qannotate ui unresponsive for long time when opening file with long history.

[Alexander Belchenko]

qannotate for NEWS from bzr.dev performs badly: almost minute or so the qannotate window is just white without any content and don't react on anything. I don't think it's right: we should be able to show main gui elements (menu, internal windows) and actual content of the file much quickier.

[Gary van der Merwe (garyvdm)]

Things we can do:

* Cat the file first, so that we show the contents of the file quickly.
* Only load revision that are on screen.

But most importantly, we must not lock up the ui while we run annotate. There may be a way to get annotate to call processEvents. If not, threads ftw.

[Alexander Belchenko (bialix)]

Gary van der Merwe пишет:
> Things we can do:
>
> * Cat the file first, so that we show the contents of the file quickly.

That's my guess as well.

> * Only load revision that are on screen.
>
> But most importantly, we must not lock up the ui while we run annotate.
> There may be a way to get annotate to call processEvents. If not,
> threads ftw.

Yep, threads will help definitely. But at least we can grab low-hanging
fruits here.