Fix panics when resizing (#1408)

* Change buffer.get & buffer.get_mut to return Option, Implement Trait Index & IndexMut to panic

* Prevent FilePicker from drawing outside buffer (rust panics)

* apply suggestion

* add function in_bounds to avoid useless calculations

Co-authored-by: mathis <mathis.brossier@universite-paris-saclay.fr>

4 files changed, 10 insertions, 12 deletions

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 8d811ed2..c8c94e14 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -97,8 +97,7 @@ impl EditorView {
             let x = area.right();
             let border_style = theme.get("ui.window");
             for y in area.top()..area.bottom() {
-                surface
-                    .get_mut(x, y)
+                surface[(x, y)]
                     .set_symbol(tui::symbols::line::VERTICAL)
                     //.set_symbol(" ")
                     .set_style(border_style);
@@ -393,8 +392,7 @@ impl EditorView {
                             .add_modifier(Modifier::DIM)
                     });
 
-                    surface
-                        .get_mut(viewport.x + pos.col as u16, viewport.y + pos.row as u16)
+                    surface[(viewport.x + pos.col as u16, viewport.y + pos.row as u16)]
                         .set_style(style);
                 }
             }
diff --git a/helix-term/src/ui/menu.rs b/helix-term/src/ui/menu.rs
index 69053db3..9758732c 100644
--- a/helix-term/src/ui/menu.rs
+++ b/helix-term/src/ui/menu.rs
@@ -301,7 +301,7 @@ impl<T: Item + 'static> Component for Menu<T> {
             let is_marked = i >= scroll_line && i < scroll_line + scroll_height;
 
             if is_marked {
-                let cell = surface.get_mut(area.x + area.width - 2, area.y + i as u16);
+                let cell = &mut surface[(area.x + area.width - 2, area.y + i as u16)];
                 cell.set_symbol("▐ ");
                 // cell.set_style(selected);
                 // cell.set_style(if is_marked { selected } else { style });
diff --git a/helix-term/src/ui/picker.rs b/helix-term/src/ui/picker.rs
index 1ef94df0..a061513c 100644
--- a/helix-term/src/ui/picker.rs
+++ b/helix-term/src/ui/picker.rs
@@ -159,6 +159,7 @@ impl<T: 'static> Component for FilePicker<T> {
         // |picker   | |         |
         // |         | |         |
         // +---------+ +---------+
+
         let render_preview = area.width > MIN_SCREEN_WIDTH_FOR_PREVIEW;
         let area = inner_rect(area);
         // -- Render the frame:
@@ -492,10 +493,9 @@ impl<T: 'static> Component for Picker<T> {
         let sep_style = Style::default().fg(Color::Rgb(90, 89, 119));
         let borders = BorderType::line_symbols(BorderType::Plain);
         for x in inner.left()..inner.right() {
-            surface
-                .get_mut(x, inner.y + 1)
-                .set_symbol(borders.horizontal)
-                .set_style(sep_style);
+            if let Some(cell) = surface.get_mut(x, inner.y + 1) {
+                cell.set_symbol(borders.horizontal).set_style(sep_style);
+            }
         }
 
         // -- Render the contents:
@@ -505,7 +505,7 @@ impl<T: 'static> Component for Picker<T> {
         let selected = cx.editor.theme.get("ui.text.focus");
 
         let rows = inner.height;
-        let offset = self.cursor / (rows as usize) * (rows as usize);
+        let offset = self.cursor / std::cmp::max(1, (rows as usize) * (rows as usize));
 
         let files = self.matches.iter().skip(offset).map(|(index, _score)| {
             (index, self.options.get(*index).unwrap()) // get_unchecked
@@ -513,7 +513,7 @@ impl<T: 'static> Component for Picker<T> {
 
         for (i, (_index, option)) in files.take(rows as usize).enumerate() {
             if i == (self.cursor - offset) {
-                surface.set_string(inner.x - 2, inner.y + i as u16, ">", selected);
+                surface.set_string(inner.x.saturating_sub(2), inner.y + i as u16, ">", selected);
             }
 
             surface.set_string_truncated(
diff --git a/helix-term/src/ui/prompt.rs b/helix-term/src/ui/prompt.rs
index 0202de23..4c4fef26 100644
--- a/helix-term/src/ui/prompt.rs
+++ b/helix-term/src/ui/prompt.rs
@@ -330,7 +330,7 @@ impl Prompt {
             .max(BASE_WIDTH);
 
         let cols = std::cmp::max(1, area.width / max_len);
-        let col_width = (area.width - (cols)) / cols;
+        let col_width = (area.width.saturating_sub(cols)) / cols;
 
         let height = ((self.completion.len() as u16 + cols - 1) / cols)
             .min(10) // at most 10 rows (or less)