support end button in file tree (#43)

Author: Stephan Dilly

src/components/changes.rs

@@ -361,6 +361,9 @@ impl Component for ChangesComponent {
                     keys::HOME | keys::SHIFT_UP => {
                         self.move_selection(MoveSelection::Home)
                     }
+                    keys::END | keys::SHIFT_DOWN => {
+                        self.move_selection(MoveSelection::End)
+                    }
                     keys::MOVE_LEFT => {
                         self.move_selection(MoveSelection::Left)
                     }

src/components/diff.rs

@@ -99,11 +99,9 @@ impl DiffComponent {
                     self.scroll.saturating_add(1),
                 );
             }
-
             ScrollType::Up => {
                 self.scroll = self.scroll.saturating_sub(1);
             }
-
             ScrollType::Home => self.scroll = 0,
             ScrollType::End => self.scroll = scroll_max,
         }

src/components/statustree.rs

@@ -19,6 +19,7 @@ pub enum MoveSelection {
     Left,
     Right,
     Home,
+    End,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -73,6 +74,7 @@ impl StatusTree {
                     self.selection_right(selection)
                 }
                 MoveSelection::Home => SelectionChange::new(0, false),
+                MoveSelection::End => self.selection_end(),
             };
 
             let changed_index =
@@ -162,6 +164,27 @@ impl StatusTree {
         SelectionChange::new(new_index, false)
     }
 
+    fn selection_end(&self) -> SelectionChange {
+        let items_max = self.tree.len().saturating_sub(1);
+
+        let mut new_index = items_max;
+
+        loop {
+            if self.is_visible_index(new_index) {
+                break;
+            }
+
+            if new_index == 0 {
+                break;
+            }
+
+            new_index = new_index.saturating_sub(1);
+            new_index = cmp::min(new_index, items_max);
+        }
+
+        SelectionChange::new(new_index, false)
+    }
+
     fn is_visible_index(&self, idx: usize) -> bool {
         self.tree[idx].info.visible
     }