fix unicode characters in line printing (#4420)

* fix unicode characters in line printing

* remove outdated comment

packages/cli/src/serve/ansi_buffer.rs

@@ -1,88 +1,37 @@
-use ratatui::prelude::*;
-use std::fmt::{self, Display, Formatter};
+use ratatui::{buffer::Cell, prelude::*};
+use std::fmt::{self, Write};
 
 /// A buffer that can be rendered to and then dumped as raw ansi codes
 ///
 /// This is taken from a PR on the ratatui repo (<https://github.com/ratatui/ratatui/pull/1065>) and
 /// modified to be more appropriate for our use case.
-pub struct AnsiStringLine {
-    buf: Buffer,
+pub fn ansi_string_to_line(line: Line) -> String {
+    let graphemes = line.styled_graphemes(Style::default());
+    let mut out = String::with_capacity(line.spans.first().map_or(0, |s| s.content.len() * 2));
+    let mut last_style = None;
+    for grapheme in graphemes {
+        let mut cell = Cell::default();
+        cell.set_symbol(grapheme.symbol);
+        cell.set_style(grapheme.style);
+
+        let style = (cell.fg, cell.bg, cell.modifier);
+        if last_style.is_none() || last_style != Some(style) {
+            _ = write_cell_style(&mut out, cell.modifier, cell.fg, cell.bg);
+            last_style = Some(style);
+        }
+
+        _ = out.write_str(cell.symbol());
+    }
+
+    _ = out.write_str("\u{1b}[0m");
+
+    out
 }
 
-// The sentinel character used to mark the end of the ansi string so when we dump it, we know where to stop
-// Not sure if we actually still need this....
-const SENTINEL: &str = "✆";
-
-impl AnsiStringLine {
-    /// Creates a new `AnsiStringBuffer` with the given width and height.
-    pub(crate) fn new(width: u16) -> Self {
-        Self {
-            buf: Buffer::empty(Rect::new(0, 0, width, 1)),
-        }
-    }
-
-    /// Renders the given widget to the buffer, returning the string with the ansi codes
-    pub(crate) fn render(mut self, widget: impl Widget) -> String {
-        widget.render(self.buf.area, &mut self.buf);
-        self.trim_end();
-        self.to_string()
-    }
-
-    /// Trims the buffer to the last line, returning the number of cells to be rendered
-    #[allow(deprecated)]
-    fn trim_end(&mut self) {
-        for y in 0..self.buf.area.height {
-            let start_x = self.buf.area.width;
-            let mut first_non_empty = start_x;
-            for x in (0..start_x).rev() {
-                if self.buf.get(x, y) != &buffer::Cell::EMPTY {
-                    break;
-                }
-                first_non_empty = x;
-            }
-
-            if first_non_empty != start_x {
-                self.buf.get_mut(first_non_empty, y).set_symbol(SENTINEL);
-            }
-        }
-    }
-
-    fn write_fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        let mut last_style = None;
-        for y in 0..self.buf.area.height {
-            for x in 0..self.buf.area.width {
-                let cell = self.buf.cell((x, y)).unwrap();
-                if cell.symbol() == SENTINEL {
-                    break;
-                }
-
-                let style = (cell.fg, cell.bg, cell.modifier);
-                if last_style.is_none() || last_style != Some(style) {
-                    write_cell_style(f, cell)?;
-                    last_style = Some(style);
-                }
-                f.write_str(cell.symbol())?;
-            }
-        }
-        f.write_str("\u{1b}[0m")
-    }
-}
-
-impl Display for AnsiStringLine {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.write_fmt(f)
-    }
-}
-
-fn write_cell_style(f: &mut Formatter, cell: &buffer::Cell) -> fmt::Result {
+fn write_cell_style(f: &mut impl Write, modifier: Modifier, fg: Color, bg: Color) -> fmt::Result {
     f.write_str("\u{1b}[")?;
-    write_modifier(f, cell.modifier)?;
-    write_fg(f, cell.fg)?;
-    write_bg(f, cell.bg)?;
-    f.write_str("m")
-}
 
-fn write_modifier(f: &mut Formatter, modifier: Modifier) -> fmt::Result {
+    // Write the modifier codes
     if modifier.contains(Modifier::BOLD) {
         f.write_str("1;")?;
     }
@@ -110,11 +59,9 @@ fn write_modifier(f: &mut Formatter, modifier: Modifier) -> fmt::Result {
     if modifier.contains(Modifier::CROSSED_OUT) {
         f.write_str("9;")?;
     }
-    Ok(())
-}
 
-fn write_fg(f: &mut Formatter, color: Color) -> fmt::Result {
-    f.write_str(match color {
+    // Write the foreground
+    f.write_str(match fg {
         Color::Reset => "39",
         Color::Black => "30",
         Color::Red => "31",
@@ -134,17 +81,16 @@ fn write_fg(f: &mut Formatter, color: Color) -> fmt::Result {
         Color::White => "97",
         _ => "",
     })?;
-    if let Color::Rgb(red, green, blue) = color {
+    if let Color::Rgb(red, green, blue) = fg {
         f.write_fmt(format_args!("38;2;{red};{green};{blue}"))?;
     }
-    if let Color::Indexed(i) = color {
+    if let Color::Indexed(i) = fg {
         f.write_fmt(format_args!("38;5;{i}"))?;
     }
-    f.write_str(";")
-}
+    f.write_str(";")?;
 
-fn write_bg(f: &mut Formatter, color: Color) -> fmt::Result {
-    f.write_str(match color {
+    // Write the background
+    f.write_str(match bg {
         Color::Reset => "49",
         Color::Black => "40",
         Color::Red => "41",
@@ -164,11 +110,12 @@ fn write_bg(f: &mut Formatter, color: Color) -> fmt::Result {
         Color::White => "107",
         _ => "",
     })?;
-    if let Color::Rgb(red, green, blue) = color {
+    if let Color::Rgb(red, green, blue) = bg {
         f.write_fmt(format_args!("48;2;{red};{green};{blue}"))?;
     }
-    if let Color::Indexed(i) = color {
+    if let Color::Indexed(i) = bg {
         f.write_fmt(format_args!("48;5;{i}"))?;
     }
-    Ok(())
+
+    f.write_str("m")
 }

packages/cli/src/serve/output.rs

@@ -1,5 +1,5 @@
 use crate::{
-    serve::{ansi_buffer::AnsiStringLine, ServeUpdate, WebServer},
+    serve::{ansi_buffer::ansi_string_to_line, ServeUpdate, WebServer},
     BuildId, BuildStage, BuilderUpdate, Platform, TraceContent, TraceMsg, TraceSrc,
 };
 use cargo_metadata::diagnostic::Diagnostic;
@@ -1022,13 +1022,7 @@ impl Output {
                     line = line.dark_gray();
                 }
 
-                // Create the ansi -> raw string line with a width of either the viewport width or the max width
-                let line_length = line.styled_graphemes(Style::default()).count();
-                if line_length < u16::MAX as usize {
-                    lines.push(AnsiStringLine::new(line_length as _).render(&line));
-                } else {
-                    lines.push(line.to_string())
-                }
+                lines.push(ansi_string_to_line(line));
             }
         }