search: incremental scrollback search with match highlight and prompt

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I0a0450eba48d308763db297f105565346a6a6964

src/grid.rs

@@ -142,6 +142,22 @@ pub struct Point {
     pub col: usize,
 }
 
+/// One scrollback-search hit: a run of `len` cells at absolute `(row, col)`.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+struct Match {
+    row: usize,
+    col: usize,
+    len: usize,
+}
+
+/// Incremental scrollback search: the query, every hit, and the focused one.
+#[derive(Clone, Debug, Default)]
+struct SearchState {
+    query: String,
+    matches: Vec<Match>,
+    current: usize,
+}
+
 /// The active screen plus cursor, scroll region, and current pen.
 #[derive(Debug)]
 pub struct Grid {
@@ -190,6 +206,8 @@ pub struct Grid {
     mouse_encoding: MouseEncoding,
     /// Focus in/out reporting (DECSET 1004).
     focus_events: bool,
+    /// Active incremental scrollback search, if any.
+    search: Option<SearchState>,
 }
 
 fn default_tabs(cols: usize) -> Vec<bool> {
@@ -239,6 +257,7 @@ impl Grid {
             mouse_protocol: MouseProtocol::Off,
             mouse_encoding: MouseEncoding::X10,
             focus_events: false,
+            search: None,
         }
     }
 
@@ -582,6 +601,7 @@ impl Grid {
             }
             if evicted > 0 {
                 self.shift_selection(evicted);
+                self.shift_search(evicted);
             }
             // Keep a scrolled-back viewport anchored to the same content.
             if self.view_offset > 0 {
@@ -976,6 +996,135 @@ impl Grid {
             .collect()
     }
 
+    // --- scrollback search ---
+
+    /// Set the search query and recompute matches over scrollback + the live
+    /// screen, focusing the most recent hit and scrolling it into view. An
+    /// empty query keeps search mode active but clears the hit list.
+    pub fn set_search(&mut self, query: &str) {
+        let matches = if query.is_empty() {
+            Vec::new()
+        } else {
+            self.compute_matches(query)
+        };
+        let current = matches.len().saturating_sub(1);
+        self.search = Some(SearchState {
+            query: query.to_string(),
+            matches,
+            current,
+        });
+        self.jump_to_current();
+    }
+
+    /// Move the focused match `forward` (toward newer) or back (toward older),
+    /// wrapping, and scroll it into view.
+    pub fn search_step(&mut self, forward: bool) {
+        if let Some(s) = self.search.as_mut()
+            && !s.matches.is_empty()
+        {
+            let n = s.matches.len();
+            s.current = if forward {
+                (s.current + 1) % n
+            } else {
+                (s.current + n - 1) % n
+            };
+        }
+        self.jump_to_current();
+    }
+
+    pub fn clear_search(&mut self) {
+        self.search = None;
+    }
+
+    /// The current query, while search mode is active.
+    pub fn search_query(&self) -> Option<&str> {
+        self.search.as_ref().map(|s| s.query.as_str())
+    }
+
+    /// `(focused match index 1-based, total matches)` for the search prompt.
+    pub fn search_count(&self) -> (usize, usize) {
+        self.search.as_ref().map_or((0, 0), |s| {
+            let total = s.matches.len();
+            (if total == 0 { 0 } else { s.current + 1 }, total)
+        })
+    }
+
+    /// Match spans `(lo, hi, is_current)` on absolute row `row`, for highlight.
+    pub fn search_spans_on(&self, row: usize) -> Vec<(usize, usize, bool)> {
+        let Some(s) = self.search.as_ref() else {
+            return Vec::new();
+        };
+        s.matches
+            .iter()
+            .enumerate()
+            .filter(|(_, m)| m.row == row && m.len > 0)
+            .map(|(i, m)| (m.col, m.col + m.len - 1, i == s.current))
+            .collect()
+    }
+
+    fn compute_matches(&self, query: &str) -> Vec<Match> {
+        // Smart case: an uppercase letter in the query forces case sensitivity.
+        let sensitive = query.chars().any(|c| c.is_ascii_uppercase());
+        let fold = |c: char| {
+            if sensitive { c } else { c.to_ascii_lowercase() }
+        };
+        let needle: Vec<char> = query.chars().map(fold).collect();
+        if needle.is_empty() {
+            return Vec::new();
+        }
+        let total = self.scrollback.len() + self.rows;
+        let mut matches = Vec::new();
+        for row in 0..total {
+            let hay: Vec<char> = self.abs_row(row).iter().map(|cell| fold(cell.c)).collect();
+            let mut i = 0;
+            while i + needle.len() <= hay.len() {
+                if hay[i..i + needle.len()] == needle[..] {
+                    matches.push(Match {
+                        row,
+                        col: i,
+                        len: needle.len(),
+                    });
+                    i += needle.len();
+                } else {
+                    i += 1;
+                }
+            }
+        }
+        matches
+    }
+
+    /// Scroll the viewport so the focused match is on screen, centering it only
+    /// when it would otherwise be off the visible range.
+    fn jump_to_current(&mut self) {
+        let Some(abs) = self
+            .search
+            .as_ref()
+            .and_then(|s| s.matches.get(s.current))
+            .map(|m| m.row)
+        else {
+            return;
+        };
+        let sb = self.scrollback.len();
+        let top = sb - self.view_offset;
+        let bottom = top + self.rows - 1;
+        if abs < top || abs > bottom {
+            let target = sb as isize + self.rows as isize / 2 - abs as isize;
+            self.view_offset = target.clamp(0, sb as isize) as usize;
+        }
+    }
+
+    /// Slide search hits up by `n` rows after scrollback eviction, dropping any
+    /// that scrolled off the top.
+    fn shift_search(&mut self, n: usize) {
+        if let Some(s) = self.search.as_mut() {
+            s.matches.retain(|m| m.row >= n);
+            for m in &mut s.matches {
+                m.row -= n;
+            }
+            s.current = s.current.min(s.matches.len().saturating_sub(1));
+        }
+    }
+
     pub fn set_bracketed_paste(&mut self, on: bool) {
         self.bracketed_paste = on;
     }
@@ -1198,6 +1347,33 @@ mod tests {
         assert_eq!(g.selection_text().as_deref(), Some("bc\nfg\njk"));
     }
 
+    #[test]
+    fn search_finds_matches_across_history() {
+        let mut g = Grid::new(16, 2);
+        for line in ["alpha", "beta", "ALPHA", "gamma"] {
+            for c in line.chars() {
+                g.print(c);
+            }
+            g.carriage_return();
+            g.line_feed();
+        }
+        // Case-insensitive (no uppercase in query) matches both alphas.
+        g.set_search("alpha");
+        assert_eq!(g.search_count(), (2, 2)); // focus starts on the latest hit
+        let spans0 = g.search_spans_on(0);
+        assert_eq!(spans0, vec![(0, 4, false)]);
+        // Smart case: an uppercase letter restricts to the exact-case hit.
+        g.set_search("ALPHA");
+        assert_eq!(g.search_count(), (1, 1));
+        assert_eq!(g.search_spans_on(2), vec![(0, 4, true)]);
+        // Stepping wraps and the no-match query reports zero.
+        g.set_search("zzz");
+        assert_eq!(g.search_count(), (0, 0));
+        assert_eq!(g.search_query(), Some("zzz"));
+        g.clear_search();
+        assert_eq!(g.search_query(), None);
+    }
+
     #[test]
     fn scroll_region_limits_line_feed() {
         let mut g = Grid::new(4, 4);

src/render.rs

@@ -13,6 +13,11 @@ const DEFAULT_FG: Rgb = Rgb(0xc5, 0xc8, 0xc6);
 const DEFAULT_BG: Rgb = Rgb(0x18, 0x18, 0x18);
 /// Background painted behind selected cells.
 const SELECTION_BG: Rgb = Rgb(0x44, 0x47, 0x5a);
+/// Background behind a search match, and the focused match.
+const MATCH_BG: Rgb = Rgb(0x5a, 0x51, 0x2a);
+const CURRENT_MATCH_BG: Rgb = Rgb(0xb8, 0x8a, 0x2a);
+/// Search prompt bar drawn along the bottom row.
+const SEARCH_BAR_BG: Rgb = Rgb(0x30, 0x30, 0x40);
 
 #[derive(Clone, Copy, PartialEq, Eq)]
 struct Rgb(u8, u8, u8);
@@ -131,11 +136,20 @@ impl Renderer {
         // `cols` after a resize, so clamp with `take`.
         let abs = grid.view_to_abs(y);
         let cells = grid.view_row(y);
+        let search = grid.search_spans_on(abs);
+        let match_at = |x: usize| -> Option<bool> {
+            search
+                .iter()
+                .find(|(lo, hi, _)| x >= *lo && x <= *hi)
+                .map(|(_, _, current)| *current)
+        };
         for (x, cell) in cells.iter().take(cols).enumerate() {
-            let bg = if grid.is_selected(abs, x) {
-                SELECTION_BG
-            } else {
-                cell_colors(cell).1
+            // Focused match > selection > other match > the cell's own bg.
+            let bg = match match_at(x) {
+                Some(true) => CURRENT_MATCH_BG,
+                _ if grid.is_selected(abs, x) => SELECTION_BG,
+                Some(false) => MATCH_BG,
+                None => cell_colors(cell).1,
             };
             if bg != DEFAULT_BG {
                 canvas.fill_rect(x as i32 * m.width as i32, row_top, m.width, m.height, bg);
@@ -163,6 +177,36 @@ impl Renderer {
         }
     }
 
+    /// Draw the incremental-search prompt across the bottom row, over whatever
+    /// grid content was there. The caller marks the bottom row dirty so this
+    /// repaints whenever the query or match count changes.
+    pub fn render_search_bar(&mut self, pixels: &mut [u8], dims: (usize, usize), text: &str) {
+        let (width, height) = dims;
+        let mut canvas = Canvas {
+            pixels,
+            width,
+            height,
+        };
+        let m = self.fonts.metrics();
+        let rows = (height / m.height as usize).max(1);
+        let row_top = (rows - 1) as i32 * m.height as i32;
+        canvas.fill_rect(0, row_top, width as u32, m.height, SEARCH_BAR_BG);
+        let style = Style {
+            bold: false,
+            italic: false,
+        };
+        let mut x = 0i32;
+        for c in text.chars() {
+            if x as usize + m.width as usize > width {
+                break;
+            }
+            if c != ' ' {
+                self.draw_glyph(&mut canvas, c, style, x, row_top, DEFAULT_FG);
+            }
+            x += m.width as i32;
+        }
+    }
+
     /// Draw the cursor: a solid block/underline/beam when focused, a hollow
     /// outline when not. A blinking cursor shape is only drawn while `blink_on`.
     fn draw_cursor(

src/wayland.rs

@@ -122,6 +122,10 @@ struct RowSnap {
     cursor: Option<(usize, CursorShape, bool)>,
     /// Inclusive selected column span on this row.
     sel: Option<(usize, usize)>,
+    /// Search-match spans `(lo, hi, is_current)` highlighted on this row.
+    search: Vec<(usize, usize, bool)>,
+    /// Search-prompt text drawn over this row (only the bottom row, when active).
+    overlay: Option<String>,
     /// Blink phase, but only varied when the row actually has blinking ink, so
     /// non-blinking rows stay equal across phase toggles.
     blink: bool,
@@ -151,6 +155,8 @@ fn row_snap(grid: &Grid, y: usize, focused: bool, blink_on: bool) -> RowSnap {
         cells,
         cursor,
         sel: grid.selection_span_on(abs),
+        search: grid.search_spans_on(abs),
+        overlay: None,
         blink: if has_blink { blink_on } else { true },
     }
 }
@@ -241,6 +247,7 @@ pub fn run() -> anyhow::Result<ExitCode> {
         buf_dims: (0, 0),
         blink_on: true,
         sync_timeout: None,
+        searching: false,
         focused: true,
         exit: false,
         exit_code: ExitCode::SUCCESS,
@@ -359,6 +366,8 @@ struct App {
     blink_on: bool,
     /// Armed while synchronized output holds the screen, to force it open.
     sync_timeout: Option<RegistrationToken>,
+    /// Whether incremental search mode is active (the query lives in the grid).
+    searching: bool,
     /// Whether the toplevel currently has keyboard focus (drives the cursor).
     focused: bool,
     exit: bool,
@@ -429,6 +438,19 @@ impl App {
     /// viewport locally; anything else is encoded to the shell and snaps the
     /// viewport back to the live screen.
     fn handle_key(&mut self, event: &KeyEvent) {
+        // Ctrl+Shift+F toggles incremental search mode.
+        if self.modifiers.ctrl
+            && self.modifiers.shift
+            && matches!(event.keysym, Keysym::F | Keysym::f)
+        {
+            self.toggle_search();
+            return;
+        }
+        // While searching, the keyboard edits the query and navigates matches.
+        if self.searching {
+            self.search_key(event);
+            return;
+        }
         // Ctrl+Shift+C/V copy the selection and paste the clipboard; these take
         // precedence over the control bytes the chord would otherwise encode.
         if self.modifiers.ctrl && self.modifiers.shift {
@@ -475,6 +497,55 @@ impl App {
         }
     }
 
+    /// Enter or leave incremental search mode.
+    fn toggle_search(&mut self) {
+        self.searching = !self.searching;
+        if let Some(session) = self.session.as_mut() {
+            if self.searching {
+                session.term.grid_mut().set_search("");
+            } else {
+                session.term.grid_mut().clear_search();
+            }
+        }
+        self.needs_draw = true;
+    }
+
+    /// Handle a key while search mode is active: edit the query incrementally,
+    /// step between matches, or exit.
+    fn search_key(&mut self, event: &KeyEvent) {
+        let Some(session) = self.session.as_mut() else {
+            return;
+        };
+        let grid = session.term.grid_mut();
+        match event.keysym {
+            Keysym::Escape => {
+                grid.clear_search();
+                self.searching = false;
+            }
+            Keysym::Return | Keysym::KP_Enter | Keysym::Up | Keysym::Page_Up => {
+                grid.search_step(false);
+            }
+            Keysym::Down | Keysym::Page_Down => grid.search_step(true),
+            Keysym::BackSpace => {
+                let mut query = grid.search_query().unwrap_or("").to_string();
+                query.pop();
+                grid.set_search(&query);
+            }
+            _ => {
+                // Append typed text, ignoring control characters.
+                if let Some(text) = event.utf8.as_ref() {
+                    let printable: String = text.chars().filter(|c| !c.is_control()).collect();
+                    if !printable.is_empty() {
+                        let mut query = grid.search_query().unwrap_or("").to_string();
+                        query.push_str(&printable);
+                        grid.set_search(&query);
+                    }
+                }
+            }
+        }
+        self.needs_draw = true;
+    }
+
     /// Map window pixel coordinates to an absolute `(row, col)` grid point.
     fn cell_at(&self, px: f64, py: f64) -> Option<(usize, usize)> {
         let session = self.session.as_ref()?;
@@ -974,10 +1045,25 @@ impl App {
         };
         let grid = session.term.grid();
         let rows = grid.rows();
-        let cur: Vec<RowSnap> = (0..rows)
+        let mut cur: Vec<RowSnap> = (0..rows)
             .map(|y| row_snap(grid, y, focused, blink_on))
             .collect();
 
+        // The search prompt occupies the bottom row while search mode is active.
+        // Recording it in the snapshot keeps the row's damage/diff correct.
+        let bar_text = self.searching.then(|| {
+            let (n, total) = grid.search_count();
+            format!(
+                "search: {}  [{n}/{total}]",
+                grid.search_query().unwrap_or("")
+            )
+        });
+        if let Some(text) = &bar_text
+            && rows > 0
+        {
+            cur[rows - 1].overlay = Some(text.clone());
+        }
+
         // Reuse a buffer the compositor has released, else grow the ring.
         let stride = w as i32 * 4;
         let mut idx = None;
@@ -1032,6 +1118,12 @@ impl App {
             self.renderer
                 .render_row(canvas, dims, grid, y, focused, blink_on);
         }
+        // Draw the search prompt over the (now repainted) bottom row.
+        if let Some(text) = &bar_text
+            && dirty.contains(&(rows - 1))
+        {
+            self.renderer.render_search_bar(canvas, dims, text);
+        }
         self.frames[idx].rows = cur;
 
         let surface = self.window.wl_surface();