summaryrefslogtreecommitdiff
path: root/src/node_object_wrap.h
blob: 96b9115adac86027206772f663bd2aea832fbe3b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_NODE_OBJECT_WRAP_H_
#define SRC_NODE_OBJECT_WRAP_H_

#include "v8.h"
#include <assert.h>


namespace node {

class ObjectWrap {
 public:
  ObjectWrap() {
    refs_ = 0;
  }


  virtual ~ObjectWrap() {
    if (persistent().IsEmpty())
      return;
    assert(persistent().IsNearDeath());
    persistent().ClearWeak();
    persistent().Reset();
  }


  template <class T>
  static inline T* Unwrap(v8::Local<v8::Object> handle) {
    assert(!handle.IsEmpty());
    assert(handle->InternalFieldCount() > 0);
    // Cast to ObjectWrap before casting to T.  A direct cast from void
    // to T won't work right when T has more than one base class.
    void* ptr = handle->GetAlignedPointerFromInternalField(0);
    ObjectWrap* wrap = static_cast<ObjectWrap*>(ptr);
    return static_cast<T*>(wrap);
  }


  inline v8::Local<v8::Object> handle() {
    return handle(v8::Isolate::GetCurrent());
  }


  inline v8::Local<v8::Object> handle(v8::Isolate* isolate) {
    return v8::Local<v8::Object>::New(isolate, persistent());
  }


  inline v8::Persistent<v8::Object>& persistent() {
    return handle_;
  }


 protected:
  inline void Wrap(v8::Local<v8::Object> handle) {
    assert(persistent().IsEmpty());
    assert(handle->InternalFieldCount() > 0);
    handle->SetAlignedPointerInInternalField(0, this);
    persistent().Reset(v8::Isolate::GetCurrent(), handle);
    MakeWeak();
  }


  inline void MakeWeak() {
    persistent().SetWeak(this, WeakCallback, v8::WeakCallbackType::kParameter);
  }

  /* Ref() marks the object as being attached to an event loop.
   * Refed objects will not be garbage collected, even if
   * all references are lost.
   */
  virtual void Ref() {
    assert(!persistent().IsEmpty());
    persistent().ClearWeak();
    refs_++;
  }

  /* Unref() marks an object as detached from the event loop.  This is its
   * default state.  When an object with a "weak" reference changes from
   * attached to detached state it will be freed. Be careful not to access
   * the object after making this call as it might be gone!
   * (A "weak reference" means an object that only has a
   * persistent handle.)
   *
   * DO NOT CALL THIS FROM DESTRUCTOR
   */
  virtual void Unref() {
    assert(!persistent().IsEmpty());
    assert(!persistent().IsWeak());
    assert(refs_ > 0);
    if (--refs_ == 0)
      MakeWeak();
  }

  int refs_;  // ro

 private:
  static void WeakCallback(
      const v8::WeakCallbackInfo<ObjectWrap>& data) {
    ObjectWrap* wrap = data.GetParameter();
    assert(wrap->refs_ == 0);
    wrap->handle_.Reset();
    delete wrap;
  }

  v8::Persistent<v8::Object> handle_;
};

}  // namespace node

#endif  // SRC_NODE_OBJECT_WRAP_H_