The format of Shared MIME Database magic values

[Alexander Kamyshnikov]

Yep, i had a lot of fun learning mime database details.
This is a real contest to the programmer, even to qualified one. And i'm
not belong to those group :)
So, i will try to eviscerate the Windows registry to find MIME info
storage. And how are Windows users lives without such MIME database... i
don't understand this. Just extension gives too limited information to
software.


2013/12/16 Jerome Leclanche <adys.wh at gmail.com>

> Mime types are interesting to know about, so if you want to learn more
> about them why not. A windows-compatible lib would be interesting. But
> all in all, Qt already has a mime type solution.
>
> J. Leclanche
>
>
> On Mon, Dec 16, 2013 at 9:55 AM, Alexander Kamyshnikov
> <axill777 at gmail.com> wrote:
> > Oh thanks, Kevin! This library is exactly i need for.
> > However, yet-another-implementation-of MIME loader might be useful for
> > somebody, or i'm just wasted my time? :)
> > This was funny and interesting quest.
> >
> >
> > 2013/12/16 Kevin Krammer <krammer at kde.org>
> >>
> >> On Monday, 2013-12-16, 12:45:47, Alexander Kamyshnikov wrote:
> >> > I'm confused a bit.
> >> > So, you want to say that QMimeDatabase from Qt5 can be separately used
> >> > in
> >> > Qt4?
> >> > I.e. i can just include this code in mine.
> >>
> >> Not the Qt5 based code obviously. But Jerome said that there is a Qt4
> port
> >> of
> >> the Qt5 code.
> >>
> >> I guess he is referring to
> >> https://github.com/pasnox/mimetypes-qt4
> >>
> >> Cheers,
> >> Kevin
> >>
> >> > Also, i'm trying to google "qmimedatabase qt4", but find nothing
> >> > appropriate.
> >> > A more concrete search direction will be welcome.
> >> > P.S. Sorry, if i don't understand simple things. My english is not
> >> > perfect
> >> > yet.
> >> >
> >> >
> >> > 2013/12/16 Kevin Krammer <krammer at kde.org>
> >> >
> >> > > 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_sourc
> >> > > e
> >> > > .
> >> > >
> >> > > > 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
> >> > >
> >> > > _______________________________________________
> >> > > 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
> >>
> >
> >
> > _______________________________________________
> > xdg mailing list
> > xdg at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/xdg
> >
>
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