gin/wrappable.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "gin/wrappable.h"
   6
   7 #include "base/logging.h"
   8 #include "gin/object_template_builder.h"
   9 #include "gin/per_isolate_data.h"
  10
  11 namespace gin {
  12
  13 WrappableBase::WrappableBase() {
  14 }
  15
  16 WrappableBase::~WrappableBase() {
  17   wrapper_.Reset();
  18 }
  19
  20 ObjectTemplateBuilder WrappableBase::GetObjectTemplateBuilder(
  21     v8::Isolate* isolate) {
  22   return ObjectTemplateBuilder(isolate);
  23 }
  24
  25 void WrappableBase::FirstWeakCallback(
  26     const v8::WeakCallbackInfo<WrappableBase>& data) {
  27   WrappableBase* wrappable = data.GetParameter();
  28   wrappable->wrapper_.Reset();
  29   data.SetSecondPassCallback(SecondWeakCallback);
  30 }
  31
  32 void WrappableBase::SecondWeakCallback(
  33     const v8::WeakCallbackInfo<WrappableBase>& data) {
  34   WrappableBase* wrappable = data.GetParameter();
  35   delete wrappable;
  36 }
  37
  38 v8::Local<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
  39                                                     WrapperInfo* info) {
  40   if (!wrapper_.IsEmpty()) {
  41     return v8::Local<v8::Object>::New(isolate, wrapper_);
  42   }
  43
  44   PerIsolateData* data = PerIsolateData::From(isolate);
  45   v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(info);
  46   if (templ.IsEmpty()) {
  47     templ = GetObjectTemplateBuilder(isolate).Build();
  48     CHECK(!templ.IsEmpty());
  49     data->SetObjectTemplate(info, templ);
  50   }
  51   CHECK_EQ(kNumberOfInternalFields, templ->InternalFieldCount());
  52   v8::Local<v8::Object> wrapper;
  53   // |wrapper| may be empty in some extreme cases, e.g., when
  54   // Object.prototype.constructor is overwritten.
  55   if (!templ->NewInstance(isolate->GetCurrentContext()).ToLocal(&wrapper)) {
  56     // The current wrappable object will be no longer managed by V8. Delete this
  57     // now.
  58     delete this;
  59     return wrapper;
  60   }
  61   wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
  62   wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
  63   wrapper_.Reset(isolate, wrapper);
  64   wrapper_.SetWeak(this, FirstWeakCallback, v8::WeakCallbackType::kParameter);
  65   return wrapper;
  66 }
  67
  68 namespace internal {
  69
  70 void* FromV8Impl(v8::Isolate* isolate, v8::Local<v8::Value> val,
  71                  WrapperInfo* wrapper_info) {
  72   if (!val->IsObject())
  73     return NULL;
  74   v8::Local<v8::Object> obj = v8::Local<v8::Object>::Cast(val);
  75   WrapperInfo* info = WrapperInfo::From(obj);
  76
  77   // If this fails, the object is not managed by Gin. It is either a normal JS
  78   // object that's not wrapping any external C++ object, or it is wrapping some
  79   // C++ object, but that object isn't managed by Gin (maybe Blink).
  80   if (!info)
  81     return NULL;
  82
  83   // If this fails, the object is managed by Gin, but it's not wrapping an
  84   // instance of the C++ class associated with wrapper_info.
  85   if (info != wrapper_info)
  86     return NULL;
  87
  88   return obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
  89 }
  90
  91 }  // namespace internal
  92
  93 }  // namespace gin