EncodedJSValue JSC_HOST_CALL objectConstructorIsFrozen(ExecState* exec)
{
// 1. If Type(O) is not Object throw a TypeError exception.
JSValue obj = exec->argument(0);
if (!obj.isObject())
return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.isFrozen can only be called on Objects.")));
JSObject* object = asObject(obj);
if (isJSFinalObject(object))
return JSValue::encode(jsBoolean(object->isFrozen(exec->vm())));
// 2. For each named own property name P of O,
PropertyNameArray properties(exec);
object->methodTable()->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
PropertyNameArray::const_iterator end = properties.end();
for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
// a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
PropertyDescriptor desc;
if (!object->methodTable()->getOwnPropertyDescriptor(object, exec, *iter, desc))
continue;
// b. If IsDataDescriptor(desc) is true then
// i. If desc.[[Writable]] is true, return false. c. If desc.[[Configurable]] is true, then return false.
if ((desc.isDataDescriptor() && desc.writable()) || desc.configurable())
return JSValue::encode(jsBoolean(false));
}
// 3. If the [[Extensible]] internal property of O is false, then return true.
// 4. Otherwise, return false.
return JSValue::encode(jsBoolean(!object->isExtensible()));
}
static JSValue defineProperties(ExecState* exec, JSObject* object, JSObject* properties)
{
PropertyNameArray propertyNames(exec);
asObject(properties)->methodTable()->getOwnPropertyNames(asObject(properties), exec, propertyNames, ExcludeDontEnumProperties);
size_t numProperties = propertyNames.size();
Vector<PropertyDescriptor> descriptors;
MarkedArgumentBuffer markBuffer;
for (size_t i = 0; i < numProperties; i++) {
PropertySlot slot;
JSValue prop = properties->get(exec, propertyNames[i]);
if (exec->hadException())
return jsNull();
PropertyDescriptor descriptor;
if (!toPropertyDescriptor(exec, prop, descriptor))
return jsNull();
descriptors.append(descriptor);
// Ensure we mark all the values that we're accumulating
if (descriptor.isDataDescriptor() && descriptor.value())
markBuffer.append(descriptor.value());
if (descriptor.isAccessorDescriptor()) {
if (descriptor.getter())
markBuffer.append(descriptor.getter());
if (descriptor.setter())
markBuffer.append(descriptor.setter());
}
}
for (size_t i = 0; i < numProperties; i++) {
object->methodTable()->defineOwnProperty(object, exec, propertyNames[i], descriptors[i], true);
if (exec->hadException())
return jsNull();
}
return object;
}
static bool putDescriptor(ExecState* exec, JSObject* target, const Identifier& propertyName, PropertyDescriptor& descriptor, unsigned attributes, JSValue oldValue)
{
if (descriptor.isGenericDescriptor() || descriptor.isDataDescriptor()) {
target->putWithAttributes(exec, propertyName, descriptor.value() ? descriptor.value() : oldValue, attributes & ~(Getter | Setter));
return true;
}
attributes &= ~ReadOnly;
if (descriptor.getter() && descriptor.getter().isObject())
target->defineGetter(exec, propertyName, asObject(descriptor.getter()), attributes);
if (exec->hadException())
return false;
if (descriptor.setter() && descriptor.setter().isObject())
target->defineSetter(exec, propertyName, asObject(descriptor.setter()), attributes);
return !exec->hadException();
}
unsigned PropertyDescriptor::attributesWithOverride(const PropertyDescriptor& other) const
{
unsigned mismatch = other.m_attributes ^ m_attributes;
unsigned sharedSeen = other.m_seenAttributes & m_seenAttributes;
unsigned newAttributes = m_attributes & defaultAttributes;
if (sharedSeen & WritablePresent && mismatch & ReadOnly)
newAttributes ^= ReadOnly;
if (sharedSeen & ConfigurablePresent && mismatch & DontDelete)
newAttributes ^= DontDelete;
if (sharedSeen & EnumerablePresent && mismatch & DontEnum)
newAttributes ^= DontEnum;
if (isAccessorDescriptor() && other.isDataDescriptor())
newAttributes |= ReadOnly;
return newAttributes;
}
EncodedJSValue JSC_HOST_CALL objectConstructorFreeze(ExecState* exec)
{
// 1. If Type(O) is not Object throw a TypeError exception.
JSValue obj = exec->argument(0);
if (!obj.isObject())
return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.freeze can only be called on Objects.")));
JSObject* object = asObject(obj);
if (isJSFinalObject(object) && !hasIndexedProperties(object->structure()->indexingType())) {
object->freeze(exec->vm());
return JSValue::encode(obj);
}
// 2. For each named own property name P of O,
PropertyNameArray properties(exec);
object->methodTable()->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
PropertyNameArray::const_iterator end = properties.end();
for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
// a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
PropertyDescriptor desc;
if (!object->methodTable()->getOwnPropertyDescriptor(object, exec, *iter, desc))
continue;
// b. If IsDataDescriptor(desc) is true, then
// i. If desc.[[Writable]] is true, set desc.[[Writable]] to false.
if (desc.isDataDescriptor())
desc.setWritable(false);
// c. If desc.[[Configurable]] is true, set desc.[[Configurable]] to false.
desc.setConfigurable(false);
// d. Call the [[DefineOwnProperty]] internal method of O with P, desc, and true as arguments.
object->methodTable()->defineOwnProperty(object, exec, *iter, desc, true);
if (exec->hadException())
return JSValue::encode(obj);
}
// 3. Set the [[Extensible]] internal property of O to false.
object->preventExtensions(exec->vm());
// 4. Return O.
return JSValue::encode(obj);
}
bool JSObject::defineOwnProperty(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor, bool throwException)
{
// If we have a new property we can just put it on normally
PropertyDescriptor current;
if (!getOwnPropertyDescriptor(exec, propertyName, current))
return putDescriptor(exec, this, propertyName, descriptor, descriptor.attributes(), jsUndefined());
if (descriptor.isEmpty())
return true;
if (current.equalTo(descriptor))
return true;
// Filter out invalid changes
if (!current.configurable()) {
if (descriptor.configurable()) {
if (throwException)
throwError(exec, TypeError, "Attempting to configurable attribute of unconfigurable property.");
return false;
}
if (descriptor.enumerablePresent() && descriptor.enumerable() != current.enumerable()) {
if (throwException)
throwError(exec, TypeError, "Attempting to change enumerable attribute of unconfigurable property.");
return false;
}
}
// A generic descriptor is simply changing the attributes of an existing property
if (descriptor.isGenericDescriptor()) {
if (!current.attributesEqual(descriptor)) {
deleteProperty(exec, propertyName);
putDescriptor(exec, this, propertyName, descriptor, current.attributesWithOverride(descriptor), current.value());
}
return true;
}
// Changing between a normal property or an accessor property
if (descriptor.isDataDescriptor() != current.isDataDescriptor()) {
if (!current.configurable()) {
if (throwException)
throwError(exec, TypeError, "Attempting to change access mechanism for an unconfigurable property.");
return false;
}
deleteProperty(exec, propertyName);
return putDescriptor(exec, this, propertyName, descriptor, current.attributesWithOverride(descriptor), current.value() ? current.value() : jsUndefined());
}
// Changing the value and attributes of an existing property
if (descriptor.isDataDescriptor()) {
if (!current.configurable()) {
if (!current.writable() && descriptor.writable()) {
if (throwException)
throwError(exec, TypeError, "Attempting to change writable attribute of unconfigurable property.");
return false;
}
if (!current.writable()) {
if (descriptor.value() || !JSValue::strictEqual(current.value(), descriptor.value())) {
if (throwException)
throwError(exec, TypeError, "Attempting to change value of a readonly property.");
return false;
}
}
} else if (current.attributesEqual(descriptor)) {
if (!descriptor.value())
return true;
PutPropertySlot slot;
put(exec, propertyName, descriptor.value(), slot);
if (exec->hadException())
return false;
return true;
}
deleteProperty(exec, propertyName);
return putDescriptor(exec, this, propertyName, descriptor, current.attributesWithOverride(descriptor), current.value());
}
// Changing the accessor functions of an existing accessor property
ASSERT(descriptor.isAccessorDescriptor());
if (!current.configurable()) {
if (descriptor.setterPresent() && !(current.setter() && JSValue::strictEqual(current.setter(), descriptor.setter()))) {
if (throwException)
throwError(exec, TypeError, "Attempting to change the setter of an unconfigurable property.");
return false;
}
if (descriptor.getterPresent() && !(current.getter() && JSValue::strictEqual(current.getter(), descriptor.getter()))) {
if (throwException)
throwError(exec, TypeError, "Attempting to change the getter of an unconfigurable property.");
return false;
}
}
JSValue accessor = getDirect(propertyName);
if (!accessor)
return false;
GetterSetter* getterSetter = asGetterSetter(accessor);
if (current.attributesEqual(descriptor)) {
if (descriptor.setter())
getterSetter->setSetter(asObject(descriptor.setter()));
if (descriptor.getter())
getterSetter->setGetter(asObject(descriptor.getter()));
return true;
}
deleteProperty(exec, propertyName);
unsigned attrs = current.attributesWithOverride(descriptor);
if (descriptor.setter())
attrs |= Setter;
if (descriptor.getter())
attrs |= Getter;
putDirect(propertyName, getterSetter, attrs);
return true;
}
