micropython-lib/select/select.py

73 wiersze
2.1 KiB
Python

import ffi
import struct
import os
import errno
libc = ffi.open("libc.so.6")
#int epoll_create(int size);
epoll_create = libc.func("i", "epoll_create", "i")
#int epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);
epoll_ctl = libc.func("i", "epoll_ctl", "iiiP")
#int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);
epoll_wait = libc.func("i", "epoll_wait", "ipii")
EPOLLIN = 0x001
EPOLLPRI = 0x002
EPOLLOUT = 0x004
EPOLL_CTL_ADD = 1
EPOLL_CTL_DEL = 2
EPOLL_CTL_MOD = 3
class Epoll:
# Second value is actually of uint64_t size, so struct
# will be smaller on 32bit, but seem to not segfault.
epoll_event = "IO"
def __init__(self, epfd):
self.epfd = epfd
self.evbuf = struct.pack(self.epoll_event, 0, 0)
self.registry = {}
def register(self, fd, eventmask=EPOLLIN|EPOLLPRI|EPOLLOUT, retval=None):
"retval is extension to stdlib, value to use in results from .poll()."
if retval is None:
retval = fd
s = struct.pack(self.epoll_event, eventmask, retval)
r = epoll_ctl(self.epfd, EPOLL_CTL_ADD, fd, s)
if r == -1 and os.errno.get() == errno.EEXIST:
r = epoll_ctl(self.epfd, EPOLL_CTL_MOD, fd, s)
os.check_error(r)
# We must keep reference to retval, or it may be GCed. And we must
# keep mapping from fd to retval to be able to get rid of retval reference.
self.registry[fd] = retval
def unregister(self, fd):
# Pass dummy event structure, to workaround kernel bug
r = epoll_ctl(self.epfd, EPOLL_CTL_DEL, fd, self.evbuf)
os.check_error(r)
del self.registry[fd]
def poll(self, timeout=-1):
s = bytearray(self.evbuf)
n = epoll_wait(self.epfd, s, 1, timeout)
os.check_error(n)
res = []
if n > 0:
vals = struct.unpack(self.epoll_event, s)
res.append((vals[1], vals[0]))
return res
def close(self):
os.close(self.epfd)
def epoll(sizehint=4):
fd = epoll_create(sizehint)
os.check_error(fd)
return Epoll(fd)