Add dynamic title support for Window

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - MSI installer for Windows is now available
 - New default key bindings Alt+Home, Alt+End, Alt+PageUp and Alt+PageDown
+- Dynamic title support on Windows
 
 ### Fixed
 

src/term/mod.rs

@@ -786,6 +786,7 @@ pub struct Term {
     /// Default style for resetting the cursor
     default_cursor_style: CursorStyle,
 
+    /// Whether to permit updating the terminal title
     dynamic_title: bool,
 
     /// Number of spaces in one tab
@@ -1357,6 +1358,19 @@ impl ansi::Handler for Term {
     fn set_title(&mut self, title: &str) {
         if self.dynamic_title {
             self.next_title = Some(title.to_owned());
+
+            #[cfg(windows)]
+            {
+                // cmd.exe in winpty: winpty incorrectly sets the title to ' ' instead of
+                // 'Alacritty' - thus we have to substitute this back to get equivalent
+                // behaviour as conpty.
+                //
+                // The starts_with check is necessary because other shells e.g. bash set a
+                // different title and don't need Alacritty prepended.
+                if !tty::is_conpty() && title.starts_with(' ') {
+                    self.next_title = Some(format!("Alacritty {}", title.trim()));
+                }
+            }
         }
     }
 

src/tty/windows/conpty.rs

@@ -27,7 +27,7 @@ use widestring::U16CString;
 use winapi::ctypes::c_void;
 use winapi::shared::basetsd::{PSIZE_T, SIZE_T};
 use winapi::shared::minwindef::{BYTE, DWORD};
-use winapi::shared::ntdef::{HANDLE, HRESULT, LPCWSTR, LPWSTR};
+use winapi::shared::ntdef::{HANDLE, HRESULT, LPWSTR};
 use winapi::shared::winerror::S_OK;
 use winapi::um::libloaderapi::{GetModuleHandleA, GetProcAddress};
 use winapi::um::processthreadsapi::{
@@ -147,6 +147,11 @@ pub fn new<'a>(
     let mut size: SIZE_T = 0;
 
     let mut startup_info_ex: STARTUPINFOEXW = Default::default();
+
+    let title = options.title.as_ref().map(|w| w.as_str()).unwrap_or("Alacritty");
+    let title = U16CString::from_str(title).unwrap();
+    startup_info_ex.StartupInfo.lpTitle = title.as_ptr() as LPWSTR;
+
     startup_info_ex.StartupInfo.cb = mem::size_of::<STARTUPINFOEXW>() as u32;
 
     // Setting this flag but leaving all the handles as default (null) ensures the
@@ -216,24 +221,20 @@ pub fn new<'a>(
     let cwd = cwd.as_ref().map(|dir| dir.to_str().unwrap());
 
     // Create the client application, using startup info containing ConPTY info
-    let cmdline = U16CString::from_str(&cmdline.join(" ")).unwrap().into_raw();
+    let cmdline = U16CString::from_str(&cmdline.join(" ")).unwrap();
     let cwd = cwd.map(|s| U16CString::from_str(&s).unwrap());
-    let cwd_ptr = match &cwd {
-        Some(b) => b.as_ptr() as LPCWSTR,
-        None => ptr::null(),
-    };
 
     let mut proc_info: PROCESS_INFORMATION = Default::default();
     unsafe {
         success = CreateProcessW(
             ptr::null(),
-            cmdline as LPWSTR,
+            cmdline.as_ptr() as LPWSTR,
             ptr::null_mut(),
             ptr::null_mut(),
             false as i32,
             EXTENDED_STARTUPINFO_PRESENT,
             ptr::null_mut(),
-            cwd_ptr,
+            cwd.map_or_else(ptr::null, |s| s.as_ptr()),
             &mut startup_info_ex.StartupInfo as *mut STARTUPINFOW,
             &mut proc_info as *mut PROCESS_INFORMATION,
         ) > 0;
@@ -241,11 +242,6 @@ pub fn new<'a>(
         assert!(success);
     }
 
-    // Recover raw memory to cmdline so it can be freed
-    unsafe {
-        U16CString::from_raw(cmdline);
-    }
-
     // Store handle to console
     unsafe {
         HANDLE = proc_info.hProcess;

src/tty/windows/mod.rs

@@ -14,6 +14,7 @@
 
 use std::io::{self, Read, Write};
 use std::os::raw::c_void;
+use std::sync::atomic::{AtomicBool, Ordering};
 
 use mio::{self, Evented, Poll, PollOpt, Ready, Token};
 use mio_anonymous_pipes::{EventedAnonRead, EventedAnonWrite};
@@ -34,6 +35,7 @@ mod winpty;
 
 /// Handle to the winpty agent or conpty process. Required so we know when it closes.
 static mut HANDLE: *mut c_void = 0usize as *mut c_void;
+static IS_CONPTY: AtomicBool = AtomicBool::new(false);
 
 pub fn process_should_exit() -> bool {
     unsafe {
@@ -54,6 +56,10 @@ pub fn process_should_exit() -> bool {
     }
 }
 
+pub fn is_conpty() -> bool {
+    IS_CONPTY.load(Ordering::Relaxed)
+}
+
 #[derive(Clone)]
 pub enum PtyHandle<'a> {
     Winpty(winpty::WinptyHandle<'a>),
@@ -86,6 +92,7 @@ pub fn new<'a>(
 ) -> Pty<'a> {
     if let Some(pty) = conpty::new(config, options, size, window_id) {
         info!("Using Conpty agent");
+        IS_CONPTY.store(true, Ordering::Relaxed);
         pty
     } else {
         info!("Using Winpty agent");

src/window.rs

@@ -224,11 +224,8 @@ impl Window {
 
     /// Set the window title
     #[inline]
-    pub fn set_title(&self, _title: &str) {
-        // Because winpty doesn't know anything about OSC escapes this gets set to an empty
-        // string on windows
-        #[cfg(not(windows))]
-        self.window.set_title(_title);
+    pub fn set_title(&self, title: &str) {
+        self.window.set_title(title);
     }
 
     #[inline]