python - 从回调中查找父函数的参数

Question

如何从 callback 中找到为调用 callback 函数的函数提供的参数？

下面的代码(不完整)将启动一个调用回调函数的音频流。它使用 pyaudio。

现在，callback 函数中有硬编码的内容。我正在努力摆脱这些。

我已阅读 pyaudio 文档，但似乎无法将额外的参数传递给 callback 函数。我读过有关 inspect python 模块的内容，它的 getsource 或 getouterframes 对我来说似乎很有趣，以便希望能够了解给 PlayStream 函数的参数，但这并没有给我带来任何结果。

如何在 callback 中引用 SoundGeneratorObject 参数？

def PlayStream(SoundGeneratorObject):
    p = pyaudio.PyAudio()
    stream = p.open(format = p.get_format_from_width(SoundGeneratorObject.WIDTH), 
                 channels = SoundGeneratorObject.CHANNELS, 
                 rate = SoundGeneratorObject.BITRATE, 
                 frames_per_buffer = SoundGeneratorObject.CHUNKSIZE,
                 output = True,
                 stream_callback = callback)
    stream.start_stream()
    while stream.is_active():
        time.sleep(0.1)
    stream.stop_stream()
    stream.close()
    p.terminate()

def callback(in_data, frame_count, time_info, status_flags):
    signal = waves.next()
    return (signal, pyaudio.paContinue)

waves = SoundGenerator()
PlayStream(waves)

Answer 1

你能做这样的事情来为你传递的回调创建一个范围吗？

def callback_maker(waves):
    def callback(in_data, frame_count, time_info, status_flags):
        # do stuff (waves is in scope)
        signal = waves.next()
        return (signal, pyaudio.paContinue)
    return callback

如果可以的话，像这样使用它:

stream = p.open(format = p.get_format_from_width(SoundGeneratorObject.WIDTH), 
                channels = SoundGeneratorObject.CHANNELS, 
                rate = SoundGeneratorObject.BITRATE, 
                frames_per_buffer = SoundGeneratorObject.CHUNKSIZE,
                output = True,
                stream_callback = callback_maker(SoundGeneratorObject))