Add support for title stack escape sequences

This commit adds the concept of a "title stack" to the terminal. Some programs
(e.g. vim) send control sequences `CSI 22 ; 0` (push title) and `CSI 23 ; 0`
(pop title).

The title stack is just a history of previous titles.  Applications can push
the current title onto the stack, and pop it back off (setting the window title
in the process).

Fixes #2840.

2 files changed, 10 insertions, 8 deletions

diff --git a/alacritty/src/cli.rs b/alacritty/src/cli.rs
index 99387a61..b0e3cc94 100644
--- a/alacritty/src/cli.rs
+++ b/alacritty/src/cli.rs
@@ -266,9 +266,12 @@ impl Options {
 
         config.window.dimensions = self.dimensions.unwrap_or(config.window.dimensions);
         config.window.position = self.position.or(config.window.position);
-        config.window.title = self.title.or(config.window.title);
         config.window.embed = self.embed.and_then(|embed| embed.parse().ok());
 
+        if let Some(title) = self.title {
+            config.window.title = title.clone();
+        }
+
         if let Some(class) = self.class {
             let parts: Vec<_> = class.split(',').collect();
             config.window.class.instance = parts[0].into();
@@ -277,7 +280,7 @@ impl Options {
             }
         }
 
-        config.set_dynamic_title(config.dynamic_title() && config.window.title.is_none());
+        config.set_dynamic_title(config.dynamic_title() && config.window.title == DEFAULT_NAME);
 
         config.debug.print_events = self.print_events || config.debug.print_events;
         config.debug.log_level = max(config.debug.log_level, self.log_level);
@@ -298,7 +301,8 @@ mod test {
 
     #[test]
     fn dynamic_title_ignoring_options_by_default() {
-        let config = Config::default();
+        let mut config = Config::default();
+        config.window.title = "Alacritty".to_string();
         let old_dynamic_title = config.dynamic_title();
 
         let config = Options::default().into_config(config);
@@ -321,7 +325,7 @@ mod test {
     fn dynamic_title_overridden_by_config() {
         let mut config = Config::default();
 
-        config.window.title = Some("foo".to_owned());
+        config.window.title = "foo".to_owned();
         let config = Options::default().into_config(config);
 
         assert!(!config.dynamic_title());
diff --git a/alacritty/src/window.rs b/alacritty/src/window.rs
index c783dc69..0394296e 100644
--- a/alacritty/src/window.rs
+++ b/alacritty/src/window.rs
@@ -31,7 +31,7 @@ use image::ImageFormat;
 #[cfg(not(any(target_os = "macos", windows)))]
 use x11_dl::xlib::{Display as XDisplay, PropModeReplace, XErrorEvent, Xlib};
 
-use alacritty_terminal::config::{Decorations, StartupMode, WindowConfig, DEFAULT_NAME};
+use alacritty_terminal::config::{Decorations, StartupMode, WindowConfig};
 use alacritty_terminal::event::Event;
 use alacritty_terminal::gl;
 use alacritty_terminal::term::{SizeInfo, Term};
@@ -146,9 +146,7 @@ impl Window {
         config: &Config,
         logical: Option<LogicalSize>,
     ) -> Result<Window> {
-        let title = config.window.title.as_ref().map_or(DEFAULT_NAME, |t| t);
-
-        let window_builder = Window::get_platform_window(title, &config.window);
+        let window_builder = Window::get_platform_window(&config.window.title, &config.window);
         let windowed_context =
             create_gl_window(window_builder.clone(), &event_loop, false, logical)
                 .or_else(|_| create_gl_window(window_builder, &event_loop, true, logical))?;