Add an automated updater script and definitions for its use for WebKit

svn path=/nixpkgs/trunk/; revision=16816

pkgs/build-support/upstream-updater/update-upstream-data.sh

@@ -0,0 +1,51 @@
+#! /bin/sh
+
+own_dir="$(cd "$(dirname "$0")"; sh -c pwd)"
+
+main_file="$1"
+main_dir="$(cd "$(dirname "$main_file")" ; sh -c pwd)"
+file_name="$(basename "$main_file")"
+defs_file="$main_dir"/src-info-for-"$file_name"
+src_file="$main_dir"/src-for-"$file_name"
+new_src_file="$main_dir"/updated-src-for-"$file_name"
+
+defs_dir="$("$own_dir"/attrset-to-dir.sh "$defs_file")"
+src_defs_dir="$("$own_dir"/attrset-to-dir.sh "$src_file")"
+
+getAttr () {
+    file="$defs_dir"/"$1"
+    data="$( ( [ -f "$file" ] && cat "$file" ) || echo "$2" )"
+    echo "attribute $1 obtained as: [[$data]]" >&2
+    echo "$data"
+}
+
+freshUrl="$("$own_dir"/urls-from-page.sh "$(getAttr downloadPage)" |
+  egrep "$(getAttr sourceRegexp '.*[.]tar[.].*')" | 
+  sh -c "$(getAttr choiceCommand 'head -1')")"
+
+echo "Found download link: $freshUrl" >&2
+
+if [ x"$freshUrl" = x"$(cat "$src_defs_dir"/advertisedUrl)" ]; then
+    echo "Source link not changed" >&2
+    exit
+fi
+
+version="$(echo "$freshUrl" | 
+  sed -re "$(getAttr versionExtractorSedScript \
+    's/.*-([0-9.]+)[.].*/\1/')")"
+
+mirrorUrl="$(echo "$freshUrl" | 
+  sed -r -e "$(getAttr versionReferenceCreator \
+    's/-([0-9.]+)[.]/-${version}./')" |
+  sed -r -e "$(getAttr mirrorSedScript)")"
+
+hash=$(nix-prefetch-url "$freshUrl")
+
+cat << EOF > "$new_src_file"
+rec {
+  advertisedUrl="$freshUrl";
+  version = "$version";
+  url="$mirrorUrl";
+  hash = "$hash";
+}
+EOF