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(exec, 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(exec, 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(exec, 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(exec, 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;
}
bool RuntimeObject::deletePropertyVirtual(ExecState* exec, const Identifier& propertyName)
{
return deleteProperty(this, exec, propertyName);
}
bool JSObject::deleteProperty(ExecState* exec, unsigned propertyName)
{
return deleteProperty(exec, Identifier::from(exec, propertyName));
}