Implement custom element construction and some 'define' checks

third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.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 "core/dom/custom/CustomElementsRegistry.h"
 
+// TODO(dominicc): Stop including Document.h when
+// v0CustomElementIsDefined has been removed.
+#include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptState.h"
+#include "bindings/core/v8/ScriptValue.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8BindingMacros.h"
+#include "bindings/core/v8/V8HiddenValue.h"
+#include "core/dom/Document.h"
 #include "core/dom/ElementRegistrationOptions.h"
+#include "core/dom/ExceptionCode.h"
+#include "core/dom/custom/CustomElement.h"
+#include "core/dom/custom/CustomElementDefinition.h"
+#include "core/dom/custom/V0CustomElementRegistrationContext.h"
+#include "core/dom/custom/V0CustomElementRegistry.h"
 
 namespace blink {
 
-CustomElementsRegistry::CustomElementsRegistry()
+CustomElementsRegistry* CustomElementsRegistry::create(
+    ScriptState* scriptState,
+    V0CustomElementRegistrationContext* v0)
+{
+    DCHECK(scriptState->world().isMainWorld());
+    CustomElementsRegistry* registry = new CustomElementsRegistry(v0);
+    if (v0)
+        v0->setV1(registry);
+
+    v8::Isolate* isolate = scriptState->isolate();
+    v8::Local<v8::Object> wrapper =
+        toV8(registry, scriptState->context()->Global(), isolate)
+        .As<v8::Object>();

[haraken, 2016/05/12 08:19:41]

Add DCHECK(!wrapper.IsEmpty()).

+    v8::Local<v8::String> name =
+        V8HiddenValue::customElementsRegistryMap(isolate);
+    v8::Local<v8::Map> map = v8::Map::New(isolate);
+    DCHECK(V8HiddenValue::setHiddenValue(scriptState, wrapper, name, map));
+
+    return registry;
+}
+
+CustomElementsRegistry::CustomElementsRegistry(
+    const V0CustomElementRegistrationContext* v0)
+    : m_v0(v0)
 {
 }
 
+// http://w3c.github.io/webcomponents/spec/custom/#dfn-element-definition
 void CustomElementsRegistry::define(ScriptState* scriptState,
-    const AtomicString& name, const ScriptValue& constructor,
+    const AtomicString& name, const ScriptValue& constructorScriptValue,
     const ElementRegistrationOptions& options, ExceptionState& exceptionState)
 {
-    // TODO(kojii): Element definition process not implemented yet.
-    // http://w3c.github.io/webcomponents/spec/custom/#dfn-element-definition
+    DCHECK(scriptState->world().isMainWorld());
+    v8::Isolate* isolate = scriptState->isolate();
+    v8::Local<v8::Context> context = scriptState->context();
+
+    // TODO(dominicc): Make this check for constructors and not just
+    // functions when
+    // https://bugs.chromium.org/p/v8/issues/detail?id=4993 is fixed.
+    v8::Local<v8::Value> constructorValue = constructorScriptValue.v8Value();
+    if (!constructorValue->IsFunction()) {
+        exceptionState.throwTypeError(
+            "constructor argument is not a constructor");
+        return;
+    }
+    v8::Local<v8::Object> constructor = constructorValue.As<v8::Object>();
+
+    // Raise an exception if the name is not valid.
+    if (!CustomElement::isValidName(name)) {
+        exceptionState.throwDOMException(

[haraken, 2016/05/12 08:19:41]

Do you want to throw a DOM exception, not JS's syntax error?

+            SyntaxError,
+            "\"" + name + "\" is not a valid custom element name");
+        return;
+    }
+
+    // Raise an exception if the name is already in use.
+    if (nameIsDefined(name) || v0NameIsDefined(name)) {
+        exceptionState.throwDOMException(
+            NotSupportedError,
+            "this name has already been used with this registry");
+        return;
+    }
+
+    // Raise an exception if the constructor is already registered.
+    if (definitionForConstructor(scriptState, constructor)) {
+        exceptionState.throwDOMException(
+            NotSupportedError,
+            "this constructor has already been used with this registry");
+        return;
+    }
+
+    // TODO(dominicc): Implement steps:
+    // 5: localName
+    // 6-7: extends processing
+    // 8-9: observed attributes caching
+
+    v8::TryCatch tryCatch(isolate);
+    v8::Local<v8::String> prototypeString =
+        v8AtomicString(isolate, "prototype");
+    v8::Local<v8::Value> prototypeValue;
+    if (!v8Call(
+        constructor->Get(context, prototypeString), prototypeValue)) {
+        DCHECK(tryCatch.HasCaught());
+        tryCatch.ReThrow();
+        return;
+    }
+    if (!prototypeValue->IsObject()) {
+        DCHECK(!tryCatch.HasCaught());
+        exceptionState.throwTypeError("constructor prototype is not an object");
+        return;
+    }
+    v8::Local<v8::Object> prototype = prototypeValue.As<v8::Object>();
+
+    // TODO(dominicc): Implement steps:
+    // 12-13: connected callback
+    // 14-15: disconnected callback
+    // 16-17: attribute changed callback
+
+    Id id = m_definitions.size();
+    v8::Local<v8::Value> idValue = v8::Integer::NewFromUnsigned(isolate, id);
+    m_definitions.append(new CustomElementDefinition(this, id, name));
+    v8::Local<v8::Map> map = idMap(scriptState);
+    v8CallOrCrash(map->Set(context, constructor, idValue));
+    v8CallOrCrash(map->Set(context, idValue, prototype));

[haraken, 2016/05/12 08:19:41]

Hmm, would you help me understand why you cannot simply add a hidden reference
from constructor to idValue? I want to understand why you need a v8::Map.

+    m_names.add(name);
+
+    // TODO(dominicc): Implement steps:
+    // 20: when-defined promise processing
+    DCHECK(!tryCatch.HasCaught() || tryCatch.HasTerminated());
+}
+
+CustomElementDefinition* CustomElementsRegistry::definitionForConstructor(
+    ScriptState* scriptState,
+    v8::Local<v8::Value> constructor)
+{
+    Id id;
+    if (!idForConstructor(scriptState, constructor, id))
+        return nullptr;
+    return m_definitions[id];
+}
+
+v8::Local<v8::Object> CustomElementsRegistry::prototype(
+    ScriptState* scriptState,
+    const CustomElementDefinition& def)
+{
+    v8::Local<v8::Value> idValue =
+        v8::Integer::NewFromUnsigned(scriptState->isolate(), def.id());
+    return v8CallOrCrash(
+        idMap(scriptState)->Get(scriptState->context(), idValue))
+        .As<v8::Object>();
+}
+
+bool CustomElementsRegistry::nameIsDefined(const AtomicString& name) const
+{
+    return m_names.contains(name);
+}
+
+v8::Local<v8::Map> CustomElementsRegistry::idMap(ScriptState* scriptState)
+{
+    v8::Local<v8::String> name = V8HiddenValue::customElementsRegistryMap(
+        scriptState->isolate());
+    return V8HiddenValue::getHiddenValueFromMainWorldWrapper(

[haraken, 2016/05/12 08:19:41]

getHiddenValueFromMainWorldWrapper => getHiddenValue

(getHiddenValueFromMainWorldWrapper is a method only for some hacky cases.)

+        scriptState,
+        this,
+        name).As<v8::Map>();
+}
+
+bool CustomElementsRegistry::idForConstructor(
+    ScriptState* scriptState,
+    v8::Local<v8::Value> constructor,
+    Id& id)
+{
+    v8::Local<v8::Value> entry = v8CallOrCrash(
+        idMap(scriptState)->Get(scriptState->context(), constructor));
+    if (!entry->IsUint32())
+        return false;
+    id = v8CallOrCrash(entry->Uint32Value(scriptState->context()));
+    return true;
+}
+
+bool CustomElementsRegistry::v0NameIsDefined(const AtomicString& name)
+{
+    return m_v0.get() && m_v0->nameIsDefined(name);
 }
 
 DEFINE_TRACE(CustomElementsRegistry)
 {
+    visitor->trace(m_definitions);
+    visitor->trace(m_v0);
 }
 
 } // namespace blink