old_contents: # Copyright 2009 Google Inc.
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  #
  # Licensed to the PSF under a Contributor Agreement.
  #
  # Author: Gregory P. Smith <greg@krypto.org>
  
  """
  This module provides code to setup appropriate atfork() calls within the
  Python standard library in order to make it safe for use in programs that
  mix fork() and threads.
  
  Import this and call the appropriate fixers very early in your program's
  initialization sequence, preferrably -before- importing the modules you
  need to fix.
  
  Provided fixers:
  
      fix_logging_module()
  
  TODO(gps): Audit more of the stdlib and provide necessary fixers.
  In 2.4.5 the following additional stdlib modules use locks:
  
    threading.Condition and similar classes could use it.
    Queue
    cookielib
    mimetools
    _strptime
  """
  
  import atfork
  import sys
  import warnings
  
  
  class Error(Exception):
      pass
  
  
  def fix_logging_module():
      if 'logging' in sys.modules:
          warnings.warn('logging module already imported before fixup.')
      import logging
      # Prevent fixing multiple times as that would cause a deadlock.
      if getattr(logging, 'fixed_for_atfork', None):
          return
      if logging.getLogger().handlers:
          # We could register each lock with atfork for these handlers but if
          # these exist, other loggers or not yet added handlers could as well.
          # Its safer to insist that this fix is applied before logging has been
          # configured.
          raise Error('logging handlers already registered.')
  
      logging._acquireLock()
      try:
          def fork_safe_createLock(self):
              self._orig_createLock()
              atfork.atfork(self.lock.acquire,
                            self.lock.release, self.lock.release)
  
          # Fix the logging.Handler lock (a major source of deadlocks).
          logging.Handler._orig_createLock = logging.Handler.createLock
          logging.Handler.createLock = fork_safe_createLock
  
          # Fix the module level lock.
          atfork.atfork(logging._acquireLock,
                        logging._releaseLock, logging._releaseLock)
  
          logging.fixed_for_atfork = True
      finally:
          logging._releaseLock()
  
new_contents: # Copyright 2009 Google Inc.
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  #
  # Licensed to the PSF under a Contributor Agreement.
  #
  # Author: Gregory P. Smith <greg@krypto.org>
  
  """
  This module provides code to setup appropriate atfork() calls within the
  Python standard library in order to make it safe for use in programs that
  mix fork() and threads.
  
  Import this and call the appropriate fixers very early in your program's
  initialization sequence, preferrably -before- importing the modules you
  need to fix.
  
  Provided fixers:
  
      fix_logging_module()
  
  TODO(gps): Audit more of the stdlib and provide necessary fixers.
  In 2.4.5 the following additional stdlib modules use locks:
  
    threading.Condition and similar classes could use it.
    Queue
    cookielib
    mimetools
    _strptime
  """
  
  import atfork
  import sys
  import warnings
  
  
  class Error(Exception):
      pass
  
  
  def fix_logging_module():
      logging = sys.modules.get('logging')
      # Prevent fixing multiple times as that would cause a deadlock.
      if logging and getattr(logging, 'fixed_for_atfork', None):
          return
      if logging:
          warnings.warn('logging module already imported before fixup.')
      import logging
      if logging.getLogger().handlers:
          # We could register each lock with atfork for these handlers but if
          # these exist, other loggers or not yet added handlers could as well.
          # Its safer to insist that this fix is applied before logging has been
          # configured.
          raise Error('logging handlers already registered.')
  
      logging._acquireLock()
      try:
          def fork_safe_createLock(self):
              self._orig_createLock()
              atfork.atfork(self.lock.acquire,
                            self.lock.release, self.lock.release)
  
          # Fix the logging.Handler lock (a major source of deadlocks).
          logging.Handler._orig_createLock = logging.Handler.createLock
          logging.Handler.createLock = fork_safe_createLock
  
          # Fix the module level lock.
          atfork.atfork(logging._acquireLock,
                        logging._releaseLock, logging._releaseLock)
  
          logging.fixed_for_atfork = True
      finally:
          logging._releaseLock()
  
subject: Abort the fixer before issuing a warning if the fix has already been applied.