class ThreadPool: 
 """A thread pool, distributing work requests and collecting results. 
 
 See the module docstring for more information. 
 
 """ 
 def __init__(self, num_workers, q_size=0, resq_size=0, poll_timeout=5): 
  pass 
 def createWorkers(self, num_workers, poll_timeout=5): 
  pass 
 def dismissWorkers(self, num_workers, do_join=False): 
  pass 
 def joinAllDismissedWorkers(self): 
  pass 
 def putRequest(self, request, block=True, timeout=None): 
  pass 
 def poll(self, block=False): 
  pass 
 def wait(self): 
  pass 

task_pool=threadpool.ThreadPool(num_works) 
 def __init__(self, num_workers, q_size=0, resq_size=0, poll_timeout=5): 
  """Set up the thread pool and start num_workers worker threads. 
 
  ``num_workers`` is the number of worker threads to start initially. 
 
  If ``q_size > 0`` the size of the work *request queue* is limited and 
  the thread pool blocks when the queue is full and it tries to put 
  more work requests in it (see ``putRequest`` method), unless you also 
  use a positive ``timeout`` value for ``putRequest``. 
 
  If ``resq_size > 0`` the size of the *results queue* is limited and the 
  worker threads will block when the queue is full and they try to put 
  new results in it. 
 
  .. warning: 
   If you set both ``q_size`` and ``resq_size`` to ``!= 0`` there is 
   the possibilty of a deadlock, when the results queue is not pulled 
   regularly and too many jobs are put in the work requests queue. 
   To prevent this, always set ``timeout > 0`` when calling 
   ``ThreadPool.putRequest()`` and catch ``Queue.Full`` exceptions. 
 
  """ 
  self._requests_queue = Queue.Queue(q_size)#任務(wù)隊(duì)列，通過(guò)threadpool.makeReuests(args)創(chuàng)建的任務(wù)都會(huì)放到此隊(duì)列中 
  self._results_queue = Queue.Queue(resq_size)#字典，任務(wù)對(duì)應(yīng)的任務(wù)執(zhí)行結(jié)果</span> 
  self.workers = []#工作線(xiàn)程list，通過(guò)self.createWorkers()函數(shù)內(nèi)創(chuàng)建的工作線(xiàn)程會(huì)放到此工作線(xiàn)程list中 
  self.dismissedWorkers = []#被設(shè)置線(xiàn)程事件并且沒(méi)有被join的工作線(xiàn)程 
  self.workRequests = {}#字典，記錄任務(wù)被分配到哪個(gè)工作線(xiàn)程中</span> 
  self.createWorkers(num_workers, poll_timeout) 

def createWorkers(self, num_workers, poll_timeout=5): 
  """Add num_workers worker threads to the pool. 
 
  ``poll_timout`` sets the interval in seconds (int or float) for how 
  ofte threads should check whether they are dismissed, while waiting for 
  requests. 
 
  """ 
  for i in range(num_workers): 
   self.workers.append(WorkerThread(self._requests_queue, 
    self._results_queue, poll_timeout=poll_timeout)) 

class WorkerThread(threading.Thread): 
 """Background thread connected to the requests/results queues. 
 
 A worker thread sits in the background and picks up work requests from 
 one queue and puts the results in another until it is dismissed. 
 
 """ 
 
 def __init__(self, requests_queue, results_queue, poll_timeout=5, **kwds): 
  """Set up thread in daemonic mode and start it immediatedly. 
 
  ``requests_queue`` and ``results_queue`` are instances of 
  ``Queue.Queue`` passed by the ``ThreadPool`` class when it creates a 
  new worker thread. 
 
  """ 
  threading.Thread.__init__(self, **kwds) 
  self.setDaemon(1)# 
  self._requests_queue = requests_queue#任務(wù)隊(duì)列 
  self._results_queue = results_queue#任務(wù)結(jié)果隊(duì)列 
  self._poll_timeout = poll_timeout#run函數(shù)中從任務(wù)隊(duì)列中g(shù)et任務(wù)時(shí)的超時(shí)時(shí)間，如果超時(shí)則繼續(xù)while(true)； 
  self._dismissed = threading.Event()#線(xiàn)程事件，如果set線(xiàn)程事件則run會(huì)執(zhí)行break,直接退出工作線(xiàn)程； 
  self.start() 
 
 def run(self): 
  """Repeatedly process the job queue until told to exit.""" 
  while True: 
   if self._dismissed.isSet():#如果設(shè)置了self._dismissed則退出工作線(xiàn)程 
 
    # we are dismissed, break out of loop 
    break 
   # get next work request. If we don't get a new request from the 
   # queue after self._poll_timout seconds, we jump to the start of 
   # the while loop again, to give the thread a chance to exit. 
   try: 
    request = self._requests_queue.get(True, self._poll_timeout) 
   except Queue.Empty:#嘗從任務(wù) 隊(duì)列self._requests_queue 中g(shù)et任務(wù)，如果隊(duì)列為空，則continue 
    continue 
   else: 
    if self._dismissed.isSet():#檢測(cè)此工作線(xiàn)程事件是否被set,如果被設(shè)置，意味著要結(jié)束此工作線(xiàn)程，那么就需要將取到的任務(wù)返回到任務(wù)隊(duì)列中，并且退出線(xiàn)程 
     # we are dismissed, put back request in queue and exit loop 
     self._requests_queue.put(request) 
     break 
    try:<span style="color:#如果線(xiàn)程事件沒(méi)有被設(shè)置，那么執(zhí)行任務(wù)處理函數(shù)request.callable，并將返回的result，壓入到任務(wù)結(jié)果隊(duì)列中 
     result = request.callable(*request.args, **request.kwds) 
     self._results_queue.put((request, result)) 
    except: 
     request.exception = True 
     self._results_queue.put((request, sys.exc_info()))#如果任務(wù)處理函數(shù)出現(xiàn)異常，則將異常壓入到隊(duì)列中 
 
 def dismiss(self):</span> 
  """Sets a flag to tell the thread to exit when done with current job. 
  """ 
  self._dismissed.set() 

# utility functions 
def makeRequests(callable_, args_list, callback=None, 
  exc_callback=_handle_thread_exception): 
 """Create several work requests for same callable with different arguments. 
 
 Convenience function for creating several work requests for the same 
 callable where each invocation of the callable receives different values 
 for its arguments. 
 
 ``args_list`` contains the parameters for each invocation of callable. 
 Each item in ``args_list`` should be either a 2-item tuple of the list of 
 positional arguments and a dictionary of keyword arguments or a single, 
 non-tuple argument. 
 
 See docstring for ``WorkRequest`` for info on ``callback`` and 
 ``exc_callback``. 
 
 """ 
 requests = [] 
 for item in args_list: 
  if isinstance(item, tuple): 
   requests.append( 
    WorkRequest(callable_, item[0], item[1], callback=callback, 
     exc_callback=exc_callback) 
   ) 
  else: 
   requests.append( 
    WorkRequest(callable_, [item], None, callback=callback, 
     exc_callback=exc_callback) 
   ) 
 return requests 

class WorkRequest: 
 """A request to execute a callable for putting in the request queue later. 
 
 See the module function ``makeRequests`` for the common case 
 where you want to build several ``WorkRequest`` objects for the same 
 callable but with different arguments for each call. 
 
 """ 
 
 def __init__(self, callable_, args=None, kwds=None, requestID=None, 
   callback=None, exc_callback=_handle_thread_exception): 
  """Create a work request for a callable and attach callbacks. 
 
  A work request consists of the a callable to be executed by a 
  worker thread, a list of positional arguments, a dictionary 
  of keyword arguments. 
 
  A ``callback`` function can be specified, that is called when the 
  results of the request are picked up from the result queue. It must 
  accept two anonymous arguments, the ``WorkRequest`` object and the 
  results of the callable, in that order. If you want to pass additional 
  information to the callback, just stick it on the request object. 
 
  You can also give custom callback for when an exception occurs with 
  the ``exc_callback`` keyword parameter. It should also accept two 
  anonymous arguments, the ``WorkRequest`` and a tuple with the exception 
  details as returned by ``sys.exc_info()``. The default implementation 
  of this callback just prints the exception info via 
  ``traceback.print_exception``. If you want no exception handler 
  callback, just pass in ``None``. 
 
  ``requestID``, if given, must be hashable since it is used by 
  ``ThreadPool`` object to store the results of that work request in a 
  dictionary. It defaults to the return value of ``id(self)``. 
 
  """ 
  if requestID is None: 
   self.requestID = id(self) 
  else: 
   try: 
    self.requestID = hash(requestID) 
   except TypeError: 
    raise TypeError("requestID must be hashable.") 
  self.exception = False 
  self.callback = callback 
  self.exc_callback = exc_callback 
  self.callable = callable_ 
  self.args = args or [] 
  self.kwds = kwds or {} 
 
 def __str__(self): 
  return "<WorkRequest id=%s args=%r kwargs=%r exception=%s>" % \ 
   (self.requestID, self.args, self.kwds, self.exception) 

def putRequest(self, request, block=True, timeout=None): 
 """Put work request into work queue and save its id for later.""" 
 assert isinstance(request, WorkRequest) 
 # don't reuse old work requests 
 assert not getattr(request, 'exception', None) 
 self._requests_queue.put(request, block, timeout) 
 self.workRequests[request.requestID] = request 

try: 
 request = self._requests_queue.get(True, self._poll_timeout) 
except Queue.Empty:#嘗從任務(wù) 隊(duì)列self._requests_queue 中g(shù)et任務(wù)，如果隊(duì)列為空，則continue 
 continue 

def run(self): 
  """Repeatedly process the job queue until told to exit.""" 
  while True: 
   if self._dismissed.isSet():#如果設(shè)置了self._dismissed則退出工作線(xiàn)程 
 
    # we are dismissed, break out of loop 
    break 
   # get next work request. If we don't get a new request from the 
   # queue after self._poll_timout seconds, we jump to the start of 
   # the while loop again, to give the thread a chance to exit. 
   try: 
    request = self._requests_queue.get(True, self._poll_timeout) 
   except Queue.Empty:#嘗從任務(wù) 隊(duì)列self._requests_queue 中g(shù)et任務(wù)，如果隊(duì)列為空，則continue 
    continue 
   else: 
    if self._dismissed.isSet():#檢測(cè)此工作線(xiàn)程事件是否被set,如果被設(shè)置，意味著要結(jié)束此工作線(xiàn)程，那么就需要將取到的任務(wù)返回到任務(wù)隊(duì)列中，并且退出線(xiàn)程 
     # we are dismissed, put back request in queue and exit loop 
     self._requests_queue.put(request) 
     break 
    try:#如果線(xiàn)程事件沒(méi)有被設(shè)置，那么執(zhí)行任務(wù)處理函數(shù)request.callable，并將返回的result，壓入到任務(wù)結(jié)果隊(duì)列中 
     result = request.callable(*request.args, **request.kwds) 
     self._results_queue.put((request, result)) 
    except: 
     request.exception = True 
     self._results_queue.put((request, sys.exc_info()))#如果任務(wù)處理函數(shù)出現(xiàn)異常，則將異常壓入到隊(duì)列中 

def wait(self): 
 """Wait for results, blocking until all have arrived.""" 
 while 1: 
  try: 
   self.poll(True) 
  except NoResultsPending: 
   break 

def poll(self, block=False): 
 """Process any new results in the queue.""" 
 while True: 
  # still results pending? 
  if not self.workRequests: 
   raise NoResultsPending 
  # are there still workers to process remaining requests? 
  elif block and not self.workers: 
   raise NoWorkersAvailable 
  try: 
   # get back next results 
   request, result = self._results_queue.get(block=block) 
   # has an exception occured? 
   if request.exception and request.exc_callback: 
    request.exc_callback(request, result) 
   # hand results to callback, if any 
   if request.callback and not \ 
     (request.exception and request.exc_callback): 
    request.callback(request, result) 
   del self.workRequests[request.requestID] 
  except Queue.Empty: 
   break 

def dismissWorkers(self, num_workers, do_join=False): 
 """Tell num_workers worker threads to quit after their current task.""" 
 dismiss_list = [] 
 for i in range(min(num_workers, len(self.workers))): 
  worker = self.workers.pop() 
  worker.dismiss() 
  dismiss_list.append(worker) 
 
 if do_join: 
  for worker in dismiss_list: 
   worker.join() 
 else: 
  self.dismissedWorkers.extend(dismiss_list) 
 
def joinAllDismissedWorkers(self): 
 """Perform Thread.join() on all worker threads that have been dismissed. 
 """ 
 for worker in self.dismissedWorkers: 
  worker.join() 
 self.dismissedWorkers = []