Class Event

Lib/multiprocessing/synchronize.py:335–372

#

class Event(object):

    def __init__(self, *, ctx):
        self._cond = ctx.Condition(ctx.Lock())
        self._flag = ctx.Semaphore(0)

    def is_set(self):
        with self._cond:
            if self._flag.acquire(False):
                self._flag.release()
                return True
            return False

    def set(self):
        with self._cond:
            self._flag.acquire(False)
            self._flag.release()
            self._cond.notify_all()

    def clear(self):
        with self._cond:
            self._flag.acquire(False)

    def wait(self, timeout=None):
        with self._cond:
            if self._flag.acquire(False):
                self._flag.release()
            else:
                self._cond.wait(timeout)

            if self._flag.acquire(False):
                self._flag.release()
                return True
            return False

    def __repr__(self):
        set_status = 'set' if self.is_set() else 'unset'
        return f"<{type(self).__qualname__} at {id(self):#x} {set_status}>"
#
# Barrier
#