The format of Shared MIME Database magic values

[Kevin Krammer]

On Monday, 2013-12-16, 11:41:34, Alexander Kamyshnikov wrote:
> Hi Kevin. I'm glad to see KDE developer here because i'm KDE fan for many
> years :)
> But this KDE MIME-support code hardly depend from other KDE stuff, isn't it?
> I need "pure" Qt code - this is our software client requirement :/ So i'm
> wrote CMimeDatabase class. And just want to make it fully compliant with
> freedesktop standart.

Just wanted to point out that the Qt5 implementation was contributed by KDE 
developers, so additional to the Qt4 port of that code there is also "the 
original" Qt4 code available.

But of course if you need a pure C++ implementation without Qt then writing a 
new one is your only choice.

Cheers,
Kevin

> 
> (see
> http://api.kde.org/4.0-api/kdelibs-apidocs/kdecore/html/kmimetype_8h_source.
> html -
> KUrl, KServiceType etc.)
> 
> 
> 2013/12/14 Kevin Krammer <krammer at kde.org>
> 
> > On Friday, 2013-12-13, 20:11:34, Jerome Leclanche wrote:
> > > There is a Qt 4 port of this.
> > 
> > And there should also be the original Qt4 based code in the kdelibs
> > repository.
> > 
> > Cheers,
> > Kevin
> > 
> > > As for windows support... I've been down that road, trying to provide
> > > it. Windows' feature set doesn't even sort of come close; it only
> > > provides real mime types for a limited set of registered extensions,
> > > and it doesn't provide any of the very useful features such as
> > > subclassing, etc. In the end, I gave up and am only providing
> > > xdg-based mime types. I think Qt made an excellent choice in providing
> > > the xdg database itself. But if you choose against that, good luck.
> > > 
> > > Anyway you can have a look at my python-based mimetype lib. Magic
> > > matches are implemented on line 192 onwards.
> > > 
> > > https://github.com/Adys/python-xdg/blob/master/xdg/mime.py
> > > 
> > > J. Leclanche
> > > 
> > > 
> > > On Fri, Dec 13, 2013 at 7:56 PM, Alexander Kamyshnikov
> > > 
> > > <axill777 at gmail.com> wrote:
> > > > Yes, i had. But i decided to write my own implementation because:
> > > > a) my project is forced to use Qt4 only (clients have very old
> > 
> > versions of
> > 
> > > > modified Red Hat with XDG_DATA_DIRS undefined);
> > > > b) Windows support (through reading registry HKCR/.ext keys) is
> > 
> > required;
> > 
> > > > c) I'm very curious :)
> > > > 
> > > > You think i'm should look deeply at the qmimedatabase.cpp however?
> > > > 
> > > > 
> > > > 2013/12/13 Jerome Leclanche <adys.wh at gmail.com>
> > > > 
> > > >> Have you had a look at the Qt 5 mimetype module?
> > > >> 
> > > >> http://qt-project.org/doc/qt-5.0/qtcore/qmimedatabase.html
> > > >> J. Leclanche
> > > >> 
> > > >> 
> > > >> On Fri, Dec 13, 2013 at 7:35 PM, Alexander Kamyshnikov
> > > >> 
> > > >> <axill777 at gmail.com> wrote:
> > > >> > Hi all!
> > > >> > I'm developing the implementation of MIME database in C++/Qt for
> > > >> > one
> > > >> > commercial program (requirement managment tool, if one will be
> > > >> > interested).
> > > >> > So my question is: the format of magic values to compare file
> > > >> > header
> > > >> > data
> > > >> > with is not specified exactly in the spec. I mean the
> > 
> > magic/match/value
> > 
> > > >> > attribute.
> > > >> > What exactly mean those magic strings from
> > > >> > /usr/share/mime/packages/freedesktop.org.xml from my Kubuntu?
> > > >> > 1) "\1\9"
> > > >> > 2) "\376\067\0\043"
> > > >> > 3) "\x8AMNG\x0D\x0A\x1A\x0A"
> > > >> > Second is looks like octal number in C notation, third -
> > 
> > hexadecimal,
> > 
> > > >> > but
> > > >> > about first i'm not sure. It is just "usual" decimal value?
> > > >> > What format exactly should use magic values?
> > > >> > Thanks for your help. WBR, Alexander
> > 
> > > >> > P.S. Spec i'm using living here:
> > http://standards.freedesktop.org/shared-mime-info-spec/shared-mime-info
> > 
> > > >> > -spec-latest.html#id2661973 P.S. <match> items can be nested. But i
> > > >> > can't find yet the clear way to implement their storage
> > > >> > programmatically. Some kind of tree, or reverse polish notation
> > 
> > should
> > 
> > > >> > be used here? nevermind
> > > >> > 
> > > >> > _______________________________________________
> > > >> > xdg mailing list
> > > >> > xdg at lists.freedesktop.org
> > > >> > http://lists.freedesktop.org/mailman/listinfo/xdg
> > > 
> > > _______________________________________________
> > > xdg mailing list
> > > xdg at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/xdg
> > 
> > --
> > Kevin Krammer, KDE developer, xdg-utils developer
> > KDE user support, developer mentoring
> > 
> > _______________________________________________
> > xdg mailing list
> > xdg at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/xdg
-- 
Kevin Krammer, KDE developer, xdg-utils developer
KDE user support, developer mentoring
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