V8世界探险 (1)

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V8世界探险 (1) - v8 API概览

v8是Google开发的JavaScript引擎,自推出后就对js生态产生了巨大的影响。比如产生了运行在服务端的Node.js的巨大生态。

这么好玩的东西,我们当然要冲起去看看它的内部是如何实现的了。

Hello,v8 World!

首先好玩的一点是,v8可以作为一个库来嵌入到其它的应用中。

我们废话不多说,直接上代码.这是Google官方的调用在代码中嵌入一个v8引擎的例子,地址在:https://chromium.googlesource.com/v8/v8/+/branch-heads/4.8/samples/hello-world.cc

// Copyright 2015 the V8 project authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "include/libplatform/libplatform.h"

#include "include/v8.h"

using namespace v8;

class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {

 public:

  virtual void* Allocate(size_t length) {

    void* data = AllocateUninitialized(length);

    return data == NULL ? data : memset(data, 0, length);

  }

  virtual void* AllocateUninitialized(size_t length) { return malloc(length); }

  virtual void Free(void* data, size_t) { free(data); }

};

int main(int argc, char* argv[]) {

  // Initialize V8.

  V8::InitializeICU();

  V8::InitializeExternalStartupData(argv[0]);

  Platform* platform = platform::CreateDefaultPlatform();

  V8::InitializePlatform(platform);

  V8::Initialize();

  // Create a new Isolate and make it the current one.

  ArrayBufferAllocator allocator;

  Isolate::CreateParams create_params;

  create_params.array_buffer_allocator = &allocator;

  Isolate* isolate = Isolate::New(create_params);

  {

    Isolate::Scope isolate_scope(isolate);

    // Create a stack-allocated handle scope.

    HandleScope handle_scope(isolate);

    // Create a new context.

    Local context = Context::New(isolate);

    // Enter the context for compiling and running the hello world script.

    Context::Scope context_scope(context);

    // Create a string containing the JavaScript source code.

    Local source =

        String::NewFromUtf8(isolate, "'Hello' + ', World!'",

                            NewStringType::kNormal).ToLocalChecked();

    // Compile the source code.

    Local