diff -r ffa851df0825 -r 2fb8b9db1c86 symbian-qemu-0.9.1-12/python-2.6.1/Lib/multiprocessing/pool.py --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/symbian-qemu-0.9.1-12/python-2.6.1/Lib/multiprocessing/pool.py Fri Jul 31 15:01:17 2009 +0100 @@ -0,0 +1,596 @@ +# +# Module providing the `Pool` class for managing a process pool +# +# multiprocessing/pool.py +# +# Copyright (c) 2007-2008, R Oudkerk --- see COPYING.txt +# + +__all__ = ['Pool'] + +# +# Imports +# + +import threading +import Queue +import itertools +import collections +import time + +from multiprocessing import Process, cpu_count, TimeoutError +from multiprocessing.util import Finalize, debug + +# +# Constants representing the state of a pool +# + +RUN = 0 +CLOSE = 1 +TERMINATE = 2 + +# +# Miscellaneous +# + +job_counter = itertools.count() + +def mapstar(args): + return map(*args) + +# +# Code run by worker processes +# + +def worker(inqueue, outqueue, initializer=None, initargs=()): + put = outqueue.put + get = inqueue.get + if hasattr(inqueue, '_writer'): + inqueue._writer.close() + outqueue._reader.close() + + if initializer is not None: + initializer(*initargs) + + while 1: + try: + task = get() + except (EOFError, IOError): + debug('worker got EOFError or IOError -- exiting') + break + + if task is None: + debug('worker got sentinel -- exiting') + break + + job, i, func, args, kwds = task + try: + result = (True, func(*args, **kwds)) + except Exception, e: + result = (False, e) + put((job, i, result)) + +# +# Class representing a process pool +# + +class Pool(object): + ''' + Class which supports an async version of the `apply()` builtin + ''' + Process = Process + + def __init__(self, processes=None, initializer=None, initargs=()): + self._setup_queues() + self._taskqueue = Queue.Queue() + self._cache = {} + self._state = RUN + + if processes is None: + try: + processes = cpu_count() + except NotImplementedError: + processes = 1 + + self._pool = [] + for i in range(processes): + w = self.Process( + target=worker, + args=(self._inqueue, self._outqueue, initializer, initargs) + ) + self._pool.append(w) + w.name = w.name.replace('Process', 'PoolWorker') + w.daemon = True + w.start() + + self._task_handler = threading.Thread( + target=Pool._handle_tasks, + args=(self._taskqueue, self._quick_put, self._outqueue, self._pool) + ) + self._task_handler.daemon = True + self._task_handler._state = RUN + self._task_handler.start() + + self._result_handler = threading.Thread( + target=Pool._handle_results, + args=(self._outqueue, self._quick_get, self._cache) + ) + self._result_handler.daemon = True + self._result_handler._state = RUN + self._result_handler.start() + + self._terminate = Finalize( + self, self._terminate_pool, + args=(self._taskqueue, self._inqueue, self._outqueue, self._pool, + self._task_handler, self._result_handler, self._cache), + exitpriority=15 + ) + + def _setup_queues(self): + from .queues import SimpleQueue + self._inqueue = SimpleQueue() + self._outqueue = SimpleQueue() + self._quick_put = self._inqueue._writer.send + self._quick_get = self._outqueue._reader.recv + + def apply(self, func, args=(), kwds={}): + ''' + Equivalent of `apply()` builtin + ''' + assert self._state == RUN + return self.apply_async(func, args, kwds).get() + + def map(self, func, iterable, chunksize=None): + ''' + Equivalent of `map()` builtin + ''' + assert self._state == RUN + return self.map_async(func, iterable, chunksize).get() + + def imap(self, func, iterable, chunksize=1): + ''' + Equivalent of `itertool.imap()` -- can be MUCH slower than `Pool.map()` + ''' + assert self._state == RUN + if chunksize == 1: + result = IMapIterator(self._cache) + self._taskqueue.put((((result._job, i, func, (x,), {}) + for i, x in enumerate(iterable)), result._set_length)) + return result + else: + assert chunksize > 1 + task_batches = Pool._get_tasks(func, iterable, chunksize) + result = IMapIterator(self._cache) + self._taskqueue.put((((result._job, i, mapstar, (x,), {}) + for i, x in enumerate(task_batches)), result._set_length)) + return (item for chunk in result for item in chunk) + + def imap_unordered(self, func, iterable, chunksize=1): + ''' + Like `imap()` method but ordering of results is arbitrary + ''' + assert self._state == RUN + if chunksize == 1: + result = IMapUnorderedIterator(self._cache) + self._taskqueue.put((((result._job, i, func, (x,), {}) + for i, x in enumerate(iterable)), result._set_length)) + return result + else: + assert chunksize > 1 + task_batches = Pool._get_tasks(func, iterable, chunksize) + result = IMapUnorderedIterator(self._cache) + self._taskqueue.put((((result._job, i, mapstar, (x,), {}) + for i, x in enumerate(task_batches)), result._set_length)) + return (item for chunk in result for item in chunk) + + def apply_async(self, func, args=(), kwds={}, callback=None): + ''' + Asynchronous equivalent of `apply()` builtin + ''' + assert self._state == RUN + result = ApplyResult(self._cache, callback) + self._taskqueue.put(([(result._job, None, func, args, kwds)], None)) + return result + + def map_async(self, func, iterable, chunksize=None, callback=None): + ''' + Asynchronous equivalent of `map()` builtin + ''' + assert self._state == RUN + if not hasattr(iterable, '__len__'): + iterable = list(iterable) + + if chunksize is None: + chunksize, extra = divmod(len(iterable), len(self._pool) * 4) + if extra: + chunksize += 1 + + task_batches = Pool._get_tasks(func, iterable, chunksize) + result = MapResult(self._cache, chunksize, len(iterable), callback) + self._taskqueue.put((((result._job, i, mapstar, (x,), {}) + for i, x in enumerate(task_batches)), None)) + return result + + @staticmethod + def _handle_tasks(taskqueue, put, outqueue, pool): + thread = threading.current_thread() + + for taskseq, set_length in iter(taskqueue.get, None): + i = -1 + for i, task in enumerate(taskseq): + if thread._state: + debug('task handler found thread._state != RUN') + break + try: + put(task) + except IOError: + debug('could not put task on queue') + break + else: + if set_length: + debug('doing set_length()') + set_length(i+1) + continue + break + else: + debug('task handler got sentinel') + + + try: + # tell result handler to finish when cache is empty + debug('task handler sending sentinel to result handler') + outqueue.put(None) + + # tell workers there is no more work + debug('task handler sending sentinel to workers') + for p in pool: + put(None) + except IOError: + debug('task handler got IOError when sending sentinels') + + debug('task handler exiting') + + @staticmethod + def _handle_results(outqueue, get, cache): + thread = threading.current_thread() + + while 1: + try: + task = get() + except (IOError, EOFError): + debug('result handler got EOFError/IOError -- exiting') + return + + if thread._state: + assert thread._state == TERMINATE + debug('result handler found thread._state=TERMINATE') + break + + if task is None: + debug('result handler got sentinel') + break + + job, i, obj = task + try: + cache[job]._set(i, obj) + except KeyError: + pass + + while cache and thread._state != TERMINATE: + try: + task = get() + except (IOError, EOFError): + debug('result handler got EOFError/IOError -- exiting') + return + + if task is None: + debug('result handler ignoring extra sentinel') + continue + job, i, obj = task + try: + cache[job]._set(i, obj) + except KeyError: + pass + + if hasattr(outqueue, '_reader'): + debug('ensuring that outqueue is not full') + # If we don't make room available in outqueue then + # attempts to add the sentinel (None) to outqueue may + # block. There is guaranteed to be no more than 2 sentinels. + try: + for i in range(10): + if not outqueue._reader.poll(): + break + get() + except (IOError, EOFError): + pass + + debug('result handler exiting: len(cache)=%s, thread._state=%s', + len(cache), thread._state) + + @staticmethod + def _get_tasks(func, it, size): + it = iter(it) + while 1: + x = tuple(itertools.islice(it, size)) + if not x: + return + yield (func, x) + + def __reduce__(self): + raise NotImplementedError( + 'pool objects cannot be passed between processes or pickled' + ) + + def close(self): + debug('closing pool') + if self._state == RUN: + self._state = CLOSE + self._taskqueue.put(None) + + def terminate(self): + debug('terminating pool') + self._state = TERMINATE + self._terminate() + + def join(self): + debug('joining pool') + assert self._state in (CLOSE, TERMINATE) + self._task_handler.join() + self._result_handler.join() + for p in self._pool: + p.join() + + @staticmethod + def _help_stuff_finish(inqueue, task_handler, size): + # task_handler may be blocked trying to put items on inqueue + debug('removing tasks from inqueue until task handler finished') + inqueue._rlock.acquire() + while task_handler.is_alive() and inqueue._reader.poll(): + inqueue._reader.recv() + time.sleep(0) + + @classmethod + def _terminate_pool(cls, taskqueue, inqueue, outqueue, pool, + task_handler, result_handler, cache): + # this is guaranteed to only be called once + debug('finalizing pool') + + task_handler._state = TERMINATE + taskqueue.put(None) # sentinel + + debug('helping task handler/workers to finish') + cls._help_stuff_finish(inqueue, task_handler, len(pool)) + + assert result_handler.is_alive() or len(cache) == 0 + + result_handler._state = TERMINATE + outqueue.put(None) # sentinel + + if pool and hasattr(pool[0], 'terminate'): + debug('terminating workers') + for p in pool: + p.terminate() + + debug('joining task handler') + task_handler.join(1e100) + + debug('joining result handler') + result_handler.join(1e100) + + if pool and hasattr(pool[0], 'terminate'): + debug('joining pool workers') + for p in pool: + p.join() + +# +# Class whose instances are returned by `Pool.apply_async()` +# + +class ApplyResult(object): + + def __init__(self, cache, callback): + self._cond = threading.Condition(threading.Lock()) + self._job = job_counter.next() + self._cache = cache + self._ready = False + self._callback = callback + cache[self._job] = self + + def ready(self): + return self._ready + + def successful(self): + assert self._ready + return self._success + + def wait(self, timeout=None): + self._cond.acquire() + try: + if not self._ready: + self._cond.wait(timeout) + finally: + self._cond.release() + + def get(self, timeout=None): + self.wait(timeout) + if not self._ready: + raise TimeoutError + if self._success: + return self._value + else: + raise self._value + + def _set(self, i, obj): + self._success, self._value = obj + if self._callback and self._success: + self._callback(self._value) + self._cond.acquire() + try: + self._ready = True + self._cond.notify() + finally: + self._cond.release() + del self._cache[self._job] + +# +# Class whose instances are returned by `Pool.map_async()` +# + +class MapResult(ApplyResult): + + def __init__(self, cache, chunksize, length, callback): + ApplyResult.__init__(self, cache, callback) + self._success = True + self._value = [None] * length + self._chunksize = chunksize + if chunksize <= 0: + self._number_left = 0 + self._ready = True + else: + self._number_left = length//chunksize + bool(length % chunksize) + + def _set(self, i, success_result): + success, result = success_result + if success: + self._value[i*self._chunksize:(i+1)*self._chunksize] = result + self._number_left -= 1 + if self._number_left == 0: + if self._callback: + self._callback(self._value) + del self._cache[self._job] + self._cond.acquire() + try: + self._ready = True + self._cond.notify() + finally: + self._cond.release() + + else: + self._success = False + self._value = result + del self._cache[self._job] + self._cond.acquire() + try: + self._ready = True + self._cond.notify() + finally: + self._cond.release() + +# +# Class whose instances are returned by `Pool.imap()` +# + +class IMapIterator(object): + + def __init__(self, cache): + self._cond = threading.Condition(threading.Lock()) + self._job = job_counter.next() + self._cache = cache + self._items = collections.deque() + self._index = 0 + self._length = None + self._unsorted = {} + cache[self._job] = self + + def __iter__(self): + return self + + def next(self, timeout=None): + self._cond.acquire() + try: + try: + item = self._items.popleft() + except IndexError: + if self._index == self._length: + raise StopIteration + self._cond.wait(timeout) + try: + item = self._items.popleft() + except IndexError: + if self._index == self._length: + raise StopIteration + raise TimeoutError + finally: + self._cond.release() + + success, value = item + if success: + return value + raise value + + __next__ = next # XXX + + def _set(self, i, obj): + self._cond.acquire() + try: + if self._index == i: + self._items.append(obj) + self._index += 1 + while self._index in self._unsorted: + obj = self._unsorted.pop(self._index) + self._items.append(obj) + self._index += 1 + self._cond.notify() + else: + self._unsorted[i] = obj + + if self._index == self._length: + del self._cache[self._job] + finally: + self._cond.release() + + def _set_length(self, length): + self._cond.acquire() + try: + self._length = length + if self._index == self._length: + self._cond.notify() + del self._cache[self._job] + finally: + self._cond.release() + +# +# Class whose instances are returned by `Pool.imap_unordered()` +# + +class IMapUnorderedIterator(IMapIterator): + + def _set(self, i, obj): + self._cond.acquire() + try: + self._items.append(obj) + self._index += 1 + self._cond.notify() + if self._index == self._length: + del self._cache[self._job] + finally: + self._cond.release() + +# +# +# + +class ThreadPool(Pool): + + from .dummy import Process + + def __init__(self, processes=None, initializer=None, initargs=()): + Pool.__init__(self, processes, initializer, initargs) + + def _setup_queues(self): + self._inqueue = Queue.Queue() + self._outqueue = Queue.Queue() + self._quick_put = self._inqueue.put + self._quick_get = self._outqueue.get + + @staticmethod + def _help_stuff_finish(inqueue, task_handler, size): + # put sentinels at head of inqueue to make workers finish + inqueue.not_empty.acquire() + try: + inqueue.queue.clear() + inqueue.queue.extend([None] * size) + inqueue.not_empty.notify_all() + finally: + inqueue.not_empty.release()