Source code for traits_futures.qt.pingee

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Qt cross-thread pinger.

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

from pyface.qt.QtCore import QObject, Qt, Signal, Slot

from traits_futures.i_pingee import IPingee, IPinger

class _Signaller(QObject):
    Private object used to send signals to the corresponding Qt receiver.

    ping = Signal()

[docs]@IPingee.register class Pingee(QObject): """ 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. """ def __init__(self, on_ping): QObject.__init__(self) self._on_ping = on_ping @Slot() def _execute_ping_callback(self): 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)
[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. """ def __init__(self, pingee): self._pingee = pingee
[docs] def connect(self): """ Connect to the ping receiver. No pings should be sent until this function is called. """ self._signaller = _Signaller() self._pingee._execute_ping_callback, Qt.QueuedConnection, )
[docs] def disconnect(self): """ Disconnect from the ping receiver. No pings should be sent after calling this function. """ del self._signaller del self._pingee
[docs] def ping(self): """ Send a ping to the receiver. """