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1/*********************************************************************
2 * NAN - Native Abstractions for Node.js
3 *
4 * Copyright (c) 2018 NAN contributors
5 *
6 * MIT License <https://github.com/nodejs/nan/blob/master/LICENSE.md>
7 ********************************************************************/
8
9#ifndef NAN_OBJECT_WRAP_H_
10#define NAN_OBJECT_WRAP_H_
11
12class ObjectWrap {
13 public:
14 ObjectWrap() {
15 refs_ = 0;
16 }
17
18
19 virtual ~ObjectWrap() {
20 if (persistent().IsEmpty()) {
21 return;
22 }
23
24 assert(persistent().IsNearDeath());
25 persistent().ClearWeak();
26 persistent().Reset();
27 }
28
29
30 template <class T>
31 static inline T* Unwrap(v8::Local<v8::Object> object) {
32 assert(!object.IsEmpty());
33 assert(object->InternalFieldCount() > 0);
34 // Cast to ObjectWrap before casting to T. A direct cast from void
35 // to T won't work right when T has more than one base class.
36 void* ptr = GetInternalFieldPointer(object, 0);
37 ObjectWrap* wrap = static_cast<ObjectWrap*>(ptr);
38 return static_cast<T*>(wrap);
39 }
40
41
42 inline v8::Local<v8::Object> handle() const {
43 return New(handle_);
44 }
45
46
47 inline Persistent<v8::Object>& persistent() {
48 return handle_;
49 }
50
51
52 protected:
53 inline void Wrap(v8::Local<v8::Object> object) {
54 assert(persistent().IsEmpty());
55 assert(object->InternalFieldCount() > 0);
56 SetInternalFieldPointer(object, 0, this);
57 persistent().Reset(object);
58 MakeWeak();
59 }
60
61#if defined(V8_MAJOR_VERSION) && (V8_MAJOR_VERSION > 4 || \
62 (V8_MAJOR_VERSION == 4 && defined(V8_MINOR_VERSION) && V8_MINOR_VERSION >= 3))
63
64 inline void MakeWeak() {
65 persistent().v8::PersistentBase<v8::Object>::SetWeak(
66 this, WeakCallback, v8::WeakCallbackType::kParameter);
67 persistent().MarkIndependent();
68 }
69
70#elif NODE_MODULE_VERSION > NODE_0_10_MODULE_VERSION
71
72 inline void MakeWeak() {
73 persistent().v8::PersistentBase<v8::Object>::SetWeak(this, WeakCallback);
74 persistent().MarkIndependent();
75 }
76
77#else
78
79 inline void MakeWeak() {
80 persistent().persistent.MakeWeak(this, WeakCallback);
81 persistent().MarkIndependent();
82 }
83
84#endif
85
86 /* Ref() marks the object as being attached to an event loop.
87 * Refed objects will not be garbage collected, even if
88 * all references are lost.
89 */
90 virtual void Ref() {
91 assert(!persistent().IsEmpty());
92 persistent().ClearWeak();
93 refs_++;
94 }
95
96 /* Unref() marks an object as detached from the event loop. This is its
97 * default state. When an object with a "weak" reference changes from
98 * attached to detached state it will be freed. Be careful not to access
99 * the object after making this call as it might be gone!
100 * (A "weak reference" means an object that only has a
101 * persistant handle.)
102 *
103 * DO NOT CALL THIS FROM DESTRUCTOR
104 */
105 virtual void Unref() {
106 assert(!persistent().IsEmpty());
107 assert(!persistent().IsWeak());
108 assert(refs_ > 0);
109 if (--refs_ == 0)
110 MakeWeak();
111 }
112
113 int refs_; // ro
114
115 private:
116 NAN_DISALLOW_ASSIGN_COPY_MOVE(ObjectWrap)
117#if defined(V8_MAJOR_VERSION) && (V8_MAJOR_VERSION > 4 || \
118 (V8_MAJOR_VERSION == 4 && defined(V8_MINOR_VERSION) && V8_MINOR_VERSION >= 3))
119
120 static void
121 WeakCallback(v8::WeakCallbackInfo<ObjectWrap> const& info) {
122 ObjectWrap* wrap = info.GetParameter();
123 assert(wrap->refs_ == 0);
124 assert(wrap->handle_.IsNearDeath());
125 wrap->handle_.Reset();
126 delete wrap;
127 }
128
129#elif NODE_MODULE_VERSION > NODE_0_10_MODULE_VERSION
130
131 static void
132 WeakCallback(v8::WeakCallbackData<v8::Object, ObjectWrap> const& data) {
133 ObjectWrap* wrap = data.GetParameter();
134 assert(wrap->refs_ == 0);
135 assert(wrap->handle_.IsNearDeath());
136 wrap->handle_.Reset();
137 delete wrap;
138 }
139
140#else
141
142 static void WeakCallback(v8::Persistent<v8::Value> value, void *data) {
143 ObjectWrap *wrap = static_cast<ObjectWrap*>(data);
144 assert(wrap->refs_ == 0);
145 assert(wrap->handle_.IsNearDeath());
146 wrap->handle_.Reset();
147 delete wrap;
148 }
149
150#endif
151 Persistent<v8::Object> handle_;
152};
153
154
155#endif // NAN_OBJECT_WRAP_H_