C++ RETURN_IF_EXCEPTION函数代码示例

EncodedJSValue JSC_HOST_CALL moduleLoaderPrototypeParseModule(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    const Identifier moduleKey = exec->argument(0).toPropertyKey(exec);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    auto* jsSourceCode = jsDynamicCast<JSSourceCode*>(vm, exec->argument(1));
    if (!jsSourceCode)
        return throwVMTypeError(exec, scope);
    SourceCode sourceCode = jsSourceCode->sourceCode();

    CodeProfiling profile(sourceCode);

    ParserError error;
    std::unique_ptr<ModuleProgramNode> moduleProgramNode = parse<ModuleProgramNode>(
        &vm, sourceCode, Identifier(), JSParserBuiltinMode::NotBuiltin,
        JSParserStrictMode::Strict, JSParserScriptMode::Module, SourceParseMode::ModuleAnalyzeMode, SuperBinding::NotNeeded, error);

    if (error.isValid()) {
        throwVMError(exec, scope, error.toErrorObject(exec->lexicalGlobalObject(), sourceCode));
        return JSValue::encode(jsUndefined());
    }
    ASSERT(moduleProgramNode);

    ModuleAnalyzer moduleAnalyzer(exec, moduleKey, sourceCode, moduleProgramNode->varDeclarations(), moduleProgramNode->lexicalVariables());
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    JSModuleRecord* moduleRecord = moduleAnalyzer.analyze(*moduleProgramNode);

    return JSValue::encode(moduleRecord);
}

static EncodedJSValue JSC_HOST_CALL constructWeakSet(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    JSGlobalObject* globalObject = asInternalFunction(exec->jsCallee())->globalObject();
    Structure* weakSetStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), globalObject->weakSetStructure());
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    JSWeakSet* weakSet = JSWeakSet::create(exec, weakSetStructure);
    JSValue iterable = exec->argument(0);
    if (iterable.isUndefinedOrNull())
        return JSValue::encode(weakSet);

    JSValue adderFunction = weakSet->JSObject::get(exec, vm.propertyNames->add);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    CallData adderFunctionCallData;
    CallType adderFunctionCallType = getCallData(adderFunction, adderFunctionCallData);
    if (adderFunctionCallType == CallType::None)
        return JSValue::encode(throwTypeError(exec, scope));

    scope.release();
    forEachInIterable(exec, iterable, [&](VM&, ExecState* exec, JSValue nextValue) {
        MarkedArgumentBuffer arguments;
        arguments.append(nextValue);
        call(exec, adderFunction, adderFunctionCallType, adderFunctionCallData, weakSet, arguments);
    });

    return JSValue::encode(weakSet);
}

JSValue iteratorForIterable(ExecState* state, JSValue iterable)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    
    JSValue iteratorFunction = iterable.get(state, state->propertyNames().iteratorSymbol);
    RETURN_IF_EXCEPTION(scope, JSValue());
    
    CallData iteratorFunctionCallData;
    CallType iteratorFunctionCallType = getCallData(iteratorFunction, iteratorFunctionCallData);
    if (iteratorFunctionCallType == CallType::None) {
        throwTypeError(state, scope);
        return JSValue();
    }

    ArgList iteratorFunctionArguments;
    JSValue iterator = call(state, iteratorFunction, iteratorFunctionCallType, iteratorFunctionCallData, iterable, iteratorFunctionArguments);
    RETURN_IF_EXCEPTION(scope, JSValue());

    if (!iterator.isObject()) {
        throwTypeError(state, scope);
        return JSValue();
    }

    return iterator;
}

IterationRecord iteratorForIterable(ExecState* state, JSValue iterable)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    
    JSValue iteratorFunction = iterable.get(state, vm.propertyNames->iteratorSymbol);
    RETURN_IF_EXCEPTION(scope, { });
    
    CallData iteratorFunctionCallData;
    CallType iteratorFunctionCallType = getCallData(vm, iteratorFunction, iteratorFunctionCallData);
    if (iteratorFunctionCallType == CallType::None) {
        throwTypeError(state, scope);
        return { };
    }

    ArgList iteratorFunctionArguments;
    JSValue iterator = call(state, iteratorFunction, iteratorFunctionCallType, iteratorFunctionCallData, iterable, iteratorFunctionArguments);
    RETURN_IF_EXCEPTION(scope, { });

    if (!iterator.isObject()) {
        throwTypeError(state, scope);
        return { };
    }

    JSValue nextMethod = iterator.getObject()->get(state, vm.propertyNames->next);
    RETURN_IF_EXCEPTION(scope, { });

    return { iterator, nextMethod };
}

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_IF_EXCEPTION(scope, nullptr);
    }
    return result;
}

// Based on ErrorPrototype's errorProtoFuncToString(), but is modified to
// have no observable side effects to the user (i.e. does not call proxies,
// and getters).
String ErrorInstance::sanitizedToString(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    JSValue nameValue;
    auto namePropertName = vm.propertyNames->name;
    PropertySlot nameSlot(this, PropertySlot::InternalMethodType::VMInquiry);

    JSValue currentObj = this;
    unsigned prototypeDepth = 0;

    // We only check the current object and its prototype (2 levels) because normal
    // Error objects may have a name property, and if not, its prototype should have
    // a name property for the type of error e.g. "SyntaxError".
    while (currentObj.isCell() && prototypeDepth++ < 2) {
        JSObject* obj = jsCast<JSObject*>(currentObj);
        if (JSObject::getOwnPropertySlot(obj, exec, namePropertName, nameSlot) && nameSlot.isValue()) {
            nameValue = nameSlot.getValue(exec, namePropertName);
            break;
        }
        currentObj = obj->getPrototypeDirect();
    }
    ASSERT(!scope.exception());

    String nameString;
    if (!nameValue)
        nameString = ASCIILiteral("Error");
    else {
        nameString = nameValue.toWTFString(exec);
        RETURN_IF_EXCEPTION(scope, String());
    }

    JSValue messageValue;
    auto messagePropertName = vm.propertyNames->message;
    PropertySlot messageSlot(this, PropertySlot::InternalMethodType::VMInquiry);
    if (JSObject::getOwnPropertySlot(this, exec, messagePropertName, messageSlot) && messageSlot.isValue())
        messageValue = messageSlot.getValue(exec, messagePropertName);
    ASSERT(!scope.exception());

    String messageString;
    if (!messageValue)
        messageString = String();
    else {
        messageString = messageValue.toWTFString(exec);
        RETURN_IF_EXCEPTION(scope, String());
    }

    if (!nameString.length())
        return messageString;

    if (!messageString.length())
        return nameString;

    StringBuilder builder;
    builder.append(nameString);
    builder.appendLiteral(": ");
    builder.append(messageString);
    return builder.toString();
}

static EncodedJSValue JSC_HOST_CALL IntlCollatorFuncCompare(ExecState* state)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    // 10.3.4 Collator Compare Functions (ECMA-402 2.0)
    // 1. Let collator be the this value.
    // 2. Assert: Type(collator) is Object and collator has an [[initializedCollator]] internal slot whose value is true.
    IntlCollator* collator = jsCast<IntlCollator*>(state->thisValue());

    // 3. If x is not provided, let x be undefined.
    // 4. If y is not provided, let y be undefined.
    // 5. Let X be ToString(x).
    JSString* x = state->argument(0).toString(state);
    // 6. ReturnIfAbrupt(X).
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    // 7. Let Y be ToString(y).
    JSString* y = state->argument(1).toString(state);
    // 8. ReturnIfAbrupt(Y).
    RETURN_IF_EXCEPTION(scope, encodedJSValue());

    // 9. Return CompareStrings(collator, X, Y).
    auto xViewWithString = x->viewWithUnderlyingString(*state);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    auto yViewWithString = y->viewWithUnderlyingString(*state);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    scope.release();
    return JSValue::encode(collator->compareStrings(*state, xViewWithString.view, yViewWithString.view));
}

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);
}

// HTMLAllCollections are strange objects, they support both get and call.
static EncodedJSValue JSC_HOST_CALL callHTMLAllCollection(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    if (exec->argumentCount() < 1)
        return JSValue::encode(jsUndefined());

    // Do not use thisObj here. It can be the JSHTMLDocument, in the document.forms(i) case.
    JSHTMLAllCollection* jsCollection = jsCast<JSHTMLAllCollection*>(exec->callee());
    HTMLAllCollection& collection = jsCollection->wrapped();

    // Also, do we need the TypeError test here ?

    if (exec->argumentCount() == 1) {
        // Support for document.all(<index>) etc.
        String string = exec->argument(0).toString(exec)->value(exec);
        RETURN_IF_EXCEPTION(scope, encodedJSValue());
        if (Optional<uint32_t> index = parseIndex(*string.impl()))
            return JSValue::encode(toJS(exec, jsCollection->globalObject(), collection.item(index.value())));

        // Support for document.images('<name>') etc.
        return JSValue::encode(namedItems(*exec, jsCollection, Identifier::fromString(exec, string)));
    }

    // The second arg, if set, is the index of the item we want
    String string = exec->argument(0).toString(exec)->value(exec);
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    if (Optional<uint32_t> index = parseIndex(*exec->argument(1).toWTFString(exec).impl())) {
        if (auto* item = collection.namedItemWithIndex(string, index.value()))
            return JSValue::encode(toJS(exec, jsCollection->globalObject(), *item));
    }

    return JSValue::encode(jsUndefined());
}

static EncodedJSValue JSC_HOST_CALL constructArrayBuffer(ExecState* exec)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    JSArrayBufferConstructor* constructor =
        jsCast<JSArrayBufferConstructor*>(exec->jsCallee());
    
    unsigned length;
    if (exec->argumentCount()) {
        length = exec->uncheckedArgument(0).toIndex(exec, "length");
        RETURN_IF_EXCEPTION(scope, encodedJSValue());
    } else {
        // Although the documentation doesn't say so, it is in fact correct to say
        // "new ArrayBuffer()". The result is the same as allocating an array buffer
        // with a zero length.
        length = 0;
    }
    
    auto buffer = ArrayBuffer::tryCreate(length, 1);
    if (!buffer)
        return JSValue::encode(throwOutOfMemoryError(exec, scope));
    
    if (constructor->sharingMode() == ArrayBufferSharingMode::Shared)
        buffer->makeShared();
    
    ASSERT(constructor->sharingMode() == buffer->sharingMode());
    
    Structure* arrayBufferStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), constructor->globalObject()->arrayBufferStructure(constructor->sharingMode()));
    RETURN_IF_EXCEPTION(scope, encodedJSValue());
    JSArrayBuffer* result = JSArrayBuffer::create(vm, arrayBufferStructure, WTFMove(buffer));
    
    return JSValue::encode(result);
}

EncodedJSValue JSC_HOST_CALL webAssemblyModuleCustomSections(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.customSections called with non WebAssembly.Module argument"_s)));

    const String sectionNameString = exec->argument(1).getString(exec);
    RETURN_IF_EXCEPTION(throwScope, { });

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

    const auto& customSections = module->moduleInformation().customSections;
    for (const Wasm::CustomSection& section : customSections) {
        if (String::fromUTF8(section.name) == sectionNameString) {
            auto buffer = ArrayBuffer::tryCreate(section.payload.data(), section.payload.size());
            if (!buffer)
                return JSValue::encode(throwException(exec, throwScope, createOutOfMemoryError(exec)));

            result->push(exec, JSArrayBuffer::create(vm, globalObject->arrayBufferStructure(ArrayBufferSharingMode::Default), WTFMove(buffer)));
            RETURN_IF_EXCEPTION(throwScope, { });
        }
    }

    return JSValue::encode(result);
}

JSValue JSWebKitSubtleCrypto::exportKey(ExecState& state)
{
    VM& vm = state.vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    if (state.argumentCount() < 2)
        return throwException(&state, scope, createNotEnoughArgumentsError(&state));

    auto keyFormat = cryptoKeyFormatFromJSValue(state, scope, state.uncheckedArgument(0));
    RETURN_IF_EXCEPTION(scope, { });

    RefPtr<CryptoKey> key = JSCryptoKey::toWrapped(vm, state.uncheckedArgument(1));
    if (!key)
        return throwTypeError(&state, scope);

    RefPtr<DeferredPromise> wrapper = createDeferredPromise(state, domWindow());
    auto promise = wrapper->promise();
    auto successCallback = [wrapper](const Vector<uint8_t>& result) mutable {
        fulfillPromiseWithArrayBuffer(wrapper.releaseNonNull(), result.data(), result.size());
    };
    auto failureCallback = [wrapper]() mutable {
        wrapper->reject(); // FIXME: This should reject with an Exception.
    };

    WebCore::exportKey(state, keyFormat, *key, WTFMove(successCallback), WTFMove(failureCallback));
    RETURN_IF_EXCEPTION(scope, JSValue());

    return promise;
}

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;
}

static EncodedJSValue JSC_HOST_CALL webAssemblyTableProtoFuncSet(ExecState* exec)
{
    VM& vm = exec->vm();
    auto throwScope = DECLARE_THROW_SCOPE(vm);

    JSWebAssemblyTable* table = getTable(exec, vm, exec->thisValue());
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    JSValue value = exec->argument(1);
    WebAssemblyFunction* wasmFunction;
    WebAssemblyWrapperFunction* wasmWrapperFunction;
    if (!value.isNull() && !isWebAssemblyHostFunction(vm, value, wasmFunction, wasmWrapperFunction))
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, "WebAssembly.Table.prototype.set expects the second argument to be null or an instance of WebAssembly.Function"_s)));

    uint32_t index = toNonWrappingUint32(exec, exec->argument(0));
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    if (index >= table->length())
        return JSValue::encode(throwException(exec, throwScope, createRangeError(exec, "WebAssembly.Table.prototype.set expects an integer less than the length of the table"_s)));

    if (value.isNull())
        table->clearFunction(index);
    else {
        ASSERT(value.isObject() && isWebAssemblyHostFunction(vm, jsCast<JSObject*>(value), wasmFunction, wasmWrapperFunction));
        ASSERT(!!wasmFunction || !!wasmWrapperFunction);
        if (wasmFunction)
            table->setFunction(vm, index, wasmFunction);
        else
            table->setFunction(vm, index, wasmWrapperFunction);
    }
    
    return JSValue::encode(jsUndefined());
}

// 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));
}