mirror of https://github.com/python/cpython
(Queue.Empty): When class based exceptions are in force, derive this
class from the standard base exception Exception. Otherwise define Queue.Empty as a string exception. (Queue): 8-space to 4-space indentation conversion. Also, basically recast all method comments into docstrings.
This commit is contained in:
parent
17c8e781c0
commit
3d96d522ec
36
Lib/Queue.py
36
Lib/Queue.py
|
@ -1,12 +1,20 @@
|
||||||
# A multi-producer, multi-consumer queue.
|
# A multi-producer, multi-consumer queue.
|
||||||
|
|
||||||
Empty = 'Queue.Empty' # Exception raised by get_nowait()
|
# define this exception to be compatible with Python 1.5's class
|
||||||
|
# exceptions, but also when -X option is used.
|
||||||
|
try:
|
||||||
|
class Empty(Exception):
|
||||||
|
pass
|
||||||
|
except TypeError:
|
||||||
|
# string based exceptions
|
||||||
|
Empty = 'Queue.Empty' # Exception raised by get_nowait()
|
||||||
|
|
||||||
class Queue:
|
class Queue:
|
||||||
|
|
||||||
# Initialize a queue object with a given maximum size
|
|
||||||
# (If maxsize is <= 0, the maximum size is infinite)
|
|
||||||
def __init__(self, maxsize):
|
def __init__(self, maxsize):
|
||||||
|
"""Initialize a queue object with a given maximum size.
|
||||||
|
|
||||||
|
If maxsize is <= 0, the queue size is infinite.
|
||||||
|
"""
|
||||||
import thread
|
import thread
|
||||||
self._init(maxsize)
|
self._init(maxsize)
|
||||||
self.mutex = thread.allocate_lock()
|
self.mutex = thread.allocate_lock()
|
||||||
|
@ -14,29 +22,29 @@ class Queue:
|
||||||
self.esema.acquire_lock()
|
self.esema.acquire_lock()
|
||||||
self.fsema = thread.allocate_lock()
|
self.fsema = thread.allocate_lock()
|
||||||
|
|
||||||
# Get an approximation of the queue size (not reliable!)
|
|
||||||
def qsize(self):
|
def qsize(self):
|
||||||
|
"""Returns the approximate size of the queue (not reliable!)."""
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
n = self._qsize()
|
n = self._qsize()
|
||||||
self.mutex.release_lock()
|
self.mutex.release_lock()
|
||||||
return n
|
return n
|
||||||
|
|
||||||
# Check if the queue is empty (not reliable!)
|
|
||||||
def empty(self):
|
def empty(self):
|
||||||
|
"""Returns 1 if the queue is empty, 0 otherwise (not reliable!)."""
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
n = self._empty()
|
n = self._empty()
|
||||||
self.mutex.release_lock()
|
self.mutex.release_lock()
|
||||||
return n
|
return n
|
||||||
|
|
||||||
# Check if the queue is full (not reliable!)
|
|
||||||
def full(self):
|
def full(self):
|
||||||
|
"""Returns 1 if the queue is full, 0 otherwise (not reliable!)."""
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
n = self._full()
|
n = self._full()
|
||||||
self.mutex.release_lock()
|
self.mutex.release_lock()
|
||||||
return n
|
return n
|
||||||
|
|
||||||
# Put a new item into the queue
|
|
||||||
def put(self, item):
|
def put(self, item):
|
||||||
|
"""Put an item into the queue."""
|
||||||
self.fsema.acquire_lock()
|
self.fsema.acquire_lock()
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
was_empty = self._empty()
|
was_empty = self._empty()
|
||||||
|
@ -47,9 +55,10 @@ class Queue:
|
||||||
self.fsema.release_lock()
|
self.fsema.release_lock()
|
||||||
self.mutex.release_lock()
|
self.mutex.release_lock()
|
||||||
|
|
||||||
# Get an item from the queue,
|
|
||||||
# blocking if necessary until one is available
|
|
||||||
def get(self):
|
def get(self):
|
||||||
|
"""Gets and returns an item from the queue.
|
||||||
|
This method blocks if necessary until an item is available.
|
||||||
|
"""
|
||||||
self.esema.acquire_lock()
|
self.esema.acquire_lock()
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
was_full = self._full()
|
was_full = self._full()
|
||||||
|
@ -64,10 +73,15 @@ class Queue:
|
||||||
# Get an item from the queue if one is immediately available,
|
# Get an item from the queue if one is immediately available,
|
||||||
# raise Empty if the queue is empty or temporarily unavailable
|
# raise Empty if the queue is empty or temporarily unavailable
|
||||||
def get_nowait(self):
|
def get_nowait(self):
|
||||||
|
"""Gets and returns an item from the queue.
|
||||||
|
Only gets an item if one is immediately available, Otherwise
|
||||||
|
this raises the Empty exception if the queue is empty or
|
||||||
|
temporarily unavailable.
|
||||||
|
"""
|
||||||
locked = self.esema.acquire_lock(0)
|
locked = self.esema.acquire_lock(0)
|
||||||
self.mutex.acquire_lock()
|
self.mutex.acquire_lock()
|
||||||
if self._empty():
|
if self._empty():
|
||||||
# The queue is empyt -- we can't have esema
|
# The queue is empty -- we can't have esema
|
||||||
self.mutex.release_lock()
|
self.mutex.release_lock()
|
||||||
raise Empty
|
raise Empty
|
||||||
if not locked:
|
if not locked:
|
||||||
|
|
Loading…
Reference in New Issue