python队列queue模块详解

import Queque 
a=[1,2,3] 
device_que=Queque.queue() 
device_que.put(a) 
device=device_que.get() 

def __init__(self, maxsize=0): 
 self.maxsize = maxsize 
 self._init(maxsize) 
 # mutex must be held whenever the queue is mutating. All methods 
 # that acquire mutex must release it before returning. mutex 
 # is shared between the three conditions, so acquiring and 
 # releasing the conditions also acquires and releases mutex. 
 self.mutex = _threading.Lock() 
 # Notify not_empty whenever an item is added to the queue; a 
 # thread waiting to get is notified then. 
 self.not_empty = _threading.Condition(self.mutex) 
 # Notify not_full whenever an item is removed from the queue; 
 # a thread waiting to put is notified then. 
 self.not_full = _threading.Condition(self.mutex) 
 # Notify all_tasks_done whenever the number of unfinished tasks 
 # drops to zero; thread waiting to join() is notified to resume 
 self.all_tasks_done = _threading.Condition(self.mutex) 
 self.unfinished_tasks = 0 

def put(self, item, block=True, timeout=None): 
 """Put an item into the queue. 
 
 If optional args 'block' is true and 'timeout' is None (the default), 
 block if necessary until a free slot is available. If 'timeout' is 
 a non-negative number, it blocks at most 'timeout' seconds and raises 
 the 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 Full exception ('timeout' 
 is ignored in that case). 
 """ 
 self.not_full.acquire() 
 try: 
  if self.maxsize > 0: 
   if not block: 
    if self._qsize() == self.maxsize: 
     raise Full 
   elif timeout is None: 
    while self._qsize() == self.maxsize: 
     self.not_full.wait() 
   elif timeout < 0: 
    raise ValueError("'timeout' must be a non-negative number") 
   else: 
    endtime = _time() + timeout 
    while self._qsize() == self.maxsize: 
     remaining = endtime - _time() 
     if remaining <= 0.0: 
      raise Full 
     self.not_full.wait(remaining) 
  self._put(item) 
  self.unfinished_tasks += 1 
  self.not_empty.notify() 
 finally: 
  self.not_full.release() 

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 non-negative number, it blocks at most 'timeout' seconds and raises 
 the 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 Empty exception ('timeout' is ignored 
 in that case). 
 """ 
 self.not_empty.acquire() 
 try: 
  if not block: 
   if not self._qsize(): 
    raise Empty 
  elif timeout is None: 
   while not self._qsize(): 
    self.not_empty.wait() 
  elif timeout < 0: 
   raise ValueError("'timeout' must be a non-negative number") 
  else: 
   endtime = _time() + timeout 
   while not self._qsize(): 
    remaining = endtime - _time() 
    if remaining <= 0.0: 
     raise Empty 
    self.not_empty.wait(remaining) 
  item = self._get() 
  self.not_full.notify() 
  return item 
 finally: 
  self.not_empty.release() 

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 Full exception. 
 """ 
 return self.put(item, False) 

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 Empty exception. 
  """ 
  return self.get(False) 

def qsize(self): 
 """Return the approximate size of the queue (not reliable!).""" 
 self.mutex.acquire() 
 n = self._qsize() 
 self.mutex.release() 
 return n 
 
def empty(self): 
 """Return True if the queue is empty, False otherwise (not reliable!).""" 
 self.mutex.acquire() 
 n = not self._qsize() 
 self.mutex.release() 
 return n 
 
def full(self): 
 """Return True if the queue is full, False otherwise (not reliable!).""" 
 self.mutex.acquire() 
 n = 0 < self.maxsize == self._qsize() 
 self.mutex.release() 
 return n 

def task_done(self): 
 """Indicate that a formerly enqueued task is complete. 
 
 Used by Queue consumer threads. For each get() used to fetch a task, 
 a subsequent call to task_done() tells the queue that the processing 
 on the task is complete. 
 
 If a join() is currently blocking, it will resume when all items 
 have been processed (meaning that a task_done() call was received 
 for every item that had been put() into the queue). 
 
 Raises a ValueError if called more times than there were items 
 placed in the queue. 
 """ 
 self.all_tasks_done.acquire() 
 try: 
  unfinished = self.unfinished_tasks - 1 
  if unfinished <= 0: 
   if unfinished < 0: 
    raise ValueError('task_done() called too many times') 
   self.all_tasks_done.notify_all() 
  self.unfinished_tasks = unfinished 
 finally: 
  self.all_tasks_done.release() 
 
def join(self): 
 """Blocks 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 task_done() 
 to indicate the item was retrieved and all work on it is complete. 
 
 When the count of unfinished tasks drops to zero, join() unblocks. 
 """ 
 self.all_tasks_done.acquire() 
 try: 
  while self.unfinished_tasks: 
   self.all_tasks_done.wait() 
 finally: 
  self.all_tasks_done.release() 

class PriorityQueue(Queue): 
 '''''Variant of Queue that retrieves open entries in priority order (lowest first). 
 
 Entries are typically tuples of the form: (priority number, data). 
 ''' 
 
 def _init(self, maxsize): 
  self.queue = [] 
 
 def _qsize(self, len=len): 
  return len(self.queue) 
 
 def _put(self, item, heappush=heapq.heappush): 
  heappush(self.queue, item) 
 
 def _get(self, heappop=heapq.heappop): 
  return heappop(self.queue) 
 
 
class LifoQueue(Queue): 
 '''''Variant of Queue that retrieves most recently added entries first.''' 
 
 def _init(self, maxsize): 
  self.queue = [] 
 
 def _qsize(self, len=len): 
  return len(self.queue) 
 
 def _put(self, item): 
  self.queue.append(item) 
 
 def _get(self): 
  return self.queue.pop() 

class Queue: 
 """Create a queue object with a given maximum size. 
 
 If maxsize is <= 0, the queue size is infinite. 
 """ 
 def __init__(self, maxsize=0): 
  self.maxsize = maxsize 
  self._init(maxsize) 
  # mutex must be held whenever the queue is mutating. All methods 
  # that acquire mutex must release it before returning. mutex 
  # is shared between the three conditions, so acquiring and 
  # releasing the conditions also acquires and releases mutex. 
  self.mutex = _threading.Lock() 
  # Notify not_empty whenever an item is added to the queue; a 
  # thread waiting to get is notified then. 
  self.not_empty = _threading.Condition(self.mutex) 
  # Notify not_full whenever an item is removed from the queue; 
  # a thread waiting to put is notified then. 
  self.not_full = _threading.Condition(self.mutex) 
  # Notify all_tasks_done whenever the number of unfinished tasks 
  # drops to zero; thread waiting to join() is notified to resume 
  self.all_tasks_done = _threading.Condition(self.mutex) 
  self.unfinished_tasks = 0 
 
 def task_done(self): 
  """Indicate that a formerly enqueued task is complete. 
 
  Used by Queue consumer threads. For each get() used to fetch a task, 
  a subsequent call to task_done() tells the queue that the processing 
  on the task is complete. 
 
  If a join() is currently blocking, it will resume when all items 
  have been processed (meaning that a task_done() call was received 
  for every item that had been put() into the queue). 
 
  Raises a ValueError if called more times than there were items 
  placed in the queue. 
  """ 
  self.all_tasks_done.acquire() 
  try: 
   unfinished = self.unfinished_tasks - 1 
   if unfinished <= 0: 
    if unfinished < 0: 
     raise ValueError('task_done() called too many times') 
    self.all_tasks_done.notify_all() 
   self.unfinished_tasks = unfinished 
  finally: 
   self.all_tasks_done.release() 
 
 def join(self): 
  """Blocks 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 task_done() 
  to indicate the item was retrieved and all work on it is complete. 
 
  When the count of unfinished tasks drops to zero, join() unblocks. 
  """ 
  self.all_tasks_done.acquire() 
  try: 
   while self.unfinished_tasks: 
    self.all_tasks_done.wait() 
  finally: 
   self.all_tasks_done.release() 
 
 def qsize(self): 
  """Return the approximate size of the queue (not reliable!).""" 
  self.mutex.acquire() 
  n = self._qsize() 
  self.mutex.release() 
  return n 
 
 def empty(self): 
  """Return True if the queue is empty, False otherwise (not reliable!).""" 
  self.mutex.acquire() 
  n = not self._qsize() 
  self.mutex.release() 
  return n 
 
 def full(self): 
  """Return True if the queue is full, False otherwise (not reliable!).""" 
  self.mutex.acquire() 
  n = 0 < self.maxsize == self._qsize() 
  self.mutex.release() 
  return n 
 
 def put(self, item, block=True, timeout=None): 
  """Put an item into the queue. 
 
  If optional args 'block' is true and 'timeout' is None (the default), 
  block if necessary until a free slot is available. If 'timeout' is 
  a non-negative number, it blocks at most 'timeout' seconds and raises 
  the 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 Full exception ('timeout' 
  is ignored in that case). 
  """ 
  self.not_full.acquire() 
  try: 
   if self.maxsize > 0: 
    if not block: 
     if self._qsize() == self.maxsize: 
      raise Full 
    elif timeout is None: 
     while self._qsize() == self.maxsize: 
      self.not_full.wait() 
    elif timeout < 0: 
     raise ValueError("'timeout' must be a non-negative number") 
    else: 
     endtime = _time() + timeout 
     while self._qsize() == self.maxsize: 
      remaining = endtime - _time() 
      if remaining <= 0.0: 
       raise Full 
      self.not_full.wait(remaining) 
   self._put(item) 
   self.unfinished_tasks += 1 
   self.not_empty.notify() 
  finally: 
   self.not_full.release() 
 
 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 Full exception. 
  """ 
  return self.put(item, False) 
 
 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 non-negative number, it blocks at most 'timeout' seconds and raises 
  the 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 Empty exception ('timeout' is ignored 
  in that case). 
  """ 
  self.not_empty.acquire() 
  try: 
   if not block: 
    if not self._qsize(): 
     raise Empty 
   elif timeout is None: 
    while not self._qsize(): 
     self.not_empty.wait() 
   elif timeout < 0: 
    raise ValueError("'timeout' must be a non-negative number") 
   else: 
    endtime = _time() + timeout 
    while not self._qsize(): 
     remaining = endtime - _time() 
     if remaining <= 0.0: 
      raise Empty 
     self.not_empty.wait(remaining) 
   item = self._get() 
   self.not_full.notify() 
   return item 
  finally: 
   self.not_empty.release() 
 
 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 Empty exception. 
  """ 
  return self.get(False) 
 
 # Override these methods to implement other queue organizations 
 # (e.g. stack or priority queue). 
 # These will only be called with appropriate locks held 
 
 # Initialize the queue representation 
 def _init(self, maxsize): 
  self.queue = deque() 
 
 def _qsize(self, len=len): 
  return len(self.queue) 
 
 # Put a new item in the queue 
 def _put(self, item): 
  self.queue.append(item) 
 
 # Get an item from the queue 
 def _get(self): 
  return self.queue.popleft()