BTwoDImensionalLayout::AlignWith() segfaults

[yourpalal]

Currently, the BTwoDimensionalLayout::AlignWith() method segfaults. This is due to out of bounds access of a BList (which returns NULL). The only place this method is ever called is in LayoutTest1 (according to OpenGrok), so this has gone undetected for quite a while, I think.

[yourpalal]

Patch to fix segfault, also replaces an old style cast with a static_cast.

[bonefish]

Why that would fix anything isn't obvious to me. Can you explain, please.

[yourpalal]

Replying to bonefish:

Why that would fix anything isn't obvious to me. Can you explain, please.

Certainly! The problem is that with the original code, the for loop moves forwards through the list, 0,1,2,3... n, but for each local layouter calls SetCompoundLayouter. LocalLayouter::SetCompoundLayouter() calls CompoundLayouter::RemoveLocalLayouter(this) on the compound layouter that is being replaced, which then removes this LocalLayouter from its fLocalLayouters BList. The problem is that when you remove an item from index 0, all the other items get shifted down an index, so now the LocalLayouter that had previously been at index n is now at index n-1. There is nothing at index n, so the BList will return NULL when you request something at index n. Another solution is to always work at index 0, and use a while (other->fLocalLayouters.CountItems() > 0). Its a bit hard to see at first because of the different levels of abstraction in the AbsorbCompoundLayouters() method.

[pulkomandy]

Applied in hrev37348.