Archive:PackagingDrafts/ScriptletSnippets/iconcache

Changelog
0.1: first try 0.2: simplify to xdg-utils (only) usage. 0.3: drop "if no existing dependent packages..." 0.4: xdg-utils applies only to F7+ Core packages 0.5: drop xdg-utils usage (Core NACK'd v0.4) 0.6: gtk2 icon cache coherency issues in separate section 0.7: use xdg-utils again (for abstraction, allows use of guic --delay)

Currently deadlocked. This proposal asserts that updating guildelines to strictly follow the icon-theme-spec and solving gtk icon cache coherency are independent problems, and that the latter is/should-be outside the scope of packaging guidlines. Core cabal disagrees, postponing ACK of this proposal pending resolution of gtk icon cache coherency issue first.

= Existing Guideline =

GTK+ icon cache
If an application installs icons into one of the subdirectories in  (such as   in the following examples),   should be run after the package is installed/uninstalled on FC4 and later. This is required so that the installed icons show up in GNOME menus right after package installation, and speeds up GTK+ applications' access to the icons. For KDE, just 'touch'ing the top-level icon directory is enough.

Note that no dependencies should be added for this. If gtk-update-icon-cache is not available, there's nothing that would be needing the cache update. Not adding the dependency on gtk-update-icon-cache (ie. gtk2 >= 2.6.0) makes it easier to use the package (or the same specfile) on systems where it's not available nor needed, such as older distro versions or (very) trimmed down installations.

%post touch --no-create %{_datadir}/icons/hicolor || : %{_bindir}/gtk-update-icon-cache --quiet %{_datadir}/icons/hicolor || :

%postun touch --no-create %{_datadir}/icons/hicolor || : %{_bindir}/gtk-update-icon-cache --quiet %{_datadir}/icons/hicolor || :

= Proposal =

Motivations for changing the existing guideline:
 * include footnote/reference to fdo icon-theme-spec.
 * simplify guideline by removing toolkit-specific optimization details.
 * gtk-update-icon-cache currently runs on every pkg install (that includes icons), which is potentially very inefficient. (see %posttrans).  Informal benchmarks show 0.2-0.5 (user) seconds for every invocation.  This appears to have been addressed in a recent update to guic to include a --delay option.

icon cache
If an application installs icons into one of the subdirectories in  (such as   in the following examples), care must be taken to ensure the installed icons appear properly after package installation[[FootNote.

Use the following scriptlets: %post %{_bindir}/xdg-icon-resource forceupdate --theme hicolor 2> /dev/null || :

%postun %{_bindir}/xdg-icon-resource forceupdate --theme hicolor 2> /dev/null || :

gtk icon cache coherency brainstorm (not part of packaging guidelines)
Brainstorming methods to keep gtk icon cache fresh. See also bugzilla bug tracking this: gtk2: create/maintain iconcache Ideas include:
 * cron job (like prelink)
 * on boot (init) + file-system monitoring daemon (e.g. incron)
 * rpm %posttrans scriptlet hook. No, %posttransun doesn't work (rpm bug?)