C++ JSValue::asUInt32方法代码示例

EncodedJSValue DFG_OPERATION operationGetByVal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty)
{
    JSGlobalData* globalData = &exec->globalData();
    NativeCallFrameTracer tracer(globalData, exec);
    
    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);

    if (LIKELY(baseValue.isCell())) {
        JSCell* base = baseValue.asCell();

        if (property.isUInt32()) {
            return getByVal(exec, base, property.asUInt32());
        } else 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)->value(exec));
    return JSValue::encode(baseValue.get(exec, ident));
}

ALWAYS_INLINE static void DFG_OPERATION operationPutByValInternal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty, EncodedJSValue encodedValue)
{
    JSGlobalData* globalData = &exec->globalData();
    NativeCallFrameTracer tracer(globalData, exec);

    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);
    JSValue value = JSValue::decode(encodedValue);

    if (LIKELY(property.isUInt32())) {
        putByVal<strict>(exec, baseValue, property.asUInt32(), value);
        return;
    }

    if (property.isDouble()) {
        double propertyAsDouble = property.asDouble();
        uint32_t propertyAsUInt32 = static_cast<uint32_t>(propertyAsDouble);
        if (propertyAsDouble == propertyAsUInt32) {
            putByVal<strict>(exec, baseValue, propertyAsUInt32, value);
            return;
        }
    }


    // Don't put to an object if toString throws an exception.
    Identifier ident(exec, property.toString(exec)->value(exec));
    if (!globalData->exception) {
        PutPropertySlot slot(strict);
        baseValue.put(exec, ident, value, slot);
    }
}

EncodedJSValue JIT_OPERATION operationGetByValCell(ExecState* exec, JSCell* base, EncodedJSValue encodedProperty)
{
    VM& vm = exec->vm();
    NativeCallFrameTracer tracer(&vm, exec);
    
    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()) {
        Structure& structure = *base->structure(vm);
        if (JSCell::canUseFastGetOwnProperty(structure)) {
            if (AtomicStringImpl* existingAtomicString = asString(property)->toExistingAtomicString(exec)) {
                if (JSValue result = base->fastGetOwnProperty(vm, structure, existingAtomicString))
                    return JSValue::encode(result);
            }
        }
    }

    PropertyName propertyName = property.toPropertyKey(exec);
    return JSValue::encode(JSValue(base).get(exec, propertyName));
}

static inline T toSmallerUInt(ExecState* exec, JSValue value, IntegerConversionConfiguration configuration)
{
    typedef IntTypeLimits<T> LimitsTrait;
    // Fast path if the value is already a 32-bit unsigned integer in the right range.
    if (value.isUInt32()) {
        uint32_t d = value.asUInt32();
        if (d <= LimitsTrait::maxValue)
            return static_cast<T>(d);
        if (configuration == EnforceRange) {
            throwTypeError(exec);
            return 0;
        }
        return static_cast<T>(d);
    }

    double x = value.toNumber(exec);
    if (exec->hadException())
        return 0;

    if (configuration == EnforceRange)
        return enforceRange(exec, x, 0, LimitsTrait::maxValue);

    if (std::isnan(x) || std::isinf(x) || !x)
        return 0;

    x = x < 0 ? -floor(fabs(x)) : floor(fabs(x));
    return static_cast<T>(fmod(x, LimitsTrait::numberOfValues));
}

// http://www.w3.org/TR/WebIDL/#es-octet
uint8_t toUInt8(ExecState* exec, JSValue value, IntegerConversionConfiguration configuration)
{
    // Fast path if the value is already a 32-bit unsigned integer in the right range.
    if (value.isUInt32()) {
        uint32_t d = value.asUInt32();
        if (d <= kMaxUInt8)
            return static_cast<uint8_t>(d);
        if (configuration == EnforceRange) {
            throwTypeError(exec);
            return 0;
        }
        return static_cast<uint8_t>(d % 256); // 2^8.
    }

    double x = value.toNumber(exec);
    if (exec->hadException())
        return 0;

    if (configuration == EnforceRange)
        return enforceRange(exec, x, 0, kMaxUInt8);

    if (std::isnan(x) || std::isinf(x) || !x)
        return 0;

    x = x < 0 ? -floor(fabs(x)) : floor(fabs(x));
    return static_cast<uint8_t>(fmod(x, 256)); // 2^8.
}

// Shared implementation used by test and exec.
MatchResult RegExpObject::match(ExecState* exec, JSString* string)
{
    RegExp* regExp = this->regExp();
    RegExpConstructor* regExpConstructor = exec->lexicalGlobalObject()->regExpConstructor();
    String input = string->value(exec);
    VM& vm = exec->vm();
    if (!regExp->global())
        return regExpConstructor->performMatch(vm, regExp, string, input, 0);

    JSValue jsLastIndex = getLastIndex();
    unsigned lastIndex;
    if (LIKELY(jsLastIndex.isUInt32())) {
        lastIndex = jsLastIndex.asUInt32();
        if (lastIndex > input.length()) {
            setLastIndex(exec, 0);
            return MatchResult::failed();
        }
    } else {
        double doubleLastIndex = jsLastIndex.toInteger(exec);
        if (doubleLastIndex < 0 || doubleLastIndex > input.length()) {
            setLastIndex(exec, 0);
            return MatchResult::failed();
        }
        lastIndex = static_cast<unsigned>(doubleLastIndex);
    }

    MatchResult result = regExpConstructor->performMatch(vm, regExp, string, input, lastIndex);
    setLastIndex(exec, result.end);
    return result;
}

ALWAYS_INLINE static void JIT_OPERATION operationPutByValInternal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty, EncodedJSValue encodedValue)
{
    VM* vm = &exec->vm();
    NativeCallFrameTracer tracer(vm, exec);

    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);
    JSValue value = JSValue::decode(encodedValue);

    if (LIKELY(property.isUInt32())) {
        // Despite its name, JSValue::isUInt32 will return true only for positive boxed int32_t; all those values are valid array indices.
        ASSERT(isIndex(property.asUInt32()));
        putByVal<strict, direct>(exec, baseValue, property.asUInt32(), value);
        return;
    }

    if (property.isDouble()) {
        double propertyAsDouble = property.asDouble();
        uint32_t propertyAsUInt32 = static_cast<uint32_t>(propertyAsDouble);
        if (propertyAsDouble == propertyAsUInt32 && isIndex(propertyAsUInt32)) {
            putByVal<strict, direct>(exec, baseValue, propertyAsUInt32, value);
            return;
        }
    }

    // Don't put to an object if toString throws an exception.
    auto propertyName = property.toPropertyKey(exec);
    if (vm->exception())
        return;

    PutPropertySlot slot(baseValue, strict);
    if (direct) {
        RELEASE_ASSERT(baseValue.isObject());
        if (Optional<uint32_t> index = parseIndex(propertyName))
            asObject(baseValue)->putDirectIndex(exec, index.value(), value, 0, strict ? PutDirectIndexShouldThrow : PutDirectIndexShouldNotThrow);
        else
            asObject(baseValue)->putDirect(*vm, propertyName, value, slot);
    } else
        baseValue.put(exec, propertyName, value, slot);
}

ALWAYS_INLINE static void operationPutByValInternal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty, EncodedJSValue encodedValue)
{
    JSGlobalData* globalData = &exec->globalData();

    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);
    JSValue value = JSValue::decode(encodedValue);

    if (LIKELY(property.isUInt32())) {
        uint32_t i = property.asUInt32();

        if (isJSArray(globalData, baseValue)) {
            JSArray* jsArray = asArray(baseValue);
            if (jsArray->canSetIndex(i)) {
                jsArray->setIndex(*globalData, i, value);
                return;
            }

            jsArray->JSArray::put(exec, i, value);
            return;
        }

        if (isJSByteArray(globalData, baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
            JSByteArray* jsByteArray = asByteArray(baseValue);
            // FIXME: the JITstub used to relink this to an optimized form!
            if (value.isInt32()) {
                jsByteArray->setIndex(i, value.asInt32());
                return;
            }

            double dValue = 0;
            if (value.getNumber(dValue)) {
                jsByteArray->setIndex(i, dValue);
                return;
            }
        }

        baseValue.put(exec, i, value);
        return;
    }

    // Don't put to an object if toString throws an exception.
    Identifier ident(exec, property.toString(exec));
    if (!globalData->exception) {
        PutPropertySlot slot(strict);
        baseValue.put(exec, ident, value, slot);
    }
}

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))));
}

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);
    // Though CodeBlock is a JSCell, it is not safe to return it directly back to JS code
    // as it is an internal type that the JS code cannot handle. Hence, we first encode the
    // CodeBlock* as a double token (which is safe for JS code to handle) before returning it.
    return JSValue::encode(JSValue(bitwise_cast<double>(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(codeBlock)))));
}

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));
}

// Shared implementation used by test and exec.
bool RegExpObject::match(ExecState* exec)
{
    RegExpConstructor* regExpConstructor = exec->lexicalGlobalObject()->regExpConstructor();
    UString input = exec->argument(0).toString(exec);
    JSGlobalData* globalData = &exec->globalData();
    if (!regExp()->global()) {
        int position;
        int length;
        regExpConstructor->performMatch(*globalData, d->regExp.get(), input, 0, position, length);
        return position >= 0;
    }

    JSValue jsLastIndex = getLastIndex();
    unsigned lastIndex;
    if (LIKELY(jsLastIndex.isUInt32())) {
        lastIndex = jsLastIndex.asUInt32();
        if (lastIndex > input.length()) {
            setLastIndex(0);
            return false;
        }
    } else {
        double doubleLastIndex = jsLastIndex.toInteger(exec);
        if (doubleLastIndex < 0 || doubleLastIndex > input.length()) {
            setLastIndex(0);
            return false;
        }
        lastIndex = static_cast<unsigned>(doubleLastIndex);
    }

    int position;
    int length = 0;
    regExpConstructor->performMatch(*globalData, d->regExp.get(), input, lastIndex, position, length);
    if (position < 0) {
        setLastIndex(0);
        return false;
    }

    setLastIndex(position + length);
    return true;
}

EncodedJSValue operationGetByVal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty)
{
    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);

    if (LIKELY(baseValue.isCell())) {
        JSCell* base = baseValue.asCell();

        if (property.isUInt32()) {
            JSGlobalData* globalData = &exec->globalData();
            uint32_t i = property.asUInt32();

            // FIXME: the JIT used to handle these in compiled code!
            if (isJSArray(globalData, base) && asArray(base)->canGetIndex(i))
                return JSValue::encode(asArray(base)->getIndex(i));

            // FIXME: the JITstub used to relink this to an optimized form!
            if (isJSString(globalData, base) && asString(base)->canGetIndex(i))
                return JSValue::encode(asString(base)->getIndex(exec, i));

            // FIXME: the JITstub used to relink this to an optimized form!
            if (isJSByteArray(globalData, base) && asByteArray(base)->canAccessIndex(i))
                return JSValue::encode(asByteArray(base)->getIndex(exec, i));

            return JSValue::encode(baseValue.get(exec, i));
        }

        if (property.isString()) {
            Identifier propertyName(exec, asString(property)->value(exec));
            PropertySlot slot(base);
            if (base->fastGetOwnPropertySlot(exec, propertyName, slot))
                return JSValue::encode(slot.getValue(exec, propertyName));
        }
    }

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

EncodedJSValue JIT_OPERATION operationGetByVal(ExecState* exec, EncodedJSValue encodedBase, EncodedJSValue encodedProperty)
{
    VM& vm = exec->vm();
    NativeCallFrameTracer tracer(&vm, exec);
    
    JSValue baseValue = JSValue::decode(encodedBase);
    JSValue property = JSValue::decode(encodedProperty);

    if (LIKELY(baseValue.isCell())) {
        JSCell* base = baseValue.asCell();

        if (property.isUInt32()) {
            return getByVal(exec, base, property.asUInt32());
        } else if (property.isDouble()) {
            double propertyAsDouble = property.asDouble();
            uint32_t propertyAsUInt32 = static_cast<uint32_t>(propertyAsDouble);
            if (propertyAsUInt32 == propertyAsDouble && isIndex(propertyAsUInt32))
                return getByVal(exec, base, propertyAsUInt32);
        } else if (property.isString()) {
            Structure& structure = *base->structure(vm);
            if (JSCell::canUseFastGetOwnProperty(structure)) {
                if (AtomicStringImpl* existingAtomicString = asString(property)->toExistingAtomicString(exec)) {
                    if (JSValue result = base->fastGetOwnProperty(vm, structure, existingAtomicString))
                        return JSValue::encode(result);
                }
            }
        }
    }

    baseValue.requireObjectCoercible(exec);
    if (exec->hadException())
        return JSValue::encode(jsUndefined());
    auto propertyName = property.toPropertyKey(exec);
    if (exec->hadException())
        return JSValue::encode(jsUndefined());
    return JSValue::encode(baseValue.get(exec, propertyName));
}