import socket
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import signal
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import warnings
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from .. import _core
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from .._util import is_main_thread
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class WakeupSocketpair:
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def __init__(self):
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self.wakeup_sock, self.write_sock = socket.socketpair()
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self.wakeup_sock.setblocking(False)
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self.write_sock.setblocking(False)
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# This somewhat reduces the amount of memory wasted queueing up data
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# for wakeups. With these settings, maximum number of 1-byte sends
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# before getting BlockingIOError:
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# Linux 4.8: 6
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# macOS (darwin 15.5): 1
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# Windows 10: 525347
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# Windows you're weird. (And on Windows setting SNDBUF to 0 makes send
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# blocking, even on non-blocking sockets, so don't do that.)
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self.wakeup_sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 1)
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self.write_sock.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 1)
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# On Windows this is a TCP socket so this might matter. On other
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# platforms this fails b/c AF_UNIX sockets aren't actually TCP.
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try:
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self.write_sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
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except OSError:
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pass
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self.old_wakeup_fd = None
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def wakeup_thread_and_signal_safe(self):
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try:
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self.write_sock.send(b"\x00")
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except BlockingIOError:
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pass
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async def wait_woken(self):
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await _core.wait_readable(self.wakeup_sock)
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self.drain()
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def drain(self):
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try:
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while True:
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self.wakeup_sock.recv(2**16)
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except BlockingIOError:
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pass
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def wakeup_on_signals(self):
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assert self.old_wakeup_fd is None
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if not is_main_thread():
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return
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fd = self.write_sock.fileno()
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self.old_wakeup_fd = signal.set_wakeup_fd(fd, warn_on_full_buffer=False)
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if self.old_wakeup_fd != -1:
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warnings.warn(
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RuntimeWarning(
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"It looks like Trio's signal handling code might have "
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"collided with another library you're using. If you're "
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"running Trio in guest mode, then this might mean you "
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"should set host_uses_signal_set_wakeup_fd=True. "
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"Otherwise, file a bug on Trio and we'll help you figure "
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"out what's going on."
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)
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)
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def close(self):
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self.wakeup_sock.close()
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self.write_sock.close()
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if self.old_wakeup_fd is not None:
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signal.set_wakeup_fd(self.old_wakeup_fd)
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