问如何演示V8弱指针回调？

EN

foo = createFoo(); // creates a JavaScript object wrapping the native C++ Foo object.
doSomethingWith(foo); // do stuff with the Foo here
foo = null; // make sure there are no more JavaScript handles to the wrapper for the Foo object.
// After this point, I'm hoping V8 will eventually let me know that I can delete the native C++ Foo object

#include <iostream>
#include "include/libplatform/libplatform.h"
#include "include/v8.h"

class Foo {};

void cleanup(const v8::WeakCallbackInfo<Foo>& data)
{
  std::cout << "Weak Callback called" << std::endl;
  delete data.GetParameter();
}

int main(int argc, char* argv[]) {
  std::cout << "Start..." << std::endl;

  v8::V8::InitializeICUDefaultLocation(argv[0]);
  v8::V8::InitializeExternalStartupData(argv[0]);
  std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
  v8::V8::InitializePlatform(platform.get());
  v8::V8::Initialize();

  // Create a new isolate and make it the current one
  v8::Isolate::CreateParams create_params;
  create_params.array_buffer_allocator = v8::ArrayBuffer::Allocator::NewDefaultAllocator();
  v8::Isolate* isolate = v8::Isolate::New(create_params);

  {
    v8::Isolate::Scope isolate_scope(isolate);
    v8::HandleScope handle_scope(isolate);

    v8::Local<v8::Context> context = v8::Context::New(isolate, NULL, v8::ObjectTemplate::New(isolate));
    v8::Context::Scope context_scope(context);

    v8::Local<v8::Object> obj = v8::ObjectTemplate::New(isolate)->NewInstance(context).ToLocalChecked();
    v8::Persistent<v8::Object> persistent;
    persistent.Reset(isolate, obj);
    persistent.SetWeak(new Foo(), cleanup, v8::WeakCallbackType::kParameter);
  }

  isolate->IdleNotificationDeadline(1.0);

  std::cout << "...Finish" << std::endl;
}