Small memory optimization

src/shell.rs

@@ -1157,7 +1157,7 @@ impl State {
 
     pub fn on_put(&mut self, text: String) -> RepaintMode {
         let double_width = text.is_empty();
-        RepaintMode::Area(self.model.put(text, double_width, self.cur_attrs.as_ref()))
+        RepaintMode::Area(self.model.put(Some(text), double_width, self.cur_attrs.as_ref()))
     }
 
     pub fn on_clear(&mut self) -> RepaintMode {

src/ui_model/cell.rs

@@ -79,25 +79,21 @@ impl Attrs {
 #[derive(Clone)]
 pub struct Cell {
     pub attrs: Attrs,
-    pub ch: String,
+    pub ch: Option<String>,
     pub dirty: bool,
 }
 
 impl Cell {
     pub fn new_empty() -> Cell {
-        Cell::new(" ".to_owned())
-    }
-
-    pub fn new(ch: String) -> Cell {
         Cell {
             attrs: Attrs::new(),
-            ch,
+            ch: None,
             dirty: true,
         }
     }
 
     pub fn clear(&mut self) {
-        self.ch = " ".to_owned();
+        self.ch = None;
         self.attrs.clear();
         self.dirty = true;
     }

src/ui_model/line.rs

@@ -70,12 +70,9 @@ impl Line {
     fn set_cell_to_item(&mut self, new_item: &PangoItemPosition) -> bool {
         let start_item_idx = self.cell_to_item(new_item.start_cell);
         let start_item_cells_count = if start_item_idx >= 0 {
-            self.item_line[start_item_idx as usize].as_ref().map_or(
+            self.item_line[start_item_idx as usize]
-                -1,
+                .as_ref()
-                |item| {
+                .map_or(-1, |item| item.cells_count as i32)
-                    item.cells_count as i32
-                },
-            )
         } else {
             -1
         };
@@ -85,9 +82,9 @@ impl Line {
         // start_item == idx of item start cell
         // in case different item length was in previous iteration
         // mark all item as dirty
-        if start_item_idx != new_item.start_cell as i32 ||
+        if start_item_idx != new_item.start_cell as i32
-            new_item.cells_count() != start_item_cells_count ||
+            || new_item.cells_count() != start_item_cells_count || start_item_idx == -1
-            start_item_idx == -1 || end_item_idx == -1
+            || end_item_idx == -1
         {
             self.initialize_cell_item(new_item.start_cell, new_item.end_cell, new_item.item);
             true
@@ -110,9 +107,9 @@ impl Line {
     }
 
     pub fn merge(&mut self, old_items: &StyledLine, pango_items: &[sys_pango::Item]) {
-        let mut pango_item_iter = pango_items.iter().map(|item| {
+        let mut pango_item_iter = pango_items
-            PangoItemPosition::new(old_items, item)
+            .iter()
-        });
+            .map(|item| PangoItemPosition::new(old_items, item));
 
         let mut next_item = pango_item_iter.next();
         let mut move_to_next_item = false;
@@ -120,7 +117,7 @@ impl Line {
         let mut cell_idx = 0;
         while cell_idx < self.line.len() {
             let dirty = match next_item {
-                None => self.set_cell_to_empty(cell_idx), 
+                None => self.set_cell_to_empty(cell_idx),
                 Some(ref new_item) => {
                     if cell_idx < new_item.start_cell {
                         self.set_cell_to_empty(cell_idx)
@@ -257,7 +254,7 @@ impl StyledLine {
                 continue;
             }
 
-            line_str.push_str(&cell.ch);
+            line_str.push_str(cell.ch.as_ref().map(|ch| ch.as_str()).unwrap_or(" "));
             let len = line_str.len() - byte_offset;
 
             for _ in 0..len {
@@ -389,9 +386,9 @@ impl<'c> StyleAttr<'c> {
 
 impl<'c> PartialEq for StyleAttr<'c> {
     fn eq(&self, other: &Self) -> bool {
-        self.italic == other.italic && self.bold == other.bold &&
+        self.italic == other.italic && self.bold == other.bold
-            self.foreground == other.foreground && self.empty == other.empty &&
+            && self.foreground == other.foreground && self.empty == other.empty
-            self.background == other.background
+            && self.background == other.background
     }
 }
 
@@ -402,9 +399,9 @@ mod tests {
     #[test]
     fn test_styled_line() {
         let mut line = Line::new(3);
-        line[0].ch = "a".to_owned();
+        line[0].ch = Some("a".to_owned());
-        line[1].ch = "b".to_owned();
+        line[1].ch = Some("b".to_owned());
-        line[2].ch = "c".to_owned();
+        line[2].ch = Some("c".to_owned());
 
         let styled_line = StyledLine::from(&line, &color::ColorModel::new());
         assert_eq!("abc", styled_line.line_str);

src/ui_model/mod.rs

@@ -93,7 +93,7 @@ impl UiModel {
         (self.cur_row, self.cur_col)
     }
 
-    pub fn put(&mut self, ch: String, double_width: bool, attrs: Option<&Attrs>) -> ModelRect {
+    pub fn put(&mut self, ch: Option<String>, double_width: bool, attrs: Option<&Attrs>) -> ModelRect {
         let mut changed_region = self.cur_point();
         let line = &mut self.model[self.cur_row];
         line.dirty_line = true;
@@ -305,7 +305,7 @@ mod tests {
 
         model.set_cursor(1, 1);
 
-        let rect = model.put(" ".to_owned(), false, None);
+        let rect = model.put(Some(" ".to_owned()), false, None);
 
         assert_eq!(1, rect.top);
         assert_eq!(1, rect.left);

src/ui_model/model_layout.rs

@@ -78,7 +78,7 @@ impl ModelLayout {
             self.insert_into_lines(ch);
             self.layout_replace(0, 0);
         } else {
-            self.model.put(ch, false, None);
+            self.model.put(Some(ch), false, None);
         }
 
         self.model.set_cursor(row, col);
@@ -126,9 +126,9 @@ impl ModelLayout {
                     }
 
                     self.model.set_cursor(row_idx, col_idx as usize);
-                    self.model.put(ch.clone(), false, attr.as_ref());
+                    self.model.put(Some(ch.clone()), false, attr.as_ref());
                     if ch_width > 1 {
-                        self.model.put(" ".to_owned(), true, attr.as_ref());
+                        self.model.put(None, true, attr.as_ref());
                     }
 
                     if max_col_idx < col_idx {
@@ -220,7 +220,7 @@ mod tests {
 
         let (cols, _) = model.size();
         assert_eq!(4, cols);
-        assert_eq!("b", model.model.model()[0].line[1].ch);
+        assert_eq!(Some("b".to_owned()), model.model.model()[0].line[1].ch);
     }
 
     #[test]
@@ -234,7 +234,7 @@ mod tests {
 
         let (cols, _) = model.size();
         assert_eq!(3, cols);
-        assert_eq!("b", model.model.model()[0].line[1].ch);
+        assert_eq!(Some("b".to_owned()), model.model.model()[0].line[1].ch);
     }
 
     #[test]