handle.h revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7
1// Copyright 2013 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef GIN_HANDLE_H_ 6#define GIN_HANDLE_H_ 7 8#include "gin/converter.h" 9 10namespace gin { 11 12// You can use gin::Handle on the stack to retain a gin::Wrappable object. 13// Currently we don't have a mechanism for retaining a gin::Wrappable object 14// in the C++ heap because strong references from C++ to V8 can cause memory 15// leaks. 16template<typename T> 17class Handle { 18 public: 19 Handle() : object_(NULL) {} 20 21 Handle(v8::Handle<v8::Value> wrapper, T* object) 22 : wrapper_(wrapper), 23 object_(object) { 24 } 25 26 bool IsEmpty() const { return !object_; } 27 28 void Clear() { 29 wrapper_.Clear(); 30 object_ = NULL; 31 } 32 33 T* operator->() const { return object_; } 34 v8::Handle<v8::Value> ToV8() const { return wrapper_; } 35 T* get() const { return object_; } 36 37 private: 38 v8::Handle<v8::Value> wrapper_; 39 T* object_; 40}; 41 42template<typename T> 43struct Converter<gin::Handle<T> > { 44 static v8::Handle<v8::Value> ToV8(v8::Isolate* isolate, 45 const gin::Handle<T>& val) { 46 return val.ToV8(); 47 } 48 static bool FromV8(v8::Isolate* isolate, v8::Handle<v8::Value> val, 49 gin::Handle<T>* out) { 50 T* object = NULL; 51 if (!Converter<T*>::FromV8(isolate, val, &object)) { 52 return false; 53 } 54 *out = gin::Handle<T>(val, object); 55 return true; 56 } 57}; 58 59// This function is a convenient way to create a handle from a raw pointer 60// without having to write out the type of the object explicitly. 61template<typename T> 62gin::Handle<T> CreateHandle(v8::Isolate* isolate, T* object) { 63 return gin::Handle<T>(object->GetWrapper(isolate), object); 64} 65 66} // namespace gin 67 68#endif // GIN_HANDLE_H_ 69