digikam: improvements

-  Now usable in non kde desktop environments.

    Build a immutable sycoca database and use
    wrappers to tie programs to this
    database and avoid interference from the
    outside by specifying a fixed `KDELIBS`
    and fixed/empty `XDG_DATA_DIRS`.

    Added missing dependencies to syscoca
    database so that the program is complete.

    Added all build time optional packages.

    Kipi-plugins now properly detected. Added
    almost all optional dependencies so that
    almost all plugins are usable.

    Now with vlc phonon backend for video playback.

    Now with ffmpeg thumbnailer for video items
    thumbnail creation.

    Now run without any error log.

Tests:

 -  Ran most features of the standard program. Everything
    work perfectly without error logs.
 -  Ran some of the kipi plugins. Work fine there too.
 -  Ran face detection and fingerprint generation
    successfully.
 -  Oxygen icons are now displayed properly.
 -  Ran other wrapped executable successfully.

pkgs/applications/graphics/digikam/default.nix

@@ -3,42 +3,222 @@
 , libgphoto2, libjpeg, libkdcraw, libkexiv2, libkipi, libpgf, libtiff
 , libusb1, liblqr1, marble, mysql, opencv, perl, phonon, pkgconfig
 , qca2, qimageblitz, qjson, qt4, soprano
+
+# Optional build time dependencies
+, baloo, doxygen, kfilemetadata
+, lcms2
+, kfaceSupport ? true, libkface ? null
+, kgeomapSupport ? true, libkgeomap ? null
+, libxslt
+
+# Plugins optional build time dependencies
+, gdk_pixbuf, imagemagick
+, libgpod, libksane, libkvkontakte
+, qt_gstreamer1 /*qt_soap, <https://github.com/commontk/QtSOAP>  herqq <http://www.herqq.org> -> is missing its av part.*/
+  /*qt_koauth <http://gitorious.org/kqoauth>*/
+
+# Supplementary packages required only by the wrapper.
+, bash, kde_runtime, kde_baseapps, makeWrapper, oxygen_icons
+, phonon_backend_vlc /*phonon_backend_gstreamer,*/
+, ffmpegthumbs /*mplayerthumbs*/
+, runCommand, shared_mime_info, writeScriptBin
 }:
 
-stdenv.mkDerivation rec {
-  name = "digikam-4.12.0";
+let 
+  version = "4.12.0";
+  pName = "digikam-${version}";
 
-  src = fetchurl {
-    url = "http://download.kde.org/stable/digikam/${name}.tar.bz2";
-    sha256 = "081ldsaf3frf5khznjd3sxkjmi4dyp6w6nqnc2a0agkk0kxkl10m";
+  build = stdenv.mkDerivation rec {
+    name = "digikam-build-${version}";
+
+    src = fetchurl {
+      url = "http://download.kde.org/stable/digikam/${pName}.tar.bz2";
+      sha256 = "081ldsaf3frf5khznjd3sxkjmi4dyp6w6nqnc2a0agkk0kxkl10m";
+    };
+
+    nativeBuildInputs = [ 
+      automoc4 cmake gettext perl pkgconfig
+    ] ++ [
+      # Optional
+      doxygen 
+    ];
+
+    buildInputs = [
+      boost eigen jasper kdelibs kdepimlibs lcms lensfun
+      libgphoto2 libjpeg libkdcraw libkexiv2 libkipi liblqr1 libpgf
+      libtiff marble mysql.lib opencv phonon qca2 qimageblitz qjson qt4
+      shared_desktop_ontologies soprano ]
+    # Optional build time dependencies
+    ++ [
+      baloo 
+      kfilemetadata 
+      lcms2 ] 
+    ++ stdenv.lib.optional (kfaceSupport && null != libkface) [ libkface ]
+    ++ stdenv.lib.optional (kgeomapSupport && null != libkgeomap) [ libkgeomap ] ++ 
+    [ libxslt ]
+    # Plugins optional build time dependencies
+    ++ [
+      gdk_pixbuf imagemagick libgpod libksane
+      libkvkontakte
+      qt_gstreamer1 ];
+
+    # Make digikam find some FindXXXX.cmake
+    KDEDIRS="${marble}:${qjson}";
+
+    # Find kdepimlibs's upper case headers under `include/KDE`.
+    NIX_CFLAGS_COMPILE = "-I${kdepimlibs}/include/KDE";
+
+    # Help digiKam find libusb, otherwise gphoto2 support is disabled
+    cmakeFlags = [
+      "-DLIBUSB_LIBRARIES=${libusb1}/lib"
+      "-DLIBUSB_INCLUDE_DIR=${libusb1}/include/libusb-1.0"
+      "-DENABLE_BALOOSUPPORT=ON"
+      "-DENABLE_KDEPIMLIBSSUPPORT=ON"
+      "-DENABLE_LCMS2=ON" ] 
+    ++ stdenv.lib.optional (kfaceSupport && null == libkface) [ "-DDIGIKAMSC_COMPILE_LIBKFACE=ON" ]
+    ++ stdenv.lib.optional (kgeomapSupport && null == libkgeomap) [ "-DDIGIKAMSC_COMPILE_LIBKGEOMAP=ON" ];
+
+    enableParallelBuilding = true;
+
+    meta = {
+      description = "Photo Management Program";
+      license = stdenv.lib.licenses.gpl2;
+      homepage = http://www.digikam.org;
+      maintainers = with stdenv.lib.maintainers; [ goibhniu viric urkud ];
+      inherit (kdelibs.meta) platforms;
+    };
   };
 
-  nativeBuildInputs = [ automoc4 cmake gettext perl pkgconfig ];
 
-  buildInputs = [
-    boost eigen jasper kdelibs kdepimlibs lcms lensfun libgphoto2
-    libjpeg libkdcraw libkexiv2 libkipi liblqr1 libpgf libtiff marble
-    mysql.lib opencv phonon qca2 qimageblitz qjson qt4
-    shared_desktop_ontologies soprano
+  kdePkgs = [
+    build # digikam's own build
+    kdelibs kdepimlibs kde_runtime kde_baseapps libkdcraw oxygen_icons
+    /*phonon_backend_gstreamer*/ phonon_backend_vlc
+    ffmpegthumbs /*mplayerthumbs*/ shared_mime_info ]
+  # Optional build time dependencies
+  ++ [
+
+    baloo kfilemetadata ] 
+  ++ stdenv.lib.optional (kfaceSupport && null != libkface) [ libkface ]
+  ++ stdenv.lib.optional (kgeomapSupport && null != libkgeomap) [ libkgeomap ] 
+  ++ [ 
+    libkipi ] 
+  # Plugins optional build time dependencies
+  ++ [
+    libksane libkvkontakte
   ];
 
-  # Make digikam find some FindXXXX.cmake
-  KDEDIRS="${marble}:${qjson}";
 
-  # Help digiKam find libusb, otherwise gphoto2 support is disabled
-  cmakeFlags = [
-    "-DLIBUSB_LIBRARIES=${libusb1}/lib"
-    "-DLIBUSB_INCLUDE_DIR=${libusb1}/include/libusb-1.0"
-    "-DDIGIKAMSC_COMPILE_LIBKFACE=ON"
-  ];
+  # TODO: It should be the responsability of these packages to add themselves to `KDEDIRS`. See
+  # <https://github.com/ttuegel/nixpkgs/commit/a0efeacc0ef2cf63bbb768bfb172a483307d080b> for
+  # a practical example.
+  # IMPORTANT: Note that using `XDG_DATA_DIRS` here instead of `KDEDIRS` won't work properly.
+  KDEDIRS = with stdenv.lib; concatStrings (intersperse ":" (map (x: "${x}") kdePkgs));
 
-  enableParallelBuilding = true;
+  sycocaDirRelPath = "var/lib/kdesycoca";
+  sycocaFileRelPath = "${sycocaDirRelPath}/${pName}.sycoca";
+
+  sycoca = runCommand "${pName}" {
+
+    name = "digikam-sycoca-${version}";
+
+    nativeBuildInputs = [ kdelibs ];
+
+    dontPatchELF = true;
+    dontStrip = true;
+
+  } ''
+    # Make sure kbuildsycoca4 does not attempt to write to user home directory.
+    export HOME=$PWD
+
+    export KDESYCOCA="$out/${sycocaFileRelPath}"
+
+    mkdir -p $out/${sycocaDirRelPath}
+    export XDG_DATA_DIRS=""
+    export KDEDIRS="${KDEDIRS}"
+    kbuildsycoca4 --noincremental --nosignal
+  '';
+
+
+  replaceExeListWithWrapped = 
+    let f = exeName: ''
+        rm -f "$out/bin/${exeName}"
+        makeWrapper "${build}/bin/${exeName}" "$out/bin/${exeName}" \
+          --set XDG_DATA_DIRS "" \
+          --set KDEDIRS "${KDEDIRS}" \
+          --set KDESYCOCA "${sycoca}/${sycocaFileRelPath}"
+      '';
+    in 
+      with stdenv.lib; exeNameList: concatStrings (intersperse "\n" (map f exeNameList));
+
+in
+
+
+with stdenv.lib;
+
+/*
+  Final derivation
+  ----------------
+
+   -  Create symlinks to our original build derivation items.
+   -  Wrap specific executables so that they know of the appropriate
+      sycoca database, `KDEDIRS` to use and block any interference
+      from `XDG_DATA_DIRS` (only `dnginfo` is not wrapped).
+*/
+runCommand "${pName}" {
+  inherit build;
+  inherit sycoca;
+
+  nativeBuildInputs = [ makeWrapper ];
+
+  buildInputs = kdePkgs;
+
+  dontPatchELF = true;
+  dontStrip = true;
 
   meta = {
     description = "Photo Management Program";
     license = stdenv.lib.licenses.gpl2;
     homepage = http://www.digikam.org;
-    maintainers = with stdenv.lib.maintainers; [ goibhniu viric urkud ];
+    maintainers = with stdenv.lib.maintainers; [ /*jraygauthier*/ ];
     inherit (kdelibs.meta) platforms;
   };
-}
+
+} ''
+  pushd $build > /dev/null
+  for d in `find . -maxdepth 1 -name "*" -printf "%f\n" | tail -n+2`; do
+    mkdir -p $out/$d
+    for f in `find $d -maxdepth 1 -name "*" -printf "%f\n" | tail -n+2`; do
+        ln -s "$build/$d/$f" "$out/$d/$f"
+    done
+  done
+  popd > /dev/null
+  
+  ${replaceExeListWithWrapped [ "cleanup_digikamdb" "digitaglinktree" "digikam" "dngconverter" 
+                                "expoblending" "photolayoutseditor" "scangui" "showfoto" ]}
+''
+
+/*
+  
+TODO
+----
+
+### Useful ###
+
+ -  Per lib `KDELIBS` environment variable export. See above in-code TODO comment.
+ -  Missing optional `qt_soap` or `herqq` (av + normal package) dependencies. Those are not
+    yet (or not fully) packaged in nix. Mainly required for upnp export.
+ -  Possibility to use the `phonon_backend_gstreamer` with its own user specified set of backend.
+ -  Allow user to disable optional features or dependencies reacting properly.
+ -  Compile `kipiplugins` as a separate package (so that it can be used by other kde packages
+    and so that this package's build time is reduced).
+
+### Not so useful ###
+
+ -  Missing optional `qt_koauth` (not packaged in nix).
+ -  Missing optional `libmediawiki` (not packaged in nix)..
+ -  For some reason the cmake build does not detect `libkvkontakte`. Fix this.
+ -  Possibility to use `mplayerthumbs` thumbnail creator backend. In digikam dev docs,
+    it is however suggested to use `ffmpegthumbs`. Maybe we should stick to it.
+
+*/