touchosc: make updateScript more readable and robust

Changes:
* factor out different system attrs for nixeval function
* factor out narhash function
* avoid doing work if version has not actually changed
* better support running script directly instead of via
  maintainers/scripts/update.nix

1 files changed, 26 insertions, 5 deletions

diff --git a/pkgs/applications/audio/touchosc/update.sh b/pkgs/applications/audio/touchosc/update.sh
index f656a1df72d4b..dc3e2f0888780 100755
--- a/pkgs/applications/audio/touchosc/update.sh
+++ b/pkgs/applications/audio/touchosc/update.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i bash -p nix curl libxml2 jq common-updater-scripts
+#!nix-shell -i bash -p nix curl libxml2 jq
 
 set -euo pipefail
 
@@ -8,6 +8,20 @@ nixpkgs="$(git rev-parse --show-toplevel || (printf 'Could not find root of nixp
 attr="${UPDATE_NIX_ATTR_PATH:-touchosc}"
 version="$(curl -sSL https://hexler.net/touchosc/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 \"$nixpkgs\"")"
@@ -19,15 +33,22 @@ findpath() {
     echo "$path"
 }
 
+oldversion="${UPDATE_NIX_OLD_VERSION:-$(nixeval "$attr".version)}"
+
 pkgpath="$(findpath "$attr")"
 
-sed -i -e "/version\s*=/ s|\"$UPDATE_NIX_OLD_VERSION\"|\"$version\"|" "$pkgpath"
+if [ "$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="$(nix --extra-experimental-features nix-command eval --json --impure --argstr system "$system" -f "$nixpkgs" "$attr".src.url | jq -r .)"
+    url="$(nixeval "$attr".src.url "$system")"
 
-    curhash="$(nix --extra-experimental-features nix-command eval --json --impure --argstr system "$system" -f "$nixpkgs" "$attr".src.outputHash | jq -r .)"
-    newhash="$(nix --extra-experimental-features nix-command store prefetch-file --json "$url" | jq -r .hash)"
+    curhash="$(nixeval "$attr".src.outputHash "$system")"
+    newhash="$(narhash "$url")"
 
     sed -i -e "s|\"$curhash\"|\"$newhash\"|" "$pkgpath"
 done