Add last window closed setting (#25185)

Release Notes:

- Added an `on_last_window_closed` setting, that allows users to quit
the app when the last window is closed

---------

Co-authored-by: Richard <richard@zed.dev>

crates/workspace/src/workspace.rs

@@ -1804,6 +1804,7 @@ impl Workspace {
     }
 
     pub fn close_window(&mut self, _: &CloseWindow, window: &mut Window, cx: &mut Context<Self>) {
+        println!("workspace::close_window");
         let prepare = self.prepare_to_close(CloseIntent::CloseWindow, window, cx);
         cx.spawn_in(window, |_, mut cx| async move {
             if prepare.await? {

crates/workspace/src/workspace_settings.rs

@@ -18,11 +18,31 @@ pub struct WorkspaceSettings {
     pub autosave: AutosaveSetting,
     pub restore_on_startup: RestoreOnStartupBehavior,
     pub drop_target_size: f32,
-    pub when_closing_with_no_tabs: CloseWindowWhenNoItems,
     pub use_system_path_prompts: bool,
     pub command_aliases: HashMap<String, String>,
     pub show_user_picture: bool,
     pub max_tabs: Option<NonZeroUsize>,
+    pub when_closing_with_no_tabs: CloseWindowWhenNoItems,
+    pub on_last_window_closed: OnLastWindowClosed,
+}
+
+#[derive(Copy, Clone, Default, Serialize, Deserialize, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum OnLastWindowClosed {
+    /// Match platform conventions by default, so don't quit on macOS, and quit on other platforms
+    #[default]
+    PlatformDefault,
+    /// Quit the application the last window is closed
+    QuitApp,
+}
+
+impl OnLastWindowClosed {
+    pub fn is_quit_app(&self) -> bool {
+        match self {
+            OnLastWindowClosed::PlatformDefault => false,
+            OnLastWindowClosed::QuitApp => true,
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema)]
@@ -136,11 +156,15 @@ pub struct WorkspaceSettingsContent {
     ///
     /// Default: true
     pub show_user_picture: Option<bool>,
-    // Maximum open tabs in a pane. Will not close an unsaved
-    // tab. Set to `None` for unlimited tabs.
-    //
-    // Default: none
+    /// Maximum open tabs in a pane. Will not close an unsaved
+    /// tab. Set to `None` for unlimited tabs.
+    ///
+    /// Default: none
     pub max_tabs: Option<NonZeroUsize>,
+    /// What to do when the last window is closed
+    ///
+    /// Default: auto (nothing on macOS, "app quit" otherwise)
+    pub on_last_window_closed: Option<OnLastWindowClosed>,
 }
 
 #[derive(Deserialize)]