summaryrefslogtreecommitdiffstats
path: root/gin/wrappable.cc
blob: 0fac4e0b0b8381b24459f7f04183fec3ab28f2e2 (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
// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gin/wrappable.h"

#include "base/logging.h"
#include "gin/object_template_builder.h"
#include "gin/per_isolate_data.h"

namespace gin {

WrappableBase::WrappableBase() {
}

WrappableBase::~WrappableBase() {
  wrapper_.Reset();
}

ObjectTemplateBuilder WrappableBase::GetObjectTemplateBuilder(
    v8::Isolate* isolate) {
  return ObjectTemplateBuilder(isolate);
}

void WrappableBase::FirstWeakCallback(
    const v8::WeakCallbackInfo<WrappableBase>& data) {
  WrappableBase* wrappable = data.GetParameter();
  wrappable->wrapper_.Reset();
  data.SetSecondPassCallback(SecondWeakCallback);
}

void WrappableBase::SecondWeakCallback(
    const v8::WeakCallbackInfo<WrappableBase>& data) {
  WrappableBase* wrappable = data.GetParameter();
  delete wrappable;
}

v8::Local<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
                                                    WrapperInfo* info) {
  if (!wrapper_.IsEmpty()) {
    return v8::Local<v8::Object>::New(isolate, wrapper_);
  }

  PerIsolateData* data = PerIsolateData::From(isolate);
  v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(info);
  if (templ.IsEmpty()) {
    templ = GetObjectTemplateBuilder(isolate).Build();
    CHECK(!templ.IsEmpty());
    data->SetObjectTemplate(info, templ);
  }
  CHECK_EQ(kNumberOfInternalFields, templ->InternalFieldCount());
  v8::Local<v8::Object> wrapper;
  // |wrapper| may be empty in some extreme cases, e.g., when
  // Object.prototype.constructor is overwritten.
  if (!templ->NewInstance(isolate->GetCurrentContext()).ToLocal(&wrapper)) {
    // The current wrappable object will be no longer managed by V8. Delete this
    // now.
    delete this;
    return wrapper;
  }
  wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
  wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
  wrapper_.Reset(isolate, wrapper);
  wrapper_.SetWeak(this, FirstWeakCallback, v8::WeakCallbackType::kParameter);
  return wrapper;
}

namespace internal {

void* FromV8Impl(v8::Isolate* isolate, v8::Local<v8::Value> val,
                 WrapperInfo* wrapper_info) {
  if (!val->IsObject())
    return NULL;
  v8::Local<v8::Object> obj = v8::Local<v8::Object>::Cast(val);
  WrapperInfo* info = WrapperInfo::From(obj);

  // If this fails, the object is not managed by Gin. It is either a normal JS
  // object that's not wrapping any external C++ object, or it is wrapping some
  // C++ object, but that object isn't managed by Gin (maybe Blink).
  if (!info)
    return NULL;

  // If this fails, the object is managed by Gin, but it's not wrapping an
  // instance of the C++ class associated with wrapper_info.
  if (info != wrapper_info)
    return NULL;

  return obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
}

}  // namespace internal

}  // namespace gin