Re: r28556 - in /libs/gui/trunk: ChangeLog Source/GSTextStorage.h Source/GSTextStorage.

[Wolfgang Lux]

Hi Richard,

> Author: rfm
> Date: Thu Aug 27 16:57:00 2009
> New Revision: 28556
>
> URL: http://svn.gna.org/viewcvs/gnustep?rev=28556&view=rev
> Log:
> Fix bad return of proxy to user code
>
> Modified:
>     libs/gui/trunk/ChangeLog
>     libs/gui/trunk/Source/GSTextStorage.h
>     libs/gui/trunk/Source/GSTextStorage.m


I don't know what you attempted to fix here, but your change is  
definitely
wrong and the old code which did return a proxy was correct. Here is the
relevant quote from Apple's documentation of the NSAttributedString - 
string
method:

  "For performance reasons, this method returns the current backing  
store
  of the attributed string object. If you want to maintain a  
snapshot of
  this as you manipulate the returned string, you should make a copy of
  the appropriate substring.
  This primitive method must guarantee efficient access to an  
attributed
  string's characters; subclasses should implement it to execute in O 
(1)
  time."

Your change has introduced a nasty O(n^2) performance bug that makes a
machine with a GB of RAM start thrashing during text layout when loading
a ~100kB log file into a text view.

Wolfgang

PS: I've notice that GSAttributedString contains the same bug.