tableChangeSet.m

tableChangeSet.m

- (NSDictionary *) generateChangeSetsForSection:(NSString *) section withNewObjects:(NSOrderedSet *) newObjects fromOldObjects:(NSOrderedSet *) oldObjects {
    NSSet *newObjectsSet = [newObjects set];
    NSSet *previousObjectsSet = [oldObjects set];
    NSMutableSet *insertedObjects = [newObjectsSet mutableCopy];
    [insertedObjects minusSet:previousObjectsSet];
    NSMutableSet *deletedObjects = [previousObjectsSet mutableCopy];
    [deletedObjects minusSet:newObjectsSet];
    NSMutableSet *updatedObjects = [newObjectsSet mutableCopy];
    [updatedObjects minusSet:insertedObjects];
    [updatedObjects minusSet:deletedObjects];
    NSMutableSet *changes = [NSMutableSet set];
    for (id object in insertedObjects) {
        [changes addObject:@{kTCTableUpdateType: @(NSFetchedResultsChangeInsert),
                             kTCTableUpdateNewIndex: @([newObjects indexOfObject:object])}];
    }
    for (id object in deletedObjects) {
        [changes addObject:@{kTCTableUpdateType: @(NSFetchedResultsChangeDelete),
                             kTCTableUpdateOldIndex: @([oldObjects indexOfObject:object])}];
    }
    for (id object in updatedObjects) {
        [changes addObject:@{kTCTableUpdateType: @(NSFetchedResultsChangeMove),
                             kTCTableUpdateOldIndex: @([oldObjects indexOfObject:object]),
                             kTCTableUpdateNewIndex: @([newObjects indexOfObject:object])}];
    }
    return @{kTCTableUpdateSection: section,
             kTCTableUpdateChanges: [changes copy]};
}