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Current Path : /proc/thread-self/root/usr/lib64/python2.7/multiprocessing/ |
Current File : //proc/thread-self/root/usr/lib64/python2.7/multiprocessing/queues.py |
# # Module implementing queues # # multiprocessing/queues.py # # Copyright (c) 2006-2008, R Oudkerk # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. Neither the name of author nor the names of any contributors may be # used to endorse or promote products derived from this software # without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # __all__ = ['Queue', 'SimpleQueue', 'JoinableQueue'] import sys import os import threading import collections import time import atexit import weakref from Queue import Empty, Full import _multiprocessing from . import Pipe from .synchronize import Lock, BoundedSemaphore, Semaphore, Condition from .util import debug, info, Finalize, register_after_fork, is_exiting from .forking import assert_spawning # # Queue type using a pipe, buffer and thread # class Queue(object): def __init__(self, maxsize=0): if maxsize <= 0: maxsize = _multiprocessing.SemLock.SEM_VALUE_MAX self._maxsize = maxsize self._reader, self._writer = Pipe(duplex=False) self._rlock = Lock() self._opid = os.getpid() if sys.platform == 'win32': self._wlock = None else: self._wlock = Lock() self._sem = BoundedSemaphore(maxsize) self._after_fork() if sys.platform != 'win32': register_after_fork(self, Queue._after_fork) def __getstate__(self): assert_spawning(self) return (self._maxsize, self._reader, self._writer, self._rlock, self._wlock, self._sem, self._opid) def __setstate__(self, state): (self._maxsize, self._reader, self._writer, self._rlock, self._wlock, self._sem, self._opid) = state self._after_fork() def _after_fork(self): debug('Queue._after_fork()') self._notempty = threading.Condition(threading.Lock()) self._buffer = collections.deque() self._thread = None self._jointhread = None self._joincancelled = False self._closed = False self._close = None self._send = self._writer.send self._recv = self._reader.recv self._poll = self._reader.poll def put(self, obj, block=True, timeout=None): assert not self._closed if not self._sem.acquire(block, timeout): raise Full self._notempty.acquire() try: if self._thread is None: self._start_thread() self._buffer.append(obj) self._notempty.notify() finally: self._notempty.release() def get(self, block=True, timeout=None): if block and timeout is None: self._rlock.acquire() try: res = self._recv() self._sem.release() return res finally: self._rlock.release() else: if block: deadline = time.time() + timeout if not self._rlock.acquire(block, timeout): raise Empty try: if block: timeout = deadline - time.time() if not self._poll(timeout): raise Empty elif not self._poll(): raise Empty res = self._recv() self._sem.release() return res finally: self._rlock.release() def qsize(self): # Raises NotImplementedError on Mac OSX because of broken sem_getvalue() return self._maxsize - self._sem._semlock._get_value() def empty(self): return not self._poll() def full(self): return self._sem._semlock._is_zero() def get_nowait(self): return self.get(False) def put_nowait(self, obj): return self.put(obj, False) def close(self): self._closed = True try: self._reader.close() finally: close = self._close if close: self._close = None close() def join_thread(self): debug('Queue.join_thread()') assert self._closed if self._jointhread: self._jointhread() def cancel_join_thread(self): debug('Queue.cancel_join_thread()') self._joincancelled = True try: self._jointhread.cancel() except AttributeError: pass def _start_thread(self): debug('Queue._start_thread()') # Start thread which transfers data from buffer to pipe self._buffer.clear() self._thread = threading.Thread( target=Queue._feed, args=(self._buffer, self._notempty, self._send, self._wlock, self._writer.close), name='QueueFeederThread' ) self._thread.daemon = True debug('doing self._thread.start()') self._thread.start() debug('... done self._thread.start()') # On process exit we will wait for data to be flushed to pipe. if not self._joincancelled: self._jointhread = Finalize( self._thread, Queue._finalize_join, [weakref.ref(self._thread)], exitpriority=-5 ) # Send sentinel to the thread queue object when garbage collected self._close = Finalize( self, Queue._finalize_close, [self._buffer, self._notempty], exitpriority=10 ) @staticmethod def _finalize_join(twr): debug('joining queue thread') thread = twr() if thread is not None: thread.join() debug('... queue thread joined') else: debug('... queue thread already dead') @staticmethod def _finalize_close(buffer, notempty): debug('telling queue thread to quit') notempty.acquire() try: buffer.append(_sentinel) notempty.notify() finally: notempty.release() @staticmethod def _feed(buffer, notempty, send, writelock, close): debug('starting thread to feed data to pipe') nacquire = notempty.acquire nrelease = notempty.release nwait = notempty.wait bpopleft = buffer.popleft sentinel = _sentinel if sys.platform != 'win32': wacquire = writelock.acquire wrelease = writelock.release else: wacquire = None while 1: try: nacquire() try: if not buffer: nwait() finally: nrelease() try: while 1: obj = bpopleft() if obj is sentinel: debug('feeder thread got sentinel -- exiting') close() return if wacquire is None: send(obj) else: wacquire() try: send(obj) finally: wrelease() except IndexError: pass except Exception as e: # Since this runs in a daemon thread the resources it uses # may be become unusable while the process is cleaning up. # We ignore errors which happen after the process has # started to cleanup. if is_exiting(): info('error in queue thread: %s', e) return else: import traceback traceback.print_exc() _sentinel = object() # # A queue type which also supports join() and task_done() methods # # Note that if you do not call task_done() for each finished task then # eventually the counter's semaphore may overflow causing Bad Things # to happen. # class JoinableQueue(Queue): def __init__(self, maxsize=0): Queue.__init__(self, maxsize) self._unfinished_tasks = Semaphore(0) self._cond = Condition() def __getstate__(self): return Queue.__getstate__(self) + (self._cond, self._unfinished_tasks) def __setstate__(self, state): Queue.__setstate__(self, state[:-2]) self._cond, self._unfinished_tasks = state[-2:] def put(self, obj, block=True, timeout=None): assert not self._closed if not self._sem.acquire(block, timeout): raise Full self._notempty.acquire() self._cond.acquire() try: if self._thread is None: self._start_thread() self._buffer.append(obj) self._unfinished_tasks.release() self._notempty.notify() finally: self._cond.release() self._notempty.release() def task_done(self): self._cond.acquire() try: if not self._unfinished_tasks.acquire(False): raise ValueError('task_done() called too many times') if self._unfinished_tasks._semlock._is_zero(): self._cond.notify_all() finally: self._cond.release() def join(self): self._cond.acquire() try: if not self._unfinished_tasks._semlock._is_zero(): self._cond.wait() finally: self._cond.release() # # Simplified Queue type -- really just a locked pipe # class SimpleQueue(object): def __init__(self): self._reader, self._writer = Pipe(duplex=False) self._rlock = Lock() if sys.platform == 'win32': self._wlock = None else: self._wlock = Lock() self._make_methods() def empty(self): return not self._reader.poll() def __getstate__(self): assert_spawning(self) return (self._reader, self._writer, self._rlock, self._wlock) def __setstate__(self, state): (self._reader, self._writer, self._rlock, self._wlock) = state self._make_methods() def _make_methods(self): recv = self._reader.recv racquire, rrelease = self._rlock.acquire, self._rlock.release def get(): racquire() try: return recv() finally: rrelease() self.get = get if self._wlock is None: # writes to a message oriented win32 pipe are atomic self.put = self._writer.send else: send = self._writer.send wacquire, wrelease = self._wlock.acquire, self._wlock.release def put(obj): wacquire() try: return send(obj) finally: wrelease() self.put = put