Fix a concurrency issue happening with deep dependencies when the intermediary

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 153 matching lines @@
     else:
       # Recurse.
       rmtree(fullpath)
 
   remove(os.rmdir, path)
 
 # TODO(maruel): Rename the references.
 RemoveDirectory = rmtree
 
 
+def safe_makedirs(tree):
+  """Creates the directory in a safe manner.
+
+  Because multiple threads can create these directories concurently, trap the
+  exception and pass on.
+  """
+  count = 0
+  while not os.path.exists(tree):
+    count += 1
+    try:
+      os.makedirs(tree)
+    except OSError, e:
+      # 17 POSIX, 183 Windows
+      if e.errno not in (17, 183):
+        raise
+      if count > 40:
+        # Give up.
+        raise
+
+
 def CheckCallAndFilterAndHeader(args, always=False, **kwargs):
   """Adds 'header' support to CheckCallAndFilter.
 
   If |always| is True, a message indicating what is being done
   is printed to stdout all the time even if not output is generated. Otherwise
   the message header is printed only if the call generated any ouput.
   """
   stdout = kwargs.get('stdout', None) or sys.stdout
   if always:
     stdout.write('\n________ running \'%s\' in \'%s\'\n'
@@ skipping 480 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()