diff options
| -rw-r--r-- | Doc/library/collections.rst | 8 | ||||
| -rw-r--r-- | Lib/Queue.py | 53 |
2 files changed, 31 insertions, 30 deletions
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index b10569b..de9bcbf 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -535,6 +535,14 @@ faster versions that bypass error-checking:: def _replace(self, _map=map, **kwds): return self._make(_map(kwds.get, ('x', 'y'), self)) +Note, subclasses should set ``__slots__`` to an empty tuple so that +an instance dictionary will not be created and the memory overhead +will be kept to zero. + +Note, subclasses should set ``__slots__`` to an empty tuple. This +reduces memory usage by + + Subclassing is not useful for adding new, stored fields. Instead, simply create a new named tuple type from the :attr:`_fields` attribute:: diff --git a/Lib/Queue.py b/Lib/Queue.py index 79b0abf..ce34024 100644 --- a/Lib/Queue.py +++ b/Lib/Queue.py @@ -23,6 +23,7 @@ class Queue: import threading except ImportError: import dummy_threading as threading + 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 @@ -91,14 +92,14 @@ class Queue: def empty(self): """Return True if the queue is empty, False otherwise (not reliable!).""" self.mutex.acquire() - n = self._empty() + 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 = self._full() + n = 0 < self.maxsize == self._qsize() self.mutex.release() return n @@ -115,21 +116,22 @@ class Queue: """ self.not_full.acquire() try: - if not block: - if self._full(): - raise Full - elif timeout is None: - while self._full(): - self.not_full.wait() - else: - if timeout < 0: - raise ValueError("'timeout' must be a positive number") - endtime = _time() + timeout - while self._full(): - remaining = endtime - _time() - if remaining <= 0.0: + if self.maxsize > 0: + if not block: + if self._qsize() == self.maxsize: raise Full - self.not_full.wait(remaining) + elif timeout is None: + while self._qsize() == self.maxsize: + self.not_full.wait() + elif timeout < 0: + raise ValueError("'timeout' must be a positive 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() @@ -158,16 +160,16 @@ class Queue: self.not_empty.acquire() try: if not block: - if self._empty(): + if not self._qsize(): raise Empty elif timeout is None: - while self._empty(): + while not self._qsize(): self.not_empty.wait() + elif timeout < 0: + raise ValueError("'timeout' must be a positive number") else: - if timeout < 0: - raise ValueError("'timeout' must be a positive number") endtime = _time() + timeout - while self._empty(): + while not self._qsize(): remaining = endtime - _time() if remaining <= 0.0: raise Empty @@ -192,20 +194,11 @@ class Queue: # Initialize the queue representation def _init(self, maxsize): - self.maxsize = maxsize self.queue = deque() def _qsize(self): return len(self.queue) - # Check whether the queue is empty - def _empty(self): - return not self.queue - - # Check whether the queue is full - def _full(self): - return self.maxsize > 0 and len(self.queue) == self.maxsize - # Put a new item in the queue def _put(self, item): self.queue.append(item) |