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/per_isolate_data.h"
   9
  10 namespace gin {
  11
  12 Wrappable::Wrappable() {
  13 }
  14
  15 Wrappable::~Wrappable() {
  16   wrapper_.Reset();
  17 }
  18
  19 v8::Handle<v8::Object> Wrappable::GetWrapper(v8::Isolate* isolate) {
  20   v8::Handle<v8::Value> wrapper = ConvertToV8(isolate, this);
  21   DCHECK(wrapper->IsObject());
  22   return v8::Handle<v8::Object>::Cast(wrapper);
  23 }
  24
  25 void Wrappable::WeakCallback(
  26     const v8::WeakCallbackData<v8::Object, Wrappable>& data) {
  27   Wrappable* wrappable = data.GetParameter();
  28   wrappable->wrapper_.Reset();
  29   wrappable->Release();  // Balanced in Wrappable::ConfigureWrapper.
  30 }
  31
  32 v8::Handle<v8::Object> Wrappable::CreateWrapper(v8::Isolate* isolate) {
  33   WrapperInfo* info = GetWrapperInfo();
  34   PerIsolateData* data = PerIsolateData::From(isolate);
  35   v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(info);
  36   CHECK(!templ.IsEmpty());  // Don't forget to register an object template.
  37   CHECK(templ->InternalFieldCount() == kNumberOfInternalFields);
  38   v8::Handle<v8::Object> wrapper = templ->NewInstance();
  39   wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
  40   wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
  41   wrapper_.Reset(isolate, wrapper);
  42   AddRef();  // Balanced in Wrappable::WeakCallback.
  43   wrapper_.SetWeak(this, WeakCallback);
  44   return wrapper;
  45 }
  46
  47 v8::Handle<v8::Value> Converter<Wrappable*>::ToV8(v8::Isolate* isolate,
  48                                                   Wrappable* val) {
  49   if (val->wrapper_.IsEmpty())
  50     return val->CreateWrapper(isolate);
  51   return v8::Local<v8::Object>::New(isolate, val->wrapper_);
  52 }
  53
  54 bool Converter<Wrappable*>::FromV8(v8::Isolate* isolate,
  55                                    v8::Handle<v8::Value> val, Wrappable** out) {
  56   if (!val->IsObject())
  57     return false;
  58   v8::Handle<v8::Object> obj = v8::Handle<v8::Object>::Cast(val);
  59   WrapperInfo* info = WrapperInfo::From(obj);
  60   if (!info)
  61     return false;
  62   void* pointer = obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
  63   Wrappable* wrappable = static_cast<Wrappable*>(pointer);
  64   CHECK(wrappable->GetWrapperInfo() == info);  // Security check for cast above.
  65   *out = wrappable;
  66   return true;
  67 }
  68
  69 }  // namespace gin