Improve performance of select-all-matches (#6700)

This fixes #6440.

The previous approach was calling select-next-match in a loop, which
leaves optimizations on the table when you already know that you want to
select all of the matches.

So what we did here is to optimize the code for the "give me all
matches" case:

1. Find all results in the current buffer
2. Build up *all* selections
3. Sort selections & throw away overlapping ones (keep oldest)
4. Unfold if necessary
5. Render selections

On my M3 Max searching for `<span` in the test file [1] from the ticket,
it

previously took: ~1.07s
now takes: ~4ms

[1]:
https://github.com/standardebooks/edgar-allan-poe_poetry/blob/master/src/epub/text/poetry.xhtml

![screenshot-2024-01-25-12 49
32@2x](https://github.com/zed-industries/zed/assets/1185253/9f8ef0fa-a3a7-461c-9ed6-263e48835806)

### Release Notes:

- Improved performance of select-all-matches by factor of ~250
([#6440](https://github.com/zed-industries/zed/issues/6440)).

crates/editor/src/actions.rs

@@ -13,12 +13,6 @@ pub struct SelectPrevious {
     pub replace_newest: bool,
 }
 
-#[derive(PartialEq, Clone, Deserialize, Default)]
-pub struct SelectAllMatches {
-    #[serde(default)]
-    pub replace_newest: bool,
-}
-
 #[derive(PartialEq, Clone, Deserialize, Default)]
 pub struct SelectToBeginningOfLine {
     #[serde(default)]
@@ -81,7 +75,6 @@ impl_actions!(
     [
         SelectNext,
         SelectPrevious,
-        SelectAllMatches,
         SelectToBeginningOfLine,
         MovePageUp,
         MovePageDown,
@@ -128,6 +121,7 @@ gpui::actions!(
         DeleteToNextWordEnd,
         DeleteToPreviousSubwordStart,
         DeleteToPreviousWordStart,
+        DisplayCursorNames,
         DuplicateLine,
         ExpandMacroRecursively,
         FindAllReferences,
@@ -185,6 +179,7 @@ gpui::actions!(
         ScrollCursorCenter,
         ScrollCursorTop,
         SelectAll,
+        SelectAllMatches,
         SelectDown,
         SelectLargerSyntaxNode,
         SelectLeft,
@@ -214,6 +209,5 @@ gpui::actions!(
         Undo,
         UndoSelection,
         UnfoldLines,
-        DisplayCursorNames
     ]
 );

crates/editor/src/editor.rs

@@ -6113,6 +6113,7 @@ impl Editor {
                         || (!movement::is_inside_word(&display_map, display_range.start)
                             && !movement::is_inside_word(&display_map, display_range.end))
                     {
+                        // TODO: This is n^2, because we might check all the selections
                         if selections
                             .iter()
                             .find(|selection| selection.range().overlaps(&offset_range))
@@ -6222,25 +6223,76 @@ impl Editor {
 
     pub fn select_all_matches(
         &mut self,
-        action: &SelectAllMatches,
+        _action: &SelectAllMatches,
         cx: &mut ViewContext<Self>,
     ) -> Result<()> {
         self.push_to_selection_history();
         let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
 
-        loop {
-            self.select_next_match_internal(&display_map, action.replace_newest, None, cx)?;
+        self.select_next_match_internal(&display_map, false, None, cx)?;
+        let Some(select_next_state) = self.select_next_state.as_mut() else {
+            return Ok(());
+        };
+        if select_next_state.done {
+            return Ok(());
+        }
 
-            if self
-                .select_next_state
-                .as_ref()
-                .map(|selection_state| selection_state.done)
-                .unwrap_or(true)
+        let mut new_selections = self.selections.all::<usize>(cx);
+
+        let buffer = &display_map.buffer_snapshot;
+        let query_matches = select_next_state
+            .query
+            .stream_find_iter(buffer.bytes_in_range(0..buffer.len()));
+
+        for query_match in query_matches {
+            let query_match = query_match.unwrap(); // can only fail due to I/O
+            let offset_range = query_match.start()..query_match.end();
+            let display_range = offset_range.start.to_display_point(&display_map)
+                ..offset_range.end.to_display_point(&display_map);
+
+            if !select_next_state.wordwise
+                || (!movement::is_inside_word(&display_map, display_range.start)
+                    && !movement::is_inside_word(&display_map, display_range.end))
             {
-                break;
+                self.selections.change_with(cx, |selections| {
+                    new_selections.push(Selection {
+                        id: selections.new_selection_id(),
+                        start: offset_range.start,
+                        end: offset_range.end,
+                        reversed: false,
+                        goal: SelectionGoal::None,
+                    });
+                });
             }
         }
 
+        new_selections.sort_by_key(|selection| selection.start);
+        let mut ix = 0;
+        while ix + 1 < new_selections.len() {
+            let current_selection = &new_selections[ix];
+            let next_selection = &new_selections[ix + 1];
+            if current_selection.range().overlaps(&next_selection.range()) {
+                if current_selection.id < next_selection.id {
+                    new_selections.remove(ix + 1);
+                } else {
+                    new_selections.remove(ix);
+                }
+            } else {
+                ix += 1;
+            }
+        }
+
+        select_next_state.done = true;
+        self.unfold_ranges(
+            new_selections.iter().map(|selection| selection.range()),
+            false,
+            false,
+            cx,
+        );
+        self.change_selections(Some(Autoscroll::fit()), cx, |selections| {
+            selections.select(new_selections)
+        });
+
         Ok(())
     }
 

crates/editor/src/editor_tests.rs

@@ -3820,6 +3820,18 @@ async fn test_select_next(cx: &mut gpui::TestAppContext) {
     cx.assert_editor_state("«abcˇ»\n«abcˇ» «abcˇ»\ndefabc\n«abcˇ»");
 }
 
+#[gpui::test]
+async fn test_select_all_matches(cx: &mut gpui::TestAppContext) {
+    init_test(cx, |_| {});
+
+    let mut cx = EditorTestContext::new(cx).await;
+    cx.set_state("abc\nˇabc abc\ndefabc\nabc");
+
+    cx.update_editor(|e, cx| e.select_all_matches(&SelectAllMatches::default(), cx))
+        .unwrap();
+    cx.assert_editor_state("«abcˇ»\n«abcˇ» «abcˇ»\ndefabc\n«abcˇ»");
+}
+
 #[gpui::test]
 async fn test_select_next_with_multiple_carets(cx: &mut gpui::TestAppContext) {
     init_test(cx, |_| {});