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::WeakCallback(
  26     const v8::WeakCallbackData<v8::Object, WrappableBase>& data) {
  27   WrappableBase* wrappable = data.GetParameter();
  28   wrappable->wrapper_.Reset();
  29   delete wrappable;
  30 }
  31
  32 v8::Handle<v8::Object> WrappableBase::GetWrapperImpl(v8::Isolate* isolate,
  33                                                      WrapperInfo* info) {
  34   if (!wrapper_.IsEmpty()) {
  35     return v8::Local<v8::Object>::New(isolate, wrapper_);
  36   }
  37
  38   PerIsolateData* data = PerIsolateData::From(isolate);
  39   v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(info);
  40   if (templ.IsEmpty()) {
  41     templ = GetObjectTemplateBuilder(isolate).Build();
  42     CHECK(!templ.IsEmpty());
  43     data->SetObjectTemplate(info, templ);
  44   }
  45   CHECK_EQ(kNumberOfInternalFields, templ->InternalFieldCount());
  46   v8::Handle<v8::Object> wrapper = templ->NewInstance();
  47   // |wrapper| may be empty in some extreme cases, e.g., when
  48   // Object.prototype.constructor is overwritten.
  49   if (wrapper.IsEmpty()) {
  50     // The current wrappable object will be no longer managed by V8. Delete this
  51     // now.
  52     delete this;
  53     return wrapper;
  54   }
  55   wrapper->SetAlignedPointerInInternalField(kWrapperInfoIndex, info);
  56   wrapper->SetAlignedPointerInInternalField(kEncodedValueIndex, this);
  57   wrapper_.Reset(isolate, wrapper);
  58   wrapper_.SetWeak(this, WeakCallback);
  59   return wrapper;
  60 }
  61
  62 namespace internal {
  63
  64 void* FromV8Impl(v8::Isolate* isolate, v8::Handle<v8::Value> val,
  65                  WrapperInfo* wrapper_info) {
  66   if (!val->IsObject())
  67     return NULL;
  68   v8::Handle<v8::Object> obj = v8::Handle<v8::Object>::Cast(val);
  69   WrapperInfo* info = WrapperInfo::From(obj);
  70
  71   // If this fails, the object is not managed by Gin. It is either a normal JS
  72   // object that's not wrapping any external C++ object, or it is wrapping some
  73   // C++ object, but that object isn't managed by Gin (maybe Blink).
  74   if (!info)
  75     return NULL;
  76
  77   // If this fails, the object is managed by Gin, but it's not wrapping an
  78   // instance of the C++ class associated with wrapper_info.
  79   if (info != wrapper_info)
  80     return NULL;
  81
  82   return obj->GetAlignedPointerFromInternalField(kEncodedValueIndex);
  83 }
  84
  85 }  // namespace internal
  86
  87 }  // namespace gin