Source/bindings/v8/CustomElementConstructorBuilder.cpp

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#include "config.h"
#include "bindings/v8/CustomElementConstructorBuilder.h"

#include "HTMLNames.h"
#include "SVGNames.h"
#include "V8Document.h"
#include "V8HTMLElementWrapperFactory.h"
#include "V8SVGElementWrapperFactory.h"
#include "bindings/v8/CustomElementBinding.h"
#include "bindings/v8/DOMWrapperWorld.h"
#include "bindings/v8/Dictionary.h"
#include "bindings/v8/ExceptionState.h"
#include "bindings/v8/UnsafePersistent.h"
#include "bindings/v8/V8Binding.h"
#include "bindings/v8/V8HiddenPropertyName.h"
#include "bindings/v8/V8PerContextData.h"
#include "core/dom/CustomElementCallbackDispatcher.h"
#include "core/dom/CustomElementDefinition.h"
#include "core/dom/CustomElementDescriptor.h"
#include "core/dom/CustomElementException.h"
#include "core/dom/Document.h"
#include "wtf/Assertions.h"

namespace WebCore {

static void constructCustomElement(const v8::FunctionCallbackInfo<v8::Value>&);

CustomElementConstructorBuilder::CustomElementConstructorBuilder(ScriptState* state, const Dictionary* options)
    : m_context(state->context())
    , m_options(options)
    , m_wrapperType(0)
{
    ASSERT(m_context == v8::Isolate::GetCurrent()->GetCurrentContext());
}

bool CustomElementConstructorBuilder::isFeatureAllowed() const
{
    // Check that we are in the main world
    return !DOMWrapperWorld::isolatedWorld(m_context);
}

bool CustomElementConstructorBuilder::validateOptions(const AtomicString& type, ExceptionState& es)
{
    ASSERT(m_prototype.IsEmpty());

    ScriptValue prototypeScriptValue;
    if (!m_options->get("prototype", prototypeScriptValue)) {
        // FIXME: Implement the default value handling.
        // Currently default value of the "prototype" parameter, which
        // is HTMLSpanElement.prototype, has an ambiguity about its
        // behavior. The spec should be fixed before WebKit implements
        // it. https://www.w3.org/Bugs/Public/show_bug.cgi?id=20801
        CustomElementException::throwException(CustomElementException::NotYetImplemented, type, es);
        return false;
    }

    v8::Handle<v8::Value> prototypeValue = prototypeScriptValue.v8Value();
    if (prototypeValue.IsEmpty() || !prototypeValue->IsObject()) {
        CustomElementException::throwException(CustomElementException::PrototypeNotAnObject, type, es);
        return false;
    }
    m_prototype = prototypeValue.As<v8::Object>();

    V8PerContextData* perContextData;
    if (!(perContextData = V8PerContextData::from(m_context))) {
        // FIXME: This should generate an InvalidContext exception at a later point.
        CustomElementException::throwException(CustomElementException::ContextDestroyedCheckingPrototype, type, es);
        return false;
    }

    if (hasValidPrototypeChainFor(perContextData, &V8HTMLElement::info)) {
        m_namespaceURI = HTMLNames::xhtmlNamespaceURI;
        return true;
    }

    if (hasValidPrototypeChainFor(perContextData, &V8SVGElement::info)) {
        m_namespaceURI = SVGNames::svgNamespaceURI;
        return true;
    }

    if (hasValidPrototypeChainFor(perContextData, &V8Element::info)) {
        m_namespaceURI = nullAtom;
        // This generates a different DOM exception, so we feign success for now.
        return true;
    }

    CustomElementException::throwException(CustomElementException::PrototypeDoesNotExtendHTMLElementSVGElementPrototype, type, es);
    return false;
}

bool CustomElementConstructorBuilder::findTagName(const AtomicString& customElementType, QualifiedName& tagName)
{
    ASSERT(!m_prototype.IsEmpty());

    m_wrapperType = findWrapperType(m_prototype);
    if (!m_wrapperType) {
        // Invalid prototype.
        return false;
    }

    if (const QualifiedName* htmlName = findHTMLTagNameOfV8Type(m_wrapperType)) {
        ASSERT(htmlName->namespaceURI() == m_namespaceURI);
        tagName = *htmlName;
        return true;
    }

    if (const QualifiedName* svgName = findSVGTagNameOfV8Type(m_wrapperType)) {
        ASSERT(svgName->namespaceURI() == m_namespaceURI);
        tagName = *svgName;
        return true;
    }

    if (m_namespaceURI != nullAtom) {
        // Use the custom element type as the tag's local name.
        tagName = QualifiedName(nullAtom, customElementType, m_namespaceURI);
        return true;
    }

    return false;
}

PassRefPtr<CustomElementLifecycleCallbacks> CustomElementConstructorBuilder::createCallbacks()
{
    ASSERT(!m_prototype.IsEmpty());

    RefPtr<ScriptExecutionContext> scriptExecutionContext(toScriptExecutionContext(m_context));

    v8::TryCatch exceptionCatcher;
    exceptionCatcher.SetVerbose(true);

    v8::Isolate* isolate = v8::Isolate::GetCurrent();
    v8::Handle<v8::Function> created = retrieveCallback(isolate, "createdCallback");
    v8::Handle<v8::Function> enteredDocument = retrieveCallback(isolate, "enteredDocumentCallback");
    v8::Handle<v8::Function> leftDocument = retrieveCallback(isolate, "leftDocumentCallback");
    v8::Handle<v8::Function> attributeChanged = retrieveCallback(isolate, "attributeChangedCallback");

    m_callbacks = V8CustomElementLifecycleCallbacks::create(scriptExecutionContext.get(), m_prototype, created, enteredDocument, leftDocument, attributeChanged);
    return m_callbacks.get();
}

v8::Handle<v8::Function> CustomElementConstructorBuilder::retrieveCallback(v8::Isolate* isolate, const char* name)
{
    v8::Handle<v8::Value> value = m_prototype->Get(v8String(name, isolate));
    if (value.IsEmpty() || !value->IsFunction())
        return v8::Handle<v8::Function>();
    return value.As<v8::Function>();
}

bool CustomElementConstructorBuilder::createConstructor(Document* document, CustomElementDefinition* definition, ExceptionState& es)
{
    ASSERT(!m_prototype.IsEmpty());
    ASSERT(m_constructor.IsEmpty());
    ASSERT(document);

    v8::Isolate* isolate = m_context->GetIsolate();

    if (!prototypeIsValid(definition->descriptor().type(), es))
        return false;

    v8::Local<v8::FunctionTemplate> constructorTemplate = v8::FunctionTemplate::New();
    constructorTemplate->SetCallHandler(constructCustomElement);
    m_constructor = constructorTemplate->GetFunction();
    if (m_constructor.IsEmpty()) {
        CustomElementException::throwException(CustomElementException::ContextDestroyedRegisteringDefinition, definition->descriptor().type(), es);
        return false;
    }

    const CustomElementDescriptor& descriptor = definition->descriptor();

    v8::Handle<v8::String> v8TagName = v8String(descriptor.localName(), isolate);
    v8::Handle<v8::Value> v8Type;
    if (descriptor.isTypeExtension())
        v8Type = v8String(descriptor.type(), isolate);
    else
        v8Type = v8::Null(isolate);

    m_constructor->SetName(v8Type->IsNull() ? v8TagName : v8Type.As<v8::String>());

    V8HiddenPropertyName::setNamedHiddenReference(m_constructor, "customElementDocument", toV8(document, m_context->Global(), isolate));
    V8HiddenPropertyName::setNamedHiddenReference(m_constructor, "customElementNamespaceURI", v8String(descriptor.namespaceURI(), isolate));
    V8HiddenPropertyName::setNamedHiddenReference(m_constructor, "customElementTagName", v8TagName);
    V8HiddenPropertyName::setNamedHiddenReference(m_constructor, "customElementType", v8Type);

    v8::Handle<v8::String> prototypeKey = v8String("prototype", isolate);
    ASSERT(m_constructor->HasOwnProperty(prototypeKey));
    // This sets the property *value*; calling Set is safe because
    // "prototype" is a non-configurable data property so there can be
    // no side effects.
    m_constructor->Set(prototypeKey, m_prototype);
    // This *configures* the property. ForceSet of a function's
    // "prototype" does not affect the value, but can reconfigure the
    // property.
    m_constructor->ForceSet(prototypeKey, m_prototype, v8::PropertyAttribute(v8::ReadOnly | v8::DontEnum | v8::DontDelete));

    V8HiddenPropertyName::setNamedHiddenReference(m_prototype, "customElementIsInterfacePrototypeObject", v8::True());
    m_prototype->ForceSet(v8String("constructor", isolate), m_constructor, v8::DontEnum);

    return true;
}

bool CustomElementConstructorBuilder::prototypeIsValid(const AtomicString& type, ExceptionState& es) const
{
    if (m_prototype->InternalFieldCount() || !m_prototype->GetHiddenValue(V8HiddenPropertyName::customElementIsInterfacePrototypeObject()).IsEmpty()) {
        CustomElementException::throwException(CustomElementException::PrototypeInUse, type, es);
        return false;
    }

    if (m_prototype->GetPropertyAttributes(v8String("constructor", m_context->GetIsolate())) & v8::DontDelete) {
        CustomElementException::throwException(CustomElementException::ConstructorPropertyNotConfigurable, type, es);
        return false;
    }

    return true;
}

bool CustomElementConstructorBuilder::didRegisterDefinition(CustomElementDefinition* definition) const
{
    ASSERT(!m_constructor.IsEmpty());

    return m_callbacks->setBinding(definition, CustomElementBinding::create(m_context->GetIsolate(), m_prototype, m_wrapperType));
}

ScriptValue CustomElementConstructorBuilder::bindingsReturnValue() const
{
    return ScriptValue(m_constructor);
}

WrapperTypeInfo* CustomElementConstructorBuilder::findWrapperType(v8::Handle<v8::Value> chain)
{
    while (!chain.IsEmpty() && chain->IsObject()) {
        v8::Handle<v8::Object> chainObject = chain.As<v8::Object>();
        // Only prototype objects of native-backed types have the extra internal field storing WrapperTypeInfo.
        if (v8PrototypeInternalFieldcount == chainObject->InternalFieldCount()) {
            WrapperTypeInfo* wrapperType = reinterpret_cast<WrapperTypeInfo*>(chainObject->GetAlignedPointerFromInternalField(v8PrototypeTypeIndex));
            ASSERT(wrapperType);
            return wrapperType;
        }
        chain = chainObject->GetPrototype();
    }

    return 0;
}

bool CustomElementConstructorBuilder::hasValidPrototypeChainFor(V8PerContextData* perContextData, WrapperTypeInfo* typeInfo) const
{
    v8::Handle<v8::Object> elementConstructor = perContextData->constructorForType(typeInfo);
    v8::Handle<v8::Object> elementPrototype = elementConstructor->Get(v8String("prototype", m_context->GetIsolate())).As<v8::Object>();
    if (elementPrototype.IsEmpty())
        return false;

    v8::Handle<v8::Value> chain = m_prototype;
    while (!chain.IsEmpty() && chain->IsObject()) {
        if (chain == elementPrototype)
            return true;
        chain = chain.As<v8::Object>()->GetPrototype();
    }

    return false;
}

static void constructCustomElement(const v8::FunctionCallbackInfo<v8::Value>& args)
{
    v8::Isolate* isolate = args.GetIsolate();

    if (!args.IsConstructCall()) {
        throwTypeError("DOM object constructor cannot be called as a function.", isolate);
        return;
    }

    if (args.Length() > 0) {
        throwTypeError(isolate);
        return;
    }

    Document* document = V8Document::toNative(args.Callee()->GetHiddenValue(V8HiddenPropertyName::customElementDocument()).As<v8::Object>());
    V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, namespaceURI, args.Callee()->GetHiddenValue(V8HiddenPropertyName::customElementNamespaceURI()));
    V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, tagName, args.Callee()->GetHiddenValue(V8HiddenPropertyName::customElementTagName()));
    v8::Handle<v8::Value> maybeType = args.Callee()->GetHiddenValue(V8HiddenPropertyName::customElementType());
    V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, type, maybeType);

    ExceptionState es(args.GetIsolate());
    CustomElementCallbackDispatcher::CallbackDeliveryScope deliveryScope;
    RefPtr<Element> element = document->createElementNS(namespaceURI, tagName, maybeType->IsNull() ? nullAtom : type, es);
    if (es.throwIfNeeded())
        return;
    v8SetReturnValueFast(args, element.release(), document);
}

} // namespace WebCore