playlists + lyrics: setlists with pages of their own, and the words timed to the voice

src-tauri/src/loudness.rs

@@ -101,8 +101,14 @@ pub fn snapshot(app: &tauri::AppHandle) -> (bool, f64, Option<CurrentTrack>) {
     )
 }
 
+/// Keyed by track path, so it describes THIS library's files and belongs
+/// beside them. Measuring a whole library again on another machine is hours
+/// of work that the drive was already carrying the answer to.
 fn cache_file(app: &tauri::AppHandle) -> Option<PathBuf> {
-    app.path().app_data_dir().ok().map(|d| d.join(CACHE_FILE))
+    let cfg = crate::config::load(app);
+    crate::config::ensure_library_data_dir(app, &cfg)
+        .ok()
+        .map(|d| d.join(CACHE_FILE))
 }
 
 pub fn init(app: &tauri::AppHandle) {
@@ -947,8 +953,10 @@ mod tests {
                     .and_then(|e| e.to_str())
                     .unwrap_or_default()
                     .to_ascii_lowercase();
-                if matches!(ext.as_str(), "flac" | "mp3" | "ogg" | "opus" | "wav" | "m4a" | "aiff")
-                {
+                // Measuring means decoding, so this is the PLAYABLE table, not
+                // the recognised one — an `.opus` or `.wv` here only produces a
+                // failed decode (or, for WavPack, NaN).
+                if audio_formats::is_playable_ext(&ext) {
                     files.push(path);
                 }
             }
@@ -1092,8 +1100,7 @@ mod tests {
                     .and_then(|e| e.to_str())
                     .unwrap_or_default()
                     .to_ascii_lowercase();
-                if !matches!(ext.as_str(), "flac" | "mp3" | "ogg" | "opus" | "wav" | "m4a" | "aiff")
-                {
+                if !audio_formats::is_playable_ext(&ext) {
                     continue;
                 }
                 let artist = path