core/pkgs/by-name/gl/glibc/locales.nix

/* This function builds just the `lib/locale/locale-archive' file from
   Glibc and nothing else.  If `allLocales' is true, all supported
   locales are included; otherwise, just the locales listed in
   `locales'.  See localedata/SUPPORTED in the Glibc source tree for
   the list of all supported locales:
   https://sourceware.org/git/?p=glibc.git;a=blob;f=localedata/SUPPORTED
*/

{ lib, stdenv, buildPackages, callPackage, writeText, glibc, allLocales ? true
, locales ? [ "en_US.UTF-8/UTF-8" ] }:

(callPackage ./common.nix { inherit stdenv; } {
  pname = "glibc-locales";
  extraNativeBuildInputs = [ glibc ];
}).overrideAttrs (finalAttrs: previousAttrs: {

  builder = ./locales-builder.sh;

  outputs = [ "out" ];

  LOCALEDEF_FLAGS = [
    (if stdenv.hostPlatform.isLittleEndian then
      "--little-endian"
    else
      "--big-endian")
  ];

  preBuild = (previousAttrs.preBuild or "") + ''
    # Awful hack: `localedef' doesn't allow the path to `locale-archive'
    # to be overriden, but you *can* specify a prefix, i.e. it will use
    # <prefix>/<path-to-glibc>/lib/locale/locale-archive.  So we use
    # $TMPDIR as a prefix, meaning that the locale-archive is placed in
    # $TMPDIR/nix/store/...-glibc-.../lib/locale/locale-archive.
    LOCALEDEF_FLAGS+=" --prefix=$TMPDIR"

    mkdir -p $TMPDIR/"${buildPackages.glibc.out}/lib/locale"

    echo 'C.UTF-8/UTF-8 \' >> ../glibc-2*/localedata/SUPPORTED

    # Hack to allow building of the locales (needed since glibc-2.12)
    sed -i -e 's,^$(rtld-prefix) $(common-objpfx)locale/localedef,localedef $(LOCALEDEF_FLAGS),' ../glibc-2*/localedata/Makefile
  '' + lib.optionalString (!allLocales) ''
    # Check that all locales to be built are supported
    echo -n '${lib.concatMapStrings (s: s + " \\\n") locales}' \
      | sort -u > locales-to-build.txt
    cat ../glibc-2*/localedata/SUPPORTED | grep ' \\' \
      | sort -u > locales-supported.txt
    comm -13 locales-supported.txt locales-to-build.txt \
      > locales-unsupported.txt
    if [[ $(wc -c locales-unsupported.txt) != "0 locales-unsupported.txt" ]]; then
      cat locales-supported.txt
      echo "Error: unsupported locales detected:"
      cat locales-unsupported.txt
      echo "You should choose from the list above the error."
      false
    fi

    echo SUPPORTED-LOCALES='${
      toString locales
    }' > ../glibc-2*/localedata/SUPPORTED
  '';

  # Current `nixpkgs` way of building locales is not compatible with
  # parallel install. `locale-archive` is updated in parallel with
  # multiple `localedef` processes and causes non-deterministic result:
  #   https://github.com/NixOS/nixpkgs/issues/245360
  enableParallelBuilding = false;

  makeFlags = (previousAttrs.makeFlags or [ ]) ++ [
    "localedata/install-locales"
    "localedir=${builtins.placeholder "out"}/lib/locale"
  ];

  installPhase = ''
    mkdir -p "$out/lib/locale" "$out/share/i18n"
    cp -v "$TMPDIR/$NIX_STORE/"*"/lib/locale/locale-archive" "$out/lib/locale"
    cp -v ../glibc-2*/localedata/SUPPORTED "$out/share/i18n/SUPPORTED"
  '';

  setupHook = writeText "locales-setup-hook.sh" ''
    export LOCALE_ARCHIVE=@out@/lib/locale/locale-archive
  '';

  meta.description = "Locale information for the GNU C Library";
})