[Python-checkins] cpython: Simplify the code using with-statements.

Sun Jan 8 00:33:01 CET 2012

http://hg.python.org/cpython/rev/c68426b241ca
changeset: 74298:c68426b241ca
user: Raymond Hettinger <python at rcn.com>
date: Sat Jan 07 15:32:52 2012 -0800
summary:
 Simplify the code using with-statements.
files:
 Lib/queue.py | 42 +++++++++++++--------------------------
 1 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/Lib/queue.py b/Lib/queue.py
--- a/Lib/queue.py
+++ b/Lib/queue.py
@@ -26,17 +26,21 @@
 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)
@@ -56,16 +60,13 @@
 Raises a ValueError if called more times than there were items
 placed in the queue.
 """
- self.all_tasks_done.acquire()
- try:
+ with self.all_tasks_done:
 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.
@@ -76,19 +77,14 @@
 
 When the count of unfinished tasks drops to zero, join() unblocks.
 """
- self.all_tasks_done.acquire()
- try:
+ with self.all_tasks_done:
 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
+ with self.mutex:
+ return self._qsize()
 
 def empty(self):
 """Return True if the queue is empty, False otherwise (not reliable!).
@@ -102,10 +98,8 @@
 completed, the preferred technique is to use the join() method.
 
 """
- self.mutex.acquire()
- n = not self._qsize()
- self.mutex.release()
- return n
+ with self.mutex:
+ return not self._qsize()
 
 def full(self):
 """Return True if the queue is full, False otherwise (not reliable!).
@@ -116,10 +110,8 @@
 qsize() can be used.
 
 """
- self.mutex.acquire()
- n = 0 < self.maxsize <= self._qsize()
- self.mutex.release()
- return n
+ with self.mutex:
+ return 0 < self.maxsize <= self._qsize()
 
 def put(self, item, block=True, timeout=None):
 """Put an item into the queue.
@@ -132,8 +124,7 @@
 is immediately available, else raise the Full exception ('timeout'
 is ignored in that case).
 """
- self.not_full.acquire()
- try:
+ with self.not_full:
 if self.maxsize > 0:
 if not block:
 if self._qsize() >= self.maxsize:
@@ -153,8 +144,6 @@
 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.
@@ -175,8 +164,7 @@
 available, else raise the Empty exception ('timeout' is ignored
 in that case).
 """
- self.not_empty.acquire()
- try:
+ with self.not_empty:
 if not block:
 if not self._qsize():
 raise Empty
@@ -195,8 +183,6 @@
 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.
-- 
Repository URL: http://hg.python.org/cpython
