From 61fcd3f3d09b04368dfe51383368597e3355d88b Mon Sep 17 00:00:00 2001
From: Shane Murphy <shaneeverittmurphy@gmail.com>
Date: Tue, 30 May 2023 19:44:34 -0700
Subject: [PATCH] Fix position calculation on Windows

The implementations for Renderer::calculate_position differed slightly
between unix and Windows. Notably, the Windows implementation did not
use tty::width, but instead used UnicodeWidthStr::width. It seems that
the latter did not correctly compute the length.

For context, this bug was discovered in the boa JS interpreter, where on
Windows the prompt being bold and blue caused the cursor to be offset by
9 characters.
---
 src/tty/windows.rs | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/tty/windows.rs b/src/tty/windows.rs
index 1bd7aa314..3cd98c995 100644
--- a/src/tty/windows.rs
+++ b/src/tty/windows.rs
@@ -12,7 +12,6 @@ use std::sync::Arc;
 
 use log::{debug, warn};
 use unicode_segmentation::UnicodeSegmentation;
-use unicode_width::UnicodeWidthStr;
 use winapi::shared::minwindef::{BOOL, DWORD, FALSE, TRUE, WORD};
 use winapi::shared::winerror;
 use winapi::um::handleapi::{CloseHandle, INVALID_HANDLE_VALUE};
@@ -468,12 +467,13 @@ impl Renderer for ConsoleRenderer {
     /// Characters with 2 column width are correctly handled (not split).
     fn calculate_position(&self, s: &str, orig: Position) -> Position {
         let mut pos = orig;
+        let mut esc_sec = 0;
         for c in s.graphemes(true) {
             if c == "\n" {
                 pos.col = 0;
                 pos.row += 1;
             } else {
-                let cw = c.width();
+                let cw = width(c, &mut esc_sec);
                 pos.col += cw;
                 if pos.col > self.cols {
                     pos.row += 1;
@@ -883,7 +883,19 @@ impl Drop for Handle {
 
 #[cfg(test)]
 mod test {
-    use super::Console;
+    use super::*;
+
+    #[test]
+    fn prompt_with_ansi_escape_codes() {
+        let out = ConsoleRenderer::new(
+            unsafe { processenv::GetStdHandle(winbase::STD_OUTPUT_HANDLE) },
+            true,
+            BellStyle::default(),
+        );
+        let pos = out.calculate_position("\x1b[1;32m>>\x1b[0m ", Position::default());
+        assert_eq!(3, pos.col);
+        assert_eq!(0, pos.row);
+    }
 
     #[test]
     fn test_send() {