Merge pull request #303 from marcoarnulfo/fix/restore-last-selection

Restore Last Selection brings back the previous selection

crates/engine/src/cmd/edit.rs

@@ -10,7 +10,7 @@ pub fn specs() -> Vec<CommandSpec> {
     vec![
         cmd!(noundo "edit.undo", "Undo", ["Edit"], Some("Cmd+Z"), "{}", can_undo, |e, _| Ok(json!({"undone": e.undo()}))),
         cmd!(noundo "edit.redo", "Redo", ["Edit"], Some("Cmd+Shift+Z"), "{}", can_redo, |e, _| Ok(json!({"redone": e.redo()}))),
-        cmd!("edit.restore_last_selection", "Restore Last Selection", ["Edit"], Some("Cmd+Alt+Z"), "{}", always, restore_selection),
+        cmd!(noundo "edit.restore_last_selection", "Restore Last Selection", ["Edit"], Some("Cmd+Alt+Z"), "{}", has_last_selection, restore_selection),
         cmd!("edit.cut", "Cut", ["Edit"], Some("Cmd+X"), "{tracks?, start?, end?}", has_range, |e, p| cut_copy(e, p, true, "edit.cut")),
         cmd!(noundo "edit.copy", "Copy", ["Edit"], Some("Cmd+C"), "{tracks?, start?, end?}", has_range, |e, p| cut_copy(e, p, false, "edit.copy")),
         cmd!("edit.paste", "Paste", ["Edit"], Some("Cmd+V"), "{tracks?, at?}", has_clipboard, paste),
@@ -152,8 +152,28 @@ fn shuffle(s: &Session) -> bool {
     s.edit.edit_mode == EditMode::Shuffle
 }
 
+fn has_last_selection(e: &Engine) -> std::result::Result<(), String> {
+    if e.last_selection.is_some() { Ok(()) } else { Err("no previous selection to restore".into()) }
+}
+
+/// Remember the selection `before` had when a command changed it, for Restore Last Selection.
+pub(crate) fn remember_selection(e: &mut Engine, before: &Session) {
+    let (old, new) = (&before.edit, &e.session().edit);
+    if old.selection == new.selection && old.selected_tracks == new.selected_tracks {
+        return;
+    }
+    e.last_selection = Some((old.selection, old.selected_tracks.clone()));
+}
+
+/// Swaps in the previous selection; `remember_selection` then keeps the one replaced, so
+/// invoking it again goes back.
 fn restore_selection(e: &mut Engine, _: &Value) -> Result<Value> {
-    Ok(json!({"selection": e.session().edit.selection}))
+    let (range, mut tracks) = e.last_selection.clone().ok_or_else(|| bad("edit.restore_last_selection", "no previous selection to restore"))?;
+    tracks.retain(|t| e.session().track(*t).is_some());
+    let ed = &mut e.session_mut().edit;
+    ed.selection = range;
+    ed.selected_tracks = tracks;
+    Ok(json!({"selection": range}))
 }
 
 fn cut_copy(e: &mut Engine, p: &Value, cut: bool, id: &str) -> Result<Value> {
@@ -848,4 +868,20 @@ mod tests {
         e.execute("edit.trim_to_file_boundaries", &json!({"clips": [ids[1].0]})).unwrap();
         assert_eq!(bounds(&e, t), vec![faded[0], (9_500, 60_000, 9_500)]);
     }
+
+    #[test]
+    fn restore_last_selection_swaps_back_to_the_previous_range_and_tracks() {
+        let mut e = Engine::default();
+        assert!(e.execute("edit.restore_last_selection", &json!({})).is_err(), "nothing to restore yet");
+        let ids = e.execute("track.new", &json!({"count": 2})).unwrap()["tracks"].clone();
+        e.execute("edit.select", &json!({"tracks": [ids[0]], "start": 1_000, "end": 4_000})).unwrap();
+        e.execute("edit.select", &json!({"tracks": [ids[1]], "start": 7_000, "end": 9_000})).unwrap();
+        let tracks = |e: &Engine| e.session().edit.selected_tracks.iter().map(|t| t.0).collect::<Vec<_>>();
+        e.execute("edit.restore_last_selection", &json!({})).unwrap();
+        assert_eq!(e.session().edit.selection, soundcraft_time::Range::new(1_000, 4_000));
+        assert_eq!(json!(tracks(&e)), json!([ids[0]]));
+        e.execute("edit.restore_last_selection", &json!({})).unwrap();
+        assert_eq!(e.session().edit.selection, soundcraft_time::Range::new(7_000, 9_000));
+        assert_eq!(json!(tracks(&e)), json!([ids[1]]));
+    }
 }

crates/engine/src/cmd/mod.rs

@@ -36,6 +36,8 @@ mod view;
 mod view_more;
 mod vst3;
 
+pub(crate) use edit::remember_selection;
+
 pub type Run = fn(&mut Engine, &Value) -> Result<Value>;
 /// `Err(reason)` = disabled.
 pub type Enabled = fn(&Engine) -> std::result::Result<(), String>;

crates/engine/src/lib.rs

@@ -120,6 +120,9 @@ pub struct Engine {
     merge_key: Option<String>,
     /// Messages for the UI status line / agents.
     pub messages: Vec<String>,
+    /// The edit selection (range, tracks) before the last change, for Restore Last Selection.
+    /// Kept out of the document so selecting never marks the session modified.
+    pub last_selection: Option<(soundcraft_time::Range, Vec<TrackId>)>,
 }
 
 impl Default for Engine {
@@ -148,6 +151,7 @@ impl Engine {
             dirty_at: Cell::new((0, false)),
             merge_key: None,
             messages: Vec::new(),
+            last_selection: None,
         }
     }
 
@@ -181,6 +185,7 @@ impl Engine {
         self.saved = Arc::clone(&self.doc);
         self.undo.clear();
         self.redo.clear();
+        self.last_selection = None;
         self.revision = self.revision.wrapping_add(1);
         self.dirty = false;
     }
@@ -282,6 +287,7 @@ impl Engine {
         };
         match result {
             Ok(v) => {
+                cmd::remember_selection(self, &before);
                 if spec.undoable && !Arc::ptr_eq(&before, &self.doc) {
                     self.push_undo(spec.label, before);
                 }