core: support OSC 9 and OSC 777 for showing desktop notifications

src/apprt/embedded.zig

@@ -117,6 +117,9 @@ pub const App = struct {
 
         /// Called when the cell size changes.
         set_cell_size: ?*const fn (SurfaceUD, u32, u32) callconv(.C) void = null,
+
+        /// Show a desktop notification to the user.
+        show_desktop_notification: ?*const fn (SurfaceUD, [*:0]const u8, [*:0]const u8) void = null,
     };
 
     /// Special values for the goto_tab callback.
@@ -939,6 +942,20 @@ pub const Surface = struct {
         const scale = try self.getContentScale();
         return .{ .x = pos.x * scale.x, .y = pos.y * scale.y };
     }
+
+    /// Show a desktop notification.
+    pub fn showDesktopNotification(
+        self: *const Surface,
+        title: [:0]const u8,
+        body: [:0]const u8,
+    ) !void {
+        const func = self.app.opts.show_desktop_notification orelse {
+            log.info("runtime embedder does not support show_desktop_notification", .{});
+            return;
+        };
+
+        func(self.opts.userdata, title, body);
+    }
 };
 
 /// Inspector is the state required for the terminal inspector. A terminal

src/apprt/structs.zig

@@ -50,3 +50,13 @@ pub const ClipboardRequest = union(ClipboardRequestType) {
     /// A request to write clipboard contents via OSC 52.
     osc_52_write: Clipboard,
 };
+
+/// A desktop notification.
+pub const DesktopNotification = struct {
+    /// The title of the notification. May be an empty string to not show a
+    /// title.
+    title: []const u8,
+
+    /// The body of a notification. This will always be shown.
+    body: []const u8,
+};

src/apprt/surface.zig

@@ -45,6 +45,15 @@ pub const Message = union(enum) {
     /// The child process running in the surface has exited. This may trigger
     /// a surface close, it may not.
     child_exited: void,
+
+    /// Show a desktop notification.
+    desktop_notification: struct {
+        /// Desktop notification title.
+        title: WriteReq,
+
+        /// Desktop notification body.
+        body: WriteReq,
+    },
 };
 
 /// A surface mailbox.