Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Revision ded18d634f2e1615b746dca2698d6a98ff63045d authored by Guido van Rossum on 28 March 2002, 20:21:21 UTC, committed by Guido van Rossum on 28 March 2002, 20:21:21 UTC
this is what Zope 2 will be using in the foreseeable future). Fix an issue that was reported in but unrelated to the main problem of SF bug 535905 (Evil Trashcan and GC interaction). The SETLOCAL() macro should not DECREF the local variable in-place and then store the new value; it should copy the old value to a temporary value, then store the new value, and then DECREF the temporary value. This is because it is possible that during the DECREF the frame is accessed by other code (e.g. a __del__ method or gc.collect()) and the variable would be pointing to already-freed memory. BUGFIX CANDIDATE!
1 parent 00be96e
Tip revision: ded18d634f2e1615b746dca2698d6a98ff63045d authored by Guido van Rossum on 28 March 2002, 20:21:21 UTC
Backport for 2.1.3 (if we ever release it; we may have to because
Backport for 2.1.3 (if we ever release it; we may have to because
Tip revision: ded18d6
threading.py
"""Proposed new threading module, emulating a subset of Java's threading model."""
import sys
import time
import thread
import traceback
import StringIO
# Rename some stuff so "from threading import *" is safe
_sys = sys
del sys
_time = time.time
_sleep = time.sleep
del time
_start_new_thread = thread.start_new_thread
_allocate_lock = thread.allocate_lock
_get_ident = thread.get_ident
ThreadError = thread.error
del thread
_print_exc = traceback.print_exc
del traceback
_StringIO = StringIO.StringIO
del StringIO
# Debug support (adapted from ihooks.py)
_VERBOSE = 0
if __debug__:
class _Verbose:
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:
def __init__(self, verbose=None):
pass
def _note(self, *args):
pass
# Synchronization classes
Lock = _allocate_lock
def RLock(*args, **kwargs):
return apply(_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):
return "<%s(%s, %d)>" % (
self.__class__.__name__,
self.__owner and self.__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 succes", self, blocking)
else:
if __debug__:
self._note("%s.acquire(%s): failure", self, blocking)
return rc
def release(self):
me = currentThread()
assert self.__owner is me, "release() of un-acquire()d 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)
# 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 apply(_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 __repr__(self):
return "<Condition(%s, %d)>" % (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):
if self.__lock.acquire(0):
self.__lock.release()
return 0
else:
return 1
def wait(self, timeout=None):
me = currentThread()
assert self._is_owned(), "wait() of un-acquire()d 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:
endtime = _time() + timeout
delay = 0.000001 # 1 usec
while 1:
gotit = waiter.acquire(0)
if gotit or _time() >= endtime:
break
_sleep(delay)
if delay < 1.0:
delay = delay * 2.0
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):
me = currentThread()
assert self._is_owned(), "notify() of un-acquire()d 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 apply(_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):
assert value >= 0, "Semaphore initial value must be >= 0"
_Verbose.__init__(self, verbose)
self.__cond = Condition(Lock())
self.__value = value
def acquire(self, blocking=1):
rc = 0
self.__cond.acquire()
while self.__value == 0:
if not blocking:
break
self.__cond.wait()
else:
self.__value = self.__value - 1
rc = 1
self.__cond.release()
return rc
def release(self):
self.__cond.acquire()
self.__value = self.__value + 1
self.__cond.notify()
self.__cond.release()
def Event(*args, **kwargs):
return apply(_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 = 0
def isSet(self):
return self.__flag
def set(self):
self.__cond.acquire()
self.__flag = 1
self.__cond.notifyAll()
self.__cond.release()
def clear(self):
self.__cond.acquire()
self.__flag = 0
self.__cond.release()
def wait(self, timeout=None):
self.__cond.acquire()
if not self.__flag:
self.__cond.wait(timeout)
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 = {}
_limbo = {}
# Main class for threads
class Thread(_Verbose):
__initialized = 0
def __init__(self, group=None, target=None, name=None,
args=(), kwargs={}, verbose=None):
assert group is None, "group argument must be None for now"
_Verbose.__init__(self, verbose)
self.__target = target
self.__name = str(name or _newname())
self.__args = args
self.__kwargs = kwargs
self.__daemonic = self._set_daemon()
self.__started = 0
self.__stopped = 0
self.__block = Condition(Lock())
self.__initialized = 1
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):
assert self.__initialized, "Thread.__init__() not called"
assert not self.__started, "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 = 1
_sleep(0.000001) # 1 usec, to let the thread run (Solaris hack)
def run(self):
if self.__target:
apply(self.__target, self.__args, self.__kwargs)
def __bootstrap(self):
try:
self.__started = 1
_active_limbo_lock.acquire()
_active[_get_ident()] = self
del _limbo[self]
_active_limbo_lock.release()
if __debug__:
self._note("%s.__bootstrap(): thread started", self)
try:
self.run()
except SystemExit:
if __debug__:
self._note("%s.__bootstrap(): raised SystemExit", self)
except:
if __debug__:
self._note("%s.__bootstrap(): unhandled exception", self)
s = _StringIO()
_print_exc(file=s)
_sys.stderr.write("Exception in thread %s:\n%s\n" %
(self.getName(), s.getvalue()))
else:
if __debug__:
self._note("%s.__bootstrap(): normal return", self)
finally:
self.__stop()
try:
self.__delete()
except:
pass
def __stop(self):
self.__block.acquire()
self.__stopped = 1
self.__block.notifyAll()
self.__block.release()
def __delete(self):
_active_limbo_lock.acquire()
del _active[_get_ident()]
_active_limbo_lock.release()
def join(self, timeout=None):
assert self.__initialized, "Thread.__init__() not called"
assert self.__started, "cannot join thread before it is started"
assert self is not currentThread(), "cannot join current thread"
if __debug__:
if not self.__stopped:
self._note("%s.join(): waiting until thread stops", self)
self.__block.acquire()
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)
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):
assert self.__initialized, "Thread.__init__() not called"
assert not self.__started, "cannot set daemon status of active thread"
self.__daemonic = daemonic
# 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 = 1
_active_limbo_lock.acquire()
_active[_get_ident()] = self
_active_limbo_lock.release()
import atexit
atexit.register(self.__exitfunc)
def _set_daemon(self):
return 0
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.
# 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"))
self._Thread__started = 1
_active_limbo_lock.acquire()
_active[_get_ident()] = self
_active_limbo_lock.release()
def _set_daemon(self):
return 1
def join(self):
assert 0, "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():
import random
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[0]
del self.queue[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
import time
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()
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...