saneBackends: factor out common code into generic.nix

The git version was duplicated from the stable one and the two had
begun to diverge significantly. For example, commit
88d731925d fixed a supposedly real
bug — but only in the stable package.

Factor out the shared code to avoid trouble — or worse, subtle
differences or bugs — in future.

pkgs/applications/graphics/sane/backends-git.nix

@@ -1,64 +0,0 @@
-{ stdenv,  fetchurl, fetchgit
-, avahi ? null, libusb ? null, net_snmp ? null
-, gt68xxFirmware ? null, snapscanFirmware ? null
-, hotplugSupport ? true
-}:
-let
-  firmware = gt68xxFirmware { inherit fetchurl; };
-in
-assert hotplugSupport -> (stdenv.system == "i686-linux" || stdenv.system == "x86_64-linux");
-
-let version = "2015-12-20"; in
-stdenv.mkDerivation {
-  name = "sane-backends-${version}";
-
-  src = fetchgit {
-    url = "git://alioth.debian.org/git/sane/sane-backends.git";
-    rev = "5136e664b8608604f54a2cc1d466019922b311e6";
-    sha256 = "998fdc9cdd3f9220c38244e0b87bba3ee623d7d20726479b04ed95b3836a37ed";
-  };
-
-  udevSupport = hotplugSupport;
-
-  buildInputs = [ avahi net_snmp ]
-    ++ stdenv.lib.optional (libusb != null) libusb;
-
-  configureFlags = []
-    ++ stdenv.lib.optional (avahi != null) "--enable-avahi";
-
-  postInstall = ''
-    if test "$udevSupport" = "1"; then
-      mkdir -p $out/etc/udev/rules.d/
-      ./tools/sane-desc -m udev > $out/etc/udev/rules.d/60-libsane.rules || \
-      cp tools/udev/libsane.rules $out/etc/udev/rules.d/60-libsane.rules
-    fi
-  '';
-
-  preInstall =
-    if gt68xxFirmware != null then
-      "mkdir -p \${out}/share/sane/gt68xx ; ln -s " + firmware.fw +
-      " \${out}/share/sane/gt68xx/" + firmware.name
-    else if snapscanFirmware != null then
-      "mkdir -p \${out}/share/sane/snapscan ; ln -s " + snapscanFirmware +
-      " \${out}/share/sane/snapscan/your-firmwarefile.bin ;" +
-      "mkdir -p \${out}/etc/sane.d ; " +
-      "echo epson2 > \${out}/etc/sane.d/dll.conf"
-    else "";
-
-  meta = with stdenv.lib; {
-    inherit version;
-    homepage = "http://www.sane-project.org/";
-    description = "SANE (Scanner Access Now Easy) backends";
-    longDescription = ''
-      Collection of open-source SANE backends (device drivers).
-      SANE is a universal scanner interface providing standardized access to
-      any raster image scanner hardware: flatbed scanners, hand-held scanners,
-      video- and still-cameras, frame-grabbers, etc. For a list of supported
-      scanners, see http://www.sane-project.org/sane-backends.html.
-    '';
-    license = licenses.gpl2Plus;
-
-    maintainers = with maintainers; [ nckx simons ];
-    platforms = platforms.linux;
-  };
-}

pkgs/applications/graphics/sane/backends/default.nix

@@ -0,0 +1,13 @@
+{ callPackage, fetchurl, ... } @ args:
+
+callPackage ./generic.nix (args // rec {
+  version = "1.0.25";
+  src = fetchurl {
+    sha256 = "0b3fvhrxl4l82bf3v0j47ypjv6a0k5lqbgknrq1agpmjca6vmmx4";
+    urls = [
+      "http://pkgs.fedoraproject.org/repo/pkgs/sane-backends/sane-backends-${version}.tar.gz/f9ed5405b3c12f07c6ca51ee60225fe7/sane-backends-${version}.tar.gz"
+      "https://alioth.debian.org/frs/download.php/file/4146/sane-backends-${version}.tar.gz"
+    ];
+    curlOpts = "--insecure";
+  };
+})

pkgs/applications/graphics/sane/backends/generic.nix

@@ -1,40 +1,34 @@
 { stdenv, fetchurl
 , avahi ? null, libusb ? null, libv4l ? null, net_snmp ? null
-, pkgconfig ? null
+, pkgconfig
 , gt68xxFirmware ? null, snapscanFirmware ? null
 , hotplugSupport ? true
+, version, src, ...
 }:
 
 assert hotplugSupport -> (stdenv.system == "i686-linux" || stdenv.system == "x86_64-linux");
 
 let
+
   firmware = gt68xxFirmware { inherit fetchurl; };
-in
-stdenv.mkDerivation rec {
-  version = "1.0.25";
-  name = "sane-backends-${version}";
-
-  src = fetchurl {
-    urls = [
-      "http://pkgs.fedoraproject.org/repo/pkgs/sane-backends/sane-backends-1.0.25.tar.gz/f9ed5405b3c12f07c6ca51ee60225fe7/${name}.tar.gz"
-      "https://alioth.debian.org/frs/download.php/file/4146/${name}.tar.gz"
-    ];
-    curlOpts = "--insecure";
-    sha256 = "0b3fvhrxl4l82bf3v0j47ypjv6a0k5lqbgknrq1agpmjca6vmmx4";
-  };
-
-  outputs = [ "out" "doc" "man" ];
 
   udevSupport = hotplugSupport;
 
+in
+stdenv.mkDerivation {
+  inherit src;
+
+  name = "sane-backends-${version}";
+
+  outputs = [ "out" "doc" "man" ];
+
   configureFlags = []
     ++ stdenv.lib.optional (avahi != null) "--enable-avahi"
     ++ stdenv.lib.optional (libusb != null) "--enable-libusb_1_0";
 
-  buildInputs = [ avahi net_snmp ]
+  buildInputs = [ avahi net_snmp pkgconfig ]
     ++ stdenv.lib.optional (libusb != null) libusb
     ++ stdenv.lib.optional (libv4l != null) libv4l
-    ++ stdenv.lib.optional (pkgconfig != null) pkgconfig
     ;
 
   postInstall = ''
@@ -55,7 +49,8 @@ stdenv.mkDerivation rec {
     else "";
 
   meta = with stdenv.lib; {
-    homepage = "http://www.sane-project.org/";
+    inherit version;
+
     description = "SANE (Scanner Access Now Easy) backends";
     longDescription = ''
       Collection of open-source SANE backends (device drivers).
@@ -64,6 +59,7 @@ stdenv.mkDerivation rec {
       video- and still-cameras, frame-grabbers, etc. For a list of supported
       scanners, see http://www.sane-project.org/sane-backends.html.
     '';
+    homepage = "http://www.sane-project.org/";
     license = licenses.gpl2Plus;
 
     maintainers = with maintainers; [ nckx simons ];

pkgs/applications/graphics/sane/backends/git.nix

@@ -0,0 +1,10 @@
+{ callPackage, fetchgit, ... } @ args:
+
+callPackage ./generic.nix (args // {
+  version = "2015-12-20";
+  src = fetchgit {
+    sha256 = "998fdc9cdd3f9220c38244e0b87bba3ee623d7d20726479b04ed95b3836a37ed";
+    rev = "5136e664b8608604f54a2cc1d466019922b311e6";
+    url = "git://alioth.debian.org/git/sane/sane-backends.git";
+  };
+})

pkgs/top-level/all-packages.nix

@@ -15531,14 +15531,14 @@ let
     };
   };
 
-  saneBackends = callPackage ../applications/graphics/sane/backends.nix {
+  saneBackends = callPackage ../applications/graphics/sane/backends {
     gt68xxFirmware = config.sane.gt68xxFirmware or null;
     snapscanFirmware = config.sane.snapscanFirmware or null;
     hotplugSupport = config.sane.hotplugSupport or true;
     libusb = libusb1;
   };
 
-  saneBackendsGit = callPackage ../applications/graphics/sane/backends-git.nix {
+  saneBackendsGit = callPackage ../applications/graphics/sane/backends/git.nix {
     gt68xxFirmware = config.sane.gt68xxFirmware or null;
     snapscanFirmware = config.sane.snapscanFirmware or null;
     hotplugSupport = config.sane.hotplugSupport or true;