如何将函数包装器转换为模板？

Question

我有几个非常相似的功能:

v8::Handle<v8::Value> jsAudioPlay(const v8::Arguments &args) {
    Audio *audio = static_cast<Audio*>(args.This()->GetPointerFromInternalField(0));
    if (audio != NULL) audio->play(get(args[0], 0));
    return args.This();
}

v8::Handle<v8::Value> jsAudioPause(const v8::Arguments &args) {
    Audio *audio = static_cast<Audio*>(args.This()->GetPointerFromInternalField(0));
    if (audio != NULL) audio->pause();
    return args.This();
}

v8::Handle<v8::Value> jsAudioLoop(const v8::Arguments &args) {
    Audio *audio = static_cast<Audio*>(args.This()->GetPointerFromInternalField(0));
    if (audio != NULL) audio->loop(get(args[0], -1));
    return args.This();
}

v8::Handle<v8::Value> jsAudioVolume(const v8::Arguments &args) {
    Audio *audio = static_cast<Audio*>(args.This()->GetPointerFromInternalField(0));
    if (audio != NULL) audio->volume(get(args[0], 1.0f));
    return args.This();
}

我已经阅读了几个小时的C++模板,我确信可以摆脱这些功能并用模板替换它们.我设想最终结果将是这样的:

typedef Handle<Value> (*InvocationCallback)(const Arguments& args);

template <class T> InvocationCallback FunctionWrapper ...;
template <class T> FunctionWrapper FunctionReal ...;
template <class T, class arg1> FunctionWrapper FunctionReal ...;
template <class T, class arg1, class arg2> FunctionWrapper FunctionReal ...;

我意识到已经提出了类似的问题,但我找不到像上面那样的模板中的模板示例.

---

2012年7月21日更新

模板:

template <class T> v8::Handle<v8::Value> jsFunctionTemplate(const v8::Arguments &args) {
    T *t = static_cast<T*>(args.This()->GetPointerFromInternalField(0));
    if (t != NULL) t->volume(args[0]->NumberValue());
    return args.This();
}

用法:

audio->PrototypeTemplate()->Set("Volume", v8::FunctionTemplate::New(&jsFunctionTemplate<Audio>));

现在,如果我只能弄清楚如何传递&Audio::volume给模板,我将会开展业务.

---

2012年7月24日更新

请参阅我的答案,我是如何解决这个问题的.

Answer 1

欢迎来到lambda的魔力.

template<typename F> v8::Handle<v8::Value> jsAudio(const v8::Arguments &args, F&& f) {
    Audio *audio = static_cast<Audio*>(args.This()->GetPointerFromInternalField(0));
    if (audio != NULL) f(audio, args);
    return args.This();
}
int main() {
    jsAudio(..., [&](Audio* audio, const v8::Arguments &args) {
        audio->play(get(args[0], 0));
    });
}

例如.