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1// Copyright Joyent, Inc. and other Node contributors.2//3// Permission is hereby granted, free of charge, to any person obtaining a4// copy of this software and associated documentation files (the5// "Software"), to deal in the Software without restriction, including6// without limitation the rights to use, copy, modify, merge, publish,7// distribute, sublicense, and/or sell copies of the Software, and to permit8// persons to whom the Software is furnished to do so, subject to the9// following conditions:10//11// The above copyright notice and this permission notice shall be included12// in all copies or substantial portions of the Software.13//14// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS15// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF16// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN17// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,18// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR19// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE20// USE OR OTHER DEALINGS IN THE SOFTWARE.21 22#ifndef SRC_NODE_OBJECT_WRAP_H_23#define SRC_NODE_OBJECT_WRAP_H_24 25#include "v8.h"26#include <cassert>27 28 29namespace node {30 31class ObjectWrap {32 public:33  ObjectWrap() {34    refs_ = 0;35  }36 37 38  virtual ~ObjectWrap() {39    if (persistent().IsEmpty())40      return;41    persistent().ClearWeak();42    persistent().Reset();43  }44 45 46  template <class T>47  static inline T* Unwrap(v8::Local<v8::Object> handle) {48    assert(!handle.IsEmpty());49    assert(handle->InternalFieldCount() > 0);50    // Cast to ObjectWrap before casting to T.  A direct cast from void51    // to T won't work right when T has more than one base class.52    void* ptr = handle->GetAlignedPointerFromInternalField(0);53    ObjectWrap* wrap = static_cast<ObjectWrap*>(ptr);54    return static_cast<T*>(wrap);55  }56 57 58  inline v8::Local<v8::Object> handle() {59    return handle(v8::Isolate::GetCurrent());60  }61 62 63  inline v8::Local<v8::Object> handle(v8::Isolate* isolate) {64    return v8::Local<v8::Object>::New(isolate, persistent());65  }66 67 68  // NOLINTNEXTLINE(runtime/v8_persistent)69  inline v8::Persistent<v8::Object>& persistent() {70    return handle_;71  }72 73 74 protected:75  inline void Wrap(v8::Local<v8::Object> handle) {76    assert(persistent().IsEmpty());77    assert(handle->InternalFieldCount() > 0);78    handle->SetAlignedPointerInInternalField(0, this);79    persistent().Reset(v8::Isolate::GetCurrent(), handle);80    MakeWeak();81  }82 83 84  inline void MakeWeak() {85    persistent().SetWeak(this, WeakCallback, v8::WeakCallbackType::kParameter);86  }87 88  /* Ref() marks the object as being attached to an event loop.89   * Refed objects will not be garbage collected, even if90   * all references are lost.91   */92  virtual void Ref() {93    assert(!persistent().IsEmpty());94    persistent().ClearWeak();95    refs_++;96  }97 98  /* Unref() marks an object as detached from the event loop.  This is its99   * default state.  When an object with a "weak" reference changes from100   * attached to detached state it will be freed. Be careful not to access101   * the object after making this call as it might be gone!102   * (A "weak reference" means an object that only has a103   * persistent handle.)104   *105   * DO NOT CALL THIS FROM DESTRUCTOR106   */107  virtual void Unref() {108    assert(!persistent().IsEmpty());109    assert(!persistent().IsWeak());110    assert(refs_ > 0);111    if (--refs_ == 0)112      MakeWeak();113  }114 115  int refs_;  // ro116 117 private:118  static void WeakCallback(119      const v8::WeakCallbackInfo<ObjectWrap>& data) {120    ObjectWrap* wrap = data.GetParameter();121    assert(wrap->refs_ == 0);122    wrap->handle_.Reset();123    delete wrap;124  }125 126  // NOLINTNEXTLINE(runtime/v8_persistent)127  v8::Persistent<v8::Object> handle_;128};129 130}  // namespace node131 132#endif  // SRC_NODE_OBJECT_WRAP_H_133