Source code for traits_futures.asyncio.pingee

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asyncio cross-thread pinger.

This module provides a way for a background thread to request that
the main thread execute a (fixed, parameterless) callback.

from traits_futures.i_pingee import IPingee, IPinger

[docs]@IPingee.register class Pingee: """ Receiver for pings. Whenever a ping is received from a linked Pinger, the receiver calls the given fixed parameterless callable. The ping receiver must be connected (using the ``connect``) method before use, and should call ``disconnect`` when it's no longer expected to receive pings. Parameters ---------- on_ping Zero-argument callable that's called on the main thread every time a ping is received. event_loop : asyncio.AbstractEventLoop The asyncio event loop that pings will be sent to. """ def __init__(self, on_ping, event_loop): self._on_ping = on_ping self._event_loop = event_loop def _execute_ping_callback(self): """ Execute the ping callback, if this pingee is connected. """ callback = getattr(self, "_on_ping", None) if callback is not None: callback()
[docs] def connect(self): """ Prepare Pingee to receive pings. """ pass
[docs] def disconnect(self): """ Disconnect from the on_ping callable. """ del self._on_ping
[docs] def pinger(self): """ Create and return a new pinger linked to this pingee. This method is thread-safe. Typically the pingee will be passed to a background thread, and this method used within that background thread to create a pinger. This method should only be called after the 'connect' method has been called. Returns ------- pinger : Pinger New pinger, linked to this pingee. """ return Pinger(pingee=self, event_loop=self._event_loop)
[docs]@IPinger.register class Pinger: """ Ping emitter, which can send pings to a receiver in a thread-safe manner. Parameters ---------- pingee : Pingee The target receiver for the pings. The receiver must already be connected. event_loop : asyncio.AbstractEventLoop The asyncio event loop that will execute the ping callback. """ def __init__(self, pingee, event_loop): self.pingee = pingee self.event_loop = event_loop
[docs] def connect(self): """ Connect to the ping receiver. No pings should be sent until this function is called. """ pass
[docs] def disconnect(self): """ Disconnect from the ping receiver. No pings should be sent after calling this function. """ del self.pingee
[docs] def ping(self): """ Send a ping to the receiver. """ self.event_loop.call_soon_threadsafe( self.pingee._execute_ping_callback )