Search incrementally in chunks of 1000 lines, show progress

This makes the search feel more responsive.

We search from bottom to top so that we show the more recent results
first, but for the sake of efficiency when accumulating result chunks
we need to reverse the order of the results vec from how it was
previously.

Each result chunk is loosely ordered from top to bottom, so we sort
it and reverse it: results[0] is the bottom-most result.

New rows are accumulated on the end of the result array; this is
not only more efficient, but it preverses the match result number
ordering.

The next/prior functions need to be swapped to account for this change
in result order.

refs: https://github.com/wez/wezterm/issues/1209

wezterm-gui/src/overlay/copy.rs

@@ -33,6 +33,8 @@ lazy_static::lazy_static! {
     static ref SAVED_PATTERN: Mutex<HashMap<TabId, Pattern>> = Mutex::new(HashMap::new());
 }
 
+const SEARCH_CHUNK_SIZE: StableRowIndex = 1000;
+
 pub struct CopyOverlay {
     delegate: Rc<dyn Pane>,
     render: RefCell<CopyRenderable>,
@@ -62,6 +64,11 @@ struct CopyRenderable {
     tab_id: TabId,
     /// Used to debounce queries while the user is typing
     typing_cookie: usize,
+    searching: Option<Searching>,
+}
+
+struct Searching {
+    remain: StableRowIndex,
 }
 
 #[derive(Debug)]
@@ -127,6 +134,7 @@ impl CopyOverlay {
             result_pos: None,
             selection_mode: SelectionMode::Cell,
             typing_cookie: 0,
+            searching: None,
         };
 
         let search_row = render.compute_search_row();
@@ -194,10 +202,11 @@ impl CopyRenderable {
         self.result_pos = pos;
     }
 
-    fn recompute_results(&mut self) {
-        log::debug!("there are {} results", self.results.len());
-        self.by_line.clear();
-        for (result_index, res) in self.results.iter().enumerate() {
+    fn incrementally_recompute_results(&mut self, mut results: Vec<SearchResult>) {
+        results.sort();
+        results.reverse();
+        for (result_index, res) in results.iter().enumerate() {
+            let result_index = self.results.len() + result_index;
             for idx in res.start_y..=res.end_y {
                 let range = if idx == res.start_y && idx == res.end_y {
                     // Range on same line
@@ -224,6 +233,7 @@ impl CopyRenderable {
                 self.dirty_results.add(idx);
             }
         }
+        self.results.append(&mut results);
     }
 
     fn schedule_update_search(&mut self) {
@@ -276,16 +286,21 @@ impl CopyRenderable {
             let pane: Rc<dyn Pane> = self.delegate.clone();
             let window = self.window.clone();
             let pattern = self.pattern.clone();
+            let dims = pane.get_dimensions();
+
+            let end = dims.scrollback_top + dims.scrollback_rows as StableRowIndex;
+            let range = end
+                .saturating_sub(SEARCH_CHUNK_SIZE)
+                .max(dims.scrollback_top)..end;
+
+            self.searching.replace(Searching {
+                remain: range.start - dims.scrollback_top,
+            });
+
             promise::spawn::spawn(async move {
-                let dims = pane.get_dimensions();
-                let range = dims.scrollback_top
-                    ..dims.scrollback_top + dims.scrollback_rows as StableRowIndex;
                 let limit = None;
-                log::debug!("Searching for {pattern:?} in {range:?}");
-                let mut results = pane.search(pattern, range, limit).await?;
-                log::debug!("Sorting {} results", results.len());
-                results.sort();
-                log::debug!("Sorted");
+                log::trace!("Searching for {pattern:?} in {range:?}");
+                let results = pane.search(pattern.clone(), range.clone(), limit).await?;
 
                 let pane_id = pane.pane_id();
                 let mut results = Some(results);
@@ -294,25 +309,81 @@ impl CopyRenderable {
                     if let Some(overlay) = state.overlay.as_ref() {
                         if let Some(copy_overlay) = overlay.pane.downcast_ref::<CopyOverlay>() {
                             let mut r = copy_overlay.render.borrow_mut();
-                            r.results = results.take().unwrap();
-                            r.recompute_results();
-                            let num_results = r.results.len();
-
-                            if !r.results.is_empty() {
-                                r.activate_match_number(num_results - 1);
-                            } else {
-                                r.set_viewport(None);
-                                r.clear_selection();
-                            }
+                            r.processed_search_chunk(pattern, results.take().unwrap(), range);
                         }
                     }
                 })));
+
                 anyhow::Result::<()>::Ok(())
             })
             .detach();
         } else {
+            self.searching.take();
             self.clear_selection();
         }
+        self.window.invalidate();
+    }
+
+    fn processed_search_chunk(
+        &mut self,
+        pattern: Pattern,
+        results: Vec<SearchResult>,
+        range: Range<StableRowIndex>,
+    ) {
+        self.window.invalidate();
+        if pattern != self.pattern {
+            return;
+        }
+        let is_first = self.results.is_empty();
+        self.incrementally_recompute_results(results);
+
+        if is_first {
+            if !self.results.is_empty() {
+                self.activate_match_number(0);
+            } else {
+                self.set_viewport(None);
+                self.clear_selection();
+            }
+        }
+
+        let dims = self.delegate.get_dimensions();
+        if range.start == dims.scrollback_top {
+            self.searching.take();
+            return;
+        }
+
+        // Search next chunk
+        let pane: Rc<dyn Pane> = self.delegate.clone();
+        let window = self.window.clone();
+        let end = range.start;
+        let range = end
+            .saturating_sub(SEARCH_CHUNK_SIZE)
+            .max(dims.scrollback_top)..end;
+
+        self.searching.replace(Searching {
+            remain: range.start - dims.scrollback_top,
+        });
+
+        promise::spawn::spawn(async move {
+            let limit = None;
+            log::trace!("Searching for {pattern:?} in {range:?}");
+            let results = pane.search(pattern.clone(), range.clone(), limit).await?;
+
+            let pane_id = pane.pane_id();
+            let mut results = Some(results);
+            window.notify(TermWindowNotif::Apply(Box::new(move |term_window| {
+                let state = term_window.pane_state(pane_id);
+                if let Some(overlay) = state.overlay.as_ref() {
+                    if let Some(copy_overlay) = overlay.pane.downcast_ref::<CopyOverlay>() {
+                        let mut r = copy_overlay.render.borrow_mut();
+                        r.processed_search_chunk(pattern, results.take().unwrap(), range);
+                    }
+                }
+            })));
+
+            anyhow::Result::<()>::Ok(())
+        })
+        .detach();
     }
 
     fn clear_selection(&mut self) {
@@ -483,8 +554,8 @@ impl CopyRenderable {
         self.select_to_cursor_pos();
     }
 
-    /// Move to prior match
-    fn prior_match(&mut self) {
+    /// Move to next match
+    fn next_match(&mut self) {
         if let Some(cur) = self.result_pos.as_ref() {
             let prior = if *cur > 0 {
                 cur - 1
@@ -495,8 +566,8 @@ impl CopyRenderable {
         }
     }
 
-    /// Move to next match
-    fn next_match(&mut self) {
+    /// Move to prior match
+    fn prior_match(&mut self) {
         if let Some(cur) = self.result_pos.as_ref() {
             let next = if *cur + 1 >= self.results.len() {
                 0
@@ -506,9 +577,10 @@ impl CopyRenderable {
             self.activate_match_number(next);
         }
     }
-    /// Skip this page of matches and move up to the first match from
-    /// the prior page.
-    fn prior_match_page(&mut self) {
+
+    /// Skip this page of matches and move down to the first match from
+    /// the next page.
+    fn next_match_page(&mut self) {
         let dims = self.delegate.get_dimensions();
         if let Some(cur) = self.result_pos {
             let top = self.viewport.unwrap_or(dims.physical_top);
@@ -525,9 +597,9 @@ impl CopyRenderable {
         }
     }
 
-    /// Skip this page of matches and move down to the first match from
-    /// the next page.
-    fn next_match_page(&mut self) {
+    /// Skip this page of matches and move up to the first match from
+    /// the prior page.
+    fn prior_match_page(&mut self) {
         let dims = self.delegate.get_dimensions();
         if let Some(cur) = self.result_pos {
             let top = self.viewport.unwrap_or(dims.physical_top);
@@ -1089,10 +1161,18 @@ impl Pane for CopyOverlay {
                             Pattern::CaseInSensitiveString(_) => "ignore-case",
                             Pattern::Regex(_) => "regex",
                         };
+
+                        let remain = match &self.renderer.searching {
+                            Some(Searching { remain, .. }) => {
+                                format!(" searching {remain} lines")
+                            }
+                            None => String::new(),
+                        };
+
                         line.overlay_text_with_attribute(
                             0,
                             &format!(
-                                "Search: {} ({}/{} matches. {})",
+                                "Search: {} ({}/{} matches. {}{remain})",
                                 *self.renderer.pattern,
                                 self.renderer.result_pos.map(|x| x + 1).unwrap_or(0),
                                 self.renderer.results.len(),