klipper-dgus/klippy/reactor.py

417 lines
15 KiB
Python

# File descriptor and timer event helper
#
# Copyright (C) 2016-2020 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import os, gc, select, math, time, logging, queue
import greenlet
import chelper, util
_NOW = 0.
_NEVER = 9999999999999999.
class ReactorTimer:
def __init__(self, callback, waketime):
self.callback = callback
self.waketime = waketime
class ReactorCompletion:
class sentinel: pass
def __init__(self, reactor):
self.reactor = reactor
self.result = self.sentinel
self.waiting = []
def test(self):
return self.result is not self.sentinel
def complete(self, result):
self.result = result
for wait in self.waiting:
self.reactor.update_timer(wait.timer, self.reactor.NOW)
def wait(self, waketime=_NEVER, waketime_result=None):
if self.result is self.sentinel:
wait = greenlet.getcurrent()
self.waiting.append(wait)
self.reactor.pause(waketime)
self.waiting.remove(wait)
if self.result is self.sentinel:
return waketime_result
return self.result
class ReactorCallback:
def __init__(self, reactor, callback, waketime):
self.reactor = reactor
self.timer = reactor.register_timer(self.invoke, waketime)
self.callback = callback
self.completion = ReactorCompletion(reactor)
def invoke(self, eventtime):
self.reactor.unregister_timer(self.timer)
res = self.callback(eventtime)
self.completion.complete(res)
return self.reactor.NEVER
class ReactorFileHandler:
def __init__(self, fd, read_callback, write_callback):
self.fd = fd
self.read_callback = read_callback
self.write_callback = write_callback
def fileno(self):
return self.fd
class ReactorGreenlet(greenlet.greenlet):
def __init__(self, run):
greenlet.greenlet.__init__(self, run=run)
self.timer = None
class ReactorMutex:
def __init__(self, reactor, is_locked):
self.reactor = reactor
self.is_locked = is_locked
self.next_pending = False
self.queue = []
self.lock = self.__enter__
self.unlock = self.__exit__
def test(self):
return self.is_locked
def __enter__(self):
if not self.is_locked:
self.is_locked = True
return
g = greenlet.getcurrent()
self.queue.append(g)
while 1:
self.reactor.pause(self.reactor.NEVER)
if self.next_pending and self.queue[0] is g:
self.next_pending = False
self.queue.pop(0)
return
def __exit__(self, type=None, value=None, tb=None):
if not self.queue:
self.is_locked = False
return
self.next_pending = True
self.reactor.update_timer(self.queue[0].timer, self.reactor.NOW)
class SelectReactor:
NOW = _NOW
NEVER = _NEVER
def __init__(self, gc_checking=False):
# Main code
self._process = False
self.monotonic = chelper.get_ffi()[1].get_monotonic
# Python garbage collection
self._check_gc = gc_checking
self._last_gc_times = [0., 0., 0.]
# Timers
self._timers = []
self._next_timer = self.NEVER
# Callbacks
self._pipe_fds = None
self._async_queue = queue.Queue()
# File descriptors
self._read_fds = []
self._write_fds = []
# Greenlets
self._g_dispatch = None
self._greenlets = []
self._all_greenlets = []
def get_gc_stats(self):
return tuple(self._last_gc_times)
# Timers
def update_timer(self, timer_handler, waketime):
timer_handler.waketime = waketime
self._next_timer = min(self._next_timer, waketime)
def register_timer(self, callback, waketime=NEVER):
timer_handler = ReactorTimer(callback, waketime)
timers = list(self._timers)
timers.append(timer_handler)
self._timers = timers
self._next_timer = min(self._next_timer, waketime)
return timer_handler
def unregister_timer(self, timer_handler):
timer_handler.waketime = self.NEVER
timers = list(self._timers)
timers.pop(timers.index(timer_handler))
self._timers = timers
def _check_timers(self, eventtime, busy):
if eventtime < self._next_timer:
if busy:
return 0.
if self._check_gc:
gi = gc.get_count()
if gi[0] >= 700:
# Reactor looks idle and gc is due - run it
gc_level = 0
if gi[1] >= 10:
gc_level = 1
if gi[2] >= 10:
gc_level = 2
self._last_gc_times[gc_level] = eventtime
gc.collect(gc_level)
return 0.
return min(1., max(.001, self._next_timer - eventtime))
self._next_timer = self.NEVER
g_dispatch = self._g_dispatch
for t in self._timers:
waketime = t.waketime
if eventtime >= waketime:
t.waketime = self.NEVER
t.waketime = waketime = t.callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._next_timer = min(self._next_timer, waketime)
self._end_greenlet(g_dispatch)
return 0.
self._next_timer = min(self._next_timer, waketime)
return 0.
# Callbacks and Completions
def completion(self):
return ReactorCompletion(self)
def register_callback(self, callback, waketime=NOW):
rcb = ReactorCallback(self, callback, waketime)
return rcb.completion
# Asynchronous (from another thread) callbacks and completions
def register_async_callback(self, callback, waketime=NOW):
self._async_queue.put_nowait(
(ReactorCallback, (self, callback, waketime)))
try:
os.write(self._pipe_fds[1], b'.')
except os.error:
pass
def async_complete(self, completion, result):
self._async_queue.put_nowait((completion.complete, (result,)))
try:
os.write(self._pipe_fds[1], b'.')
except os.error:
pass
def _got_pipe_signal(self, eventtime):
try:
os.read(self._pipe_fds[0], 4096)
except os.error:
pass
while 1:
try:
func, args = self._async_queue.get_nowait()
except queue.Empty:
break
func(*args)
def _setup_async_callbacks(self):
self._pipe_fds = os.pipe()
util.set_nonblock(self._pipe_fds[0])
util.set_nonblock(self._pipe_fds[1])
self.register_fd(self._pipe_fds[0], self._got_pipe_signal)
# Greenlets
def _sys_pause(self, waketime):
# Pause using system sleep for when reactor not running
delay = waketime - self.monotonic()
if delay > 0.:
time.sleep(delay)
return self.monotonic()
def pause(self, waketime):
g = greenlet.getcurrent()
if g is not self._g_dispatch:
if self._g_dispatch is None:
return self._sys_pause(waketime)
# Switch to _check_timers (via g.timer.callback return)
return self._g_dispatch.switch(waketime)
# Pausing the dispatch greenlet - prepare a new greenlet to do dispatch
if self._greenlets:
g_next = self._greenlets.pop()
else:
g_next = ReactorGreenlet(run=self._dispatch_loop)
self._all_greenlets.append(g_next)
g_next.parent = g.parent
g.timer = self.register_timer(g.switch, waketime)
self._next_timer = self.NOW
# Switch to _dispatch_loop (via _end_greenlet or direct)
eventtime = g_next.switch()
# This greenlet activated from g.timer.callback (via _check_timers)
return eventtime
def _end_greenlet(self, g_old):
# Cache this greenlet for later use
self._greenlets.append(g_old)
self.unregister_timer(g_old.timer)
g_old.timer = None
# Switch to _check_timers (via g_old.timer.callback return)
self._g_dispatch.switch(self.NEVER)
# This greenlet reactivated from pause() - return to main dispatch loop
self._g_dispatch = g_old
# Mutexes
def mutex(self, is_locked=False):
return ReactorMutex(self, is_locked)
# File descriptors
def register_fd(self, fd, read_callback, write_callback=None):
file_handler = ReactorFileHandler(fd, read_callback, write_callback)
self.set_fd_wake(file_handle, True, False)
return file_handler
def unregister_fd(self, file_handler):
if file_handler in self._read_fds:
self._read_fds.pop(self._read_fds.index(file_handler))
if file_handler in self._write_fds:
self._write_fds.pop(self._write_fds.index(file_handler))
def set_fd_wake(self, file_handler, is_readable=True, is_writeable=False):
if file_hander in self._read_fds:
if not is_readable:
self._read_fds.pop(self._read_fds.index(file_handler))
elif is_readable:
self._read_fds.append(file_handler)
if file_hander in self._write_fds:
if not is_writeable:
self._write_fds.pop(self._write_fds.index(file_handler))
elif is_writeable:
self._write_fds.append(file_handler)
# Main loop
def _dispatch_loop(self):
self._g_dispatch = g_dispatch = greenlet.getcurrent()
busy = True
eventtime = self.monotonic()
while self._process:
timeout = self._check_timers(eventtime, busy)
busy = False
res = select.select(self._read_fds, self.write_fds, [], timeout)
eventtime = self.monotonic()
for fd in res[0]:
busy = True
fd.read_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
for fd in res[1]:
busy = True
fd.write_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
self._g_dispatch = None
def run(self):
if self._pipe_fds is None:
self._setup_async_callbacks()
self._process = True
g_next = ReactorGreenlet(run=self._dispatch_loop)
self._all_greenlets.append(g_next)
g_next.switch()
def end(self):
self._process = False
def finalize(self):
self._g_dispatch = None
self._greenlets = []
for g in self._all_greenlets:
try:
g.throw()
except:
logging.exception("reactor finalize greenlet terminate")
self._all_greenlets = []
if self._pipe_fds is not None:
os.close(self._pipe_fds[0])
os.close(self._pipe_fds[1])
self._pipe_fds = None
class PollReactor(SelectReactor):
def __init__(self, gc_checking=False):
SelectReactor.__init__(self, gc_checking)
self._poll = select.poll()
self._fds = {}
# File descriptors
def register_fd(self, fd, read_callback, write_callback=None):
file_handler = ReactorFileHandler(fd, read_callback, write_callback)
fds = self._fds.copy()
fds[fd] = file_handler
self._fds = fds
self._poll.register(file_handler, select.POLLIN | select.POLLHUP)
return file_handler
def unregister_fd(self, file_handler):
self._poll.unregister(file_handler)
fds = self._fds.copy()
del fds[file_handler.fd]
self._fds = fds
def set_fd_wake(self, file_handler, is_readable=True, is_writeable=False):
flags = select.POLLHUP
if is_readable:
flags |= select.POLLIN
if is_writeable:
flags |= select.POLLOUT
self._poll.modify(file_handler, flags)
# Main loop
def _dispatch_loop(self):
self._g_dispatch = g_dispatch = greenlet.getcurrent()
busy = True
eventtime = self.monotonic()
while self._process:
timeout = self._check_timers(eventtime, busy)
busy = False
res = self._poll.poll(int(math.ceil(timeout * 1000.)))
eventtime = self.monotonic()
for fd, event in res:
busy = True
if event & (select.POLLIN | select.POLLHUP):
self._fds[fd].read_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
if event & select.POLLOUT:
self._fds[fd].write_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
self._g_dispatch = None
class EPollReactor(SelectReactor):
def __init__(self, gc_checking=False):
SelectReactor.__init__(self, gc_checking)
self._epoll = select.epoll()
self._fds = {}
# File descriptors
def register_fd(self, fd, read_callback, write_callback=None):
file_handler = ReactorFileHandler(fd, read_callback, write_callback)
fds = self._fds.copy()
fds[fd] = callback
self._fds = fds
self._epoll.register(fd, select.EPOLLIN | select.EPOLLHUP)
return file_handler
def unregister_fd(self, file_handler):
self._epoll.unregister(file_handler.fd)
fds = self._fds.copy()
del fds[file_handler.fd]
self._fds = fds
def set_fd_wake(self, file_handler, is_readable=True, is_writeable=False):
flags = select.POLLHUP
if is_readable:
flags |= select.EPOLLIN
if is_writeable:
flags |= select.EPOLLOUT
self._epoll.modify(file_handler, flags)
# Main loop
def _dispatch_loop(self):
self._g_dispatch = g_dispatch = greenlet.getcurrent()
busy = True
eventtime = self.monotonic()
while self._process:
timeout = self._check_timers(eventtime, busy)
busy = False
res = self._epoll.poll(timeout)
eventtime = self.monotonic()
for fd, event in res:
busy = True
if event & (select.EPOLLIN | select.EPOLLHUP):
self._fds[fd].read_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
if event & select.EPOLLOUT:
self._fds[fd].write_callback(eventtime)
if g_dispatch is not self._g_dispatch:
self._end_greenlet(g_dispatch)
eventtime = self.monotonic()
break
self._g_dispatch = None
# Use the poll based reactor if it is available
try:
select.poll
Reactor = PollReactor
except:
Reactor = SelectReactor