managing the source array from plug-ins

[skurfer]

Nothing inspires confidence like a third try, right? :-)

This is the same as #801, minus a few commits that require a new iVar in QSActionProvider.

Again, this is to address the issues in #768.

[skurfer]

Added a constant as suggested. Here’s some code you can put into an action to test.

NSMutableArray *someArray = [NSMutableArray arrayWithCapacity:1];
NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:someArray, kQSResultArrayKey, nil];
QSObject *a = [QSObject objectWithString:@"One"];
QSObject *b = [QSObject objectWithString:@"Two"];
QSObject *c = [QSObject objectWithString:@"Three"];
[someArray addObject:a];
[[NSNotificationCenter defaultCenter] postNotificationName:@"QSSourceArrayCreated" object:self userInfo:userInfo];
sleep(2);
[someArray addObject:b];
[[NSNotificationCenter defaultCenter] postNotificationName:@"QSSourceArrayUpdated" object:self userInfo:userInfo];
sleep(2);
[someArray addObject:c];
[someArray removeObject:a];
[[NSNotificationCenter defaultCenter] postNotificationName:@"QSSourceArrayUpdated" object:self userInfo:userInfo];
return nil;

[pjrobertson]

We could just remove the 'run tasks in background' option and make it default. What would we lose?

It certainly creates a lot of problems when testing

[skurfer]

For posterity, if you don’t enable the “Run tasks in background” option, the example code above won’t update the results list in real-time. You get the initial list (One), then when the action returns after 4 seconds, you see the final result (Two, Three). The intermediate list (One, Two) is never visible.

For a couple of reasons, I don’t think anything needs to be changed in this pull request.

1. This is how it would have behaved before. I’m not introducing a new “problem”.
2. While this can lead to weird results, I’m not sure if it’s technically broken. If you don’t run tasks in the background, the interface is held hostage until the action returns. There are many other undesirable things that result from this. It’s not specific to the results array and it’s not new.
3. The example above is a little convoluted. In the only practical example in existence (from the Spotlight plug-in), there won’t be intermediate results. There will just be an initial place-holder object, then the final results when the action completes. So in practice, users shouldn’t see this weird behavior regardless of their preferences.

We could just remove the 'run tasks in background' option and make it default. What would we lose?

I can only speculate, but I’m guessing this was implemented as an optional experimental feature. I think its stability is proven at this point, and I can only think of examples where having it off causes problems, but none where having it on does. But that’s a larger discussion for another place.