| """Thread module emulating a subset of Java's threading model.""" |
| |
| import sys as _sys |
| import _thread |
| |
| from time import time as _time, sleep as _sleep |
| from traceback import format_exc as _format_exc |
| from _weakrefset import WeakSet |
| |
| # 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 originaly 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__ = ['active_count', 'Condition', 'current_thread', 'enumerate', 'Event', |
| 'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread', 'Barrier', |
| 'Timer', '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 |
| try: |
| _CRLock = _thread.RLock |
| except AttributeError: |
| _CRLock = None |
| TIMEOUT_MAX = _thread.TIMEOUT_MAX |
| del _thread |
| |
| |
| # Debug support (adapted from ihooks.py). |
| |
| _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): |
| global _profile_hook |
| _profile_hook = func |
| |
| def settrace(func): |
| global _trace_hook |
| _trace_hook = func |
| |
| # Synchronization classes |
| |
| Lock = _allocate_lock |
| |
| def RLock(verbose=None, *args, **kwargs): |
| if verbose is None: |
| verbose = _VERBOSE |
| if (__debug__ and verbose) or _CRLock is None: |
| return _PyRLock(verbose, *args, **kwargs) |
| return _CRLock(*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 |
| try: |
| owner = _active[owner].name |
| except KeyError: |
| pass |
| return "<%s owner=%r count=%d>" % ( |
| self.__class__.__name__, owner, self._count) |
| |
| def acquire(self, blocking=True, timeout=-1): |
| 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, timeout) |
| 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 != _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, 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 == _get_ident() |
| |
| _PyRLock = _RLock |
| |
| |
| 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-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() |
| gotit = True |
| if __debug__: |
| self._note("%s.wait(): got it", self) |
| else: |
| if timeout > 0: |
| gotit = waiter.acquire(True, timeout) |
| else: |
| gotit = waiter.acquire(False) |
| 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) |
| return gotit |
| finally: |
| self._acquire_restore(saved_state) |
| |
| def wait_for(self, predicate, timeout=None): |
| 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: |
| if __debug__: |
| self._note("%s.wait_for(%r, %r): Timed out.", |
| self, predicate, timeout) |
| break |
| if __debug__: |
| self._note("%s.wait_for(%r, %r): Waiting with timeout=%s.", |
| self, predicate, timeout, waittime) |
| self.wait(waittime) |
| result = predicate() |
| else: |
| if __debug__: |
| self._note("%s.wait_for(%r, %r): Success.", |
| self, predicate, timeout) |
| return result |
| |
| def notify(self, n=1): |
| 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 notify_all(self): |
| self.notify(len(self._waiters)) |
| |
| notifyAll = notify_all |
| |
| |
| 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=True, timeout=None): |
| if not blocking and timeout is not None: |
| raise ValueError("can't specify timeout for non-blocking acquire") |
| rc = False |
| endtime = None |
| 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) |
| 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 = 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._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 _reset_internal_locks(self): |
| # private! called by Thread._reset_internal_locks by _after_fork() |
| self._cond.__init__() |
| |
| def is_set(self): |
| return self._flag |
| |
| isSet = is_set |
| |
| 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: |
| signaled = self._flag |
| if not signaled: |
| signaled = self._cond.wait(timeout) |
| return signaled |
| finally: |
| self._cond.release() |
| |
| |
| # 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(_Verbose): |
| """ |
| Barrier. Useful for synchronizing a fixed number of threads |
| at known synchronization points. Threads block on 'wait()' and are |
| simultaneously once they have all made that call. |
| """ |
| def __init__(self, parties, action=None, timeout=None, verbose=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 uses as the default for |
| all subsequent 'wait()' calls. |
| """ |
| _Verbose.__init__(self, verbose) |
| 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 relased. 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 that are 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 = 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 = {} |
| |
| # For debug and leak testing |
| _dangling = WeakSet() |
| |
| # 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. |
| #XXX __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 |
| _dangling.add(self) |
| |
| 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, '_block'): # DummyThread deletes _block |
| self._block.__init__() |
| self._started._reset_internal_locks() |
| |
| 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("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): |
| 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: |
| _sys.stderr.write("Exception in thread %s:\n%s\n" % |
| (self.name, _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: |
| print(( |
| "Exception in thread " + self.name + |
| " (most likely raised during interpreter shutdown):"), file=self._stderr) |
| print(( |
| "Traceback (most recent call last):"), file=self._stderr) |
| while exc_tb: |
| print(( |
| ' 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)), file=self._stderr) |
| exc_tb = exc_tb.tb_next |
| print(("%s: %s" % (exc_type, exc_value)), file=self._stderr) |
| # 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. |
| #XXX self.__exc_clear() |
| pass |
| 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): |
| 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): |
| 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): |
| 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): |
| assert self._initialized, "Thread.__init__() not called" |
| return self._ident |
| |
| def is_alive(self): |
| assert self._initialized, "Thread.__init__() not called" |
| return self._started.is_set() and not self._stopped |
| |
| isAlive = is_alive |
| |
| @property |
| def daemon(self): |
| 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 |
| |
| # The timer class was contributed by Itamar Shtull-Trauring |
| |
| 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.is_set(): |
| 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._started.set() |
| self._set_ident() |
| with _active_limbo_lock: |
| _active[self._ident] = self |
| |
| def _set_daemon(self): |
| return False |
| |
| def _exitfunc(self): |
| self._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._delete() |
| |
| def _pickSomeNonDaemonThread(): |
| for t in enumerate(): |
| if not t.daemon and t.is_alive(): |
| return t |
| return None |
| |
| |
| # Dummy thread class to represent threads not started here. |
| # These aren't garbage collected when they die, nor can they be waited for. |
| # 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")) |
| |
| # 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._block |
| |
| self._started.set() |
| self._set_ident() |
| with _active_limbo_lock: |
| _active[self._ident] = self |
| |
| def _set_daemon(self): |
| return True |
| |
| def _stop(self): |
| pass |
| |
| def join(self, timeout=None): |
| assert False, "cannot join a dummy thread" |
| |
| |
| # Global API functions |
| |
| def current_thread(): |
| try: |
| return _active[_get_ident()] |
| except KeyError: |
| ##print "current_thread(): no current thread for", _get_ident() |
| return _DummyThread() |
| |
| currentThread = current_thread |
| |
| def active_count(): |
| 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(): |
| 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. |
| |
| _shutdown = _MainThread()._exitfunc |
| |
| # 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(): |
| # This function is called by Python/ceval.c:PyEval_ReInitThreads which |
| # is called from PyOS_AfterFork. Here we 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 |
| _active_limbo_lock = _allocate_lock() |
| |
| # fork() only copied the current thread; clear references to others. |
| new_active = {} |
| current = current_thread() |
| with _active_limbo_lock: |
| for thread in _active.values(): |
| # Any lock/condition variable may be currently locked or in an |
| # invalid state, so we reinitialize them. |
| thread._reset_internal_locks() |
| if thread is current: |
| # There is only one active thread. We reset the ident to |
| # its new value since it can have changed. |
| ident = _get_ident() |
| thread._ident = ident |
| new_active[ident] = thread |
| else: |
| # All the others are already stopped. |
| thread._stop() |
| |
| _limbo.clear() |
| _active.clear() |
| _active.update(new_active) |
| assert len(_active) == 1 |