#
# Analogue of `multiprocessing.connection` which uses queues instead of sockets
#
# multiprocessing/dummy/connection.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#

__all__ = [ 'Client', 'Listener', 'Pipe' ]

from queue import Queue


families = [None]


class Listener(object):

def __init__(self, address=None, family=None, backlog=1):
self._backlog_queue = Queue(backlog)

def accept(self):
return Connection(*self._backlog_queue.get())

def close(self):
self._backlog_queue = None

address = property(lambda self: self._backlog_queue)

def __enter__(self):
return self

def __exit__(self, exc_type, exc_value, exc_tb):
self.close()


def Client(address):
_in, _out = Queue(), Queue()
address.put((_out, _in))
return Connection(_in, _out)


def Pipe(duplex=True):
a, b = Queue(), Queue()
return Connection(a, b), Connection(b, a)


class Connection(object):

def __init__(self, _in, _out):
self._out = _out
self._in = _in
self.send = self.send_bytes = _out.put
self.recv = self.recv_bytes = _in.get

def poll(self, timeout=0.0):
if self._in.qsize() > 0:
return True
if timeout <= 0.0:
return False
self._in.not_empty.acquire()
self._in.not_empty.wait(timeout)
self._in.not_empty.release()
return self._in.qsize() > 0

def close(self):
pass

def __enter__(self):
return self

def __exit__(self, exc_type, exc_value, exc_tb):
self.close()