"""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 functools import wraps

from time import time as _time, sleep as _sleep

from traceback import format_exc as _format_exc

from collections import deque

# 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

                format = "%s: %s\n" % (

                    current_thread().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):

    global _profile_hook

    _profile_hook = func

def settrace(func):

    global _trace_hook

    _trace_hook = func

# Synchronization classes

Lock = _allocate_lock

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):

        owner = self.__owner

        return "<%s(%s, %d)>" % (

                self.__class__.__name__,

                owner and owner.name,

                self.__count)

    def acquire(self, blocking=1):

        me = current_thread()

        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):

        if self.__owner is not current_thread():

            raise RuntimeError("cannot release un-aquired 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 is current_thread()

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 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):

        if not self._is_owned():

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

        if not self._is_owned():

            raise RuntimeError("cannot notify on un-aquired 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))

    notify_all = notifyAll

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):

        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):

        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()

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)

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

    is_set = isSet

    def set(self):

        self.__cond.acquire()

        try:

            self.__flag = True

            self.__cond.notify_all()

        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()

# Helper to generate new thread names

_counter = 0

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

    global _counter

    _counter = _counter + 1

    return template % _counter

# Active thread administration

_active_limbo_lock = _allocate_lock()

_active = {}    # maps thread id to Thread object

_limbo = {}

# Main class for threads

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

    # 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):

        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 _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):

        if not self.__initialized:

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

        if self.__started.is_set():

            raise RuntimeError("thread already started")

        if __debug__:

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

        _active_limbo_lock.acquire()

        _limbo[self] = self

        _active_limbo_lock.release()

        _start_new_thread(self.__bootstrap, ())

        self.__started.wait()

    def run(self):

        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 __bootstrap_inner(self):

        try:

            self.__ident = _get_ident()

            self.__started.set()

            _active_limbo_lock.acquire()

            _active[self.__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)