C++ constructEmptyObject函数代码示例

JSValue JSInjectedScriptHost::functionDetails(ExecState* exec)
{
    if (exec->argumentCount() < 1)
        return jsUndefined();
    JSValue value = exec->argument(0);
    if (!value.asCell()->inherits(&JSFunction::s_info))
        return jsUndefined();
    JSFunction* function = jsCast<JSFunction*>(value);

    const SourceCode* sourceCode = function->sourceCode();
    if (!sourceCode)
        return jsUndefined();
    int lineNumber = sourceCode->firstLine();
    if (lineNumber)
        lineNumber -= 1; // In the inspector protocol all positions are 0-based while in SourceCode they are 1-based
    UString scriptId = UString::number(sourceCode->provider()->asID());

    JSObject* location = constructEmptyObject(exec);
    location->putDirect(exec->globalData(), Identifier(exec, "lineNumber"), jsNumber(lineNumber));
    location->putDirect(exec->globalData(), Identifier(exec, "scriptId"), jsString(exec, scriptId));

    JSObject* result = constructEmptyObject(exec);
    result->putDirect(exec->globalData(), Identifier(exec, "location"), location);
    UString name = function->name(exec);
    if (!name.isEmpty())
        result->putDirect(exec->globalData(), Identifier(exec, "name"), jsString(exec, name));
    UString displayName = function->displayName(exec);
    if (!displayName.isEmpty())
        result->putDirect(exec->globalData(), Identifier(exec, "displayName"), jsString(exec, displayName));
    // FIXME: provide function scope data in "scopesRaw" property when JSC supports it.
    //     https://bugs.webkit.org/show_bug.cgi?id=87192
    return result;
}

EncodedJSValue JSC_HOST_CALL objectConstructorCreate(ExecState* exec)
{
    if (!exec->argument(0).isObject() && !exec->argument(0).isNull())
        return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object prototype may only be an Object or null.")));
    JSValue proto = exec->argument(0);
    JSObject* newObject = proto.isObject()
        ? constructEmptyObject(exec, asObject(proto))
        : constructEmptyObject(exec, exec->lexicalGlobalObject()->nullPrototypeObjectStructure());
    if (exec->argument(1).isUndefined())
        return JSValue::encode(newObject);
    if (!exec->argument(1).isObject())
        return throwVMError(exec, createTypeError(exec, ASCIILiteral("Property descriptor list must be an Object.")));
    return JSValue::encode(defineProperties(exec, newObject, asObject(exec->argument(1))));
}

JSObject* createIteratorResultObject(ExecState* exec, JSValue value, bool done)
{
    JSObject* resultObject = constructEmptyObject(exec);
    resultObject->putDirect(exec->vm(), exec->propertyNames().done, jsBoolean(done));
    resultObject->putDirect(exec->vm(), exec->propertyNames().value, value);
    return resultObject;
}

JSObject* createIteratorResultObject(ExecState* exec, JSValue value, bool done)
{
    JSObject* resultObject = constructEmptyObject(exec, exec->lexicalGlobalObject()->iteratorResultObjectStructure());
    resultObject->putDirect(exec->vm(), donePropertyOffset, jsBoolean(done));
    resultObject->putDirect(exec->vm(), valuePropertyOffset, value);
    return resultObject;
}

bool JSFunction::getOwnPropertySlot(JSCell* cell, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
{
    JSFunction* thisObject = jsCast<JSFunction*>(cell);
    if (thisObject->isHostFunction())
        return Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);

    if (propertyName == exec->propertyNames().prototype) {
        JSGlobalData& globalData = exec->globalData();
        PropertyOffset offset = thisObject->getDirectOffset(globalData, propertyName);
        if (!isValidOffset(offset)) {
            JSObject* prototype = constructEmptyObject(exec);
            prototype->putDirect(globalData, exec->propertyNames().constructor, thisObject, DontEnum);
            thisObject->putDirect(globalData, exec->propertyNames().prototype, prototype, DontDelete | DontEnum);
            offset = thisObject->getDirectOffset(globalData, exec->propertyNames().prototype);
            ASSERT(isValidOffset(offset));
        }

        slot.setValue(thisObject, thisObject->getDirect(offset), offset);
    }

    if (propertyName == exec->propertyNames().arguments) {
        if (thisObject->jsExecutable()->isStrictMode()) {
            bool result = Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);
            if (!result) {
                thisObject->putDirectAccessor(exec, propertyName, thisObject->globalObject()->throwTypeErrorGetterSetter(exec), DontDelete | DontEnum | Accessor);
                result = Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);
                ASSERT(result);
            }
            return result;
        }
        slot.setCacheableCustom(thisObject, argumentsGetter);
        return true;
    }

    if (propertyName == exec->propertyNames().length) {
        slot.setCacheableCustom(thisObject, lengthGetter);
        return true;
    }

    if (propertyName == exec->propertyNames().name) {
        slot.setCacheableCustom(thisObject, nameGetter);
        return true;
    }

    if (propertyName == exec->propertyNames().caller) {
        if (thisObject->jsExecutable()->isStrictMode()) {
            bool result = Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);
            if (!result) {
                thisObject->putDirectAccessor(exec, propertyName, thisObject->globalObject()->throwTypeErrorGetterSetter(exec), DontDelete | DontEnum | Accessor);
                result = Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);
                ASSERT(result);
            }
            return result;
        }
        slot.setCacheableCustom(thisObject, callerGetter);
        return true;
    }

    return Base::getOwnPropertySlot(thisObject, exec, propertyName, slot);
}

EncodedJSValue JSC_HOST_CALL webAssemblyModuleImports(ExecState* exec)
{
    VM& vm = exec->vm();
    auto* globalObject = exec->lexicalGlobalObject();
    auto throwScope = DECLARE_THROW_SCOPE(vm);

    JSWebAssemblyModule* module = jsDynamicCast<JSWebAssemblyModule*>(vm, exec->argument(0));
    if (!module)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, "WebAssembly.Module.imports called with non WebAssembly.Module argument"_s)));

    JSArray* result = constructEmptyArray(exec, nullptr, globalObject);
    RETURN_IF_EXCEPTION(throwScope, { });

    const auto& imports = module->moduleInformation().imports;
    if (imports.size()) {
        Identifier module = Identifier::fromString(exec, "module");
        Identifier name = Identifier::fromString(exec, "name");
        Identifier kind = Identifier::fromString(exec, "kind");
        for (const Wasm::Import& imp : imports) {
            JSObject* obj = constructEmptyObject(exec);
            RETURN_IF_EXCEPTION(throwScope, { });
            obj->putDirect(vm, module, jsString(exec, String::fromUTF8(imp.module)));
            obj->putDirect(vm, name, jsString(exec, String::fromUTF8(imp.field)));
            obj->putDirect(vm, kind, jsString(exec, String(makeString(imp.kind))));
            result->push(exec, obj);
            RETURN_IF_EXCEPTION(throwScope, { });
        }
    }

    return JSValue::encode(result);
}

JSValue Origin::toJS(ExecState* exec) const
{
    JSObject* result = constructEmptyObject(exec);
    result->putDirect(exec->vm(), exec->propertyNames().bytecodesID, jsNumber(m_bytecodes->id()));
    result->putDirect(exec->vm(), exec->propertyNames().bytecodeIndex, jsNumber(m_bytecodeIndex));
    return result;
}

JSValue JSC_HOST_CALL objectConstructorGetOwnPropertyDescriptor(ExecState* exec, JSObject*, JSValue, const ArgList& args)
{
    if (!args.at(0).isObject())
        return throwError(exec, TypeError, "Requested property descriptor of a value that is not an object.");
    UString propertyName = args.at(1).toString(exec);
    if (exec->hadException())
        return jsNull();
    JSObject* object = asObject(args.at(0));
    PropertyDescriptor descriptor;
    if (!object->getOwnPropertyDescriptor(exec, Identifier(exec, propertyName), descriptor))
        return jsUndefined();
    if (exec->hadException())
        return jsUndefined();

    JSObject* description = constructEmptyObject(exec);
    if (!descriptor.isAccessorDescriptor()) {
        description->putDirect(exec->propertyNames().value, descriptor.value() ? descriptor.value() : jsUndefined(), 0);
        description->putDirect(exec->propertyNames().writable, jsBoolean(descriptor.writable()), 0);
    } else {
        description->putDirect(exec->propertyNames().get, descriptor.getter() ? descriptor.getter() : jsUndefined(), 0);
        description->putDirect(exec->propertyNames().set, descriptor.setter() ? descriptor.setter() : jsUndefined(), 0);
    }
    
    description->putDirect(exec->propertyNames().enumerable, jsBoolean(descriptor.enumerable()), 0);
    description->putDirect(exec->propertyNames().configurable, jsBoolean(descriptor.configurable()), 0);

    return description;
}

JSValue Database::toJS(ExecState* exec) const
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    JSObject* result = constructEmptyObject(exec);
    
    JSArray* bytecodes = constructEmptyArray(exec, 0);
    RETURN_IF_EXCEPTION(scope, JSValue());
    for (unsigned i = 0; i < m_bytecodes.size(); ++i)
        bytecodes->putDirectIndex(exec, i, m_bytecodes[i].toJS(exec));
    result->putDirect(vm, exec->propertyNames().bytecodes, bytecodes);
    
    JSArray* compilations = constructEmptyArray(exec, 0);
    RETURN_IF_EXCEPTION(scope, JSValue());
    for (unsigned i = 0; i < m_compilations.size(); ++i)
        compilations->putDirectIndex(exec, i, m_compilations[i]->toJS(exec));
    result->putDirect(vm, exec->propertyNames().compilations, compilations);
    
    JSArray* events = constructEmptyArray(exec, 0);
    RETURN_IF_EXCEPTION(scope, JSValue());
    for (unsigned i = 0; i < m_events.size(); ++i)
        events->putDirectIndex(exec, i, m_events[i].toJS(exec));
    result->putDirect(vm, exec->propertyNames().events, events);
    
    return result;
}

JSValue JSInjectedScriptHost::weakSetEntries(ExecState* exec)
{
    if (exec->argumentCount() < 1)
        return jsUndefined();

    JSValue value = exec->uncheckedArgument(0);
    JSWeakSet* weakSet = jsDynamicCast<JSWeakSet*>(value);
    if (!weakSet)
        return jsUndefined();

    unsigned fetched = 0;
    unsigned numberToFetch = 100;

    JSValue numberToFetchArg = exec->argument(1);
    double fetchDouble = numberToFetchArg.toInteger(exec);
    if (fetchDouble >= 0)
        numberToFetch = static_cast<unsigned>(fetchDouble);

    JSArray* array = constructEmptyArray(exec, nullptr);
    for (auto it = weakSet->weakMapData()->begin(); it != weakSet->weakMapData()->end(); ++it) {
        JSObject* entry = constructEmptyObject(exec);
        entry->putDirect(exec->vm(), Identifier::fromString(exec, "value"), it->key);
        array->putDirectIndex(exec, fetched++, entry);
        if (numberToFetch && fetched >= numberToFetch)
            break;
    }

    return array;
}

JSValue JSCommandLineAPIHost::getEventListeners(ExecState& state)
{
    if (state.argumentCount() < 1)
        return jsUndefined();

    JSValue value = state.uncheckedArgument(0);
    if (!value.isObject() || value.isNull())
        return jsUndefined();

    Node* node = JSNode::toWrapped(value);
    if (!node)
        return jsUndefined();

    Vector<EventListenerInfo> listenersArray;
    wrapped().getEventListenersImpl(node, listenersArray);

    JSObject* result = constructEmptyObject(&state);
    for (size_t i = 0; i < listenersArray.size(); ++i) {
        JSArray* listeners = getJSListenerFunctions(state, &node->document(), listenersArray[i]);
        if (!listeners->length())
            continue;
        AtomicString eventType = listenersArray[i].eventType;
        result->putDirect(state.vm(), Identifier::fromString(&state, eventType.impl()), JSValue(listeners));
    }

    return result;
}

static JSObject* constructInternalProperty(ExecState* exec, const String& name, JSValue value)
{
    JSObject* result = constructEmptyObject(exec);
    result->putDirect(exec->vm(), Identifier::fromString(exec, "name"), jsString(exec, name));
    result->putDirect(exec->vm(), Identifier::fromString(exec, "value"), value);
    return result;
}

static JSArray* getJSListenerFunctions(ExecState& state, Document* document, const EventListenerInfo& listenerInfo)
{
    VM& vm = state.vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    JSArray* result = constructEmptyArray(&state, nullptr);
    RETURN_IF_EXCEPTION(scope, nullptr);
    size_t handlersCount = listenerInfo.eventListenerVector.size();
    for (size_t i = 0, outputIndex = 0; i < handlersCount; ++i) {
        const JSEventListener* jsListener = JSEventListener::cast(&listenerInfo.eventListenerVector[i]->callback());
        if (!jsListener) {
            ASSERT_NOT_REACHED();
            continue;
        }

        // Hide listeners from other contexts.
        if (&jsListener->isolatedWorld() != &currentWorld(&state))
            continue;

        JSObject* function = jsListener->jsFunction(document);
        if (!function)
            continue;

        JSObject* listenerEntry = constructEmptyObject(&state);
        listenerEntry->putDirect(vm, Identifier::fromString(&state, "listener"), function);
        listenerEntry->putDirect(vm, Identifier::fromString(&state, "useCapture"), jsBoolean(listenerInfo.eventListenerVector[i]->useCapture()));
        result->putDirectIndex(&state, outputIndex++, JSValue(listenerEntry));
    }
    return result;
}

EncodedJSValue JSC_HOST_CALL objectConstructorGetOwnPropertyDescriptor(ExecState* exec)
{
    if (!exec->argument(0).isObject())
        return throwVMError(exec, createTypeError(exec, ASCIILiteral("Requested property descriptor of a value that is not an object.")));
    String propertyName = exec->argument(1).toString(exec)->value(exec);
    if (exec->hadException())
        return JSValue::encode(jsNull());
    JSObject* object = asObject(exec->argument(0));
    PropertyDescriptor descriptor;
    if (!object->methodTable()->getOwnPropertyDescriptor(object, exec, Identifier(exec, propertyName), descriptor))
        return JSValue::encode(jsUndefined());
    if (exec->hadException())
        return JSValue::encode(jsUndefined());

    JSObject* description = constructEmptyObject(exec);
    if (!descriptor.isAccessorDescriptor()) {
        description->putDirect(exec->vm(), exec->propertyNames().value, descriptor.value() ? descriptor.value() : jsUndefined(), 0);
        description->putDirect(exec->vm(), exec->propertyNames().writable, jsBoolean(descriptor.writable()), 0);
    } else {
        ASSERT(descriptor.getter());
        ASSERT(descriptor.setter());
        description->putDirect(exec->vm(), exec->propertyNames().get, descriptor.getter(), 0);
        description->putDirect(exec->vm(), exec->propertyNames().set, descriptor.setter(), 0);
    }

    description->putDirect(exec->vm(), exec->propertyNames().enumerable, jsBoolean(descriptor.enumerable()), 0);
    description->putDirect(exec->vm(), exec->propertyNames().configurable, jsBoolean(descriptor.configurable()), 0);

    return JSValue::encode(description);
}

EncodedJSValue JSC_HOST_CALL IntlCollatorPrototypeFuncResolvedOptions(ExecState* exec)
{
    // 10.3.5 Intl.Collator.prototype.resolvedOptions() (ECMA-402 2.0)
    IntlCollator* collator = jsDynamicCast<IntlCollator*>(exec->thisValue());
    if (!collator)
        return JSValue::encode(throwTypeError(exec, ASCIILiteral("Intl.Collator.prototype.resolvedOptions called on value that's not an object initialized as a Collator")));

    // The function returns a new object whose properties and attributes are set as if
    // constructed by an object literal assigning to each of the following properties the
    // value of the corresponding internal slot of this Collator object (see 10.4): locale,
    // usage, sensitivity, ignorePunctuation, collation, as well as those properties shown
    // in Table 1 whose keys are included in the %Collator%[[relevantExtensionKeys]]
    // internal slot of the standard built-in object that is the initial value of
    // Intl.Collator.

    VM& vm = exec->vm();
    JSObject* options = constructEmptyObject(exec);
    options->putDirect(vm, vm.propertyNames->locale, jsString(exec, collator->locale()));
    options->putDirect(vm, vm.propertyNames->usage, jsString(exec, collator->usage()));
    options->putDirect(vm, vm.propertyNames->sensitivity, jsString(exec, collator->sensitivity()));
    options->putDirect(vm, vm.propertyNames->ignorePunctuation, jsBoolean(collator->ignorePunctuation()));
    options->putDirect(vm, vm.propertyNames->collation, jsString(exec, collator->collation()));
    options->putDirect(vm, vm.propertyNames->numeric, jsBoolean(collator->numeric()));
    return JSValue::encode(options);
}