C++ JSValue::isUndefined方法代码示例

JSValue JSInspectorFrontendHost::showContextMenu(ExecState* execState, const ArgList& args)
{
    if (args.size() < 2)
        return jsUndefined();

    Event* event = toEvent(args.at(0));

    JSArray* array = asArray(args.at(1));
    Vector<ContextMenuItem*> items;

    for (size_t i = 0; i < array->length(); ++i) {
        JSObject* item = asObject(array->getIndex(i));
        JSValue label = item->get(execState, Identifier(execState, "label"));
        JSValue id = item->get(execState, Identifier(execState, "id"));
        if (label.isUndefined() || id.isUndefined())
            items.append(new ContextMenuItem(SeparatorType, ContextMenuItemTagNoAction, String()));
        else {
            ContextMenuAction typedId = static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + id.toInt32(execState));
            items.append(new ContextMenuItem(ActionType, typedId, label.toString(execState)));
        }
    }

    impl()->showContextMenu(event, items);
    return jsUndefined();
}

static void populateContextMenuItems(ExecState* exec, JSArray* array, ContextMenu& menu)
{
    for (size_t i = 0; i < array->length(); ++i) {
        JSObject* item = asObject(array->getIndex(exec, i));
        JSValue label = item->get(exec, Identifier::fromString(exec, "label"));
        JSValue type = item->get(exec, Identifier::fromString(exec, "type"));
        JSValue id = item->get(exec, Identifier::fromString(exec, "id"));
        JSValue enabled = item->get(exec, Identifier::fromString(exec, "enabled"));
        JSValue checked = item->get(exec, Identifier::fromString(exec, "checked"));
        JSValue subItems = item->get(exec, Identifier::fromString(exec, "subItems"));
        if (!type.isString())
            continue;

        String typeString = type.toWTFString(exec);
        if (typeString == "separator") {
            ContextMenuItem item(SeparatorType, ContextMenuItemTagNoAction, String());
            menu.appendItem(item);
        } else if (typeString == "subMenu" && subItems.inherits(JSArray::info())) {
            ContextMenu subMenu;
            JSArray* subItemsArray = asArray(subItems);
            populateContextMenuItems(exec, subItemsArray, subMenu);
            ContextMenuItem item(SubmenuType, ContextMenuItemTagNoAction, label.toWTFString(exec), &subMenu);
            menu.appendItem(item);
        } else {
            ContextMenuAction typedId = static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + id.toInt32(exec));
            ContextMenuItem menuItem((typeString == "checkbox" ? CheckableActionType : ActionType), typedId, label.toWTFString(exec));
            if (!enabled.isUndefined())
                menuItem.setEnabled(enabled.toBoolean(exec));
            if (!checked.isUndefined())
                menuItem.setChecked(checked.toBoolean(exec));
            menu.appendItem(menuItem);
        }
    }
}

// ECMA-262 5.1, 15.11.4.4
EncodedJSValue JSC_HOST_CALL errorProtoFuncToString(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    // 1. Let O be the this value.
    JSValue thisValue = exec->thisValue();

    // 2. If Type(O) is not Object, throw a TypeError exception.
    if (!thisValue.isObject())
        return throwVMTypeError(exec, scope);
    JSObject* thisObj = asObject(thisValue);

    // Guard against recursion!
    StringRecursionChecker checker(exec, thisObj);
    ASSERT(!scope.exception() || checker.earlyReturnValue());
    if (JSValue earlyReturnValue = checker.earlyReturnValue())
        return JSValue::encode(earlyReturnValue);

    // 3. Let name be the result of calling the [[Get]] internal method of O with argument "name".
    JSValue name = thisObj->get(exec, exec->propertyNames().name);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    // 4. If name is undefined, then let name be "Error"; else let name be ToString(name).
    String nameString;
    if (name.isUndefined())
        nameString = ASCIILiteral("Error");
    else {
        nameString = name.toWTFString(exec);
        RETURN_IF_EXCEPTION(scope, encodedJSValue());
    }

    // 5. Let msg be the result of calling the [[Get]] internal method of O with argument "message".
    JSValue message = thisObj->get(exec, exec->propertyNames().message);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    // (sic)
    // 6. If msg is undefined, then let msg be the empty String; else let msg be ToString(msg).
    // 7. If msg is undefined, then let msg be the empty String; else let msg be ToString(msg).
    String messageString;
    if (message.isUndefined())
        messageString = String();
    else {
        messageString = message.toWTFString(exec);
        RETURN_IF_EXCEPTION(scope, encodedJSValue());
    }

    // 8. If name is the empty String, return msg.
    if (!nameString.length())
        return JSValue::encode(message.isString() ? message : jsString(exec, messageString));

    // 9. If msg is the empty String, return name.
    if (!messageString.length())
        return JSValue::encode(name.isString() ? name : jsString(exec, nameString));

    // 10. Return the result of concatenating name, ":", a single space character, and msg.
    scope.release();
    return JSValue::encode(jsMakeNontrivialString(exec, nameString, ": ", messageString));
}

template<> DictionaryImplName convertDictionary<DictionaryImplName>(ExecState& state, JSValue value)
{
    VM& vm = state.vm();
    auto throwScope = DECLARE_THROW_SCOPE(vm);
    bool isNullOrUndefined = value.isUndefinedOrNull();
    auto* object = isNullOrUndefined ? nullptr : value.getObject();
    if (UNLIKELY(!isNullOrUndefined && !object)) {
        throwTypeError(&state, throwScope);
        return { };
    }
    DictionaryImplName result;
    JSValue boolMemberValue;
    if (isNullOrUndefined)
        boolMemberValue = jsUndefined();
    else {
        boolMemberValue = object->get(&state, Identifier::fromString(&state, "boolMember"));
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    if (!boolMemberValue.isUndefined()) {
        result.boolMember = convert<IDLBoolean>(state, boolMemberValue);
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    JSValue callbackMemberValue;
    if (isNullOrUndefined)
        callbackMemberValue = jsUndefined();
    else {
        callbackMemberValue = object->get(&state, Identifier::fromString(&state, "callbackMember"));
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    if (!callbackMemberValue.isUndefined()) {
        result.callbackMember = convert<IDLCallbackFunction<JSVoidCallback>>(state, callbackMemberValue, *jsCast<JSDOMGlobalObject*>(state.lexicalGlobalObject()));
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    JSValue enumMemberValue;
    if (isNullOrUndefined)
        enumMemberValue = jsUndefined();
    else {
        enumMemberValue = object->get(&state, Identifier::fromString(&state, "enumMember"));
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    if (!enumMemberValue.isUndefined()) {
        result.enumMember = convert<IDLEnumeration<TestStandaloneDictionary::EnumInStandaloneDictionaryFile>>(state, enumMemberValue);
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    JSValue stringMemberValue;
    if (isNullOrUndefined)
        stringMemberValue = jsUndefined();
    else {
        stringMemberValue = object->get(&state, Identifier::fromString(&state, "stringMember"));
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    if (!stringMemberValue.isUndefined()) {
        result.stringMember = convert<IDLDOMString>(state, stringMemberValue);
        RETURN_IF_EXCEPTION(throwScope, { });
    }
    return result;
}

JSValue RegExpConstructor::getBackref(ExecState* exec, unsigned i)
{
    JSArray* array = m_cachedResult.lastResult(exec, this);

    if (i < array->length()) {
        JSValue result = JSValue(array).get(exec, i);
        ASSERT(result.isString() || result.isUndefined());
        if (!result.isUndefined())
            return result;
    }
    return jsEmptyString(exec);
}

JSValue RegExpConstructor::getLastParen(ExecState* exec)
{
    JSArray* array = m_cachedResult.lastResult(exec, this);
    unsigned length = array->length();
    if (length > 1) {
        JSValue result = JSValue(array).get(exec, length - 1);
        ASSERT(result.isString() || result.isUndefined());
        if (!result.isUndefined())
            return result;
    }
    return jsEmptyString(exec);
}

static int compareByStringForQSort(const void *a, const void *b)
{
    ExecState *exec = execForCompareByStringForQSort;
    JSValue *va = *(JSValue **)a;
    JSValue *vb = *(JSValue **)b;
    if (va->isUndefined()) {
        return vb->isUndefined() ? 0 : 1;
    }
    if (vb->isUndefined()) {
        return -1;
    }
    return compare(va->toString(exec), vb->toString(exec));
}

JSObject* constructRegExp(ExecState* exec, JSGlobalObject* globalObject, const ArgList& args,  JSObject* callee, JSValue newTarget)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    JSValue patternArg = args.at(0);
    JSValue flagsArg = args.at(1);

    bool isPatternRegExp = patternArg.inherits(vm, RegExpObject::info());
    bool constructAsRegexp = isRegExp(vm, exec, patternArg);
    RETURN_IF_EXCEPTION(scope, nullptr);

    if (newTarget.isUndefined() && constructAsRegexp && flagsArg.isUndefined()) {
        JSValue constructor = patternArg.get(exec, vm.propertyNames->constructor);
        RETURN_IF_EXCEPTION(scope, nullptr);
        if (callee == constructor) {
            // We know that patternArg is a object otherwise constructAsRegexp would be false.
            return patternArg.getObject();
        }
    }

    if (isPatternRegExp) {
        RegExp* regExp = jsCast<RegExpObject*>(patternArg)->regExp();
        Structure* structure = getRegExpStructure(exec, globalObject, newTarget);
        RETURN_IF_EXCEPTION(scope, nullptr);

        if (!flagsArg.isUndefined()) {
            RegExpFlags flags = toFlags(exec, flagsArg);
            ASSERT(!!scope.exception() == (flags == InvalidFlags));
            if (flags == InvalidFlags)
                return nullptr;
            regExp = RegExp::create(vm, regExp->pattern(), flags);
        }

        return RegExpObject::create(vm, structure, regExp);
    }

    if (constructAsRegexp) {
        JSValue pattern = patternArg.get(exec, vm.propertyNames->source);
        RETURN_IF_EXCEPTION(scope, nullptr);
        if (flagsArg.isUndefined()) {
            flagsArg = patternArg.get(exec, vm.propertyNames->flags);
            RETURN_IF_EXCEPTION(scope, nullptr);
        }
        patternArg = pattern;
    }

    scope.release();
    return regExpCreate(exec, globalObject, newTarget, patternArg, flagsArg);
}

static EncodedJSValue JSC_HOST_CALL callSymbol(ExecState* exec)
{
    JSValue description = exec->argument(0);
    if (description.isUndefined())
        return JSValue::encode(Symbol::create(exec->vm()));
    return JSValue::encode(Symbol::create(exec, description.toString(exec)));
}

static EncodedJSValue JSC_HOST_CALL IntlDateTimeFormatFuncFormatDateTime(ExecState* state)
{
    // 12.3.4 DateTime Format Functions (ECMA-402 2.0)
    // 1. Let dtf be the this value.
    // 2. Assert: Type(dtf) is Object and dtf has an [[initializedDateTimeFormat]] internal slot whose value is true.
    IntlDateTimeFormat* format = jsCast<IntlDateTimeFormat*>(state->thisValue());

    JSValue date = state->argument(0);
    double value;

    // 3. If date is not provided or is undefined, then
    if (date.isUndefined()) {
        // a. Let x be %Date_now%().
        value = JSValue::decode(dateNow(state)).toNumber(state);
    } else {
        // 4. Else
        // a. Let x be ToNumber(date).
        value = date.toNumber(state);
        // b. ReturnIfAbrupt(x).
        if (state->hadException())
            return JSValue::encode(jsUndefined());
    }

    // 5. Return FormatDateTime(dtf, x).
    return JSValue::encode(format->format(*state, value));
}

static inline double normalizeHighWaterMark(ExecState& exec, JSObject& strategy)
{
    JSValue jsHighWaterMark = getPropertyFromObject(exec, strategy, "highWaterMark");

    if (exec.hadException())
        return 0;

    if (jsHighWaterMark.isUndefined())
        return 1;

    double highWaterMark = jsHighWaterMark.toNumber(&exec);

    if (exec.hadException())
        return 0;

    if (std::isnan(highWaterMark)) {
        throwVMError(&exec, createTypeError(&exec, ASCIILiteral("Value is NaN")));
        return 0;
    }
    if (highWaterMark < 0) {
        throwVMError(&exec, createRangeError(&exec, ASCIILiteral("Not a positive value")));
        return 0;
    }
    return highWaterMark;
}

RuntimeType TypeSet::getRuntimeTypeForValue(JSValue v)
{
    RuntimeType ret;
    if (v.isFunction())
        ret = TypeFunction;
    else if (v.isUndefined())
        ret = TypeUndefined;
    else if (v.isNull())
        ret = TypeNull;
    else if (v.isBoolean())
        ret = TypeBoolean;
    else if (v.isMachineInt())
        ret = TypeMachineInt;
    else if (v.isNumber())
        ret = TypeNumber;
    else if (v.isString())
        ret = TypeString;
    else if (v.isPrimitive())
        ret = TypePrimitive;
    else if (v.isObject())
        ret = TypeObject;
    else
        CRASH();

    return ret;
}

bool _NPN_HasMethod(NPP, NPObject* o, NPIdentifier methodName)
{
    if (o->_class == NPScriptObjectClass) {
        JavaScriptObject* obj = reinterpret_cast<JavaScriptObject*>(o); 

        PrivateIdentifier* i = static_cast<PrivateIdentifier*>(methodName);
        if (!i->isString)
            return false;

        RootObject* rootObject = obj->rootObject;
        if (!rootObject || !rootObject->isValid())
            return false;

        ExecState* exec = rootObject->globalObject()->globalExec();
        JSLock lock(false);
        JSValue* func = obj->imp->get(exec, identifierFromNPIdentifier(i->value.string));
        exec->clearException();
        return !func->isUndefined();
    }
    
    if (o->_class->hasMethod)
        return o->_class->hasMethod(o, methodName);
    
    return false;
}

bool injectIDBKeyIntoScriptValue(JSC::ExecState& exec, const IDBKeyData& keyData, JSC::JSValue value, const IDBKeyPath& keyPath)
{
    LOG(IndexedDB, "injectIDBKeyIntoScriptValue");

    ASSERT(keyPath.type() == IndexedDB::KeyPathType::String);

    Vector<String> keyPathElements;
    IDBKeyPathParseError error;
    IDBParseKeyPath(keyPath.string(), keyPathElements, error);
    ASSERT(error == IDBKeyPathParseError::None);

    if (keyPathElements.isEmpty())
        return false;

    JSValue parent = ensureNthValueOnKeyPath(&exec, value, keyPathElements, keyPathElements.size() - 1);
    if (parent.isUndefined())
        return false;

    auto key = keyData.maybeCreateIDBKey();
    if (!key)
        return false;

    if (!set(&exec, parent, keyPathElements.last(), idbKeyToJSValue(&exec, exec.lexicalGlobalObject(), key.get())))
        return false;

    return true;
}

bool _NPN_HasMethod(NPP, NPObject* o, NPIdentifier methodName)
{
    if (o->_class == NPScriptObjectClass) {
        JavaScriptObject* obj = (JavaScriptObject*)o; 
        if (!_isSafeScript(obj))
            return false;

        PrivateIdentifier* i = (PrivateIdentifier*)methodName;
        if (!i->isString)
            return false;

        RootObject* rootObject = obj->rootObject;
        if (!rootObject || !rootObject->isValid())
            return false;

        ExecState* exec = rootObject->interpreter()->globalExec();
        JSLock lock;
        JSValue* func = obj->imp->get(exec, identifierFromNPIdentifier(i->value.string));
        return !func->isUndefined();
    }
    
    if (o->_class->hasMethod)
        return o->_class->hasMethod(o, methodName);
    
    return false;
}