Facilitates finding associations between MIME types and desktop files
that report an association with that type. Combined with mailcap.el's
MIME facilities, it should be easy to use desktop files.
* lisp/xdg.el (xdg-mime-table): New variable.
(xdg-mime-apps-files, xdg-mime-collect-associations, xdg-mime-apps):
New functions.
* test/data/xdg/mimeapps.list: New file.
* test/data/xdg/mimeinfo.cache: New file.
* test/lisp/xdg-tests.el (xdg-mime-associations): New test.
* lisp/xdg.el (xdg-desktop-read-group): Add condition to catch
localized strings.
* test/lisp/xdg-tests.el (xdg-desktop-parsing): Add test to ensure
parsing l10n strings doesn't error but is essentially a no-op.
Use that to extend xdg-desktop-read-file. Also fix a bug where all
entries in all groups were read and returned by xdg-desktop-read-file.
* lisp/xdg.el (xdg-desktop-read-group): New function.
(xdg-desktop-read-file): Use it.
* test/data/xdg/malformed.desktop: New file.
* test/data/xdg/test.desktop: Add another section.
* test/lisp/xdg-tests.el (xdg-desktop-parsing): Test presence of a key
in another group. Test reading a prescribed group. Test detecting a
malformed key=value.
* lisp/xdg.el: Add support for Desktop Entry Specification.
(xdg--user-dirs-parse-line): Check if file is readable.
(xdg-desktop-group-regexp, xdg-desktop-entry-regexp): New variables.
(xdg--desktop-parse-line, xdg-desktop-read-file, xdg-desktop-strings):
New functions.
* test/lisp/xdg-tests.el:
* test/data/xdg/test.desktop:
* test/data/xdg/wrong.desktop: New files.
