380451 - Store hashcode in textrun to avoid accessing deleted text

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Robert O'Callahan (:roc) (email my personal email if necessary)]

When nsTextFrameThebes uses TEXT_IS_PERSISTENT to avoid maintaining a separate copy of DOM text in the textrun, we have a problem when the DOM text changes. We need to destroy the textrun and remove it from the cache, but gfxTextRunCache::RemoveTextRun needs the hashcode of the text to find the entry to remove, but the text is already gone so we get the wrong hashcode or we crash on invalid memory.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

We can't remove the textrun before the text changes, because there is no DOM notification for that (and adding one could be costly). So instead I just store the hashcode in the textrun so we can always get it and find the hash entry for the textrun.

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

checked in.