Python gobject 模块，SIGNAL_RUN_LAST 实例源码

def gsignal(name, *args, **kwargs):
    """
    Add a GObject signal to the current object.
    It current supports the following types:
      - str, int, float, long, object, enum
    @param name:     name of the signal
    @type name:      string
    @param args:     types for signal parameters,
      if the first one is a string 'override', the signal will be
      overridden and must therefor exists in the parent GObject.
    @keyword flags: A combination of;
      - gobject.SIGNAL_RUN_FIRST
      - gobject.SIGNAL_RUN_LAST
      - gobject.SIGNAL_RUN_CLEANUP
      - gobject.SIGNAL_NO_RECURSE
      - gobject.SIGNAL_DETAILED
      - gobject.SIGNAL_ACTION
      - gobject.SIGNAL_NO_HOOKS
    @keyword retval: return value in signal callback
    """

    frame = sys._getframe(1)
    try:
        locals = frame.f_locals
    finally:
        del frame

    dict = locals.setdefault('__gsignals__', {})

    if args and args[0] == 'override':
        dict[name] = 'override'
    else:
        retval = kwargs.get('retval', None)
        if retval is None:
            default_flags = gobject.SIGNAL_RUN_FIRST
        else:
            default_flags = gobject.SIGNAL_RUN_LAST

        flags = kwargs.get('flags', default_flags)
        if retval is not None and flags != gobject.SIGNAL_RUN_LAST:
            raise TypeError(
                "You cannot use a return value without setting flags to "
                "gobject.SIGNAL_RUN_LAST")

        dict[name] = (flags, retval, args)
# gsignal()