visualstudio_py_debugger.py 文件源码

def trace_func(self, frame, event, arg):
        # If we're so far into process shutdown that sys is already gone, just stop tracing.
        if sys is None:
            return None

        try:
            # if should_debug_code(frame.f_code) is not true during attach
            # the current frame is None and a pop_frame will cause an exception and 
            # break the debugger
            if self.cur_frame is None:
                # happens during attach, we need frame for blocking
                self.push_frame(frame)
            if self.stepping == STEPPING_BREAK and should_debug_code(frame.f_code):
                if self.detach:
                    if stackless is not None:
                        stackless.set_schedule_callback(None)
                        stackless.tasklet.__call__ = self.__oldstacklesscall__
                    sys.settrace(None)
                    return None

                self.async_break()

            return self._events[event](frame, arg)
        except (StackOverflowException, KeyboardInterrupt):
            # stack overflow, disable tracing
            return self.trace_func