C++ JSValue函数代码示例

JSValue JSActivation::argumentsGetter(ExecState*, JSValue slotBase, const Identifier&)
{
    JSActivation* activation = asActivation(slotBase);
    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
    int argumentsRegister = activation->m_argumentsRegister;
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister).jsValue())
        return arguments;
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);

    JSValue arguments = JSValue(Arguments::create(callFrame->globalData(), callFrame));
    callFrame->uncheckedR(argumentsRegister) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(&Arguments::s_info));
    return callFrame->uncheckedR(realArgumentsRegister).jsValue();
}

static EncodedJSValue JSC_HOST_CALL functionCodeBlockForFrame(ExecState* exec)
{
    if (exec->argumentCount() < 1)
        return JSValue::encode(jsUndefined());

    JSValue value = exec->uncheckedArgument(0);
    if (!value.isUInt32())
        return JSValue::encode(jsUndefined());

    // We need to inc the frame number because the caller would consider
    // its own frame as frame 0. Hence, we need discount the frame for this
    // function.
    unsigned frameNumber = value.asUInt32() + 1;
    CodeBlock* codeBlock = JSDollarVMPrototype::codeBlockForFrame(exec, frameNumber);
    return JSValue::encode(JSValue(bitwise_cast<double>(reinterpret_cast<uint64_t>(codeBlock))));
}

void JIT::compileCallEval(Instruction* instruction)
{
    addPtr(TrustedImm32(-static_cast<ptrdiff_t>(sizeof(CallerFrameAndPC))), stackPointerRegister, regT1);
    storePtr(callFrameRegister, Address(regT1, CallFrame::callerFrameOffset()));

    addPtr(TrustedImm32(stackPointerOffsetFor(m_codeBlock) * sizeof(Register)), callFrameRegister, stackPointerRegister);
    checkStackPointerAlignment();

    callOperation(operationCallEval, regT1);

    addSlowCase(branch64(Equal, regT0, TrustedImm64(JSValue::encode(JSValue()))));

    sampleCodeBlock(m_codeBlock);
    
    emitPutCallResult(instruction);
}

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

    if (UNLIKELY(state.argumentCount() < 1))
        return throwException(&state, scope, createNotEnoughArgumentsError(&state));

    auto* contentSecurityPolicy = wrapped().document() ? wrapped().document()->contentSecurityPolicy() : nullptr;
    auto action = ScheduledAction::create(&state, globalObject()->world(), contentSecurityPolicy);
    RETURN_IF_EXCEPTION(scope, JSValue());
    if (!action)
        return jsNumber(0);

    int delay = state.argument(1).toInt32(&state);
    return toJS<IDLLong>(state, scope, wrapped().setInterval(WTFMove(action), delay));
}

 JSValue::operator JSString() const {
   HAL_JSVALUE_LOCK_GUARD;
   JSValueRef exception { nullptr };
   JSStringRef js_string_ref = JSValueToStringCopy(static_cast<JSContextRef>(js_context__), js_value_ref__, &exception);
   if (exception) {
     // If this assert fails then we need to JSStringRelease
     // js_string_ref.
     assert(!js_string_ref);
     detail::ThrowRuntimeError("JSValue", JSValue(js_context__, exception));
   }
   
   assert(js_string_ref);
   JSString js_string(js_string_ref);
   JSStringRelease(js_string_ref);
   
   return js_string;
 }

void JSWeakValue::clear()
{
    switch (m_tag) {
    case WeakTypeTag::NotSet:
        return;
    case WeakTypeTag::Primitive:
        m_value.primitive = JSValue();
        return;
    case WeakTypeTag::Object:
        m_value.object.clear();
        return;
    case WeakTypeTag::String:
        m_value.string.clear();
        return;
    }
    RELEASE_ASSERT_NOT_REACHED();
}

void GetByIdVariant::dumpInContext(PrintStream& out, DumpContext* context) const
{
    if (!isSet()) {
        out.print("<empty>");
        return;
    }
    
    out.print(
        "<", inContext(structureSet(), context), ", ",
        "[", listDumpInContext(m_constantChecks, context), "]");
    if (m_alternateBase)
        out.print(", alternateBase = ", inContext(JSValue(m_alternateBase), context));
    out.print(", offset = ", offset());
    if (m_callLinkStatus)
        out.print(", call = ", *m_callLinkStatus);
    out.print(">");
}

void Debugger::exception(CallFrame* callFrame, JSValue exception, bool hasHandler)
{
    if (m_isPaused)
        return;

    PauseReasonDeclaration reason(*this, PausedForException);
    if (m_pauseOnExceptionsState == PauseOnAllExceptions || (m_pauseOnExceptionsState == PauseOnUncaughtExceptions && !hasHandler)) {
        m_pauseOnNextStatement = true;
        setSteppingMode(SteppingModeEnabled);
    }

    m_hasHandlerForExceptionCallback = true;
    m_currentException = exception;
    updateCallFrameAndPauseIfNeeded(callFrame);
    m_currentException = JSValue();
    m_hasHandlerForExceptionCallback = false;
}

void GetByIdStatus::computeForChain(GetByIdStatus& result, CodeBlock* profiledBlock, Identifier& ident, Structure* structure)
{
#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
    // Validate the chain. If the chain is invalid, then currently the best thing
    // we can do is to assume that TakesSlow is true. In the future, it might be
    // worth exploring reifying the structure chain from the structure we've got
    // instead of using the one from the cache, since that will do the right things
    // if the structure chain has changed. But that may be harder, because we may
    // then end up having a different type of access altogether. And it currently
    // does not appear to be worth it to do so -- effectively, the heuristic we
    // have now is that if the structure chain has changed between when it was
    // cached on in the baseline JIT and when the DFG tried to inline the access,
    // then we fall back on a polymorphic access.
    Structure* currentStructure = structure;
    JSObject* currentObject = 0;
    for (unsigned i = 0; i < result.m_chain.size(); ++i) {
        ASSERT(!currentStructure->isDictionary());
        currentObject = asObject(currentStructure->prototypeForLookup(profiledBlock));
        currentStructure = result.m_chain[i];
        if (currentObject->structure() != currentStructure)
            return;
    }
        
    ASSERT(currentObject);
        
    unsigned attributesIgnored;
    JSCell* specificValue;
        
    result.m_offset = currentStructure->get(
        *profiledBlock->vm(), ident, attributesIgnored, specificValue);
    if (currentStructure->isDictionary())
        specificValue = 0;
    if (!isValidOffset(result.m_offset))
        return;
        
    result.m_structureSet.add(structure);
    result.m_specificValue = JSValue(specificValue);
#else
    UNUSED_PARAM(result);
    UNUSED_PARAM(profiledBlock);
    UNUSED_PARAM(ident);
    UNUSED_PARAM(structure);
    UNREACHABLE_FOR_PLATFORM();
#endif
}

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

    JSGlobalObject* globalObject = asInternalFunction(exec->callee())->globalObject();
    Structure* weakMapStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), globalObject->weakMapStructure());
    if (exec->hadException())
        return JSValue::encode(JSValue());
    JSWeakMap* weakMap = JSWeakMap::create(exec, weakMapStructure);
    JSValue iterable = exec->argument(0);
    if (iterable.isUndefinedOrNull())
        return JSValue::encode(weakMap);

    JSValue adderFunction = weakMap->JSObject::get(exec, exec->propertyNames().set);
    if (exec->hadException())
        return JSValue::encode(jsUndefined());

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

    forEachInIterable(exec, iterable, [&](VM& vm, ExecState* exec, JSValue nextItem) {
        if (!nextItem.isObject()) {
            throwTypeError(exec, scope);
            return;
        }

        JSValue key = nextItem.get(exec, static_cast<unsigned>(0));
        if (vm.exception())
            return;

        JSValue value = nextItem.get(exec, static_cast<unsigned>(1));
        if (vm.exception())
            return;

        MarkedArgumentBuffer arguments;
        arguments.append(key);
        arguments.append(value);
        call(exec, adderFunction, adderFunctionCallType, adderFunctionCallData, weakMap, arguments);
    });

    return JSValue::encode(weakMap);
}

EncodedJSValue JSLexicalEnvironment::argumentsGetter(ExecState*, JSObject* slotBase, EncodedJSValue, PropertyName)
{
    JSLexicalEnvironment* lexicalEnvironment = jsCast<JSLexicalEnvironment*>(slotBase);
    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(lexicalEnvironment->m_registers));
    return JSValue::encode(jsUndefined());

    VirtualRegister argumentsRegister = callFrame->codeBlock()->argumentsRegister();
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister.offset()).jsValue())
        return JSValue::encode(arguments);
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister).offset();

    JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
    callFrame->uncheckedR(argumentsRegister.offset()) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(Arguments::info()));
    return JSValue::encode(callFrame->uncheckedR(realArgumentsRegister).jsValue());
}

void AbstractValue::setType(Graph& graph, SpeculatedType type)
{
    SpeculatedType cellType = type & SpecCell;
    if (cellType) {
        if (!(cellType & ~SpecString))
            m_structure = graph.m_vm.stringStructure.get();
        else if (isSymbolSpeculation(cellType))
            m_structure = graph.m_vm.symbolStructure.get();
        else
            m_structure.makeTop();
        m_arrayModes = ALL_ARRAY_MODES;
    } else {
        m_structure.clear();
        m_arrayModes = 0;
    }
    m_type = type;
    m_value = JSValue();
    checkConsistency();
}

void JIT::compileCallEval(Instruction* instruction)
{
    addPtr(TrustedImm32(-static_cast<ptrdiff_t>(sizeof(CallerFrameAndPC))), stackPointerRegister, regT1);
    callOperationNoExceptionCheck(operationCallEval, regT1);

    Jump noException = emitExceptionCheck(InvertedExceptionCheck);
    addPtr(TrustedImm32(stackPointerOffsetFor(m_codeBlock) * sizeof(Register)), callFrameRegister, stackPointerRegister);    
    exceptionCheck(jump());

    noException.link(this);
    addSlowCase(branch64(Equal, regT0, TrustedImm64(JSValue::encode(JSValue()))));

    addPtr(TrustedImm32(stackPointerOffsetFor(m_codeBlock) * sizeof(Register)), callFrameRegister, stackPointerRegister);
    checkStackPointerAlignment();

    sampleCodeBlock(m_codeBlock);
    
    emitPutCallResult(instruction);
}

JSValue JSActivation::argumentsGetter(ExecState*, JSValue slotBase, PropertyName)
{
    JSActivation* activation = jsCast<JSActivation*>(slotBase);
    if (activation->isTornOff())
        return jsUndefined();

    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
    int argumentsRegister = callFrame->codeBlock()->argumentsRegister();
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister).jsValue())
        return arguments;
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);

    JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
    callFrame->uncheckedR(argumentsRegister) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(Arguments::info()));
    return callFrame->uncheckedR(realArgumentsRegister).jsValue();
}

EncodedJSValue DFG_OPERATION operationGetByValCell(ExecState* exec, JSCell* base, EncodedJSValue encodedProperty)
{
    JSValue property = JSValue::decode(encodedProperty);

    if (property.isUInt32())
        return getByVal(exec, base, property.asUInt32());
    if (property.isDouble()) {
        double propertyAsDouble = property.asDouble();
        uint32_t propertyAsUInt32 = static_cast<uint32_t>(propertyAsDouble);
        if (propertyAsUInt32 == propertyAsDouble)
            return getByVal(exec, base, propertyAsUInt32);
    } else if (property.isString()) {
        if (JSValue result = base->fastGetOwnProperty(exec, asString(property)->value(exec)))
            return JSValue::encode(result);
    }

    Identifier ident(exec, property.toString(exec));
    return JSValue::encode(JSValue(base).get(exec, ident));
}