Review Request: Use QPixmapCache for KStandardItemListWidget::pixmapForIcon

[Christoph Feck]

> On Oct. 25, 2012, 9:05 p.m., Christoph Feck wrote:
> > Sorry, QPixmapCache is obsolete, please port to KImageCache.
> 
> Christoph Feck wrote:
>     Before you ask, here is what the API docs say:
>     
>     Deprecated:
>     KPixmapCache is susceptible to various non-trivial locking bugs and inefficiencies, and is supported for backward compatibility only (since it exposes a QDataStream API for subclasses). Users should port to KImageCache for a very close work-alike, or KSharedDataCache if they need more control.
> 
> Michael Pyne wrote:
>     In fairness, QPixmapCache is nowhere near the same as KPixmapCache. QPixmapCache is a thread-shared cache (i.e. different processes will have different QPixmapCaches). There are plausible scenarios where you might not need either the additional features or different semantics of KImageCache.
>     
>     However, given that QPixmapCache has no means for namespacing it should not be your first choice for library code (e.g. if the library adds a pixmap called "icon_back", what happens if an application using that library also tries to add or use a pixmap called "icon_back"). If used in library code the key should be modified to include a namespace element e.g. key = QLatin1String("org.kde.KSILW.") + key. But doing this will make the cache itself slower as it has to fight with many different elements with a long common prefix (using a common suffix is probably OK but introduces a minor risk of collision again).

AHHHH... sorry, indeed this is about QPixmapCache, not KPixmapCache. So just forget my comment.


- Christoph


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On Oct. 25, 2012, 3:43 p.m., Emmanuel Pescosta wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> http://git.reviewboard.kde.org/r/107039/
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> 
> (Updated Oct. 25, 2012, 3:43 p.m.)
> 
> 
> Review request for Dolphin and Frank Reininghaus.
> 
> 
> Description
> -------
> 
> Use QPixmapCache for KStandardItemListWidget::pixmapForIcon(const QString& name, int size) -> Avoid KIcon loading and rescaleing
> 
> 
> Diffs
> -----
> 
>   dolphin/src/kitemviews/kstandarditemlistwidget.cpp 72d10cf 
> 
> Diff: http://git.reviewboard.kde.org/r/107039/diff/
> 
> 
> Testing
> -------
> 
> According to valgrind/callgrind lesser cpu time and according to valgrind/massif lesser memory consume
> 
> 
> Thanks,
> 
> Emmanuel Pescosta
> 
>

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