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 CHROME_RENDERER_EXTENSIONS_UNSAFE_PERSISTENT_H_ 6 #define CHROME_RENDERER_EXTENSIONS_UNSAFE_PERSISTENT_H_ 7 8 #include "v8/include/v8.h" 9 10 namespace extensions { 11 12 // An unsafe way to pass Persistent handles around. Do not use unless you know 13 // what you're doing. UnsafePersistent is only safe to use when we know that the 14 // memory pointed by it is not going away: 1) When GC cannot happen while the 15 // UnsafePersistent is alive or 2) when there is a strong Persistent keeping the 16 // memory alive while the UnsafePersistent is alive. 17 template<typename T> class UnsafePersistent { 18 public: 19 UnsafePersistent() : value_(0) { } 20 21 explicit UnsafePersistent(v8::Persistent<T>* handle) { 22 value_ = handle->ClearAndLeak(); 23 } 24 25 UnsafePersistent(v8::Isolate* isolate, const v8::Handle<T>& handle) { 26 v8::Persistent<T> persistent(isolate, handle); 27 value_ = persistent.ClearAndLeak(); 28 } 29 30 // Usage of this function requires 31 // V8_ALLOW_ACCESS_TO_RAW_HANDLE_CONSTRUCTOR to be defined 32 void dispose() { 33 v8::Persistent<T> handle(value_); 34 handle.Dispose(); 35 value_ = 0; 36 } 37 38 // Usage of this function requires 39 // V8_ALLOW_ACCESS_TO_RAW_HANDLE_CONSTRUCTOR to be defined 40 v8::Local<T> newLocal(v8::Isolate* isolate) { 41 return v8::Local<T>::New(isolate, v8::Local<T>(value_)); 42 } 43 44 private: 45 T* value_; 46 }; 47 48 } // namespace extensions 49 50 #endif // CHROME_RENDERER_EXTENSIONS_UNSAFE_PERSISTENT_H_ 51
