KSaveFile, QSaveFile, QFile

[Dominik Haumann]

Hi David,

since you pushed QSaveFile to Qt5.1, can you comment on this?

Thanks!
Dominik

On Sunday, March 10, 2013 16:03:06 Dominik Haumann wrote:
> Hi k-c-d / kwrite-devel,
> 
> Kate uses KSaveFile in KDE 4.10 to avoid data loss during save operations.
> According to [1] KSaveFile will be deprecated in favor of QSaveFile with
> kf5/Qt5.1.
> 
> Unfortunately, using KSaveFile introduces quite some regressions in Kate:
> 
> 1. KSaveFile: Kate/kwrite makes a copy of a file while editing a hard link
>    https://bugs.kde.org/show_bug.cgi?id=316240
> 
> 2. KSaveFile: Unable to save file (777 permission) when the directory have
> 444 https://bugs.kde.org/show_bug.cgi?id=312415
> 
> 3. Kate changes owner of editing file (edit)
>    https://bugs.kde.org/show_bug.cgi?id=316234 (likely KSaveFile issue)
> 
> Looking at the API/the code [1], QSaveFile seems to have the same behavior
> as KSaveFile.
> 
> It looks like 1 (hard links) and 3 (file permissions/owner) are definitely
> bugs in KSaveFile. Maybe QSaveFile is also affected (David?)?
> The code in line 214 in [2] does look ok. Does it also set file owner?
> 
> 2 (directory permissions) are hard to fix in KSaveFile. The only way out
> would be to allow saving to the file directly in case of file permissions
> are ok, but directory permissions are not.
> 
> What's the best way to fix that? I already see us writing yet another
> KateFile class that tries to use K/QSaveFile, and in case of failure
> falls back to QFile directly... doesn't sound too appealing to me :-)
> 
> Greetings,
> Dominik
> 
> [1] https://codereview.qt-project.org/#change,41790
> [2]
> https://codereview.qt-project.org/#patch,sidebyside,41790,10,src/corelib/io
> /qsavefile.cpp