[prev in list] [next in list] [prev in thread] [next in thread] 

List:       kde-commits
Subject:    Re: KDE/kdepim/plugins/kmail/bodypartformatter
From:       David Faure <dfaure () kdab ! net>
Date:       2008-02-18 11:11:28
Message-ID: 200802181211.31982.dfaure () kdab ! net
[Download RAW message or body]

On Sunday 17 February 2008, Ingo Klöcker wrote:
> On Saturday 16 February 2008, Till Adam wrote:
> > +      const QString addedLineStyle( "style=\"" "color: green;\"" );
> 
> Why is this a QString while everything else is a QLatin1String?
> 
> And wouldn't it make sense to make those static const so that they are 
> constructed only once? I guess it doesn't really matter because the 
> c'tor of QLatin1String is dead-cheap, but it might serve as example for 
> other usages of constants.

This looks like funny optimization "lookalike" to me.

text_xdiff.cpp:      static const QLatin1String tableStyle(
Very fast, whether static or not.

text_xdiff.cpp:      html += "<pre " + tableStyle + '>';
Slow anyway, has to convert the QLatin1String to a QString at that point.

QLatin1String saves you time only when you are comparing with it, not when you are going to assign from it...

All those strings are used only once so it doesn't matter, but if they were used more than 
once then making them QString in the first place would actually be faster :-)

Oh well, no big deal, just a common misconception about QLatin1String IMHO.

-- 
David Faure, faure@kde.org, dfaure@klaralvdalens-datakonsult.se
KDE/KOffice developer, Qt consultancy projects
Klarälvdalens Datakonsult AB, Platform-independent software solutions

[prev in list] [next in list] [prev in thread] [next in thread]