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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 persistent().ClearWeak();
25 persistent().Reset();
26 }
27
28
29 template <class T>
30 static inline T* Unwrap(v8::Local<v8::Object> object) {
31 assert(!object.IsEmpty());
32 assert(object->InternalFieldCount() > 0);
33 // Cast to ObjectWrap before casting to T. A direct cast from void
34 // to T won't work right when T has more than one base class.
35 void* ptr = GetInternalFieldPointer(object, 0);
36 ObjectWrap* wrap = static_cast<ObjectWrap*>(ptr);
37 return static_cast<T*>(wrap);
38 }
39
40
41 inline v8::Local<v8::Object> handle() const {
42 return New(handle_);
43 }
44
45
46 inline Persistent<v8::Object>& persistent() {
47 return handle_;
48 }
49
50
51 protected:
52 inline void Wrap(v8::Local<v8::Object> object) {
53 assert(persistent().IsEmpty());
54 assert(object->InternalFieldCount() > 0);
55 SetInternalFieldPointer(object, 0, this);
56 persistent().Reset(object);
57 MakeWeak();
58 }
59
60#if defined(V8_MAJOR_VERSION) && (V8_MAJOR_VERSION > 4 || \
61 (V8_MAJOR_VERSION == 4 && defined(V8_MINOR_VERSION) && V8_MINOR_VERSION >= 3))
62
63 inline void MakeWeak() {
64 persistent().v8::PersistentBase<v8::Object>::SetWeak(
65 this, WeakCallback, v8::WeakCallbackType::kParameter);
66#if NODE_MAJOR_VERSION < 10
67 // FIXME(bnoordhuis) Probably superfluous in older Node.js versions too.
68 persistent().MarkIndependent();
69#endif
70 }
71
72#elif NODE_MODULE_VERSION > NODE_0_10_MODULE_VERSION
73
74 inline void MakeWeak() {
75 persistent().v8::PersistentBase<v8::Object>::SetWeak(this, WeakCallback);
76 persistent().MarkIndependent();
77 }
78
79#else
80
81 inline void MakeWeak() {
82 persistent().persistent.MakeWeak(this, WeakCallback);
83 persistent().MarkIndependent();
84 }
85
86#endif
87
88 /* Ref() marks the object as being attached to an event loop.
89 * Refed objects will not be garbage collected, even if
90 * 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 its
99 * default state. When an object with a "weak" reference changes from
100 * attached to detached state it will be freed. Be careful not to access
101 * the object after making this call as it might be gone!
102 * (A "weak reference" means an object that only has a
103 * persistent handle.)
104 *
105 * DO NOT CALL THIS FROM DESTRUCTOR
106 */
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_; // ro
116
117 private:
118 NAN_DISALLOW_ASSIGN_COPY_MOVE(ObjectWrap)
119#if defined(V8_MAJOR_VERSION) && (V8_MAJOR_VERSION > 4 || \
120 (V8_MAJOR_VERSION == 4 && defined(V8_MINOR_VERSION) && V8_MINOR_VERSION >= 3))
121
122 static void
123 WeakCallback(v8::WeakCallbackInfo<ObjectWrap> const& info) {
124 ObjectWrap* wrap = info.GetParameter();
125 assert(wrap->refs_ == 0);
126 wrap->handle_.Reset();
127 delete wrap;
128 }
129
130#elif NODE_MODULE_VERSION > NODE_0_10_MODULE_VERSION
131
132 static void
133 WeakCallback(v8::WeakCallbackData<v8::Object, ObjectWrap> const& data) {
134 ObjectWrap* wrap = data.GetParameter();
135 assert(wrap->refs_ == 0);
136 assert(wrap->handle_.IsNearDeath());
137 wrap->handle_.Reset();
138 delete wrap;
139 }
140
141#else
142
143 static void WeakCallback(v8::Persistent<v8::Value> value, void *data) {
144 ObjectWrap *wrap = static_cast<ObjectWrap*>(data);
145 assert(wrap->refs_ == 0);
146 assert(wrap->handle_.IsNearDeath());
147 wrap->handle_.Reset();
148 delete wrap;
149 }
150
151#endif
152 Persistent<v8::Object> handle_;
153};
154
155
156#endif // NAN_OBJECT_WRAP_H_