        # under CPython, since new objects tend to have increasing
        # hash values, this tended to roughly maintain order anyway,
        # but that's not true under PyPy. An alternative to a deque
        # (to avoid the linear scan of remove()) might be an
        # OrderedDict, but it's 2.7 only; we don't expect to have so
        # many waiters that removing an arbitrary element is a
        # bottleneck, though.
        self.getters = collections.deque()
        self.putters = collections.deque()
        self.hub = get_hub()
        self._event_unlock = None
        if items:
            self._init(maxsize, items)
        else:
            self._init(maxsize)

    # QQQ make maxsize into a property with setter that schedules unlock if necessary

    def copy(self):
        return type(self)(self.maxsize, self.queue)

    def _init(self, maxsize, items=None):
        # FIXME: Why is maxsize unused or even passed?
        # pylint:disable=unused-argument
        if items:
            self.queue = collections.deque(items)
        else:
            self.queue = collections.deque()

    def _get(self):
        return self.queue.popleft()

    def _peek(self):
        return self.queue[0]

    def _put(self, item):
        self.queue.append(item)

    def __repr__(self):
        return '<%s at %s%s>' % (type(self).__name__, hex(id(self)), self._format())

    def __str__(self):
        return '<%s%s>' % (type(self).__name__, self._format())

    def _format(self):
        result = []
        if self.maxsize is not None:
            result.append('maxsize=%r' % (self.maxsize, ))
        if getattr(self, 'queue', None):
            result.append('queue=%r' % (self.queue, ))
        if self.getters:
            result.append('getters[%s]' % len(self.getters))
        if self.putters:
            result.append('putters[%s]' % len(self.putters))
        if result:
            return ' ' + ' '.join(result)
        else:
            return ''

    def qsize(self):
        """Return the size of the queue."""
        return len(self.queue)

    def __len__(self):
        """
        Return the size of the queue. This is the same as :meth:`qsize`.

        .. versionadded: 1.1b3

            Previously, getting len() of a queue would raise a TypeError.
        """

        return self.qsize()

    def __bool__(self):
        """
        A queue object is always True.

        .. versionadded: 1.1b3

           Now that queues support len(), they need to implement ``__bool__``
           to return True for backwards compatibility.
        """
        return True
    __nonzero__ = __bool__

    def empty(self):
        """Return ``True`` if the queue is empty, ``False`` otherwise."""
        return not self.qsize()

    def full(self):
        """Return ``True`` if the queue is full, ``False`` otherwise.

        ``Queue(None)`` is never full.
        """
        return self.maxsize is not None and self.qsize() >= self.maxsize

    def put(self, item, block=True, timeout=None):
        """Put an item into the queue.

        If optional arg *block* is true and *timeout* is ``None`` (the default),
        block if necessary until a free slot is available. If *timeout* is
        a positive number, it blocks at most *timeout* seconds and raises
        the :class:`Full` exception if no free slot was available within that time.
        Otherwise (*block* is false), put an item on the queue if a free slot
        is immediately available, else raise the :class:`Full` exception (*timeout*
        is ignored in that case).
        """
        if self.maxsize is None or self.qsize() < self.maxsize:
            # there's a free slot, put an item right away
            self._put(item)
            if self.getters:
                self._schedule_unlock()
        elif self.hub is getcurrent():
            # We're in the mainloop, so we cannot wait; we can switch to other greenlets though.
            # Check if possible to get a free slot in the queue.
            while self.getters and self.qsize() and self.qsize() >= self.maxsize:
                getter = self.getters.popleft()
                getter.switch(getter)
            if self.qsize() < self.maxsize:
                self._put(item)
                return
            raise Full
        elif block:
            waiter = ItemWaiter(item, self)
            self.putters.append(waiter)
            timeout = Timeout._start_new_or_dummy(timeout, Full)
            try:
                if self.getters:
                    self._schedule_unlock()
                result = waiter.get()
                if result is not waiter:
                    raise InvalidSwitchError("Invalid switch into Queue.put: %r" % (result, ))
            finally:
                timeout.cancel()
                _safe_remove(self.putters, waiter)
        else:
            raise Full

    def put_nowait(self, item):
        """Put an item into the queue without blocking.

        Only enqueue the item if a free slot is immediately available.
        Otherwise raise the :class:`Full` exception.
        """
        self.put(item, False)

    def __get_or_peek(self, method, block, timeout):
        # Internal helper method. The `method` should be either
        # self._get when called from self.get() or self._peek when
        # called from self.peek(). Call this after the initial check
        # to see if there are items in the queue.

        if self.hub is getcurrent():
            # special case to make get_nowait() or peek_nowait() runnable in the mainloop greenlet
            # there are no items in the queue; try to fix the situation by unlocking putters
            while self.putters:
                # Note: get() used popleft(), peek used pop(); popleft
                # is almost certainly correct.
                self.putters.popleft().put_and_switch()
                if self.qsize():
                    return method()
            raise Empty()

        if not block:
            # We can't block, we're not the hub, and we have nothing
            # to return. No choice...
            raise Empty()

        waiter = Waiter()
        timeout = Timeout._start_new_or_dummy(timeout, Empty)
        try:
            self.getters.append(waiter)
            if self.putters:
                self._schedule_unlock()
            result = waiter.get()
            if result is not waiter:
                raise InvalidSwitchError('Invalid switch into Queue.get: %r' % (result, ))
            return method()
        finally:
            timeout.cancel()
            _safe_remove(self.getters, waiter)

    def get(self, block=True, timeout=None):
        """Remove and return an item from the queue.

        If optional args *block* is true and *timeout* is ``None`` (the default),
        block if necessary until an item is available. If *timeout* is a positive number,
        it blocks at most *timeout* seconds and raises the :class:`Empty` exception
        if no item was available within that time. Otherwise (*block* is false), return
        an item if one is immediately available, else raise the :class:`Empty` exception
        (*timeout* is ignored in that case).
        """
        if self.qsize():
            if self.putters:
                self._schedule_unlock()
            return self._get()

        return self.__get_or_peek(self._get, block, timeout)

    def get_nowait(self):
        """Remove and return an item from the queue without blocking.

        Only get an item if one is immediately available. Otherwise
        raise the :class:`Empty` exception.
        """
        return self.get(False)

    def peek(self, block=True, timeout=None):
        """Return an item from the queue without removing it.

        If optional args *block* is true and *timeout* is ``None`` (the default),
        block if necessary until an item is available. If *timeout* is a positive number,
        it blocks at most *timeout* seconds and raises the :class:`Empty` exception
        if no item was available within that time. Otherwise (*block* is false), return
        an item if one is immediately available, else raise the :class:`Empty` exception
        (*timeout* is ignored in that case).
        """
        if self.qsize():
            # XXX: Why doesn't this schedule an unlock like get() does?
            return self._peek()

        return self.__get_or_peek(self._peek, block, timeout)

    def peek_nowait(self):
        """Return an item from the queue without blocking.

        Only return an item if one is immediately available. Otherwise
        raise the :class:`Empty` exception.
        """
        return self.peek(False)

    def _unlock(self):
        while True:
            repeat = False
            if self.putters and (self.maxsize is None or self.qsize() < self.maxsize):
                repeat = True
                try:
                    putter = self.putters.popleft()
                    self._put(putter.item)
                except: # pylint:disable=bare-except
                    putter.throw(*sys.exc_info())
                else:
                    putter.switch(putter)
            if self.getters and self.qsize():
                repeat = True
                getter = self.getters.popleft()
                getter.switch(getter)
            if not repeat:
                return

    def _schedule_unlock(self):
        if not self._event_unlock:
            self._event_unlock = self.hub.loop.run_callback(self._unlock)

    def __iter__(self):
        return self

    def next(self):
        result = self.get()
        if result is StopIteration:
            raise result
        return result

    if PY3:
        __next__ = next
        del next


class ItemWaiter(Waiter):
    __slots__ = ['item', 'queue']

    def __init__(self, item, queue):
        Waiter.__init__(self)
        self.item = item
        self.queue = queue

    def put_and_switch(self):
        self.queue._put(self.item)
        self.queue = None
        self.item = None
        return self.switch(self)


class PriorityQueue(Queue):
    '''A subclass of :class:`Queue` that retrieves entries in priority order (lowest first).

    Entries are typically tuples of the form: ``(priority number, data)``.
    '''

    def _init(self, maxsize, items=None):
        if items:
            self.queue = list(items)
        else:
            self.queue = []

    def _put(self, item, heappush=heapq.heappush):
        # pylint:disable=arguments-differ
        heappush(self.queue, item)

    def _get(self, heappop=heapq.heappop):
        # pylint:disable=arguments-differ
        return heappop(self.queue)


class LifoQueue(Queue):
    '''A subclass of :class:`Queue` that retrieves most recently added entries first.'''

    def _init(self, maxsize, items=None):
        if items:
            self.queue = list(items)
        else:
            self.queue = []

    def _put(self, item):
        self.queue.append(item)

    def _get(self):
        return self.queue.pop()

    def _peek(self):
        return self.queue[-1]


class JoinableQueue(Queue):
    """
    A subclass of :class:`Queue` that additionally has
    :meth:`task_done` and :meth:`join` methods.
    """

    def __init__(self, maxsize=None, items=None, unfinished_tasks=None):
        """

        .. versionchanged:: 1.1a1
           If *unfinished_tasks* is not given, then all the given *items*
           (if any) will be considered unfinished.

        """
        from gevent.event import Event
        Queue.__init__(self, maxsize, items)
        self._cond = Event()
        self._cond.set()

        if unfinished_tasks:
            self.unfinished_tasks = unfinished_tasks
        elif items:
            self.unfinished_tasks = len(items)
        else:
            self.unfinished_tasks = 0

        if self.unfinished_tasks:
            self._cond.clear()

    def copy(self):
        return type(self)(self.maxsize, self.queue, self.unfinished_tasks)

    def _format(self):
        result = Queue._format(self)
        if self.unfinished_tasks:
            result += ' tasks=%s _cond=%s' % (self.unfinished_tasks, self._cond)
        return result

    def _put(self, item):
        Queue._put(self, item)
        self.unfinished_tasks += 1
        self._cond.clear()

    def task_done(self):
        '''Indicate that a formerly enqueued task is complete. Used by queue consumer threads.
        For each :meth:`get <Queue.get>` used to fetch a task, a subsequent call to :meth:`task_done` tells the queue
        that the processing on the task is complete.

        If a :meth:`join` is currently blocking, it will resume when all items have been processed
        (meaning that a :meth:`task_done` call was received for every item that had been
        :meth:`put <Queue.put>` into the queue).

        Raises a :exc:`ValueError` if called more times than there were items placed in the queue.
        '''
        if self.unfinished_tasks <= 0:
            raise ValueError('task_done() called too many times')
        self.unfinished_tasks -= 1
        if self.unfinished_tasks == 0:
            self._cond.set()

    def join(self, timeout=None):
        '''
        Block until all items in the queue have been gotten and processed.

        The count of unfinished tasks goes up whenever an item is added to the queue.
        The count goes down whenever a consumer thread calls :meth:`task_done` to indicate
        that the item was retrieved and all work on it is complete. When the count of
        unfinished tasks drops to zero, :meth:`join` unblocks.

        :param float timeout: If not ``None``, then wait no more than this time in seconds
            for all tasks to finish.
        :return: ``True`` if all tasks have finished; if ``timeout`` was given and expired before
            all tasks finished, ``False``.

        .. versionchanged:: 1.1a1
           Add the *timeout* parameter.
        '''
        return self._cond.wait(timeout=timeout)


class Channel(object):

    def __init__(self):
        self.getters = collections.deque()
        self.putters = collections.deque()
        self.hub = get_hub()
        self._event_unlock = None

    def __repr__(self):
        return '<%s at %s %s>' % (type(self).__name__, hex(id(self)), self._format())

    def __str__(self):
        return '<%s %s>' % (type(self).__name__, self._format())

    def _format(self):
        result = ''
        if self.getters:
            result += ' getters[%s]' % len(self.getters)
        if self.putters:
            result += ' putters[%s]' % len(self.putters)
        return result

    @property
    def balance(self):
        return len(self.putters) - len(self.getters)

    def qsize(self):
        return 0

    def empty(self):
        return True

    def full(self):
        return True

    def put(self, item, block=True, timeout=None):
        if self.hub is getcurrent():
            if self.getters:
                getter = self.getters.popleft()
                getter.switch(item)
                return
            raise Full

        if not block:
            timeout = 0

        waiter = Waiter()
        item = (item, waiter)
        self.putters.append(item)
        timeout = Timeout._start_new_or_dummy(timeout, Full)
        try:
            if self.getters:
                self._schedule_unlock()
            result = waiter.get()
            if result is not waiter:
                raise InvalidSwitchError("Invalid switch into Channel.put: %r" % (result, ))
        except:
            _safe_remove(self.putters, item)
            raise
        finally:
            timeout.cancel()

    def put_nowait(self, item):
        self.put(item, False)

    def get(self, block=True, timeout=None):
        if self.hub is getcurrent():
            if self.putters:
                item, putter = self.putters.popleft()
                self.hub.loop.run_callback(putter.switch, putter)
                return item

        if not block:
            timeout = 0

        waiter = Waiter()
        timeout = Timeout._start_new_or_dummy(timeout, Empty)
        try:
            self.getters.append(waiter)
            if self.putters:
                self._schedule_unlock()
            return waiter.get()
        except:
            self.getters.remove(waiter)
            raise
        finally:
            timeout.cancel()

    def get_nowait(self):
        return self.get(False)

    def _unlock(self):
        while self.putters and self.getters:
            getter = self.getters.popleft()
            item, putter = self.putters.popleft()
            getter.switch(item)
            putter.switch(putter)

    def _schedule_unlock(self):
        if not self._event_unlock:
            self._event_unlock = self.hub.loop.run_callback(self._unlock)

    def __iter__(self):
        return self

    def next(self):
        result = self.get()
        if result is StopIteration:
            raise result
        return result

    __next__ = next # py3