Processing before didImportChanges: merges and saves

[neilt]

My project has two core data models, one that is iCloud synched, and the other which is local only, both in the same context. I need to update some things in the local only model when data changes in iCloud model.

In looking at the following from UbiquityStoreManager.m it looks like I would not get the USMStoreDidImportChangesNotification until after deleted managed objects were already removed from the persistent store?

- (void)didImportChanges:(NSNotification *)note {

    NSManagedObjectContext *moc = nil;
    if ([self.delegate respondsToSelector:@selector(managedObjectContextForUbiquityChangesInManager:)])
        moc = [self.delegate managedObjectContextForUbiquityChangesInManager:self];
    if (moc) {
        [self log:@"Importing ubiquity changes into application's MOC.  Changes:\n%@", note.userInfo];
        [moc performBlockAndWait:^{
            [moc mergeChangesFromContextDidSaveNotification:note];

            NSError *error = nil;
            if ([moc hasChanges] && ![moc save:&error]) {
                [self error:error cause:UbiquityStoreErrorCauseImportChanges context:note];
                [self reloadStore];
                return;
            }
        }];
    }
    else
        [self log:@"Application did not specify an import MOC, not importing ubiquity changes:\n%@", note.userInfo];

    dispatch_async( dispatch_get_main_queue(), ^{
        [[NSNotificationCenter defaultCenter] postNotificationName:USMStoreDidImportChangesNotification
                                                            object:self userInfo:[note userInfo]];
    } );
}

If I register for NSPersistentStoreDidImportUbiquitousContentChangesNotification directly how do I know that I received this notifications before UbiquityStoreManager has merged the changes and saved?

Is it possible to get a delegate call at the beginning of didImportChanges:. Something like:

    if ([self.delegate respondsToSelector:@selector(willMergeAndSaveImportChangesFromNote:)])
        [self.delegate willMergeAndSaveImportChangesFromNote:note];

This way I can save what I need to process from the notifications, multithreaded aware, for later processing before the data goes away or changes.

Thank you. Neil

[lhunath]

In 6f959da I've modified the delegate method to:

- (NSManagedObjectContext *)ubiquityStoreManager:(UbiquityStoreManager *)manager
          managedObjectContextForUbiquityChanges:(NSNotification *)note;

You should now be able to do your custom logic before returning the MOC to USM.

[neilt]

Wow, excellent! When to lunch and when I returned the change was made.

Thank you. Neil

[lhunath]

That's because I made it during my lunch time ;-)