fix(windows): preserve ctrl+slash key identity (#3578)

refs #2954

1 files changed, 28 insertions, 2 deletions

diff --git a/src/platform/windows.rs b/src/platform/windows.rs
index b05b9e6f..890c24ca 100644
--- a/src/platform/windows.rs
+++ b/src/platform/windows.rs
@@ -105,8 +105,8 @@ use windows_sys::{
             Input::{
                 Ime::ImmGetDefaultIMEWnd,
                 KeyboardAndMouse::{
-                    GetKeyboardLayout, SendInput, INPUT, INPUT_0, INPUT_KEYBOARD, KEYBDINPUT,
-                    KEYEVENTF_KEYUP,
+                    GetKeyboardLayout, SendInput, ToUnicodeEx, INPUT, INPUT_0, INPUT_KEYBOARD,
+                    KEYBDINPUT, KEYEVENTF_KEYUP,
                 },
             },
             Shell::{
@@ -134,6 +134,32 @@ pub(crate) fn terminal_title_for_presentation(title: &str) -> &str {
     title.strip_prefix("Administrator: ").unwrap_or(title)
 }
 
+/// Resolves against the current foreground layout because asynchronous console
+/// records do not retain the layout that was active when the key was pressed.
+pub(crate) fn resolve_base_printable_key(vk: u16, scan: u16) -> Option<char> {
+    // SAFETY: Win32 owns the handles; the fixed buffers match the API lengths.
+    unsafe {
+        let thread_id = GetWindowThreadProcessId(GetForegroundWindow(), null_mut());
+        let layout = GetKeyboardLayout(thread_id);
+
+        let key_state = [0u8; 256];
+        let mut output = [0u16; 2];
+        let written = ToUnicodeEx(
+            vk.into(),
+            scan.into(),
+            key_state.as_ptr(),
+            output.as_mut_ptr(),
+            output.len() as i32,
+            0x4,
+            layout,
+        );
+        let units = output.get(..usize::try_from(written).ok()?)?;
+        let mut chars = char::decode_utf16(units.iter().copied());
+        let ch = chars.next()?.ok()?;
+        (chars.next().is_none() && !ch.is_control()).then_some(ch)
+    }
+}
+
 const MAX_PROCESS_ENVIRONMENT_BYTES: usize = 256 * 1024;
 const PROCESS_ENVIRONMENT_READ_CHUNK_BYTES: usize = 16 * 1024;
 const PROCESS_RUNTIME_MARKER_CACHE_CAPACITY: usize = 1_024;