Question

我有一个C ++方法（哪个角色会杀死一些进程）。她需要2个参数：a hostname and a port。

另一方面，我正在开发一个在Google Chrome上运行的网络应用程序（使用Nodejs和AngularJS）。当我通过浏览器点击按钮时，我希望能够通过我的app.js文件调用C ++函数。

我还没有找到如何用C ++“绑定”javascript。

编辑：我认为这个链接可能非常有用 How can I use a C++ library from node.js?

Answer 1

您可以使用Google's V8。 V8是Google的开源JavaScript引擎。 V8可以运行standalone，也可以embedded投放到任何C++应用中。

http://code.google.com/p/v8/

以下来自github演示的示例，将C++类与Google V8绑定。 v8_wrap_class.cpp - 作者是尼古拉斯

/*
 * v8_wrap_class.cpp
 *
 *  Created on: 14/01/2013
 *      Author: nicholas
 *     License: public domain
 */


#include <v8.h>
#include <cstdio>
#include <string>
#include <stdexcept>
#include <memory>

using namespace v8;

/*
var Simple = function(v)
{
    this.value = v;
}
Simple.prototype.func = function()
{
    alert(this.value);
}

var obj = new Simple(4);
obj.func();
*/
struct Simple
{
    double value;

    Simple(double v)
     : value(v)
    {
        fprintf(stderr, "Simple::ctor\n");
    }

    void func()
    {
        fprintf(stderr, "Simple::func(%f)\n", value);
    }

    ~Simple()
    {
        fprintf(stderr, "Simple::dtor\n");
    }
};

namespace js
{

/*
 * Retrieve the c++ object pointer from the js object
 */
template <typename T>
T* unwrap(const Arguments& args)
{
    auto self = args.Holder();
    auto wrap = Local<External>::Cast(self->GetInternalField(0));
    return static_cast<T*>(wrap->Value());
}

/*
 * Construct a new c++ object and wrap it in a js object
 */
template <typename T, typename... Args>
Persistent<Object> make_object(Handle<Object> object, Args&&... args)
{
    auto x = new T(std::forward<Args>(args)...);
    auto obj = Persistent<Object>::New(object);
    obj->SetInternalField(0, External::New(x));

    obj.MakeWeak(x, [](Persistent<Value> obj, void* data)
    {
        auto x = static_cast<T*>(data);
        delete x;

        obj.Dispose();
        obj.Clear();
    });

    return obj;
}

}

void bind_Simple(Local<Object> global)
{
    // Name the class in js
    auto name = String::NewSymbol("Simple");

    auto tpl = FunctionTemplate::New([&](const Arguments& args) -> Handle<Value>
    {
        if (!args.IsConstructCall())
            return ThrowException(String::New("Cannot call constructor as function"));

        HandleScope scope;

        // Read and pass constructor arguments
        js::make_object<Simple>(args.This(), args[0]->NumberValue());

        return args.This();
    });

    tpl->SetClassName(name);
    tpl->InstanceTemplate()->SetInternalFieldCount(1);

    auto prototype = tpl->PrototypeTemplate();

    // Add object properties to the prototype
    // Methods, Properties, etc.
    prototype->Set(String::New("func"), FunctionTemplate::New([](const Arguments& args) -> Handle<Value>
    {
        auto s = js::unwrap<Simple>(args);
        s->func();
        return {};
    })->GetFunction());

    auto constructor = Persistent<Function>::New(tpl->GetFunction());
    global->Set(name, constructor);
}

int main()
{
    std::string js_source = R"(
        for(var i = 0; i < 1000; ++i)
        {
            var s = new Simple(4);
            s.value = 5;
            s.func();
        }
    )";

    /*
     * This code is mostly uninteresting.
     * Just run the vm with the script provided.
     */
    {
        HandleScope handle_scope;
        Handle<ObjectTemplate> global_template = ObjectTemplate::New();

        Persistent<Context> context = Context::New(0, global_template);
        Context::Scope context_scope(context);

        auto global = context->Global();

        // Wrap the class and bind to the global scope.
        bind_Simple(global);

        {
            HandleScope handle_scope;

            TryCatch trycatch;

            Local<String> source = String::New(js_source.c_str(), js_source.size());

            Local<Script> script = Script::Compile(source);
            if (script.IsEmpty())
            {
                Handle<Value> exception = trycatch.Exception();
                String::AsciiValue exception_str(exception);
                throw std::runtime_error(*exception_str);
            }

            Local<Value> result = script->Run();
            if (result.IsEmpty())
            {
                Local<Value> exception = trycatch.Exception();
                String::AsciiValue exception_str(exception);
                throw std::runtime_error(*exception_str);
            }
        }

        context.Dispose();
        context.Clear();
    }

    // Run the GC until there is nothing to reclaim.
    while (!V8::IdleNotification())
        ;
    return 0;
}

Answer 2

您可以向服务器发出ajax请求，并在后端调用c ++，也许在php中。或者这可能有用https://code.google.com/p/tiny-js/

如何从javascript调用C ++方法

2 个答案: