lib-python.2.5.threading.py Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jython Show documentation
Show all versions of jython Show documentation
Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
"""Thread module emulating a subset of Java's threading model."""
import sys as _sys
try:
import thread
except ImportError:
del _sys.modules[__name__]
raise
from time import time as _time, sleep as _sleep
from traceback import format_exc as _format_exc
from collections import deque
# Rename some stuff so "from threading import *" is safe
__all__ = ['activeCount', 'Condition', 'currentThread', 'enumerate', 'Event',
'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread',
'Timer', 'setprofile', 'settrace', 'local', 'stack_size']
_start_new_thread = thread.start_new_thread
_allocate_lock = thread.allocate_lock
_get_ident = thread.get_ident
ThreadError = thread.error
del thread
# Debug support (adapted from ihooks.py).
# All the major classes here derive from _Verbose. We force that to
# be a new-style class so that all the major classes here are new-style.
# This helps debugging (type(instance) is more revealing for instances
# of new-style classes).
_VERBOSE = False
if __debug__:
class _Verbose(object):
def __init__(self, verbose=None):
if verbose is None:
verbose = _VERBOSE
self.__verbose = verbose
def _note(self, format, *args):
if self.__verbose:
format = format % args
format = "%s: %s\n" % (
currentThread().getName(), format)
_sys.stderr.write(format)
else:
# Disable this when using "python -O"
class _Verbose(object):
def __init__(self, verbose=None):
pass
def _note(self, *args):
pass
# Support for profile and trace hooks
_profile_hook = None
_trace_hook = None
def setprofile(func):
global _profile_hook
_profile_hook = func
def settrace(func):
global _trace_hook
_trace_hook = func
# Synchronization classes
Lock = _allocate_lock
def RLock(*args, **kwargs):
return _RLock(*args, **kwargs)
class _RLock(_Verbose):
def __init__(self, verbose=None):
_Verbose.__init__(self, verbose)
self.__block = _allocate_lock()
self.__owner = None
self.__count = 0
def __repr__(self):
owner = self.__owner
return "<%s(%s, %d)>" % (
self.__class__.__name__,
owner and owner.getName(),
self.__count)
def acquire(self, blocking=1):
me = currentThread()
if self.__owner is me:
self.__count = self.__count + 1
if __debug__:
self._note("%s.acquire(%s): recursive success", self, blocking)
return 1
rc = self.__block.acquire(blocking)
if rc:
self.__owner = me
self.__count = 1
if __debug__:
self._note("%s.acquire(%s): initial success", self, blocking)
else:
if __debug__:
self._note("%s.acquire(%s): failure", self, blocking)
return rc
__enter__ = acquire
def release(self):
if self.__owner is not currentThread():
raise RuntimeError("cannot release un-aquired lock")
self.__count = count = self.__count - 1
if not count:
self.__owner = None
self.__block.release()
if __debug__:
self._note("%s.release(): final release", self)
else:
if __debug__:
self._note("%s.release(): non-final release", self)
def __exit__(self, t, v, tb):
self.release()
# Internal methods used by condition variables
def _acquire_restore(self, (count, owner)):
self.__block.acquire()
self.__count = count
self.__owner = owner
if __debug__:
self._note("%s._acquire_restore()", self)
def _release_save(self):
if __debug__:
self._note("%s._release_save()", self)
count = self.__count
self.__count = 0
owner = self.__owner
self.__owner = None
self.__block.release()
return (count, owner)
def _is_owned(self):
return self.__owner is currentThread()
def Condition(*args, **kwargs):
return _Condition(*args, **kwargs)
class _Condition(_Verbose):
def __init__(self, lock=None, verbose=None):
_Verbose.__init__(self, verbose)
if lock is None:
lock = RLock()
self.__lock = lock
# Export the lock's acquire() and release() methods
self.acquire = lock.acquire
self.release = lock.release
# If the lock defines _release_save() and/or _acquire_restore(),
# these override the default implementations (which just call
# release() and acquire() on the lock). Ditto for _is_owned().
try:
self._release_save = lock._release_save
except AttributeError:
pass
try:
self._acquire_restore = lock._acquire_restore
except AttributeError:
pass
try:
self._is_owned = lock._is_owned
except AttributeError:
pass
self.__waiters = []
def __enter__(self):
return self.__lock.__enter__()
def __exit__(self, *args):
return self.__lock.__exit__(*args)
def __repr__(self):
return "" % (self.__lock, len(self.__waiters))
def _release_save(self):
self.__lock.release() # No state to save
def _acquire_restore(self, x):
self.__lock.acquire() # Ignore saved state
def _is_owned(self):
# Return True if lock is owned by currentThread.
# This method is called only if __lock doesn't have _is_owned().
if self.__lock.acquire(0):
self.__lock.release()
return False
else:
return True
def wait(self, timeout=None):
if not self._is_owned():
raise RuntimeError("cannot wait on un-aquired lock")
waiter = _allocate_lock()
waiter.acquire()
self.__waiters.append(waiter)
saved_state = self._release_save()
try: # restore state no matter what (e.g., KeyboardInterrupt)
if timeout is None:
waiter.acquire()
if __debug__:
self._note("%s.wait(): got it", self)
else:
# Balancing act: We can't afford a pure busy loop, so we
# have to sleep; but if we sleep the whole timeout time,
# we'll be unresponsive. The scheme here sleeps very
# little at first, longer as time goes on, but never longer
# than 20 times per second (or the timeout time remaining).
endtime = _time() + timeout
delay = 0.0005 # 500 us -> initial delay of 1 ms
while True:
gotit = waiter.acquire(0)
if gotit:
break
remaining = endtime - _time()
if remaining <= 0:
break
delay = min(delay * 2, remaining, .05)
_sleep(delay)
if not gotit:
if __debug__:
self._note("%s.wait(%s): timed out", self, timeout)
try:
self.__waiters.remove(waiter)
except ValueError:
pass
else:
if __debug__:
self._note("%s.wait(%s): got it", self, timeout)
finally:
self._acquire_restore(saved_state)
def notify(self, n=1):
if not self._is_owned():
raise RuntimeError("cannot notify on un-aquired lock")
__waiters = self.__waiters
waiters = __waiters[:n]
if not waiters:
if __debug__:
self._note("%s.notify(): no waiters", self)
return
self._note("%s.notify(): notifying %d waiter%s", self, n,
n!=1 and "s" or "")
for waiter in waiters:
waiter.release()
try:
__waiters.remove(waiter)
except ValueError:
pass
def notifyAll(self):
self.notify(len(self.__waiters))
def Semaphore(*args, **kwargs):
return _Semaphore(*args, **kwargs)
class _Semaphore(_Verbose):
# After Tim Peters' semaphore class, but not quite the same (no maximum)
def __init__(self, value=1, verbose=None):
if value < 0:
raise ValueError("semaphore initial value must be >= 0")
_Verbose.__init__(self, verbose)
self.__cond = Condition(Lock())
self.__value = value
def acquire(self, blocking=1):
rc = False
self.__cond.acquire()
while self.__value == 0:
if not blocking:
break
if __debug__:
self._note("%s.acquire(%s): blocked waiting, value=%s",
self, blocking, self.__value)
self.__cond.wait()
else:
self.__value = self.__value - 1
if __debug__:
self._note("%s.acquire: success, value=%s",
self, self.__value)
rc = True
self.__cond.release()
return rc
__enter__ = acquire
def release(self):
self.__cond.acquire()
self.__value = self.__value + 1
if __debug__:
self._note("%s.release: success, value=%s",
self, self.__value)
self.__cond.notify()
self.__cond.release()
def __exit__(self, t, v, tb):
self.release()
def BoundedSemaphore(*args, **kwargs):
return _BoundedSemaphore(*args, **kwargs)
class _BoundedSemaphore(_Semaphore):
"""Semaphore that checks that # releases is <= # acquires"""
def __init__(self, value=1, verbose=None):
_Semaphore.__init__(self, value, verbose)
self._initial_value = value
def release(self):
if self._Semaphore__value >= self._initial_value:
raise ValueError, "Semaphore released too many times"
return _Semaphore.release(self)
def Event(*args, **kwargs):
return _Event(*args, **kwargs)
class _Event(_Verbose):
# After Tim Peters' event class (without is_posted())
def __init__(self, verbose=None):
_Verbose.__init__(self, verbose)
self.__cond = Condition(Lock())
self.__flag = False
def isSet(self):
return self.__flag
def set(self):
self.__cond.acquire()
try:
self.__flag = True
self.__cond.notifyAll()
finally:
self.__cond.release()
def clear(self):
self.__cond.acquire()
try:
self.__flag = False
finally:
self.__cond.release()
def wait(self, timeout=None):
self.__cond.acquire()
try:
if not self.__flag:
self.__cond.wait(timeout)
finally:
self.__cond.release()
# Helper to generate new thread names
_counter = 0
def _newname(template="Thread-%d"):
global _counter
_counter = _counter + 1
return template % _counter
# Active thread administration
_active_limbo_lock = _allocate_lock()
_active = {} # maps thread id to Thread object
_limbo = {}
# Main class for threads
class Thread(_Verbose):
__initialized = False
# Need to store a reference to sys.exc_info for printing
# out exceptions when a thread tries to use a global var. during interp.
# shutdown and thus raises an exception about trying to perform some
# operation on/with a NoneType
__exc_info = _sys.exc_info
def __init__(self, group=None, target=None, name=None,
args=(), kwargs=None, verbose=None):
assert group is None, "group argument must be None for now"
_Verbose.__init__(self, verbose)
if kwargs is None:
kwargs = {}
self.__target = target
self.__name = str(name or _newname())
self.__args = args
self.__kwargs = kwargs
self.__daemonic = self._set_daemon()
self.__started = False
self.__stopped = False
self.__block = Condition(Lock())
self.__initialized = True
# sys.stderr is not stored in the class like
# sys.exc_info since it can be changed between instances
self.__stderr = _sys.stderr
def _set_daemon(self):
# Overridden in _MainThread and _DummyThread
return currentThread().isDaemon()
def __repr__(self):
assert self.__initialized, "Thread.__init__() was not called"
status = "initial"
if self.__started:
status = "started"
if self.__stopped:
status = "stopped"
if self.__daemonic:
status = status + " daemon"
return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)
def start(self):
if not self.__initialized:
raise RuntimeError("thread.__init__() not called")
if self.__started:
raise RuntimeError("thread already started")
if __debug__:
self._note("%s.start(): starting thread", self)
_active_limbo_lock.acquire()
_limbo[self] = self
_active_limbo_lock.release()
_start_new_thread(self.__bootstrap, ())
self.__started = True
_sleep(0.000001) # 1 usec, to let the thread run (Solaris hack)
def run(self):
if self.__target:
self.__target(*self.__args, **self.__kwargs)
def __bootstrap(self):
# Wrapper around the real bootstrap code that ignores
# exceptions during interpreter cleanup. Those typically
# happen when a daemon thread wakes up at an unfortunate
# moment, finds the world around it destroyed, and raises some
# random exception *** while trying to report the exception in
# __bootstrap_inner() below ***. Those random exceptions
# don't help anybody, and they confuse users, so we suppress
# them. We suppress them only when it appears that the world
# indeed has already been destroyed, so that exceptions in
# __bootstrap_inner() during normal business hours are properly
# reported. Also, we only suppress them for daemonic threads;
# if a non-daemonic encounters this, something else is wrong.
try:
self.__bootstrap_inner()
except:
if self.__daemonic and _sys is None:
return
raise
def __bootstrap_inner(self):
try:
self.__started = True
_active_limbo_lock.acquire()
_active[_get_ident()] = self
del _limbo[self]
_active_limbo_lock.release()
if __debug__:
self._note("%s.__bootstrap(): thread started", self)
if _trace_hook:
self._note("%s.__bootstrap(): registering trace hook", self)
_sys.settrace(_trace_hook)
if _profile_hook:
self._note("%s.__bootstrap(): registering profile hook", self)
_sys.setprofile(_profile_hook)
try:
self.run()
except SystemExit:
if __debug__:
self._note("%s.__bootstrap(): raised SystemExit", self)
except:
if __debug__:
self._note("%s.__bootstrap(): unhandled exception", self)
# If sys.stderr is no more (most likely from interpreter
# shutdown) use self.__stderr. Otherwise still use sys (as in
# _sys) in case sys.stderr was redefined since the creation of
# self.
if _sys:
_sys.stderr.write("Exception in thread %s:\n%s\n" %
(self.getName(), _format_exc()))
else:
# Do the best job possible w/o a huge amt. of code to
# approximate a traceback (code ideas from
# Lib/traceback.py)
exc_type, exc_value, exc_tb = self.__exc_info()
try:
print>>self.__stderr, (
"Exception in thread " + self.getName() +
" (most likely raised during interpreter shutdown):")
print>>self.__stderr, (
"Traceback (most recent call last):")
while exc_tb:
print>>self.__stderr, (
' File "%s", line %s, in %s' %
(exc_tb.tb_frame.f_code.co_filename,
exc_tb.tb_lineno,
exc_tb.tb_frame.f_code.co_name))
exc_tb = exc_tb.tb_next
print>>self.__stderr, ("%s: %s" % (exc_type, exc_value))
# Make sure that exc_tb gets deleted since it is a memory
# hog; deleting everything else is just for thoroughness
finally:
del exc_type, exc_value, exc_tb
else:
if __debug__:
self._note("%s.__bootstrap(): normal return", self)
finally:
_active_limbo_lock.acquire()
try:
self.__stop()
try:
# We don't call self.__delete() because it also
# grabs _active_limbo_lock.
del _active[_get_ident()]
except:
pass
finally:
_active_limbo_lock.release()
def __stop(self):
self.__block.acquire()
self.__stopped = True
self.__block.notifyAll()
self.__block.release()
def __delete(self):
"Remove current thread from the dict of currently running threads."
# Notes about running with dummy_thread:
#
# Must take care to not raise an exception if dummy_thread is being
# used (and thus this module is being used as an instance of
# dummy_threading). dummy_thread.get_ident() always returns -1 since
# there is only one thread if dummy_thread is being used. Thus
# len(_active) is always <= 1 here, and any Thread instance created
# overwrites the (if any) thread currently registered in _active.
#
# An instance of _MainThread is always created by 'threading'. This
# gets overwritten the instant an instance of Thread is created; both
# threads return -1 from dummy_thread.get_ident() and thus have the
# same key in the dict. So when the _MainThread instance created by
# 'threading' tries to clean itself up when atexit calls this method
# it gets a KeyError if another Thread instance was created.
#
# This all means that KeyError from trying to delete something from
# _active if dummy_threading is being used is a red herring. But
# since it isn't if dummy_threading is *not* being used then don't
# hide the exception.
_active_limbo_lock.acquire()
try:
try:
del _active[_get_ident()]
except KeyError:
if 'dummy_threading' not in _sys.modules:
raise
finally:
_active_limbo_lock.release()
def join(self, timeout=None):
if not self.__initialized:
raise RuntimeError("Thread.__init__() not called")
if not self.__started:
raise RuntimeError("cannot join thread before it is started")
if self is currentThread():
raise RuntimeError("cannot join current thread")
if __debug__:
if not self.__stopped:
self._note("%s.join(): waiting until thread stops", self)
self.__block.acquire()
try:
if timeout is None:
while not self.__stopped:
self.__block.wait()
if __debug__:
self._note("%s.join(): thread stopped", self)
else:
deadline = _time() + timeout
while not self.__stopped:
delay = deadline - _time()
if delay <= 0:
if __debug__:
self._note("%s.join(): timed out", self)
break
self.__block.wait(delay)
else:
if __debug__:
self._note("%s.join(): thread stopped", self)
finally:
self.__block.release()
def getName(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__name
def setName(self, name):
assert self.__initialized, "Thread.__init__() not called"
self.__name = str(name)
def isAlive(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__started and not self.__stopped
def isDaemon(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__daemonic
def setDaemon(self, daemonic):
if not self.__initialized:
raise RuntimeError("Thread.__init__() not called")
if self.__started:
raise RuntimeError("cannot set daemon status of active thread");
self.__daemonic = daemonic
# The timer class was contributed by Itamar Shtull-Trauring
def Timer(*args, **kwargs):
return _Timer(*args, **kwargs)
class _Timer(Thread):
"""Call a function after a specified number of seconds:
t = Timer(30.0, f, args=[], kwargs={})
t.start()
t.cancel() # stop the timer's action if it's still waiting
"""
def __init__(self, interval, function, args=[], kwargs={}):
Thread.__init__(self)
self.interval = interval
self.function = function
self.args = args
self.kwargs = kwargs
self.finished = Event()
def cancel(self):
"""Stop the timer if it hasn't finished yet"""
self.finished.set()
def run(self):
self.finished.wait(self.interval)
if not self.finished.isSet():
self.function(*self.args, **self.kwargs)
self.finished.set()
# Special thread class to represent the main thread
# This is garbage collected through an exit handler
class _MainThread(Thread):
def __init__(self):
Thread.__init__(self, name="MainThread")
self._Thread__started = True
_active_limbo_lock.acquire()
_active[_get_ident()] = self
_active_limbo_lock.release()
def _set_daemon(self):
return False
def _exitfunc(self):
self._Thread__stop()
t = _pickSomeNonDaemonThread()
if t:
if __debug__:
self._note("%s: waiting for other threads", self)
while t:
t.join()
t = _pickSomeNonDaemonThread()
if __debug__:
self._note("%s: exiting", self)
self._Thread__delete()
def _pickSomeNonDaemonThread():
for t in enumerate():
if not t.isDaemon() and t.isAlive():
return t
return None
# Dummy thread class to represent threads not started here.
# These aren't garbage collected when they die, nor can they be waited for.
# If they invoke anything in threading.py that calls currentThread(), they
# leave an entry in the _active dict forever after.
# Their purpose is to return *something* from currentThread().
# They are marked as daemon threads so we won't wait for them
# when we exit (conform previous semantics).
class _DummyThread(Thread):
def __init__(self):
Thread.__init__(self, name=_newname("Dummy-%d"))
# Thread.__block consumes an OS-level locking primitive, which
# can never be used by a _DummyThread. Since a _DummyThread
# instance is immortal, that's bad, so release this resource.
del self._Thread__block
self._Thread__started = True
_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
from thread import stack_size
# Create the main thread object,
# and make it available for the interpreter
# (Py_Main) as threading._shutdown.
_shutdown = _MainThread()._exitfunc
# get thread-local implementation, either from the thread
# module, or from the python fallback
try:
from thread import _local as local
except ImportError:
from _threading_local import local
def _after_fork():
# This function is called by Python/ceval.c:PyEval_ReInitThreads which
# is called from PyOS_AfterFork. Here we cleanup threading module state
# that should not exist after a fork.
# Reset _active_limbo_lock, in case we forked while the lock was held
# by another (non-forked) thread. http://bugs.python.org/issue874900
global _active_limbo_lock
_active_limbo_lock = _allocate_lock()
# fork() only copied the current thread; clear references to others.
new_active = {}
current = currentThread()
_active_limbo_lock.acquire()
try:
for thread in _active.itervalues():
if thread is current:
# There is only one active thread. We reset the ident to
# its new value since it can have changed.
ident = _get_ident()
thread._Thread__ident = ident
new_active[ident] = thread
else:
# All the others are already stopped.
# We don't call _Thread__stop() because it tries to acquire
# thread._Thread__block which could also have been held while
# we forked.
thread._Thread__stopped = True
_limbo.clear()
_active.clear()
_active.update(new_active)
assert len(_active) == 1
finally:
_active_limbo_lock.release()
# 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 = deque()
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.popleft()
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()