On Thu, 28 Nov 2013 20:22:21 -0200 Gustavo Sverzut Barbieri <[email protected]> said:
> Hi, > > I was debugging the crash with elm_genlist_clear() in 1.8 and I'm > wondering the rationale of "rel". Currently it is badly broken given > that you use anything other than append/prepend without parent. > > The current code keeps a list of items in the smart data (sd->items). > Although these are ordered as they would be displayed, the code will > replicate that information in the "rel" (it->items->rel), that means > the item the current one is relative to. Then it keeps a boolean > "before" flag and a reverse relative list (who is relative to it). i remember putting in rel ONLY for the purpose of the queue handling. ie the item is queued but since it is relative TO something, rel is filled in with before true/false. after the item is no longer in the queue - rel should be unused and ignored. we could happily set it to NULL if we wanted. > Bad things happens if you insert or move before, after or sorted as > the siblings are not updated. Take _item_move_before(it, before): > > sd->items = > eina_inlist_remove(sd->items, EINA_INLIST_GET(it)); > if (it->item->block) _item_block_del(it); > sd->items = eina_inlist_prepend_relative > (sd->items, EINA_INLIST_GET(it), EINA_INLIST_GET(before)); > > So far, so good. remove from old position and place it where it should > be. Delete the block so it would be recreated when needed. > > > if (it->item->rel) > it->item->rel->item->rel_revs = > eina_list_remove(it->item->rel->item->rel_revs, it); > > It was relative to another item, then remove the current item from the > reverse relative list of that other item as it's not relative to it > anymore. Good. > > it->item->rel = before; > before->item->rel_revs = eina_list_append(before->item->rel_revs, it); > it->item->before = EINA_TRUE; > > Now make the item relative to the given parameter "before", also > appending itself to its reverse relative list. Flag as "before". Just > that? > > Did you notice the problem? If not take the given list as input: > - a (rel = , before=False, rel_revs=[c]) > - c (rel = a, before=False, rel_revs=[d]) > - d (rel = c, before=False, rel_revs=[b]) > - b (rel = d, before=False, rel_revs=[]) > > Now move "b" before "c". The result will be: > - a (rel = , before=False, rel_revs=[c]) > - b (rel = c, before=True, rel_revs=[]) > - c (rel = a, before=False, rel_revs=[d, b]) > - d (rel = c, before=False, rel_revs=[]). > > Wait, "c" is still relative to "a" even if should be after "b"... To > fix this is quite cumbersome as other elements would be relative given > they can be before=True or False. Would need to walk the reverse > relative's list of "c" and see if "b" got in the way of them, changing > their relative members. > > Looking at the code it seems the user of that is _item_block_add(), > does it need all of that complexity to do its job? I didn't review > such function, but if we could remove all those pointer+boolean+list > we would save memory AND complexity. but then you'd be forced to evaluate all queued items immediately. either that or re-architect how the queue works. ie insert items immediately into the actual list AND keep a queue entry, but this will have all sorts of nasty knock-on effects when a user scrolls as they will encounter entire block or sets of items not yet sized and identified. > Would someone with more experience in that code review the usage of > "rel" and either remove that or fix its handling in the code? > > > PS: I'm also not sure but this can be related to the problem of > keyboard navigation where you expand a genlist item, then move down it > would go to the next top item, then down again and it goes to the > first child of the expanded. Very easy to notice with espionage (d-bus > inspector in python-efl). > > -- > Gustavo Sverzut Barbieri > -------------------------------------- > Mobile: +55 (19) 9225-2202 > Contact: http://www.gustavobarbieri.com.br/contact > > ------------------------------------------------------------------------------ > Rapidly troubleshoot problems before they affect your business. Most IT > organizations don't have a clear picture of how application performance > affects their revenue. With AppDynamics, you get 100% visibility into your > Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! > http://pubads.g.doubleclick.net/gampad/clk?id=84349351&iu=/4140/ostg.clktrk > _______________________________________________ > enlightenment-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/enlightenment-devel > -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) [email protected] ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. 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