694 lines
20 KiB
Python
694 lines
20 KiB
Python
"""Thread module emulating a subset of Java's threading model."""
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import sys
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import time
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import thread
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import traceback
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import StringIO
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# Rename some stuff so "from threading import *" is safe
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_sys = sys
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del sys
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_time = time.time
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_sleep = time.sleep
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del time
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_start_new_thread = thread.start_new_thread
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_allocate_lock = thread.allocate_lock
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_get_ident = thread.get_ident
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ThreadError = thread.error
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del thread
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_print_exc = traceback.print_exc
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del traceback
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_StringIO = StringIO.StringIO
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del StringIO
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# Debug support (adapted from ihooks.py)
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_VERBOSE = 0 # XXX Bool or int?
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if __debug__:
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class _Verbose:
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def __init__(self, verbose=None):
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if verbose is None:
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verbose = _VERBOSE
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self.__verbose = verbose
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def _note(self, format, *args):
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if self.__verbose:
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format = format % args
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format = "%s: %s\n" % (
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currentThread().getName(), format)
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_sys.stderr.write(format)
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else:
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# Disable this when using "python -O"
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class _Verbose:
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def __init__(self, verbose=None):
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pass
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def _note(self, *args):
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pass
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# Synchronization classes
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Lock = _allocate_lock
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def RLock(*args, **kwargs):
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return apply(_RLock, args, kwargs)
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class _RLock(_Verbose):
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def __init__(self, verbose=None):
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_Verbose.__init__(self, verbose)
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self.__block = _allocate_lock()
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self.__owner = None
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self.__count = 0
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def __repr__(self):
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return "<%s(%s, %d)>" % (
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self.__class__.__name__,
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self.__owner and self.__owner.getName(),
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self.__count)
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def acquire(self, blocking=1):
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me = currentThread()
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if self.__owner is me:
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self.__count = self.__count + 1
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if __debug__:
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self._note("%s.acquire(%s): recursive success", self, blocking)
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return 1
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rc = self.__block.acquire(blocking)
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if rc:
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self.__owner = me
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self.__count = 1
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if __debug__:
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self._note("%s.acquire(%s): initial succes", self, blocking)
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else:
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if __debug__:
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self._note("%s.acquire(%s): failure", self, blocking)
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return rc
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def release(self):
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me = currentThread()
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assert self.__owner is me, "release() of un-acquire()d lock"
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self.__count = count = self.__count - 1
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if not count:
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self.__owner = None
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self.__block.release()
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if __debug__:
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self._note("%s.release(): final release", self)
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else:
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if __debug__:
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self._note("%s.release(): non-final release", self)
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# Internal methods used by condition variables
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def _acquire_restore(self, (count, owner)):
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self.__block.acquire()
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self.__count = count
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self.__owner = owner
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if __debug__:
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self._note("%s._acquire_restore()", self)
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def _release_save(self):
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if __debug__:
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self._note("%s._release_save()", self)
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count = self.__count
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self.__count = 0
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owner = self.__owner
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self.__owner = None
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self.__block.release()
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return (count, owner)
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def _is_owned(self):
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return self.__owner is currentThread()
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def Condition(*args, **kwargs):
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return apply(_Condition, args, kwargs)
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class _Condition(_Verbose):
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def __init__(self, lock=None, verbose=None):
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_Verbose.__init__(self, verbose)
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if lock is None:
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lock = RLock()
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self.__lock = lock
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# Export the lock's acquire() and release() methods
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self.acquire = lock.acquire
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self.release = lock.release
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# If the lock defines _release_save() and/or _acquire_restore(),
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# these override the default implementations (which just call
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# release() and acquire() on the lock). Ditto for _is_owned().
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try:
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self._release_save = lock._release_save
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except AttributeError:
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pass
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try:
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self._acquire_restore = lock._acquire_restore
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except AttributeError:
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pass
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try:
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self._is_owned = lock._is_owned
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except AttributeError:
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pass
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self.__waiters = []
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def __repr__(self):
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return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
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def _release_save(self):
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self.__lock.release() # No state to save
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def _acquire_restore(self, x):
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self.__lock.acquire() # Ignore saved state
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def _is_owned(self):
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# Return True if lock is owned by currentThread.
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# This method is called only if __lock doesn't have _is_owned().
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if self.__lock.acquire(0):
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self.__lock.release()
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return False
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else:
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return True
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def wait(self, timeout=None):
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currentThread() # for side-effect
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assert self._is_owned(), "wait() of un-acquire()d lock"
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waiter = _allocate_lock()
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waiter.acquire()
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self.__waiters.append(waiter)
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saved_state = self._release_save()
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try: # restore state no matter what (e.g., KeyboardInterrupt)
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if timeout is None:
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waiter.acquire()
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if __debug__:
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self._note("%s.wait(): got it", self)
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else:
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# Balancing act: We can't afford a pure busy loop, so we
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# have to sleep; but if we sleep the whole timeout time,
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# we'll be unresponsive. The scheme here sleeps very
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# little at first, longer as time goes on, but never longer
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# than 20 times per second (or the timeout time remaining).
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endtime = _time() + timeout
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delay = 0.0005 # 500 us -> initial delay of 1 ms
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while True:
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gotit = waiter.acquire(0)
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if gotit:
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break
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remaining = endtime - _time()
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if remaining <= 0:
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break
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delay = min(delay * 2, remaining, .05)
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_sleep(delay)
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if not gotit:
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if __debug__:
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self._note("%s.wait(%s): timed out", self, timeout)
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try:
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self.__waiters.remove(waiter)
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except ValueError:
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pass
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else:
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if __debug__:
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self._note("%s.wait(%s): got it", self, timeout)
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finally:
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self._acquire_restore(saved_state)
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def notify(self, n=1):
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currentThread() # for side-effect
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assert self._is_owned(), "notify() of un-acquire()d lock"
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__waiters = self.__waiters
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waiters = __waiters[:n]
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if not waiters:
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if __debug__:
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self._note("%s.notify(): no waiters", self)
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return
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self._note("%s.notify(): notifying %d waiter%s", self, n,
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n!=1 and "s" or "")
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for waiter in waiters:
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waiter.release()
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try:
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__waiters.remove(waiter)
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except ValueError:
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pass
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def notifyAll(self):
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self.notify(len(self.__waiters))
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def Semaphore(*args, **kwargs):
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return apply(_Semaphore, args, kwargs)
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class _Semaphore(_Verbose):
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# After Tim Peters' semaphore class, but not quite the same (no maximum)
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def __init__(self, value=1, verbose=None):
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assert value >= 0, "Semaphore initial value must be >= 0"
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_Verbose.__init__(self, verbose)
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self.__cond = Condition(Lock())
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self.__value = value
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def acquire(self, blocking=1):
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rc = False
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self.__cond.acquire()
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while self.__value == 0:
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if not blocking:
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break
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if __debug__:
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self._note("%s.acquire(%s): blocked waiting, value=%s",
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self, blocking, self.__value)
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self.__cond.wait()
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else:
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self.__value = self.__value - 1
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if __debug__:
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self._note("%s.acquire: success, value=%s",
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self, self.__value)
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rc = True
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self.__cond.release()
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return rc
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def release(self):
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self.__cond.acquire()
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self.__value = self.__value + 1
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if __debug__:
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self._note("%s.release: success, value=%s",
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self, self.__value)
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self.__cond.notify()
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self.__cond.release()
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def BoundedSemaphore(*args, **kwargs):
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return apply(_BoundedSemaphore, args, kwargs)
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class _BoundedSemaphore(_Semaphore):
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"""Semaphore that checks that # releases is <= # acquires"""
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def __init__(self, value=1, verbose=None):
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_Semaphore.__init__(self, value, verbose)
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self._initial_value = value
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def release(self):
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if self._Semaphore__value >= self._initial_value:
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raise ValueError, "Semaphore released too many times"
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return _Semaphore.release(self)
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def Event(*args, **kwargs):
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return apply(_Event, args, kwargs)
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class _Event(_Verbose):
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# After Tim Peters' event class (without is_posted())
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def __init__(self, verbose=None):
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_Verbose.__init__(self, verbose)
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self.__cond = Condition(Lock())
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self.__flag = False
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def isSet(self):
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return self.__flag
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def set(self):
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self.__cond.acquire()
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self.__flag = True
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self.__cond.notifyAll()
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self.__cond.release()
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def clear(self):
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self.__cond.acquire()
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self.__flag = False
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self.__cond.release()
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def wait(self, timeout=None):
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self.__cond.acquire()
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if not self.__flag:
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self.__cond.wait(timeout)
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self.__cond.release()
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# Helper to generate new thread names
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_counter = 0
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def _newname(template="Thread-%d"):
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global _counter
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_counter = _counter + 1
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return template % _counter
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# Active thread administration
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_active_limbo_lock = _allocate_lock()
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_active = {}
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_limbo = {}
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# Main class for threads
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class Thread(_Verbose):
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__initialized = False
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def __init__(self, group=None, target=None, name=None,
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args=(), kwargs={}, verbose=None):
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assert group is None, "group argument must be None for now"
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_Verbose.__init__(self, verbose)
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self.__target = target
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self.__name = str(name or _newname())
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self.__args = args
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self.__kwargs = kwargs
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self.__daemonic = self._set_daemon()
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self.__started = False
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self.__stopped = False
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self.__block = Condition(Lock())
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self.__initialized = True
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def _set_daemon(self):
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# Overridden in _MainThread and _DummyThread
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return currentThread().isDaemon()
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def __repr__(self):
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assert self.__initialized, "Thread.__init__() was not called"
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status = "initial"
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if self.__started:
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status = "started"
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if self.__stopped:
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status = "stopped"
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if self.__daemonic:
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status = status + " daemon"
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return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)
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def start(self):
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assert self.__initialized, "Thread.__init__() not called"
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assert not self.__started, "thread already started"
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if __debug__:
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self._note("%s.start(): starting thread", self)
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_active_limbo_lock.acquire()
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_limbo[self] = self
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_active_limbo_lock.release()
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_start_new_thread(self.__bootstrap, ())
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self.__started = True
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_sleep(0.000001) # 1 usec, to let the thread run (Solaris hack)
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def run(self):
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if self.__target:
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apply(self.__target, self.__args, self.__kwargs)
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def __bootstrap(self):
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try:
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self.__started = True
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_active_limbo_lock.acquire()
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_active[_get_ident()] = self
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del _limbo[self]
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_active_limbo_lock.release()
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if __debug__:
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self._note("%s.__bootstrap(): thread started", self)
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try:
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self.run()
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except SystemExit:
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if __debug__:
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self._note("%s.__bootstrap(): raised SystemExit", self)
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except:
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if __debug__:
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self._note("%s.__bootstrap(): unhandled exception", self)
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s = _StringIO()
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_print_exc(file=s)
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_sys.stderr.write("Exception in thread %s:\n%s\n" %
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(self.getName(), s.getvalue()))
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else:
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if __debug__:
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self._note("%s.__bootstrap(): normal return", self)
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finally:
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self.__stop()
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try:
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self.__delete()
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except:
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pass
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def __stop(self):
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self.__block.acquire()
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self.__stopped = True
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self.__block.notifyAll()
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self.__block.release()
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def __delete(self):
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_active_limbo_lock.acquire()
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del _active[_get_ident()]
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_active_limbo_lock.release()
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def join(self, timeout=None):
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assert self.__initialized, "Thread.__init__() not called"
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assert self.__started, "cannot join thread before it is started"
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assert self is not currentThread(), "cannot join current thread"
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if __debug__:
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if not self.__stopped:
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self._note("%s.join(): waiting until thread stops", self)
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self.__block.acquire()
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if timeout is None:
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while not self.__stopped:
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self.__block.wait()
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if __debug__:
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self._note("%s.join(): thread stopped", self)
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else:
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deadline = _time() + timeout
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while not self.__stopped:
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delay = deadline - _time()
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if delay <= 0:
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if __debug__:
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self._note("%s.join(): timed out", self)
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break
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self.__block.wait(delay)
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else:
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if __debug__:
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self._note("%s.join(): thread stopped", self)
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self.__block.release()
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def getName(self):
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assert self.__initialized, "Thread.__init__() not called"
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return self.__name
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def setName(self, name):
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assert self.__initialized, "Thread.__init__() not called"
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self.__name = str(name)
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def isAlive(self):
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assert self.__initialized, "Thread.__init__() not called"
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return self.__started and not self.__stopped
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def isDaemon(self):
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assert self.__initialized, "Thread.__init__() not called"
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return self.__daemonic
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def setDaemon(self, daemonic):
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assert self.__initialized, "Thread.__init__() not called"
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assert not self.__started, "cannot set daemon status of active thread"
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self.__daemonic = daemonic
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# The timer class was contributed by Itamar Shtull-Trauring
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def Timer(*args, **kwargs):
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return _Timer(*args, **kwargs)
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class _Timer(Thread):
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"""Call a function after a specified number of seconds:
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t = Timer(30.0, f, args=[], kwargs={})
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t.start()
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t.cancel() # stop the timer's action if it's still waiting
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"""
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def __init__(self, interval, function, args=[], kwargs={}):
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Thread.__init__(self)
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self.interval = interval
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self.function = function
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self.args = args
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self.kwargs = kwargs
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self.finished = Event()
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def cancel(self):
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"""Stop the timer if it hasn't finished yet"""
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self.finished.set()
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def run(self):
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self.finished.wait(self.interval)
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if not self.finished.isSet():
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self.function(*self.args, **self.kwargs)
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self.finished.set()
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# Special thread class to represent the main thread
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# This is garbage collected through an exit handler
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class _MainThread(Thread):
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def __init__(self):
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Thread.__init__(self, name="MainThread")
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self._Thread__started = True
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_active_limbo_lock.acquire()
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_active[_get_ident()] = self
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_active_limbo_lock.release()
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import atexit
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atexit.register(self.__exitfunc)
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def _set_daemon(self):
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return False
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def __exitfunc(self):
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self._Thread__stop()
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t = _pickSomeNonDaemonThread()
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if t:
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if __debug__:
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self._note("%s: waiting for other threads", self)
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while t:
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t.join()
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t = _pickSomeNonDaemonThread()
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if __debug__:
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self._note("%s: exiting", self)
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self._Thread__delete()
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def _pickSomeNonDaemonThread():
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for t in enumerate():
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if not t.isDaemon() and t.isAlive():
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return t
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return None
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# Dummy thread class to represent threads not started here.
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# These aren't garbage collected when they die,
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# nor can they be waited for.
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# Their purpose is to return *something* from currentThread().
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# They are marked as daemon threads so we won't wait for them
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# when we exit (conform previous semantics).
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class _DummyThread(Thread):
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def __init__(self):
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Thread.__init__(self, name=_newname("Dummy-%d"))
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self._Thread__started = True
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_active_limbo_lock.acquire()
|
|
_active[_get_ident()] = self
|
|
_active_limbo_lock.release()
|
|
|
|
def _set_daemon(self):
|
|
return True
|
|
|
|
def join(self, timeout=None):
|
|
assert False, "cannot join a dummy thread"
|
|
|
|
|
|
# Global API functions
|
|
|
|
def currentThread():
|
|
try:
|
|
return _active[_get_ident()]
|
|
except KeyError:
|
|
##print "currentThread(): no current thread for", _get_ident()
|
|
return _DummyThread()
|
|
|
|
def activeCount():
|
|
_active_limbo_lock.acquire()
|
|
count = len(_active) + len(_limbo)
|
|
_active_limbo_lock.release()
|
|
return count
|
|
|
|
def enumerate():
|
|
_active_limbo_lock.acquire()
|
|
active = _active.values() + _limbo.values()
|
|
_active_limbo_lock.release()
|
|
return active
|
|
|
|
|
|
# Create the main thread object
|
|
|
|
_MainThread()
|
|
|
|
|
|
# Self-test code
|
|
|
|
def _test():
|
|
|
|
class BoundedQueue(_Verbose):
|
|
|
|
def __init__(self, limit):
|
|
_Verbose.__init__(self)
|
|
self.mon = RLock()
|
|
self.rc = Condition(self.mon)
|
|
self.wc = Condition(self.mon)
|
|
self.limit = limit
|
|
self.queue = []
|
|
|
|
def put(self, item):
|
|
self.mon.acquire()
|
|
while len(self.queue) >= self.limit:
|
|
self._note("put(%s): queue full", item)
|
|
self.wc.wait()
|
|
self.queue.append(item)
|
|
self._note("put(%s): appended, length now %d",
|
|
item, len(self.queue))
|
|
self.rc.notify()
|
|
self.mon.release()
|
|
|
|
def get(self):
|
|
self.mon.acquire()
|
|
while not self.queue:
|
|
self._note("get(): queue empty")
|
|
self.rc.wait()
|
|
item = self.queue.pop(0)
|
|
self._note("get(): got %s, %d left", item, len(self.queue))
|
|
self.wc.notify()
|
|
self.mon.release()
|
|
return item
|
|
|
|
class ProducerThread(Thread):
|
|
|
|
def __init__(self, queue, quota):
|
|
Thread.__init__(self, name="Producer")
|
|
self.queue = queue
|
|
self.quota = quota
|
|
|
|
def run(self):
|
|
from random import random
|
|
counter = 0
|
|
while counter < self.quota:
|
|
counter = counter + 1
|
|
self.queue.put("%s.%d" % (self.getName(), counter))
|
|
_sleep(random() * 0.00001)
|
|
|
|
|
|
class ConsumerThread(Thread):
|
|
|
|
def __init__(self, queue, count):
|
|
Thread.__init__(self, name="Consumer")
|
|
self.queue = queue
|
|
self.count = count
|
|
|
|
def run(self):
|
|
while self.count > 0:
|
|
item = self.queue.get()
|
|
print item
|
|
self.count = self.count - 1
|
|
|
|
NP = 3
|
|
QL = 4
|
|
NI = 5
|
|
|
|
Q = BoundedQueue(QL)
|
|
P = []
|
|
for i in range(NP):
|
|
t = ProducerThread(Q, NI)
|
|
t.setName("Producer-%d" % (i+1))
|
|
P.append(t)
|
|
C = ConsumerThread(Q, NI*NP)
|
|
for t in P:
|
|
t.start()
|
|
_sleep(0.000001)
|
|
C.start()
|
|
for t in P:
|
|
t.join()
|
|
C.join()
|
|
|
|
if __name__ == '__main__':
|
|
_test()
|