# Copyright (C) 2002-2011 John Goerzen & contributors # Thread support module # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA from threading import Lock, Thread, BoundedSemaphore from Queue import Queue, Empty import traceback from thread import get_ident # python < 2.6 support import os.path import sys from offlineimap.ui import getglobalui ###################################################################### # General utilities ###################################################################### def semaphorereset(semaphore, originalstate): """Wait until the semaphore gets back to its original state -- all acquired resources released.""" for i in range(originalstate): semaphore.acquire() # Now release these. for i in range(originalstate): semaphore.release() class threadlist: def __init__(self): self.lock = Lock() self.list = [] def add(self, thread): self.lock.acquire() try: self.list.append(thread) finally: self.lock.release() def remove(self, thread): self.lock.acquire() try: self.list.remove(thread) finally: self.lock.release() def pop(self): self.lock.acquire() try: if not len(self.list): return None return self.list.pop() finally: self.lock.release() def reset(self): while 1: thread = self.pop() if not thread: return thread.join() ###################################################################### # Exit-notify threads ###################################################################### exitthreads = Queue(100) def exitnotifymonitorloop(callback): """An infinite "monitoring" loop watching for finished ExitNotifyThread's. This one is supposed to run in the main thread. :param callback: the function to call when a thread terminated. That function is called with a single argument -- the ExitNotifyThread that has terminated. The monitor will not continue to monitor for other threads until 'callback' returns, so if it intends to perform long calculations, it should start a new thread itself -- but NOT an ExitNotifyThread, or else an infinite loop may result. Furthermore, the monitor will hold the lock all the while the other thread is waiting. :type callback: a callable function """ global exitthreads while 1: # Loop forever and call 'callback' for each thread that exited try: # we need a timeout in the get() call, so that ctrl-c can throw # a SIGINT (http://bugs.python.org/issue1360). A timeout with empty # Queue will raise `Empty`. thrd = exitthreads.get(True, 60) callback(thrd) except Empty: pass def threadexited(thread): """Called when a thread exits.""" ui = getglobalui() if thread.getExitCause() == 'EXCEPTION': if isinstance(thread.getExitException(), SystemExit): # Bring a SystemExit into the main thread. # Do not send it back to UI layer right now. # Maybe later send it to ui.terminate? raise SystemExit ui.threadException(thread) # Expected to terminate sys.exit(100) # Just in case... elif thread.getExitMessage() == 'SYNC_WITH_TIMER_TERMINATE': ui.terminate() # Just in case... sys.exit(100) else: ui.threadExited(thread) class ExitNotifyThread(Thread): """This class is designed to alert a "monitor" to the fact that a thread has exited and to provide for the ability for it to find out why. All instances are made daemon threads (setDaemon(True), so we bail out when the mainloop dies.""" profiledir = None """class variable that is set to the profile directory if required""" def __init__(self, *args, **kwargs): super(ExitNotifyThread, self).__init__(*args, **kwargs) # These are all child threads that are supposed to go away when # the main thread is killed. self.setDaemon(True) def run(self): global exitthreads self.threadid = get_ident() try: if not ExitNotifyThread.profiledir: # normal case Thread.run(self) else: try: import cProfile as profile except ImportError: import profile prof = profile.Profile() try: prof = prof.runctx("Thread.run(self)", globals(), locals()) except SystemExit: pass prof.dump_stats(os.path.join(ExitNotifyThread.profiledir, "%s_%s.prof" % (self.threadid, self.getName()))) except: self.setExitCause('EXCEPTION') if sys: self.setExitException(sys.exc_info()[1]) tb = traceback.format_exc() self.setExitStackTrace(tb) else: self.setExitCause('NORMAL') if not hasattr(self, 'exitmessage'): self.setExitMessage(None) if exitthreads: exitthreads.put(self, True) def setExitCause(self, cause): self.exitcause = cause def getExitCause(self): """Returns the cause of the exit, one of: 'EXCEPTION' -- the thread aborted because of an exception 'NORMAL' -- normal termination.""" return self.exitcause def setExitException(self, exc): self.exitexception = exc def getExitException(self): """If getExitCause() is 'EXCEPTION', holds the value from sys.exc_info()[1] for this exception.""" return self.exitexception def setExitStackTrace(self, st): self.exitstacktrace = st def getExitStackTrace(self): """If getExitCause() is 'EXCEPTION', returns a string representing the stack trace for this exception.""" return self.exitstacktrace def setExitMessage(self, msg): """Sets the exit message to be fetched by a subsequent call to getExitMessage. This message may be any object or type except None.""" self.exitmessage = msg def getExitMessage(self): """For any exit cause, returns the message previously set by a call to setExitMessage(), or None if there was no such message set.""" return self.exitmessage @classmethod def set_profiledir(cls, directory): """If set, will output profile information to 'directory'""" cls.profiledir = directory ###################################################################### # Instance-limited threads ###################################################################### instancelimitedsems = {} instancelimitedlock = Lock() def initInstanceLimit(instancename, instancemax): """Initialize the instance-limited thread implementation to permit up to intancemax threads with the given instancename.""" instancelimitedlock.acquire() if not instancelimitedsems.has_key(instancename): instancelimitedsems[instancename] = BoundedSemaphore(instancemax) instancelimitedlock.release() class InstanceLimitedThread(ExitNotifyThread): def __init__(self, instancename, *args, **kwargs): self.instancename = instancename super(InstanceLimitedThread, self).__init__(*args, **kwargs) def start(self): instancelimitedsems[self.instancename].acquire() ExitNotifyThread.start(self) def run(self): try: ExitNotifyThread.run(self) finally: if instancelimitedsems and instancelimitedsems[self.instancename]: instancelimitedsems[self.instancename].release()