def test_read_write_flow_control(self):
# Send a lot of messages filling up the protocol read buffer.
transport = MockTransport()
protocol = DbusProtocol(self.store_and_echo_messages, server_side=True)
transport.start(protocol)
protocol.data_received(b'\0AUTH ANONYMOUS\r\nBEGIN\r\n')
auth = protocol._authenticator
self.assertTrue(auth.authenticationSucceeded())
message = txdbus.MethodCallMessage('/org/freedesktop/DBus', 'Hello',
interface='org.freedesktop.DBus', destination='org.freedesktop.DBus')
protocol.data_received(message.rawMessage)
gruvi.sleep(0)
self.assertTrue(protocol._name_acquired.is_set())
interrupted = 0
message = txdbus.SignalMessage('/my/path', 'Signal', 'my.iface',
signature='s', body=['x'*100])
msglen = len(message.rawMessage)
protocol.max_queue_size = 10
transport.drain()
transport.set_write_buffer_limits(7*msglen)
for i in range(100):
# Fill up protocol message queue
protocol.data_received(message.rawMessage)
if transport._reading:
continue
interrupted += 1
self.assertEqual(protocol._queue.qsize(), 10)
# Run the dispatcher to fill up the transport write buffer
gruvi.sleep(0)
# Now the write buffer is full and the read buffer still contains
# some entries because it is larger.
self.assertGreater(protocol._queue.qsize(), 0)
self.assertFalse(transport._can_write.is_set())
transport.drain()
# Should be interrupted > 10 times. The write buffer is the limiting factor
# not the read buffer.
self.assertGreater(interrupted, 10)
