1 files changed, 58 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/applications/graphics/tesseract/wrapper.nix b/nixpkgs/pkgs/applications/graphics/tesseract/wrapper.nix
new file mode 100644
index 000000000000..365d68a9ee76
--- /dev/null
+++ b/nixpkgs/pkgs/applications/graphics/tesseract/wrapper.nix
@@ -0,0 +1,58 @@
+{ stdenv, makeWrapper, tesseractBase, languages
+
+# A list of languages like [ "eng" "spa" … ] or `null` for all available languages
+, enableLanguages ? null
+
+# A list of files or a directory containing files
+, tessdata ? (if enableLanguages == null then languages.all
+              else map (lang: languages.${lang}) enableLanguages)
+
+# This argument is obsolete
+, enableLanguagesHash ? null
+}:
+
+let
+  passthru = { inherit tesseractBase languages tessdata; };
+
+  tesseractWithData = tesseractBase.overrideAttrs (_: {
+    inherit tesseractBase tessdata;
+
+    buildInputs = [ makeWrapper ];
+
+    buildCommand = ''
+      makeWrapper {$tesseractBase,$out}/bin/tesseract --set-default TESSDATA_PREFIX $out/share/tessdata
+
+      # Recursively link include, share
+      cp -rs --no-preserve=mode $tesseractBase/{include,share} $out
+
+      cp -r --no-preserve=mode $tesseractBase/lib $out
+      # Fixup the store paths in lib so that the tessdata from this derivation is used.
+      if (( ''${#tesseractBase} != ''${#out} )); then
+        echo "Can't replace store paths due to differing lengths"
+        exit 1
+      fi
+      find $out/lib -type f -exec sed -i "s|$tesseractBase|$out|g" {} \;
+
+      if [[ -d "$tessdata" ]]; then
+        ln -s $tessdata/* $out/share/tessdata
+      else
+        for lang in $tessdata; do
+          ln -s $lang $out/share/tessdata/''${lang#/nix/store*-}
+        done
+      fi
+
+      if [[ ! -e $out/share/tessdata/eng.traineddata ]]; then
+         # This is a bug in Tesseract's internal tessdata discovery mechanism
+         echo "eng.traineddata must be present in tessdata for Tesseract to work"
+         exit 1
+      fi
+    '';
+  });
+
+  tesseract = (if enableLanguages == [] then tesseractBase else tesseractWithData) // passthru;
+in
+  if enableLanguagesHash == null then
+    tesseract
+  else
+    stdenv.lib.warn "Argument `enableLanguagesHash` is obsolete and can be removed."
+    tesseract