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

import os as _os
import sys as _sys
import _thread

from time import monotonic as _time
from _weakrefset import WeakSet
from itertools import islice as _islice, count as _count
try:
 from _collections import deque as _deque
except ImportError:
 from collections import deque as _deque

# Note regarding PEP 8 compliant names
# This threading model was originally inspired by Java, and inherited
# the convention of camelCase function and method names from that
# language. Those original names are not in any imminent danger of
# being deprecated (even for Py3k),so this module provides them as an
# alias for the PEP 8 compliant names
# Note that using the new PEP 8 compliant names facilitates substitution
# with the multiprocessing module, which doesn't provide the old
# Java inspired names.

__all__ = ['get_ident', 'active_count', 'Condition', 'current_thread',
 'enumerate', 'main_thread', 'TIMEOUT_MAX',
 'Event', 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread',
 'Barrier', 'BrokenBarrierError', 'Timer', 'ThreadError',
 'setprofile', 'settrace', 'local', 'stack_size',
 'excepthook', 'ExceptHookArgs']

# Rename some stuff so "from threading import *" is safe
_start_new_thread = _thread.start_new_thread
_allocate_lock = _thread.allocate_lock
_set_sentinel = _thread._set_sentinel
get_ident = _thread.get_ident
try:
 get_native_id = _thread.get_native_id
 _HAVE_THREAD_NATIVE_ID = True
 __all__.append('get_native_id')
except AttributeError:
 _HAVE_THREAD_NATIVE_ID = False
ThreadError = _thread.error
try:
 _CRLock = _thread.RLock
except AttributeError:
 _CRLock = None
TIMEOUT_MAX = _thread.TIMEOUT_MAX
del _thread


# 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.

 """
 if _CRLock is None:
 return _PyRLock(*args, **kwargs)
 return _CRLock(*args, **kwargs)

class _RLock:
 """This class implements reentrant lock objects.

 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):
 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 %s.%s object owner=%r count=%d at %s>" % (
 "locked" if self._block.locked() else "unlocked",
 self.__class__.__module__,
 self.__class__.__qualname__,
 owner,
 self._count,
 hex(id(self))
 )

 def acquire(self, blocking=True, timeout=-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.

 When invoked with the floating-point timeout argument set to a positive
 value, block for at most the number of seconds specified by timeout
 and as long as the lock cannot be acquired. Return true if the lock has
 been acquired, false if the timeout has elapsed.

 """
 me = get_ident()
 if self._owner == me:
 self._count += 1
 return 1
 rc = self._block.acquire(blocking, timeout)
 if rc:
 self._owner = me
 self._count = 1
 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()

 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

 def _release_save(self):
 if self._count == 0:
 raise RuntimeError("cannot release un-acquired lock")
 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()

_PyRLock = _RLock


class Condition:
 """Class that implements a condition variable.

 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.

 """

 def __init__(self, lock=None):
 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 = _deque()

 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 notify_all() 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()
 gotit = False
 try: # restore state no matter what (e.g., KeyboardInterrupt)
 if timeout is None:
 waiter.acquire()
 gotit = True
 else:
 if timeout > 0:
 gotit = waiter.acquire(True, timeout)
 else:
 gotit = waiter.acquire(False)
 return gotit
 finally:
 self._acquire_restore(saved_state)
 if not gotit:
 try:
 self._waiters.remove(waiter)
 except ValueError:
 pass

 def wait_for(self, predicate, timeout=None):
 """Wait until a condition evaluates to True.

 predicate should be a callable which result will be interpreted as a
 boolean value. A timeout may be provided giving the maximum time to
 wait.

 """
 endtime = None
 waittime = timeout
 result = predicate()
 while not result:
 if waittime is not None:
 if endtime is None:
 endtime = _time() + waittime
 else:
 waittime = endtime - _time()
 if waittime <= 0:
 break
 self.wait(waittime)
 result = predicate()
 return result

 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")
 all_waiters = self._waiters
 waiters_to_notify = _deque(_islice(all_waiters, n))
 if not waiters_to_notify:
 return
 for waiter in waiters_to_notify:
 waiter.release()
 try:
 all_waiters.remove(waiter)
 except ValueError:
 pass

 def notify_all(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))

 notifyAll = notify_all


class Semaphore:
 """This class implements semaphore objects.

 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):
 if value < 0:
 raise ValueError("semaphore initial value must be >= 0")
 self._cond = Condition(Lock())
 self._value = value

 def acquire(self, blocking=True, timeout=None):
 """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.

 When invoked with a timeout other than None, it will block for at
 most timeout seconds. If acquire does not complete successfully in
 that interval, return false. Return true otherwise.

 """
 if not blocking and timeout is not None:
 raise ValueError("can't specify timeout for non-blocking acquire")
 rc = False
 endtime = None
 with self._cond:
 while self._value == 0:
 if not blocking:
 break
 if timeout is not None:
 if endtime is None:
 endtime = _time() + timeout
 else:
 timeout = endtime - _time()
 if timeout <= 0:
 break
 self._cond.wait(timeout)
 else:
 self._value -= 1
 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 += 1
 self._cond.notify()

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


class BoundedSemaphore(Semaphore):
 """Implements a 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.

 """

 def __init__(self, value=1):
 Semaphore.__init__(self, value)
 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._cond:
 if self._value >= self._initial_value:
 raise ValueError("Semaphore released too many times")
 self._value += 1
 self._cond.notify()


class Event:
 """Class implementing event objects.

 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. The flag is initially false.

 """

 # After Tim Peters' event class (without is_posted())

 def __init__(self):
 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__(Lock())

 def is_set(self):
 """Return true if and only if the internal flag is true."""
 return self._flag

 isSet = is_set

 def set(self):
 """Set the internal flag to true.

 All threads waiting for it to become true are awakened. Threads
 that call wait() once the flag is true will not block at all.

 """
 with self._cond:
 self._flag = True
 self._cond.notify_all()

 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.

 """
 with self._cond:
 self._flag = False

 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.

 """
 with self._cond:
 signaled = self._flag
 if not signaled:
 signaled = self._cond.wait(timeout)
 return signaled


# A barrier class. Inspired in part by the pthread_barrier_* api and
# the CyclicBarrier class from Java. See
# http://sourceware.org/pthreads-win32/manual/pthread_barrier_init.html and
# http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/
# CyclicBarrier.html
# for information.
# We maintain two main states, 'filling' and 'draining' enabling the barrier
# to be cyclic. Threads are not allowed into it until it has fully drained
# since the previous cycle. In addition, a 'resetting' state exists which is
# similar to 'draining' except that threads leave with a BrokenBarrierError,
# and a 'broken' state in which all threads get the exception.
class Barrier:
 """Implements a Barrier.

 Useful for synchronizing a fixed number of threads at known synchronization
 points. Threads block on 'wait()' and are simultaneously awoken once they
 have all made that call.

 """

 def __init__(self, parties, action=None, timeout=None):
 """Create a barrier, initialised to 'parties' threads.

 'action' is a callable which, when supplied, will be called by one of
 the threads after they have all entered the barrier and just prior to
 releasing them all. If a 'timeout' is provided, it is used as the
 default for all subsequent 'wait()' calls.

 """
 self._cond = Condition(Lock())
 self._action = action
 self._timeout = timeout
 self._parties = parties
 self._state = 0 #0 filling, 1, draining, -1 resetting, -2 broken
 self._count = 0

 def wait(self, timeout=None):
 """Wait for the barrier.

 When the specified number of threads have started waiting, they are all
 simultaneously awoken. If an 'action' was provided for the barrier, one
 of the threads will have executed that callback prior to returning.
 Returns an individual index number from 0 to 'parties-1'.

 """
 if timeout is None:
 timeout = self._timeout
 with self._cond:
 self._enter() # Block while the barrier drains.
 index = self._count
 self._count += 1
 try:
 if index + 1 == self._parties:
 # We release the barrier
 self._release()
 else:
 # We wait until someone releases us
 self._wait(timeout)
 return index
 finally:
 self._count -= 1
 # Wake up any threads waiting for barrier to drain.
 self._exit()

 # Block until the barrier is ready for us, or raise an exception
 # if it is broken.
 def _enter(self):
 while self._state in (-1, 1):
 # It is draining or resetting, wait until done
 self._cond.wait()
 #see if the barrier is in a broken state
 if self._state < 0:
 raise BrokenBarrierError
 assert self._state == 0

 # Optionally run the 'action' and release the threads waiting
 # in the barrier.
 def _release(self):
 try:
 if self._action:
 self._action()
 # enter draining state
 self._state = 1
 self._cond.notify_all()
 except:
 #an exception during the _action handler. Break and reraise
 self._break()
 raise

 # Wait in the barrier until we are released. Raise an exception
 # if the barrier is reset or broken.
 def _wait(self, timeout):
 if not self._cond.wait_for(lambda : self._state != 0, timeout):
 #timed out. Break the barrier
 self._break()
 raise BrokenBarrierError
 if self._state < 0:
 raise BrokenBarrierError
 assert self._state == 1

 # If we are the last thread to exit the barrier, signal any threads
 # waiting for the barrier to drain.
 def _exit(self):
 if self._count == 0:
 if self._state in (-1, 1):
 #resetting or draining
 self._state = 0
 self._cond.notify_all()

 def reset(self):
 """Reset the barrier to the initial state.

 Any threads currently waiting will get the BrokenBarrier exception
 raised.

 """
 with self._cond:
 if self._count > 0:
 if self._state == 0:
 #reset the barrier, waking up threads
 self._state = -1
 elif self._state == -2:
 #was broken, set it to reset state
 #which clears when the last thread exits
 self._state = -1
 else:
 self._state = 0
 self._cond.notify_all()

 def abort(self):
 """Place the barrier into a 'broken' state.

 Useful in case of error. Any currently waiting threads and threads
 attempting to 'wait()' will have BrokenBarrierError raised.

 """
 with self._cond:
 self._break()

 def _break(self):
 # An internal error was detected. The barrier is set to
 # a broken state all parties awakened.
 self._state = -2
 self._cond.notify_all()

 @property
 def parties(self):
 """Return the number of threads required to trip the barrier."""
 return self._parties

 @property
 def n_waiting(self):
 """Return the number of threads currently waiting at the barrier."""
 # We don't need synchronization here since this is an ephemeral result
 # anyway. It returns the correct value in the steady state.
 if self._state == 0:
 return self._count
 return 0

 @property
 def broken(self):
 """Return True if the barrier is in a broken state."""
 return self._state == -2

# exception raised by the Barrier class
class BrokenBarrierError(RuntimeError):
 pass


# 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 = {}
_dangling = WeakSet()
# Set of Thread._tstate_lock locks of non-daemon threads used by _shutdown()
# to wait until all Python thread states get deleted:
# see Thread._set_tstate_lock().
_shutdown_locks_lock = _allocate_lock()
_shutdown_locks = set()

# Main class for threads

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

 This class can be safely subclassed in a limited fashion. There are two ways
 to specify the activity: by passing a callable object to the constructor, or
 by overriding the run() method in a subclass.

 """

 _initialized = False

 def __init__(self, group=None, target=None, name=None,
 args=(), kwargs=None, *, daemon=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"
 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 = current_thread().daemon
 self._ident = None
 if _HAVE_THREAD_NATIVE_ID:
 self._native_id = None
 self._tstate_lock = None
 self._started = Event()
 self._is_stopped = False
 self._initialized = True
 # Copy of sys.stderr used by self._invoke_excepthook()
 self._stderr = _sys.stderr
 self._invoke_excepthook = _make_invoke_excepthook()
 # For debugging and _after_fork()
 _dangling.add(self)

 def _reset_internal_locks(self, is_alive):
 # private! Called by _after_fork() to reset our internal locks as
 # they may be in an invalid state leading to a deadlock or crash.
 self._started._reset_internal_locks()
 if is_alive:
 self._set_tstate_lock()
 else:
 # The thread isn't alive after fork: it doesn't have a tstate
 # anymore.
 self._is_stopped = True
 self._tstate_lock = None

 def __repr__(self):
 assert self._initialized, "Thread.__init__() was not called"
 status = "initial"
 if self._started.is_set():
 status = "started"
 self.is_alive() # easy way to get ._is_stopped set when appropriate
 if self._is_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")
 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()

 if _HAVE_THREAD_NATIVE_ID:
 def _set_native_id(self):
 self._native_id = get_native_id()

 def _set_tstate_lock(self):
 """
 Set a lock object which will be released by the interpreter when
 the underlying thread state (see pystate.h) gets deleted.
 """
 self._tstate_lock = _set_sentinel()
 self._tstate_lock.acquire()

 if not self.daemon:
 with _shutdown_locks_lock:
 _shutdown_locks.add(self._tstate_lock)

 def _bootstrap_inner(self):
 try:
 self._set_ident()
 self._set_tstate_lock()
 if _HAVE_THREAD_NATIVE_ID:
 self._set_native_id()
 self._started.set()
 with _active_limbo_lock:
 _active[self._ident] = self
 del _limbo[self]

 if _trace_hook:
 _sys.settrace(_trace_hook)
 if _profile_hook:
 _sys.setprofile(_profile_hook)

 try:
 self.run()
 except:
 self._invoke_excepthook(self)
 finally:
 with _active_limbo_lock:
 try:
 # We don't call self._delete() because it also
 # grabs _active_limbo_lock.
 del _active[get_ident()]
 except:
 pass

 def _stop(self):
 # After calling ._stop(), .is_alive() returns False and .join() returns
 # immediately. ._tstate_lock must be released before calling ._stop().
 #
 # Normal case: C code at the end of the thread's life
 # (release_sentinel in _threadmodule.c) releases ._tstate_lock, and
 # that's detected by our ._wait_for_tstate_lock(), called by .join()
 # and .is_alive(). Any number of threads _may_ call ._stop()
 # simultaneously (for example, if multiple threads are blocked in
 # .join() calls), and they're not serialized. That's harmless -
 # they'll just make redundant rebindings of ._is_stopped and
 # ._tstate_lock. Obscure: we rebind ._tstate_lock last so that the
 # "assert self._is_stopped" in ._wait_for_tstate_lock() always works
 # (the assert is executed only if ._tstate_lock is None).
 #
 # Special case: _main_thread releases ._tstate_lock via this
 # module's _shutdown() function.
 lock = self._tstate_lock
 if lock is not None:
 assert not lock.locked()
 self._is_stopped = True
 self._tstate_lock = None
 if not self.daemon:
 with _shutdown_locks_lock:
 _shutdown_locks.discard(lock)

 def _delete(self):
 "Remove current thread from the dict of currently running threads."
 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.

 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
 is_alive() 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 timeout is None:
 self._wait_for_tstate_lock()
 else:
 # the behavior of a negative timeout isn't documented, but
 # historically .join(timeout=x) for x<0 has acted as if timeout=0
 self._wait_for_tstate_lock(timeout=max(timeout, 0))

 def _wait_for_tstate_lock(self, block=True, timeout=-1):
 # Issue #18808: wait for the thread state to be gone.
 # At the end of the thread's life, after all knowledge of the thread
 # is removed from C data structures, C code releases our _tstate_lock.
 # This method passes its arguments to _tstate_lock.acquire().
 # If the lock is acquired, the C code is done, and self._stop() is
 # called. That sets ._is_stopped to True, and ._tstate_lock to None.
 lock = self._tstate_lock
 if lock is None: # already determined that the C code is done
 assert self._is_stopped
 elif lock.acquire(block, timeout):
 lock.release()
 self._stop()

 @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 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

 if _HAVE_THREAD_NATIVE_ID:
 @property
 def native_id(self):
 """Native integral thread ID of this thread, or None if it has not been started.

 This is a non-negative integer. See the get_native_id() function.
 This represents the Thread ID as reported by the kernel.

 """
 assert self._initialized, "Thread.__init__() not called"
 return self._native_id

 def is_alive(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.

 """
 assert self._initialized, "Thread.__init__() not called"
 if self._is_stopped or not self._started.is_set():
 return False
 self._wait_for_tstate_lock(False)
 return not self._is_stopped

 def isAlive(self):
 """Return whether the thread is alive.

 This method is deprecated, use is_alive() instead.
 """
 import warnings
 warnings.warn('isAlive() is deprecated, use is_alive() instead',
 DeprecationWarning, stacklevel=2)
 return self.is_alive()

 @property
 def daemon(self):
 """A boolean value indicating whether this thread is a daemon thread.

 This must be set before start() is called, otherwise RuntimeError is
 raised. Its initial value is inherited from the creating thread; the
 main thread is not a daemon thread and therefore all threads created in
 the main thread default to daemon = False.

 The entire Python program exits when only daemon threads are left.

 """
 assert self._initialized, "Thread.__init__() not called"
 return self._daemonic

 @daemon.setter
 def daemon(self, daemonic):
 if not self._initialized:
 raise RuntimeError("Thread.__init__() not called")
 if self._started.is_set():
 raise RuntimeError("cannot set daemon status of active thread")
 self._daemonic = daemonic

 def isDaemon(self):
 return self.daemon

 def setDaemon(self, daemonic):
 self.daemon = daemonic

 def getName(self):
 return self.name

 def setName(self, name):
 self.name = name


try:
 from _thread import (_excepthook as excepthook,
 _ExceptHookArgs as ExceptHookArgs)
except ImportError:
 # Simple Python implementation if _thread._excepthook() is not available
 from traceback import print_exception as _print_exception
 from collections import namedtuple

 _ExceptHookArgs = namedtuple(
 'ExceptHookArgs',
 'exc_type exc_value exc_traceback thread')

 def ExceptHookArgs(args):
 return _ExceptHookArgs(*args)

 def excepthook(args, /):
 """
 Handle uncaught Thread.run() exception.
 """
 if args.exc_type == SystemExit:
 # silently ignore SystemExit
 return

 if _sys is not None and _sys.stderr is not None:
 stderr = _sys.stderr
 elif args.thread is not None:
 stderr = args.thread._stderr
 if stderr is None:
 # do nothing if sys.stderr is None and sys.stderr was None
 # when the thread was created
 return
 else:
 # do nothing if sys.stderr is None and args.thread is None
 return

 if args.thread is not None:
 name = args.thread.name
 else:
 name = get_ident()
 print(f"Exception in thread {name}:",
 file=stderr, flush=True)
 _print_exception(args.exc_type, args.exc_value, args.exc_traceback,
 file=stderr)
 stderr.flush()


def _make_invoke_excepthook():
 # Create a local namespace to ensure that variables remain alive
 # when _invoke_excepthook() is called, even if it is called late during
 # Python shutdown. It is mostly needed for daemon threads.

 old_excepthook = excepthook
 old_sys_excepthook = _sys.excepthook
 if old_excepthook is None:
 raise RuntimeError("threading.excepthook is None")
 if old_sys_excepthook is None:
 raise RuntimeError("sys.excepthook is None")

 sys_exc_info = _sys.exc_info
 local_print = print
 local_sys = _sys

 def invoke_excepthook(thread):
 global excepthook
 try:
 hook = excepthook
 if hook is None:
 hook = old_excepthook

 args = ExceptHookArgs([*sys_exc_info(), thread])

 hook(args)
 except Exception as exc:
 exc.__suppress_context__ = True
 del exc

 if local_sys is not None and local_sys.stderr is not None:
 stderr = local_sys.stderr
 else:
 stderr = thread._stderr

 local_print("Exception in threading.excepthook:",
 file=stderr, flush=True)

 if local_sys is not None and local_sys.excepthook is not None:
 sys_excepthook = local_sys.excepthook
 else:
 sys_excepthook = old_sys_excepthook

 sys_excepthook(*sys_exc_info())
 finally:
 # Break reference cycle (exception stored in a variable)
 args = None

 return invoke_excepthook


# The timer class was contributed by Itamar Shtull-Trauring

class Timer(Thread):
 """Call a function after a specified number of seconds:

 t = Timer(30.0, f, args=None, kwargs=None)
 t.start()
 t.cancel() # stop the timer's action if it's still waiting

 """

 def __init__(self, interval, function, args=None, kwargs=None):
 Thread.__init__(self)
 self.interval = interval
 self.function = function
 self.args = args if args is not None else []
 self.kwargs = kwargs if kwargs is not None else {}
 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.is_set():
 self.function(*self.args, **self.kwargs)
 self.finished.set()


# Special thread class to represent the main thread

class _MainThread(Thread):

 def __init__(self):
 Thread.__init__(self, name="MainThread", daemon=False)
 self._set_tstate_lock()
 self._started.set()
 self._set_ident()
 if _HAVE_THREAD_NATIVE_ID:
 self._set_native_id()
 with _active_limbo_lock:
 _active[self._ident] = self


# 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 current_thread(), they
# leave an entry in the _active dict forever after.
# Their purpose is to return *something* from current_thread().
# 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)

 self._started.set()
 self._set_ident()
 if _HAVE_THREAD_NATIVE_ID:
 self._set_native_id()
 with _active_limbo_lock:
 _active[self._ident] = self

 def _stop(self):
 pass

 def is_alive(self):
 assert not self._is_stopped and self._started.is_set()
 return True

 def join(self, timeout=None):
 assert False, "cannot join a dummy thread"


# Global API functions

def current_thread():
 """Return the current Thread object, corresponding to the caller's thread of control.

 If the caller's thread of control was not created through the threading
 module, a dummy thread object with limited functionality is returned.

 """
 try:
 return _active[get_ident()]
 except KeyError:
 return _DummyThread()

currentThread = current_thread

def active_count():
 """Return the number of Thread objects currently alive.

 The returned count is equal to the length of the list returned by
 enumerate().

 """
 with _active_limbo_lock:
 return len(_active) + len(_limbo)

activeCount = active_count

def _enumerate():
 # Same as enumerate(), but without the lock. Internal use only.
 return list(_active.values()) + list(_limbo.values())

def enumerate():
 """Return a list of all Thread objects currently alive.

 The list includes daemonic threads, dummy thread objects created by
 current_thread(), and the main thread. It excludes terminated threads and
 threads that have not yet been started.

 """
 with _active_limbo_lock:
 return list(_active.values()) + list(_limbo.values())

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()

def _shutdown():
 """
 Wait until the Python thread state of all non-daemon threads get deleted.
 """
 # Obscure: other threads may be waiting to join _main_thread. That's
 # dubious, but some code does it. We can't wait for C code to release
 # the main thread's tstate_lock - that won't happen until the interpreter
 # is nearly dead. So we release it here. Note that just calling _stop()
 # isn't enough: other threads may already be waiting on _tstate_lock.
 if _main_thread._is_stopped:
 # _shutdown() was already called
 return

 # Main thread
 tlock = _main_thread._tstate_lock
 # The main thread isn't finished yet, so its thread state lock can't have
 # been released.
 assert tlock is not None
 assert tlock.locked()
 tlock.release()
 _main_thread._stop()

 # Join all non-deamon threads
 while True:
 with _shutdown_locks_lock:
 locks = list(_shutdown_locks)
 _shutdown_locks.clear()

 if not locks:
 break

 for lock in locks:
 # mimick Thread.join()
 lock.acquire()
 lock.release()

 # new threads can be spawned while we were waiting for the other
 # threads to complete


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


def _after_fork():
 """
 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, _main_thread
 global _shutdown_locks_lock, _shutdown_locks
 _active_limbo_lock = _allocate_lock()

 # fork() only copied the current thread; clear references to others.
 new_active = {}

 try:
 current = _active[get_ident()]
 except KeyError:
 # fork() was called in a thread which was not spawned
 # by threading.Thread. For example, a thread spawned
 # by thread.start_new_thread().
 current = _MainThread()

 _main_thread = current

 # reset _shutdown() locks: threads re-register their _tstate_lock below
 _shutdown_locks_lock = _allocate_lock()
 _shutdown_locks = set()

 with _active_limbo_lock:
 # Dangling thread instances must still have their locks reset,
 # because someone may join() them.
 threads = set(_enumerate())
 threads.update(_dangling)
 for thread in threads:
 # Any lock/condition variable may be currently locked or in an
 # invalid state, so we reinitialize them.
 if thread is current:
 # There is only one active thread. We reset the ident to
 # its new value since it can have changed.
 thread._reset_internal_locks(True)
 ident = get_ident()
 thread._ident = ident
 new_active[ident] = thread
 else:
 # All the others are already stopped.
 thread._reset_internal_locks(False)
 thread._stop()

 _limbo.clear()
 _active.clear()
 _active.update(new_active)
 assert len(_active) == 1


if hasattr(_os, "register_at_fork"):
 _os.register_at_fork(after_in_child=_after_fork)