Workaround a limitation in cygwin with Lock creation.

gclient_utils.py

 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Generic utils."""
 
 import errno
 import logging
 import os
 import Queue
@@ skipping 462 matching lines @@
         print >> sys.stderr, 'Was deadlocked'
         raise
       return method(self, *args, **kwargs)
     finally:
       self.lock.release()
   return inner
 
 
 class WorkItem(object):
   """One work item."""
+  # On cygwin, creating a lock throwing randomly when nearing ~100 locks.
+  # As a workaround, use a single lock. Yep you read it right. Single lock for
+  # all the 100 objects.
+  lock = threading.Lock()
+
   def __init__(self, name):
     # A unique string representing this work item.
     self._name = name
-    try:
-      self.lock = threading.Lock()
-    except:  # pylint: disable=W0702
-      if sys.platform != 'cygwin':
-        raise
-      # On cygwin, it's throwing randomly. Hack and reuse the single
-      # sys.stdout.lock. Yep you read it right. Single lock.
-      self.lock = sys.stdout.lock

[Dirk Pranke, 2011/10/19 19:40:45]

so what happens if threading.Lock() fails an exception?

[M-A Ruel, 2011/10/19 19:47:56]

The problem that I started seeing is that while this code was trapping the
exception in threading._allocate_lock(), a Lock() was created somewhere else in
the library and *this one* would also fail randomly. So it's simpler to just
serialize everything. Since the code is designed to lock only on mutation, it's
not a big deal.

 
   def run(self, work_queue):
     """work_queue is passed as keyword argument so it should be
     the last parameters of the function when you override it."""
     pass
 
   @property
   def name(self):
     return self._name
 
@@ skipping 163 matching lines @@
         logging.info('Caught exception in thread %s' % self.item.name)
         logging.info(str(sys.exc_info()))
         work_queue.exceptions.put(sys.exc_info())
       logging.info('_Worker.run(%s) done' % self.item.name)
 
       work_queue.ready_cond.acquire()
       try:
         work_queue.ready_cond.notifyAll()
       finally:
         work_queue.ready_cond.release()