Implement custom element construction and some 'define' checks

third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLElementCustom.cpp

+// Copyright 2016 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 "bindings/core/v8/V8HTMLElement.h"
+
+#include "bindings/core/v8/DOMWrapperWorld.h"
+#include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8BindingMacros.h"
+#include "bindings/core/v8/V8ThrowException.h"
+#include "core/dom/Document.h"
+#include "core/dom/custom/CustomElementDefinition.h"
+#include "core/dom/custom/CustomElementsRegistry.h"
+#include "core/frame/LocalDOMWindow.h"
+#include "platform/RuntimeEnabledFeatures.h"
+
+namespace blink {
+
+void V8HTMLElement::constructorCustom(
+    const v8::FunctionCallbackInfo<v8::Value>& info)
+{
+    DCHECK(info.IsConstructCall());
+
+    v8::Isolate* isolate = info.GetIsolate();
+    ScriptState* scriptState = ScriptState::current(isolate);
+
+    if (!RuntimeEnabledFeatures::customElementsV1Enabled()
+        || !scriptState->world().isMainWorld()) {
+        V8ThrowException::throwTypeError(info.GetIsolate(), "Illegal constructor");
+        return;
+    }
+
+    LocalDOMWindow* window = scriptState->domWindow();
+    CustomElementDefinition* def =
+        window->customElements(scriptState)->definitionForConstructor(
+            scriptState,
+            info.NewTarget());
+    if (!def) {
+        V8ThrowException::throwTypeError(isolate, "Illegal constructor");
+        return;
+    }
+
+    // TODO(dominicc): Implement cases where the definition's
+    // construction stack is not empty when parser-creation is
+    // implemented.
+    ExceptionState exceptionState(
+        ExceptionState::ConstructionContext,
+        "HTMLElement",
+        info.Holder(),
+        isolate);
+    Element* element = window->document()->createElement(
+        def->localName(),
+        AtomicString(),
+        exceptionState);
+    if (exceptionState.throwIfNeeded())
+        return;
+    v8SetReturnValue(info, element);
+    v8::Local<v8::Object> wrapper =

[yosin_UTC9, 2016/05/12 01:30:34]

Just curiosity, is v8SetReturnValue(info, <C++ pointer>);
info.GetReturnValue().Get() a common pattern for converting <C++ pointer> to v8
wrapper in Blink?

[bashi, 2016/05/12 02:03:25]

No. Try toV8() if you need to do. Basically the binding layer should care of C++
<-> JS conversion though.

[haraken, 2016/05/12 02:13:58]

Please do the same thing as the generated code is doing.

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

toV8() won't work here because what you want to do here is not to create a new
wrapper but to decorate a given V8 object with wrapper functionalities (i.e.,
call associateWithWrapper).

[bashi, 2016/05/12 02:15:18]

I thought he asked a common pattten, not this specific case :)

+        info.GetReturnValue().Get().As<v8::Object>();
+    if (wrapper.IsEmpty())
+        return;
+
+    if (!v8CallBoolean(
+        wrapper->SetPrototype(scriptState->context(), def->prototype(isolate))))

[yosin_UTC9, 2016/05/12 01:30:34]

Is info.GetNewTarget().GetProperty("prototype") != def->prototype(isolate)?

+        return;
+}
+
+} // namespace blink