disable nuke callbacks for debugging

disable_callback.py

CALLBACKS = (
    'beforeRenders',
    'beforeFrameRenders',
    'afterRenders',
    'afterFrameRenders',
    'updateUIs',
    'autolabels',
    'filenameFilters',
    'onCreates',
    'onDestroys',
    'onScriptCloses',
    'onScriptLoads',
    'onScriptSaves',
    'onUserCreates',
    'knobChangeds',
)

class CallbackSwitch(object):
    """Temporarily disable callbacks to avoid them getting called recursively."""

    __instance = None

    def __new__(self):
        """Make object a singleton."""

        if self.__instance is None:
            self.__instance = super(CallbackSwitch, self).__new__(self)
            self.__instance.initialized = False
        return self.__instance

    def __init__(self):
        """Temporarily disable callbacks to avoid them getting called recursively."""
        if self.initialized:
            return
        self.initialized = True
        self.cleared = False

        self.knob_callbacks = {}
        self.callback_data = {}
        self.callbacks = []

    def clear(self, callbacks=None):
        """Clear callbacks.
        
        Args:
            callbacks (list of str): list of callbacks to clear.
            Clears all if not specified."""
        
        self.callbacks = callbacks or CALLBACKS

        # Make a backup and clear registered callbacks
        for callback in self.callbacks:
            self.callback_data[callback] = getattr(nuke.callbacks, callback)
            setattr(nuke.callbacks, callback, {})
            
        self.cleared = True

    def restore(self):
        """Restore callbacks. Opposite of CallbackSwitch.clear()"""

        if not self.cleared:
            return

        for callback in self.callbacks:
            setattr(nuke.callbacks, callback, self.callabck_data[callback])

        self.cleared