"""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()
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