Fix selection expansion across full-width glyphs

Instead of trying to expand the start and end of a selection across
full-width glyphs, the selection should now only go from its origin to
the end without any kind of expansion.

Instead, the expansion is now done where the cells are actually checked
for their selection status, expanding across the entire full-width glyph
whenever any part of it is selected.

Fixes #3106.

1 files changed, 1 insertions, 81 deletions

diff --git a/alacritty_terminal/src/selection.rs b/alacritty_terminal/src/selection.rs
index f2c98a55..333c31fb 100644
--- a/alacritty_terminal/src/selection.rs
+++ b/alacritty_terminal/src/selection.rs
@@ -23,7 +23,6 @@ use std::mem;
 use std::ops::Range;
 
 use crate::index::{Column, Line, Point, Side};
-use crate::term::cell::Flags;
 use crate::term::{Search, Term};
 
 /// A Point and side within that point.
@@ -249,67 +248,12 @@ impl Selection {
         let is_block = self.ty == SelectionType::Block;
         let (start, end) = Self::grid_clamp(start, end, is_block, grid.len()).ok()?;
 
-        let range = match self.ty {
+        match self.ty {
             SelectionType::Simple => self.range_simple(start, end, num_cols),
             SelectionType::Block => self.range_block(start, end),
             SelectionType::Semantic => Self::range_semantic(term, start.point, end.point),
             SelectionType::Lines => Self::range_lines(term, start.point, end.point),
-        };
-
-        // Expand selection across fullwidth cells
-        range.map(|range| Self::range_expand_fullwidth(term, range))
-    }
-
-    /// Expand the start/end of the selection range to account for fullwidth glyphs.
-    fn range_expand_fullwidth<T>(term: &Term<T>, mut range: SelectionRange) -> SelectionRange {
-        let grid = term.grid();
-        let num_cols = grid.num_cols();
-
-        // Helper for checking if cell at `point` contains `flag`
-        let flag_at = |point: Point<usize>, flag: Flags| -> bool {
-            grid[point.line][point.col].flags.contains(flag)
-        };
-
-        // Include all double-width cells and placeholders at top left of selection
-        if range.start.col < num_cols {
-            // Expand from wide char spacer to wide char
-            if range.start.line + 1 != grid.len() || range.start.col.0 != 0 {
-                let prev = range.start.sub(num_cols.0, 1, true);
-                if flag_at(range.start, Flags::WIDE_CHAR_SPACER) && flag_at(prev, Flags::WIDE_CHAR)
-                {
-                    range.start = prev;
-                }
-            }
-
-            // Expand from wide char to wide char spacer for linewrapping
-            if range.start.line + 1 != grid.len() || range.start.col.0 != 0 {
-                let prev = range.start.sub(num_cols.0, 1, true);
-                if (prev.line + 1 != grid.len() || prev.col.0 != 0)
-                    && flag_at(prev, Flags::WIDE_CHAR_SPACER)
-                    && !flag_at(prev.sub(num_cols.0, 1, true), Flags::WIDE_CHAR)
-                {
-                    range.start = prev;
-                }
-            }
-        }
-
-        // Include all double-width cells and placeholders at bottom right of selection
-        if range.end.line != 0 || range.end.col < num_cols {
-            // Expand from wide char spacer for linewrapping to wide char
-            if (range.end.line + 1 != grid.len() || range.end.col.0 != 0)
-                && flag_at(range.end, Flags::WIDE_CHAR_SPACER)
-                && !flag_at(range.end.sub(num_cols.0, 1, true), Flags::WIDE_CHAR)
-            {
-                range.end = range.end.add(num_cols.0, 1, true);
-            }
-
-            // Expand from wide char to wide char spacer
-            if flag_at(range.end, Flags::WIDE_CHAR) {
-                range.end = range.end.add(num_cols.0, 1, true);
-            }
         }
-
-        range
     }
 
     // Bring start and end points in the correct order
@@ -443,15 +387,11 @@ impl Selection {
 /// look like [ B] and [E ].
 #[cfg(test)]
 mod tests {
-    use std::mem;
-
     use super::{Selection, SelectionRange};
     use crate::clipboard::Clipboard;
     use crate::config::MockConfig;
     use crate::event::{Event, EventListener};
-    use crate::grid::Grid;
     use crate::index::{Column, Line, Point, Side};
-    use crate::term::cell::{Cell, Flags};
     use crate::term::{SizeInfo, Term};
 
     struct Mock;
@@ -638,26 +578,6 @@ mod tests {
     }
 
     #[test]
-    fn double_width_expansion() {
-        let mut term = term(10, 1);
-        let mut grid = Grid::new(Line(1), Column(10), 0, Cell::default());
-        grid[Line(0)][Column(0)].flags.insert(Flags::WIDE_CHAR);
-        grid[Line(0)][Column(1)].flags.insert(Flags::WIDE_CHAR_SPACER);
-        grid[Line(0)][Column(8)].flags.insert(Flags::WIDE_CHAR);
-        grid[Line(0)][Column(9)].flags.insert(Flags::WIDE_CHAR_SPACER);
-        mem::swap(term.grid_mut(), &mut grid);
-
-        let mut selection = Selection::simple(Point::new(0, Column(1)), Side::Left);
-        selection.update(Point::new(0, Column(8)), Side::Right);
-
-        assert_eq!(selection.to_range(&term).unwrap(), SelectionRange {
-            start: Point::new(0, Column(0)),
-            end: Point::new(0, Column(9)),
-            is_block: false,
-        });
-    }
-
-    #[test]
     fn simple_is_empty() {
         let mut selection = Selection::simple(Point::new(0, Column(0)), Side::Right);
         assert!(selection.is_empty());