perf: share decoded note names and skip redundant project parses

src/main/java/net/tfminecraft/musicalinstruments/studio/Note.java

@@ -1,10 +1,14 @@
 package net.tfminecraft.musicalinstruments.studio;
 
+import java.util.regex.Pattern;
+
 /** A resolved sample trigger, captured independently of subsequent config changes. */
 public record Note(int tick, String instrument, String sound, float volume, float pitch) {
+    private static final Pattern SOUND = Pattern.compile("[a-z0-9_.-]+(:[a-z0-9_./-]+)?");
+
     public Note {
         if (tick < 0 || tick >= Song.MAX_TICKS || instrument == null || instrument.length() > 100
-                || sound == null || sound.length() > 200 || !sound.matches("[a-z0-9_.-]+(:[a-z0-9_./-]+)?")
+                || sound == null || sound.length() > 200 || !SOUND.matcher(sound).matches()
                 || !Float.isFinite(volume) || volume < 0 || volume > 16
                 || !Float.isFinite(pitch) || pitch < 0.5f || pitch > 2) {
             throw new IllegalArgumentException("Invalid recorded note");

src/main/java/net/tfminecraft/musicalinstruments/studio/Song.java

@@ -41,6 +41,12 @@ public Track track(int slot) {
         return tracks.stream().filter(track -> track.slot() == slot).findFirst().orElse(null);
     }
 
+    /** Whether playback emits any sound; matches the notes {@link Timeline} schedules. */
+    public boolean audible() {
+        return tracks.stream().anyMatch(track -> !track.muted() && track.gain() > 0
+                && track.notes().stream().anyMatch(note -> note.volume() > 0));
+    }
+
     public Song replace(Track track) {
         List<Track> result = new ArrayList<>(tracks);
         result.removeIf(existing -> existing.slot() == track.slot());

src/main/java/net/tfminecraft/musicalinstruments/studio/StudioService.java

@@ -357,7 +357,7 @@ private Song publishEdition(Player player) throws IOException {
         if (project.pending() != null) {
             throw new IllegalArgumentException("Keep or discard your pending take first");
         }
-        if (new Timeline(project.song(), -1).due(Song.MAX_TICKS).isEmpty()) {
+        if (!project.song().audible()) {
             throw new IllegalArgumentException("The mix needs at least one audible note");
         }
         Song edition = project.song().edition();

src/main/java/net/tfminecraft/musicalinstruments/studio/StudioStore.java

@@ -15,13 +15,18 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
 
 /** Versioned, bounded data files. A failed write never truncates the last saved project. */
 public final class StudioStore {
     // Enough for a full 12,000-note song plus a replacement take, including escaped names.
     static final int MAX_FILE_BYTES = 32_000_000;
     private final Path root;
+    // Owners whose selected file already has its per-project copy. Both the main thread
+    // and the checkpoint writer save, so the set is concurrent.
+    private final Set<UUID> archived = ConcurrentHashMap.newKeySet();
 
     public StudioStore(Path root) throws IOException {
         this.root = root;
@@ -115,15 +120,17 @@ public void save(Project project) throws IOException {
         UUID owner = project.song().owner();
         Path selectedFile = root.resolve("projects").resolve(owner + ".yml");
         Files.createDirectories(projectFile(owner, project.song().id()).getParent());
-        // Archive the original single-project file before selecting a different song.
-        if (Files.exists(selectedFile)) {
+        // Archive the original single-project file before selecting a different song. Every save
+        // below writes both copies, so this parse runs once per owner instead of on every save.
+        if (!archived.contains(owner) && Files.exists(selectedFile)) {
             Project previous = decodeProject(selectedFile, owner, null);
             Path previousFile = projectFile(owner, previous.song().id());
             if (!Files.exists(previousFile)) write(previousFile, encodeProject(previous), true);
         }
         YamlConfiguration yaml = encodeProject(project);
         write(projectFile(owner, project.song().id()), yaml, true);
         write(selectedFile, yaml, true);
+        archived.add(owner);
     }
 
     private YamlConfiguration encodeProject(Project project) {
@@ -228,7 +235,7 @@ private Track decodeTrack(Map<?, ?> raw) {
             if (note.size() != 5) {
                 throw new IllegalArgumentException("Invalid note fields");
             }
-            notes.add(new Note(integer(note.get(0)), (String) note.get(1), (String) note.get(2),
+            notes.add(new Note(integer(note.get(0)), text(note.get(1)), text(note.get(2)),
                     number(note.get(3)).floatValue(), number(note.get(4)).floatValue()));
         }
         return new Track(integer(raw.get("slot")), integer(raw.get("length")),
@@ -247,6 +254,14 @@ private List<?> list(Object value) {
         return (List<?>) value;
     }
 
+    private String text(Object value) {
+        if (!(value instanceof String text)) {
+            throw new IllegalArgumentException("Expected text");
+        }
+        // Songs repeat a few instrument and sample names; share one copy instead of one per note.
+        return text.intern();
+    }
+
     private Number number(Object value) {
         if (!(value instanceof Number number)) {
             throw new IllegalArgumentException("Expected a number");

src/test/java/net/tfminecraft/musicalinstruments/studio/StudioModelTest.java

@@ -40,6 +40,16 @@ void backingExcludesTheTrackBeingReplacedAndMutedTracks() {
         assertEquals(List.of("backing"), new Timeline(song, 1).due(0).stream().map(t -> t.note().sound()).toList());
     }
 
+    @Test
+    void audibilityIgnoresMutedSilentAndZeroVolumeTracks() {
+        Track muted = new Track(1, 10, 1, false, List.of(note(0, "a"))).mix(1, true);
+        Track silent = new Track(2, 10, 0, false, List.of(note(0, "b")));
+        Track quiet = new Track(3, 10, 1, false, List.of(new Note(0, "lute", "c", 0, 1)));
+        assertFalse(song(muted, silent, quiet).audible());
+        assertFalse(song().audible());
+        assertTrue(song(muted, new Track(4, 10, 1, false, List.of(new Note(0, "lute", "d", 0, 1), note(1, "e")))).audible());
+    }
+
     @Test
     void acceptingOrDiscardingATakePreservesPublishedEditions() {
         Song original = song(new Track(1, 100, 1, false, List.of(note(0, "original"))));

src/test/java/net/tfminecraft/musicalinstruments/studio/StudioStoreRecoveryTest.java

@@ -102,12 +102,13 @@ void malformedNumericFieldsAndOversizedSongStructuresCannotLoad() throws Excepti
             track.put("slot", slot); yaml.set("tracks", List.of(track)); yaml.save(file.toFile());
             assertThrows(IOException.class, () -> store.song(project.song().id()));
         }
-        for (int mode = 0; mode < 3; mode++) {
+        for (int mode = 0; mode < 4; mode++) {
             YamlConfiguration yaml = new YamlConfiguration(); yaml.loadFromString(valid);
             Map<String, Object> track = new LinkedHashMap<>((Map<String, Object>) yaml.getMapList("tracks").getFirst());
             if (mode == 0) yaml.set("tracks", Collections.nCopies(9, track));
             else {
-                track.put("notes", mode == 1 ? Collections.nCopies(Song.MAX_NOTES + 1, List.of(0, "lute", "note", 1, 1)) : List.of(List.of(0, "lute")));
+                track.put("notes", mode == 1 ? Collections.nCopies(Song.MAX_NOTES + 1, List.of(0, "lute", "note", 1, 1))
+                        : mode == 2 ? List.of(List.of(0, "lute")) : List.of(List.of(0, "lute", 7, 1, 1)));
                 yaml.set("tracks", List.of(track));
             }
             yaml.save(file.toFile()); assertThrows(IOException.class, () -> store.song(project.song().id()));

src/test/java/net/tfminecraft/musicalinstruments/studio/StudioStoreTest.java

@@ -103,9 +103,9 @@ void switchingProjectsMigratesTheLegacySongWithoutLosingItsPendingTake() throws
         Project legacy = project();
         store.save(legacy);
         Path archived = directory.resolve("projects").resolve(legacy.song().owner().toString()).resolve(legacy.song().id() + ".yml");
-        Files.delete(archived); // Simulate the original single-project layout.
+        Files.delete(archived); // Simulate the original single-project layout, present when the server starts.
         Project second = new Project(new Song(UUID.randomUUID(), legacy.song().owner(), "Musician", "Second", List.of()), null, 100, true);
-        store.save(second);
+        new StudioStore(directory).save(second);
         StudioStore reopened = new StudioStore(directory);
         assertEquals(2, reopened.projects(legacy.song().owner()).size());
         assertEquals(legacy, reopened.project(legacy.song().owner(), legacy.song().id()));
@@ -115,6 +115,31 @@ void switchingProjectsMigratesTheLegacySongWithoutLosingItsPendingTake() throws
         assertEquals(second, reopened.project(legacy.song().owner(), second.song().id()));
     }
 
+    @Test
+    void decodedNotesShareRepeatedInstrumentAndSampleNames() throws Exception {
+        var notes = List.of(new Note(0, "lute", "tfmc:lute.c4", 1, 1), new Note(1, "lute", "tfmc:lute.c4", 1, 1));
+        Project project = new Project(new Song(UUID.randomUUID(), UUID.randomUUID(), "Musician", "Song",
+                List.of(new Track(1, 10, 1, false, notes))), null, 100, false);
+        new StudioStore(directory).save(project);
+        Song song = new StudioStore(directory).project(project.song().owner()).orElseThrow().song();
+        Note first = song.track(1).notes().get(0);
+        Note second = song.track(1).notes().get(1);
+        assertSame(first.instrument(), second.instrument());
+        assertSame(first.sound(), second.sound());
+    }
+
+    @Test
+    void laterSavesDoNotReparseTheSelectedFile() throws Exception {
+        StudioStore store = new StudioStore(directory);
+        Project project = project();
+        store.save(project);
+        Path selected = directory.resolve("projects").resolve(project.song().owner() + ".yml");
+        Files.writeString(selected, "[broken yaml");
+        assertThrows(IOException.class, () -> new StudioStore(directory).save(project)); // A new store checks once.
+        store.save(project.accept());
+        assertEquals(project.accept(), store.project(project.song().owner()).orElseThrow());
+    }
+
     @Test
     void projectLibrariesAndDirectSelectionCannotCrossOwners() throws Exception {
         StudioStore store = new StudioStore(directory);