266 lines
8.8 KiB
Python
Executable File
266 lines
8.8 KiB
Python
Executable File
import bisect
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import sys
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import traceback
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from eventlet.support import greenlets as greenlet
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from eventlet.hubs import timer
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from eventlet import patcher
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time = patcher.original('time')
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READ="read"
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WRITE="write"
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class FdListener(object):
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def __init__(self, evtype, fileno, cb):
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assert (evtype is READ or evtype is WRITE)
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self.evtype = evtype
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self.fileno = fileno
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self.cb = cb
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def __call__(self, *args, **kw):
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return self.cb(*args, **kw)
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def __repr__(self):
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return "%s(%r, %r, %r)" % (type(self).__name__, self.evtype, self.fileno, self.cb)
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__str__ = __repr__
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# in debug mode, track the call site that created the listener
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class DebugListener(FdListener):
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def __init__(self, evtype, fileno, cb):
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self.where_called = traceback.format_stack()
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self.greenlet = greenlet.getcurrent()
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super(DebugListener, self).__init__(evtype, fileno, cb)
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def __repr__(self):
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return "DebugListener(%r, %r, %r, %r)\n%sEndDebugFdListener" % (self.evtype,
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self.fileno,
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self.cb,
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self.greenlet,
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''.join(self.where_called))
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__str__ = __repr__
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class BaseHub(object):
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""" Base hub class for easing the implementation of subclasses that are
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specific to a particular underlying event architecture. """
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SYSTEM_EXCEPTIONS = (KeyboardInterrupt, SystemExit)
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READ = READ
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WRITE = WRITE
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def __init__(self, clock=time.time):
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self.listeners = {READ:{}, WRITE:{}}
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self.clock = clock
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self.greenlet = greenlet.greenlet(self.run)
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self.stopping = False
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self.running = False
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self.timers = []
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self.next_timers = []
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self.lclass = FdListener
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self.debug_exceptions = True
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def add(self, evtype, fileno, cb):
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""" Signals an intent to or write a particular file descriptor.
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The *evtype* argument is either the constant READ or WRITE.
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The *fileno* argument is the file number of the file of interest.
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The *cb* argument is the callback which will be called when the file
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is ready for reading/writing.
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"""
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listener = self.lclass(evtype, fileno, cb)
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self.listeners[evtype].setdefault(fileno, []).append(listener)
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return listener
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def remove(self, listener):
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listener_list = self.listeners[listener.evtype].pop(listener.fileno, [])
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try:
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listener_list.remove(listener)
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except ValueError:
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pass
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if listener_list:
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self.listeners[listener.evtype][listener.fileno] = listener_list
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def remove_descriptor(self, fileno):
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""" Completely remove all listeners for this fileno. For internal use
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only."""
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self.listeners[READ].pop(fileno, None)
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self.listeners[WRITE].pop(fileno, None)
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def stop(self):
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self.abort()
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if self.greenlet is not greenlet.getcurrent():
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self.switch()
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def switch(self):
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cur = greenlet.getcurrent()
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assert cur is not self.greenlet, 'Cannot switch to MAINLOOP from MAINLOOP'
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switch_out = getattr(cur, 'switch_out', None)
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if switch_out is not None:
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try:
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switch_out()
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except:
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self.squelch_generic_exception(sys.exc_info())
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if self.greenlet.dead:
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self.greenlet = greenlet.greenlet(self.run)
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try:
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current = greenlet.getcurrent()
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if self.greenlet.parent is not current:
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current.parent = self.greenlet
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except ValueError:
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pass # gets raised if there is a greenlet parent cycle
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sys.exc_clear()
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return self.greenlet.switch()
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def squelch_exception(self, fileno, exc_info):
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traceback.print_exception(*exc_info)
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sys.stderr.write("Removing descriptor: %r\n" % (fileno,))
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sys.stderr.flush()
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try:
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self.remove_descriptor(fileno)
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except Exception, e:
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sys.stderr.write("Exception while removing descriptor! %r\n" % (e,))
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sys.stderr.flush()
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def wait(self, seconds=None):
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raise NotImplementedError("Implement this in a subclass")
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def default_sleep(self):
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return 60.0
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def sleep_until(self):
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t = self.timers
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if not t:
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return None
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return t[0][0]
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def run(self):
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"""Run the runloop until abort is called.
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"""
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if self.running:
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raise RuntimeError("Already running!")
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try:
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self.running = True
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self.stopping = False
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while not self.stopping:
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self.prepare_timers()
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self.fire_timers(self.clock())
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self.prepare_timers()
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wakeup_when = self.sleep_until()
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if wakeup_when is None:
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sleep_time = self.default_sleep()
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else:
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sleep_time = wakeup_when - self.clock()
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if sleep_time > 0:
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self.wait(sleep_time)
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else:
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self.wait(0)
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else:
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del self.timers[:]
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del self.next_timers[:]
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finally:
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self.running = False
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self.stopping = False
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def abort(self):
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"""Stop the runloop. If run is executing, it will exit after completing
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the next runloop iteration.
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"""
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if self.running:
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self.stopping = True
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def squelch_generic_exception(self, exc_info):
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if self.debug_exceptions:
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traceback.print_exception(*exc_info)
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sys.stderr.flush()
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def squelch_timer_exception(self, timer, exc_info):
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if self.debug_exceptions:
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traceback.print_exception(*exc_info)
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sys.stderr.flush()
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def _add_absolute_timer(self, when, info):
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# the 0 placeholder makes it easy to bisect_right using (now, 1)
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self.next_timers.append((when, 0, info))
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def add_timer(self, timer):
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scheduled_time = self.clock() + timer.seconds
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self._add_absolute_timer(scheduled_time, timer)
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return scheduled_time
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def timer_finished(self, timer):
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pass
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def timer_canceled(self, timer):
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self.timer_finished(timer)
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def prepare_timers(self):
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ins = bisect.insort_right
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t = self.timers
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for item in self.next_timers:
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ins(t, item)
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del self.next_timers[:]
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def schedule_call_local(self, seconds, cb, *args, **kw):
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"""Schedule a callable to be called after 'seconds' seconds have
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elapsed. Cancel the timer if greenlet has exited.
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seconds: The number of seconds to wait.
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cb: The callable to call after the given time.
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*args: Arguments to pass to the callable when called.
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**kw: Keyword arguments to pass to the callable when called.
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"""
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t = timer.LocalTimer(seconds, cb, *args, **kw)
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self.add_timer(t)
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return t
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def schedule_call_global(self, seconds, cb, *args, **kw):
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"""Schedule a callable to be called after 'seconds' seconds have
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elapsed. The timer will NOT be cancelled if the current greenlet has
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exited before the timer fires.
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seconds: The number of seconds to wait.
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cb: The callable to call after the given time.
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*args: Arguments to pass to the callable when called.
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**kw: Keyword arguments to pass to the callable when called.
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"""
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t = timer.Timer(seconds, cb, *args, **kw)
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self.add_timer(t)
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return t
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def fire_timers(self, when):
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t = self.timers
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last = bisect.bisect_right(t, (when, 1))
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i = 0
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for i in xrange(last):
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timer = t[i][2]
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try:
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try:
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timer()
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except self.SYSTEM_EXCEPTIONS:
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raise
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except:
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self.squelch_timer_exception(timer, sys.exc_info())
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finally:
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self.timer_finished(timer)
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del t[:last]
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# for debugging:
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def get_readers(self):
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return self.listeners[READ].values()
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def get_writers(self):
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return self.listeners[WRITE].values()
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def get_timers_count(hub):
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return max(len(hub.timers), len(hub.next_timers))
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def set_debug_listeners(self, value):
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if value:
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self.lclass = DebugListener
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else:
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self.lclass = FdListener
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def set_timer_exceptions(self, value):
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self.debug_exceptions = value
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