aqbanking: Add an updater script

The promised updater, which feeds sources.nix and should help updating
all the aqbanking libraries at the same time.

I was very reluctant to write the updater entirely in Nix as I've done a
while ago for Chromium, because this would involve ugly hacks to do so.

That's why I've done a more conservative approach here, only using
nix-instantiate to get the contents of the current sources.nix.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @cillianderoiste, @urkud

pkgs/development/libraries/aqbanking/sources.nix

@@ -1,3 +1,4 @@
+# This file is autogenerated from update.sh in the same directory.
 {
   gwenhywfar.version = "4.15.3";
   gwenhywfar.sha256 = "0fp67s932x66xfljb26zbrn8ambbc5y5c3hllr6l284nr63qf3ka";

pkgs/development/libraries/aqbanking/update.sh

@@ -0,0 +1,92 @@
+#!/bin/sh -e
+basedir="$(cd "$(dirname "$0")" && pwd)"
+
+getCurrentVersions() {
+    [ -e "$basedir/sources.nix" ] || return 0
+    (cd "$basedir" && nix-instantiate --eval --strict -E '
+    toString ((import ../../../../lib).mapAttrsToList
+        (name: info: "${name}:${info.version}!${info.sha256}!${info.releaseId}")
+        (import ./sources.nix))
+    ' | tr -d '"')
+}
+
+currentVersions="$(getCurrentVersions)"
+
+getLastestVersion() {
+    local baseurl="http://www.aquamaniac.de"
+    local pkglist="sites/download/packages.php?package=$1&showall=1"
+    local url="$baseurl/$pkglist"
+    local reVersion='[0-9]+(\.[0-9]+)+' # Only release versions, no betas!
+    local reHref='href=".*release=([0-9]+).*dummy=[^0-9]*('"$reVersion"')\.tar'
+    local reFull='s/^.*<a\>.*\<'"$reHref"'.*/\2!\1/p'
+    curl -s "$url" | sed -nre "$reFull" | sort -V -k 1,1 | tail -n1
+}
+
+getEntry() {
+    local name="$1"
+    for entry in $currentVersions; do
+        if [ "${entry%%:*}" = "$name" ]; then
+            echo "${entry#*:}"
+            return 0
+        fi
+    done
+    return 1
+}
+
+prefetchNew() {
+    local name="$1"
+    local version="$2"
+    local package="$3"
+    local releaseId="$4"
+
+    local url="http://www.aquamaniac.de/sites/download/download.php"
+    local qstring="package=$package&release=$releaseId&file=01";
+
+    nix-prefetch-url --name "$name-$version.tar.gz" "$url?$qstring"
+}
+
+processPackage() {
+    local name="$1"
+    local package="$2"
+
+    local latest="$(getLastestVersion "$package")"
+    local current="$(getEntry "$name")"
+    local currentTail="${current#*!}"
+
+    local currentVersion="${current%%!*}"
+    local currentSha256="${currentTail%%!*}"
+    local currentReleaseId="${current##*!}"
+
+    local latestVersion="${latest%%!*}"
+    local latestReleaseId="${latest##*!}"
+
+    if [ "$latestVersion" = "$currentVersion" -a \
+         "$latestReleaseId" = "$currentReleaseId" ]; then
+        echo "  $name.version = \"$currentVersion\";"
+        echo "  $name.sha256 = \"$currentSha256\";"
+        echo "  $name.releaseId = \"$currentReleaseId\";"
+        return 0
+    fi
+
+    local latestSha256="$(
+        prefetchNew "$name" "$latestVersion" "$package" "$latestReleaseId"
+    )"
+
+    echo "  $name.version = \"$latestVersion\";"
+    echo "  $name.sha256 = \"$latestSha256\";"
+    echo "  $name.releaseId = \"$latestReleaseId\";"
+    return 0
+}
+
+generateNewSources() {
+    echo "# This file is autogenerated from update.sh in the same directory."
+    echo "{"
+    for package in gwenhywfar:01 libchipcard:02 aqbanking:03; do
+        processPackage "${package%%:*}" "${package##*:}"
+    done
+    echo "}"
+}
+
+if newSources="$(generateNewSources)"; then
+    echo "$newSources" > "$basedir/sources.nix"
+fi