SAMPLE: Copy files

gin/foo.cc

+foo.cc
+// 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;
+  }
+
+  int indices[] = {kWrapperInfoIndex, kEncodedValueIndex};
+  void* values[] = {info, this};
+  wrapper->SetAlignedPointerInInternalFields(2, indices, values);
+  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