v8生成字节码快照和读取快照

必须要吐槽一下，大概是没人搞这个东西，本来是想做个工具，思来想去选择了大火的v8引擎，写着写着我需要一个js加密，但是搜遍了各大引擎也没有，大概是姿势不到位把，于是想起来nodejs也有这个功能，于是下载源码把单独提取出来，分享给大家，省的到处找了。我用的版本不一定是你的版本，api稍有变化情理之中

加载快照-如下：

{
    /*
    //v8加载字节码
    v8::Handle<v8::String> source_string = v8::String::NewFromUtf8(isolate, "", v8::NewStringType::kNormal).ToLocalChecked();
    uint8_t *data = reinterpret_cast<uint8_t*>("");
    v8::ScriptCompiler::CachedData* cache = new v8::ScriptCompiler::CachedData(data, 10,v8::ScriptCompiler::CachedData::BufferNotOwned);
    v8::ScriptCompiler::Source source1(source_string, cache);
    script = v8::ScriptCompiler::CompileUnboundScript(
        isolate, &source1, v8::ScriptCompiler::kConsumeCodeCache).ToLocalChecked();
    */
}

{
    size_t*  len;
    unsigned char* data = "";
    v8::StartupData data1 = v8::CreateSnapshotDataBlob((const char*)data);//编译字节码
    bool a = paWriteToFile("hmbb.bin", data1.data, data1.raw_size);
    //js编译字节码成功
    //data1.data data1.raw_size
    //delete[] data1.data;
}

当然你会发现缺少CreateSnapshotDataBlob，在这里：

bool RunExtraCode(v8::Isolate* isolate, v8::Local<v8::Context> context,
		const char* utf8_source, const char* name) {
		v8::Context::Scope context_scope(context);
		v8::TryCatch try_catch(isolate);
		v8::Local<v8::String> source_string;
		if (!v8::String::NewFromUtf8(isolate, utf8_source, v8::NewStringType::kNormal)
			.ToLocal(&source_string)) {
			return false;
		}
		v8::Local<v8::String> resource_name =
			v8::String::NewFromUtf8(isolate, name, v8::NewStringType::kNormal)
			.ToLocalChecked();
		v8::ScriptOrigin origin(resource_name);
		v8::ScriptCompiler::Source source(source_string, origin);
		v8::Local<v8::Script> script;
		if (!v8::ScriptCompiler::Compile(context, &source).ToLocal(&script))
			return false;
		if (script->Run(context).IsEmpty()) return false;
		//CHECK(!try_catch.HasCaught());
		return true;
	}
	v8::StartupData CreateSnapshotDataBlob(const char* embedded_source = nullptr) {
		// Create a new isolate and a new context from scratch, optionally run
		// a script to embed, and serialize to create a snapshot blob.
		v8::StartupData result = { nullptr, 0 };
		{
			v8::SnapshotCreator snapshot_creator;
			v8::Isolate* isolate = snapshot_creator.GetIsolate();
			{
				v8::HandleScope scope(isolate);
				v8::Local<v8::Context> context = v8::Context::New(isolate);
				if (embedded_source != nullptr &&
					!RunExtraCode(isolate, context, embedded_source, "<embedded>")) {
					return result;
				}
				snapshot_creator.SetDefaultContext(context);
			}
			result = snapshot_creator.CreateBlob(
				v8::SnapshotCreator::FunctionCodeHandling::kClear);
		}
		return result;
	}

好了。

来源：oschina

链接：https://my.oschina.net/KFS/blog/3176229

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