""" This module reimplements Python's native threading module using Panda
threading constructs. It's designed as a drop-in replacement for the
threading module for code that works with Panda; it is necessary because
in some compilation models, Panda's threading constructs are
incompatible with the OS-provided threads used by Python's thread
module.
Unlike threading.py, this module is a more explicit implementation of
Python's threading model, designed to more precisely emulate Python's
standard threading semantics. In fact, this is a bald-face copy of
Python's threading module from Python 2.5, with a few lines at the top
to import Panda's thread reimplementation instead of the system thread
module, and so it is therefore layered on top of Panda's thread
implementation. """
import sys as _sys
import atexit as _atexit
from direct.stdpy import thread as _thread
from direct.stdpy.thread import stack_size, _newname, _local as local
from panda3d import core
_sleep = core.Thread.sleep
from time import time as _time
from traceback import format_exc as _format_exc
__all__ = ['get_ident', 'active_count', 'Condition', 'current_thread',
'enumerate', 'main_thread', 'TIMEOUT_MAX',
'Event', 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread',
'Timer', 'ThreadError',
'setprofile', 'settrace', 'local', 'stack_size']
# Rename some stuff so "from threading import *" is safe
_start_new_thread = _thread.start_new_thread
_allocate_lock = _thread.allocate_lock
get_ident = _thread.get_ident
ThreadError = _thread.error
TIMEOUT_MAX = _thread.TIMEOUT_MAX
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
[docs]def setprofile(func):
global _profile_hook
_profile_hook = func
[docs]def settrace(func):
global _trace_hook
_trace_hook = func
# Synchronization classes
Lock = _allocate_lock
[docs]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):
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 success", self, blocking)
else:
if __debug__:
self._note("%s.acquire(%s): failure", self, blocking)
return rc
__enter__ = acquire
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)
def __exit__(self, t, v, tb):
self.release()
# Internal methods used by condition variables
def _acquire_restore(self, state):
self.__block.acquire()
self.__count, self.__owner = state
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()
[docs]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 "<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):
# 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):
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:
# 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):
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))
[docs]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):
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 = 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()
[docs]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)
[docs]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()
# Active thread administration
_active_limbo_lock = _allocate_lock()
_active = {} # maps thread id to Thread object
_limbo = {}
# Main class for threads
[docs]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
# Set to True when the _shutdown handler is registered as atexit function.
# Protected by _active_limbo_lock.
__registered_atexit = False
[docs] def __init__(self, group=None, target=None, name=None,
args=(), kwargs=None, verbose=None, daemon=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
if daemon is not None:
self.__daemonic = daemon
else:
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)
[docs] 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
# If we are starting a non-daemon thread, we need to call join() on it
# when the interpreter exits. Python will call _shutdown() on the
# built-in threading module automatically, but not on our module.
if not self.__daemonic and not Thread.__registered_atexit:
_atexit.register(_shutdown)
Thread.__registered_atexit = True
_active_limbo_lock.release()
_start_new_thread(self.__bootstrap, ())
self.__started = True
_sleep(0.000001) # 1 usec, to let the thread run (Solaris hack)
[docs] def run(self):
if self.__target:
self.__target(*self.__args, **self.__kwargs)
def __bootstrap(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:
self.__stderr.write("Exception in thread " + self.getName() +
" (most likely raised during interpreter shutdown):\n")
self.__stderr.write("Traceback (most recent call last):\n")
while exc_tb:
self.__stderr.write(' File "%s", line %s, in %s\n' %
(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
self.__stderr.write("%s: %s\n" % (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:
self.__stop()
try:
self.__delete()
except:
pass
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()
[docs] 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()
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()
[docs] def getName(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__name
[docs] def setName(self, name):
assert self.__initialized, "Thread.__init__() not called"
self.__name = str(name)
[docs] def is_alive(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__started and not self.__stopped
isAlive = is_alive
[docs] def isDaemon(self):
assert self.__initialized, "Thread.__init__() not called"
return self.__daemonic
[docs] 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
name = property(getName, setName)
daemon = property(isDaemon, setDaemon)
# The timer class was contributed by Itamar Shtull-Trauring
[docs]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()
# 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"), daemon=True)
# 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
[docs]def current_thread():
try:
return _active[get_ident()]
except KeyError:
##print "current_thread(): no current thread for", get_ident()
return _DummyThread()
currentThread = current_thread
[docs]def active_count():
_active_limbo_lock.acquire()
count = len(_active) + len(_limbo)
_active_limbo_lock.release()
return count
activeCount = active_count
[docs]def enumerate():
_active_limbo_lock.acquire()
active = list(_active.values()) + list(_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.
_main_thread = _MainThread()
_shutdown = _main_thread._exitfunc
def _pickSomeNonDaemonThread():
for t in enumerate():
if not t.isDaemon() and t.isAlive():
return t
return None
[docs]def main_thread():
"""Return the main thread object.
In normal conditions, the main thread is the thread from which the
Python interpreter was started.
"""
return _main_thread
# 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
# Self-test code
if __debug__:
def _test():
from collections import deque
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()
