kodelife: add updateScript

pkgs/applications/graphics/kodelife/default.nix

@@ -95,6 +95,8 @@ stdenv.mkDerivation rec {
     runHook postInstall
   '';
 
+  passthru.updateScript = ./update.sh;
+
   meta = with lib; {
     homepage = "https://hexler.net/kodelife";
     description = "Real-time GPU shader editor";

pkgs/applications/graphics/kodelife/update.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p nix curl libxml2 jq
+
+set -euo pipefail
+
+nixpkgs="$(git rev-parse --show-toplevel || (printf 'Could not find root of nixpkgs repo\nAre we running from within the nixpkgs git repo?\n' >&2; exit 1))"
+
+attr="${UPDATE_NIX_ATTR_PATH:-kodelife}"
+version="$(curl -sSL https://hexler.net/kodelife/appcast/linux | xmllint --xpath '/rss/channel/item/enclosure/@*[local-name()="version"]' - | cut -d= -f2- | tr -d '"' | head -n1)"
+
+narhash() {
+    nix --extra-experimental-features nix-command store prefetch-file --json "$url" | jq -r .hash
+}
+
+nixeval() {
+    if [ "$#" -ge 2 ]; then
+        systemargs=(--argstr system "$2")
+    else
+        systemargs=()
+    fi
+
+    nix --extra-experimental-features nix-command eval --json --impure "${systemargs[@]}" -f "$nixpkgs" "$1" | jq -r .
+}
+
+findpath() {
+    path="$(nix --extra-experimental-features nix-command eval --json --impure -f "$nixpkgs" "$1.meta.position" | jq -r . | cut -d: -f1)"
+    outpath="$(nix --extra-experimental-features nix-command eval --json --impure --expr "builtins.fetchGit \"$nixpkgs\"")"
+
+    if [ -n "$outpath" ]; then
+        path="${path/$(echo "$outpath" | jq -r .)/$nixpkgs}"
+    fi
+
+    echo "$path"
+}
+
+oldversion="${UPDATE_NIX_OLD_VERSION:-$(nixeval "$attr".version)}"
+
+pkgpath="$(findpath "$attr")"
+
+if [ "$version" = "$oldversion" ]; then
+    echo 'update.sh: New version same as old version, nothing to do.'
+    exit 0
+fi
+
+sed -i -e "/version\s*=/ s|\"$oldversion\"|\"$version\"|" "$pkgpath"
+
+for system in aarch64-linux armv7l-linux x86_64-linux; do
+    url="$(nixeval "$attr".src.url "$system")"
+
+    curhash="$(nixeval "$attr".src.outputHash "$system")"
+    newhash="$(narhash "$url")"
+
+    sed -i -e "s|\"$curhash\"|\"$newhash\"|" "$pkgpath"
+done