"""Thread module emulating a subset of Java's threading model."""

import sys as _sys

try:

import thread

except ImportError:

del _sys.modules[__name__]

raise

import warnings

from collections import deque as _deque

from itertools import count as _count

from time import time as _time, sleep as _sleep

from traceback import format_exc as _format_exc

# Note regarding PEP 8 compliant aliases

# This threading model was originally inspired by Java, and inherited

# the convention of camelCase function and method names from that

# language. While those names are not in any imminent danger of being

# deprecated, starting with Python 2.6, the module now provides a

# PEP 8 compliant alias for any such method name.

# Using the new PEP 8 compliant names also facilitates substitution

# with the multiprocessing module, which doesn't provide the old

# Java inspired names.

# Rename some stuff so "from threading import *" is safe

__all__ = ['activeCount', 'active_count', 'Condition', 'currentThread',

'current_thread', '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

# sys.exc_clear is used to work around the fact that except blocks

# don't fully clear the exception until 3.0.

warnings.filterwarnings('ignore', category=DeprecationWarning,

module='threading', message='sys.exc_clear')

# 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

# Issue #4188: calling current_thread() can incur an infinite

# recursion if it has to create a DummyThread on the fly.

ident = _get_ident()

try:

name = _active[ident].name

except KeyError:

name = "<OS thread %d>" % ident

format = "%s: %s\n" % (name, 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):

"""Set a profile function for all threads started from the threading module.

The func will be passed to sys.setprofile() for each thread, before its

run() method is called.

"""

global _profile_hook

_profile_hook = func

def settrace(func):

"""Set a trace function for all threads started from the threading module.

The func will be passed to sys.settrace() for each thread, before its run()

method is called.

"""

global _trace_hook

_trace_hook = func

# Synchronization classes

Lock = _allocate_lock

def RLock(*args, **kwargs):

"""Factory function that returns a new reentrant lock.

A reentrant lock must be released by the thread that acquired it. Once a

thread has acquired a reentrant lock, the same thread may acquire it again

without blocking; the thread must release it once for each time it has

acquired it.

"""

return _RLock(*args, **kwargs)

class _RLock(_Verbose):

"""A reentrant lock must be released by the thread that acquired it. Once a

thread has acquired a reentrant lock, the same thread may acquire it

again without blocking; the thread must release it once for each time it

has acquired it.

"""

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

try:

owner = _active[owner].name

except KeyError:

pass

return "<%s owner=%r count=%d>" % (

self.__class__.__name__, owner, self.__count)

def acquire(self, blocking=1):

"""Acquire a lock, blocking or non-blocking.

When invoked without arguments: if this thread already owns the lock,

increment the recursion level by one, and return immediately. Otherwise,

if another thread owns the lock, block until the lock is unlocked. Once

the lock is unlocked (not owned by any thread), then grab ownership, set

the recursion level to one, and return. If more than one thread is

blocked waiting until the lock is unlocked, only one at a time will be

able to grab ownership of the lock. There is no return value in this

case.

When invoked with the blocking argument set to true, do the same thing

as when called without arguments, and return true.

When invoked with the blocking argument set to false, do not block. If a

call without an argument would block, return false immediately;

otherwise, do the same thing as when called without arguments, and

return true.

"""

me = _get_ident()

if self.__owner == 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):

"""Release a lock, decrementing the recursion level.

If after the decrement it is zero, reset the lock to unlocked (not owned

by any thread), and if any other threads are blocked waiting for the

lock to become unlocked, allow exactly one of them to proceed. If after

the decrement the recursion level is still nonzero, the lock remains

locked and owned by the calling thread.

Only call this method when the calling thread owns the lock. A

RuntimeError is raised if this method is called when the lock is

unlocked.

There is no return value.

"""

if self.__owner != _get_ident():

raise RuntimeError("cannot release un-acquired 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):

count, owner = 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 == _get_ident()

def Condition(*args, **kwargs):

"""Factory function that returns a new condition variable object.

A condition variable allows one or more threads to wait until they are

notified by another thread.

If the lock argument is given and not None, it must be a Lock or RLock

object, and it is used as the underlying lock. Otherwise, a new RLock object

is created and used as the underlying lock.

"""

return _Condition(*args, **kwargs)

class _Condition(_Verbose):

"""Condition variables allow one or more threads to wait until they are

notified by another thread.

"""

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 current_thread.

# 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):

"""Wait until notified or until a timeout occurs.

If the calling thread has not acquired the lock when this method is

called, a RuntimeError is raised.

This method releases the underlying lock, and then blocks until it is

awakened by a notify() or notifyAll() call for the same condition

variable in another thread, or until the optional timeout occurs. Once

awakened or timed out, it re-acquires the lock and returns.

When the timeout argument is present and not None, it should be a

floating point number specifying a timeout for the operation in seconds

(or fractions thereof).

When the underlying lock is an RLock, it is not released using its

release() method, since this may not actually unlock the lock when it

was acquired multiple times recursively. Instead, an internal interface

of the RLock class is used, which really unlocks it even when it has

been recursively acquired several times. Another internal interface is

then used to restore the recursion level when the lock is reacquired.

"""

if not self._is_owned():

raise RuntimeError("cannot wait on un-acquired 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):

"""Wake up one or more threads waiting on this condition, if any.

If the calling thread has not acquired the lock when this method is

called, a RuntimeError is raised.

This method wakes up at most n of the threads waiting for the condition

variable; it is a no-op if no threads are waiting.

"""

if not self._is_owned():

raise RuntimeError("cannot notify on un-acquired 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):

"""Wake up all threads waiting on this condition.

If the calling thread has not acquired the lock when this method

is called, a RuntimeError is raised.

"""

self.notify(len(self.__waiters))

notify_all = notifyAll

def Semaphore(*args, **kwargs):

"""A factory function that returns a new semaphore.

Semaphores manage a counter representing the number of release() calls minus

the number of acquire() calls, plus an initial value. The acquire() method

blocks if necessary until it can return without making the counter

negative. If not given, value defaults to 1.

"""

return _Semaphore(*args, **kwargs)

class _Semaphore(_Verbose):

"""Semaphores manage a counter representing the number of release() calls

minus the number of acquire() calls, plus an initial value. The acquire()

method blocks if necessary until it can return without making the counter

negative. If not given, value defaults to 1.

"""

# 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):

"""Acquire a semaphore, decrementing the internal counter by one.

When invoked without arguments: if the internal counter is larger than

zero on entry, decrement it by one and return immediately. If it is zero

on entry, block, waiting until some other thread has called release() to

make it larger than zero. This is done with proper interlocking so that

if multiple acquire() calls are blocked, release() will wake exactly one

of them up. The implementation may pick one at random, so the order in

which blocked threads are awakened should not be relied on. There is no

return value in this case.

When invoked with blocking set to true, do the same thing as when called

without arguments, and return true.

When invoked with blocking set to false, do not block. If a call without

an argument would block, return false immediately; otherwise, do the

same thing as when called without arguments, and return true.

"""

rc = False

with self.__cond:

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

return rc

__enter__ = acquire

def release(self):

"""Release a semaphore, incrementing the internal counter by one.

When the counter is zero on entry and another thread is waiting for it

to become larger than zero again, wake up that thread.

"""

with self.__cond:

self.__value = self.__value + 1

if __debug__:

self._note("%s.release: success, value=%s",

self, self.__value)

self.__cond.notify()

def __exit__(self, t, v, tb):

self.release()

def BoundedSemaphore(*args, **kwargs):

"""A factory function that returns a new bounded semaphore.

A bounded semaphore checks to make sure its current value doesn't exceed its

initial value. If it does, ValueError is raised. In most situations

semaphores are used to guard resources with limited capacity.

If the semaphore is released too many times it's a sign of a bug. If not

given, value defaults to 1.

Like regular semaphores, bounded semaphores manage a counter representing

the number of release() calls minus the number of acquire() calls, plus an

initial value. The acquire() method blocks if necessary until it can return

without making the counter negative. If not given, value defaults to 1.

"""

return _BoundedSemaphore(*args, **kwargs)

class _BoundedSemaphore(_Semaphore):

"""A bounded semaphore checks to make sure its current value doesn't exceed

its initial value. If it does, ValueError is raised. In most situations

semaphores are used to guard resources with limited capacity.

"""

def __init__(self, value=1, verbose=None):

_Semaphore.__init__(self, value, verbose)

self._initial_value = value

def release(self):

"""Release a semaphore, incrementing the internal counter by one.

When the counter is zero on entry and another thread is waiting for it

to become larger than zero again, wake up that thread.

If the number of releases exceeds the number of acquires,

raise a ValueError.

"""

with self._Semaphore__cond:

if self._Semaphore__value >= self._initial_value:

raise ValueError("Semaphore released too many times")

self._Semaphore__value += 1

self._Semaphore__cond.notify()

def Event(*args, **kwargs):

"""A factory function that returns a new event.

Events manage a flag that can be set to true with the set() method and reset

to false with the clear() method. The wait() method blocks until the flag is

true.

"""

return _Event(*args, **kwargs)

class _Event(_Verbose):

"""A factory function that returns a new event object. An event manages a

flag that can be set to true with the set() method and reset to false

with the clear() method. The wait() method blocks until the flag is true.

"""

# 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 _reset_internal_locks(self):

# private! called by Thread._reset_internal_locks by _after_fork()

self.__cond.__init__()

def isSet(self):

'Return true if and only if the internal flag is true.'

return self.__flag

is_set = isSet

def set(self):

"""Set the internal flag to true.

All threads waiting for the flag to become true are awakened. Threads

that call wait() once the flag is true will not block at all.

"""

self.__cond.acquire()

try:

self.__flag = True

self.__cond.notify_all()

finally:

self.__cond.release()

def clear(self):

"""Reset the internal flag to false.

Subsequently, threads calling wait() will block until set() is called to

set the internal flag to true again.

"""

self.__cond.acquire()

try:

self.__flag = False

finally:

self.__cond.release()

def wait(self, timeout=None):

"""Block until the internal flag is true.

If the internal flag is true on entry, return immediately. Otherwise,

block until another thread calls set() to set the flag to true, or until

the optional timeout occurs.

When the timeout argument is present and not None, it should be a

floating point number specifying a timeout for the operation in seconds

(or fractions thereof).

This method returns the internal flag on exit, so it will always return

True except if a timeout is given and the operation times out.

"""

self.__cond.acquire()

try:

if not self.__flag:

self.__cond.wait(timeout)

return self.__flag

finally:

self.__cond.release()

# Helper to generate new thread names

_counter = _count().next

_counter() # Consume 0 so first non-main thread has id 1.

def _newname(template="Thread-%d"):

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):

"""A class that represents a thread of control.

This class can be safely subclassed in a limited fashion.

"""

__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

# Keep sys.exc_clear too to clear the exception just before

# allowing .join() to return.

__exc_clear = _sys.exc_clear

def __init__(self, group=None, target=None, name=None,

args=(), kwargs=None, verbose=None):

"""This constructor should always be called with keyword arguments. Arguments are:

*group* should be None; reserved for future extension when a ThreadGroup

class is implemented.

*target* is the callable object to be invoked by the run()

method. Defaults to None, meaning nothing is called.

*name* is the thread name. By default, a unique name is constructed of

the form "Thread-N" where N is a small decimal number.

*args* is the argument tuple for the target invocation. Defaults to ().

*kwargs* is a dictionary of keyword arguments for the target

invocation. Defaults to {}.

If a subclass overrides the constructor, it must make sure to invoke

the base class constructor (Thread.__init__()) before doing anything

else to the thread.

"""

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.__ident = None

self.__started = Event()

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 _reset_internal_locks(self):

# private! Called by _after_fork() to reset our internal locks as

# they may be in an invalid state leading to a deadlock or crash.

if hasattr(self, '_Thread__block'): # DummyThread deletes self.__block

self.__block.__init__()

self.__started._reset_internal_locks()

@property

def _block(self):

# used by a unittest

return self.__block

def _set_daemon(self):

# Overridden in _MainThread and _DummyThread

return current_thread().daemon

def __repr__(self):

assert self.__initialized, "Thread.__init__() was not called"

status = "initial"

if self.__started.is_set():

status = "started"

if self.__stopped:

status = "stopped"

if self.__daemonic:

status += " daemon"

if self.__ident is not None:

status += " %s" % self.__ident

return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)

def start(self):

"""Start the thread's activity.

It must be called at most once per thread object. It arranges for the

object's run() method to be invoked in a separate thread of control.

This method will raise a RuntimeError if called more than once on the

same thread object.

"""

if not self.__initialized:

raise RuntimeError("thread.__init__() not called")

if self.__started.is_set():

raise RuntimeError("threads can only be started once")

if __debug__:

self._note("%s.start(): starting thread", self)

with _active_limbo_lock:

_limbo[self] = self

try:

_start_new_thread(self.__bootstrap, ())

except Exception:

with _active_limbo_lock:

del _limbo[self]

raise

self.__started.wait()

def run(self):

"""Method representing the thread's activity.

You may override this method in a subclass. The standard run() method

invokes the callable object passed to the object's constructor as the

target argument, if any, with sequential and keyword arguments taken

from the args and kwargs arguments, respectively.

"""

try:

if self.__target:

self.__target(*self.__args, **self.__kwargs)

finally:

# Avoid a refcycle if the thread is running a function with

# an argument that has a member that points to the thread.

del 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 _set_ident(self):

self.__ident = _get_ident()

def __bootstrap_inner(self):

try:

self._set_ident()

self.__started.set()

with _active_limbo_lock:

_active[self.__ident] = self

del _limbo[self]

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 and _sys.stderr is not None:

print>>_sys.stderr, ("Exception in thread %s:\n%s" %

(self.name, _format_exc()))

elif self.__stderr is not None:

# 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.name +

" (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:

# Prevent a race in

# test_threading.test_no_refcycle_through_target when

# the exception keeps the target alive past when we

# assert that it's dead.

self.__exc_clear()

finally:

with _active_limbo_lock:

self.__stop()

try:

# We don't call self.__delete() because it also

# grabs _active_limbo_lock.

del _active[_get_ident()]

except:

pass

def __stop(self):

# DummyThreads delete self.__block, but they have no waiters to

# notify anyway (join() is forbidden on them).

if not hasattr(self, '_Thread__block'):

return

self.__block.acquire()

self.__stopped = True

self.__block.notify_all()

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.

try:

with _active_limbo_lock:

del _active[_get_ident()]

# There must not be any python code between the previous line

# and after the lock is released. Otherwise a tracing function

# could try to acquire the lock again in the same thread, (in

# current_thread()), and would block.

except KeyError:

if 'dummy_threading' not in _sys.modules:

raise

def join(self, timeout=None):

"""Wait until the thread terminates.

This blocks the calling thread until the thread whose join() method is

called terminates -- either normally or through an unhandled exception

or until the optional timeout occurs.

When the timeout argument is present and not None, it should be a

floating point number specifying a timeout for the operation in seconds

(or fractions thereof). As join() always returns None, you must call

isAlive() after join() to decide whether a timeout happened -- if the

thread is still alive, the join() call timed out.

When the timeout argument is not present or None, the operation will

block until the thread terminates.

A thread can be join()ed many times.

join() raises a RuntimeError if an attempt is made to join the current

thread as that would cause a deadlock. It is also an error to join() a

thread before it has been started and attempts to do so raises the same

exception.

"""

if not self.__initialized:

raise RuntimeError("Thread.__init__() not called")

if not self.__started.is_set():

raise RuntimeError("cannot join thread before it is started")

if self is current_thread():

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()

@property

def name(self):

"""A string used for identification purposes only.

It has no semantics. Multiple threads may be given the same name. The

initial name is set by the constructor.

"""

assert self.__initialized, "Thread.__init__() not called"

return self.__name

@name.setter

def name(self, name):

assert self.__initialized, "Thread.__init__() not called"

self.__name = str(name)

@property

def ident(self):

"""Thread identifier of this thread or None if it has not been started.

This is a nonzero integer. See the thread.get_ident() function. Thread

identifiers may be recycled when a thread exits and another thread is

created. The identifier is available even after the thread has exited.

"""

assert self.__initialized, "Thread.__init__() not called"

return self.__ident

def isAlive(self):

"""Return whether the thread is alive.

This method returns True just before the run() method starts until just

after the run() method terminates. The module function enumerate()

returns a list of all alive threads.