add line rendering fallback

Author: aaron-ang

src/uu/more/src/more.rs

@@ -631,7 +631,7 @@ impl<'a> Pager<'a> {
     }
 
     // TODO: Deal with column size changes.
-    fn page_resize(&mut self, _: u16, row: u16, option_line: Option<u16>) {
+    fn page_resize(&mut self, _col: u16, row: u16, option_line: Option<u16>) {
         if option_line.is_none() {
             self.content_rows = row.saturating_sub(1) as usize;
         };
@@ -654,19 +654,20 @@ impl<'a> Pager<'a> {
         // Ensure we have enough lines loaded for display
         self.read_until_line(self.upper_mark + self.content_rows)?;
 
+        // Display lines until we've filled the screen
         let mut visible_lines = 0;
         let mut index = self.upper_mark;
-
-        // Display lines until we've filled the screen or run out of lines
-        while visible_lines < self.content_rows && index < self.lines.len() {
+        let fallback = "~\n".to_string();
+        while visible_lines < self.content_rows {
             // Skip this line if it should be squeezed
             if self.should_squeeze_line(index) {
                 self.lines_squeezed += 1;
                 index += 1;
                 continue;
             }
-            // Display the line and move to next
-            stdout.write_all(format!("\r{}", self.lines[index]).as_bytes())?;
+            // Display the line
+            let line = self.lines.get(index).unwrap_or(&fallback);
+            stdout.write_all(format!("\r{}", line).as_bytes())?;
             visible_lines += 1;
             index += 1;
         }
@@ -692,7 +693,7 @@ impl<'a> Pager<'a> {
     /// with appropriate progress information and user feedback
     fn draw_prompt(&mut self, stdout: &mut impl Write, wrong_key: Option<char>) {
         // Calculate the index of the last visible line
-        let lower_mark = (self.upper_mark + self.content_rows).min(self.lines.len());
+        let lower_mark = (self.upper_mark + self.content_rows).min(self.lines.len() - 1);
 
         // Determine progress information to display
         // - Show next file name when at EOF and there is a next file