public void RegisterSubclass(Type type)
{
var typeInfo = type.GetTypeInfo();
if (!typeof(ParseObject).GetTypeInfo().IsAssignableFrom(typeInfo))
{
throw new ArgumentException("Cannot register a type that is not a subclass of ParseObject");
}
var className = GetClassName(type);
try
{
// Perform this as a single independent transaction, so we can never get into an
// intermediate state where we *theoretically* register the wrong class due to a
// TOCTTOU bug.
_mutex.EnterWriteLock();
if (_registeredSubclasses.TryGetValue(className, out var previousInfo))
{
if (typeInfo.IsAssignableFrom(previousInfo.TypeInfo))
{
// Previous subclass is more specific or equal to the current type, do nothing.
return;
}
else if (previousInfo.TypeInfo.IsAssignableFrom(typeInfo))
{
// Previous subclass is parent of new child, fallthrough and actually register
// this class.
/* Do nothing */
}
else
{
throw new ArgumentException(
"Tried to register both " + previousInfo.TypeInfo.FullName + " and " + typeInfo.FullName +
" as the ParseObject subclass of " + className + ". Cannot determine the right class " +
"to use because neither inherits from the other."
);
}
}
ConstructorInfo constructor = type.FindConstructor();
if (constructor == null)
{
throw new ArgumentException(
"Cannot register a type that does not implement the default constructor!");
}
_registeredSubclasses[className] = new ObjectSubclassInfo(type, constructor);
}
finally
{
_mutex.ExitWriteLock();
}
_mutex.EnterReadLock();
_registerActions.TryGetValue(className, out var toPerform);
_mutex.ExitReadLock();
toPerform?.Invoke();
}
public string GetClassName(Type type)
{
return(type == typeof(ParseObject)
? ParseObjectClassName
: ObjectSubclassInfo.GetClassName(type.GetTypeInfo()));
}