GTK: move audio bell processing to the application (ghostty-org#13657)

This fixes ghostty-org#13647 by using at most one GStreamer thread per application.
This was previously addressed in ghostty-org#12815 which used at most one GStreamer
thread per surface. Originally discussed in ghostty-org#12808.

Author: jcollie

src/apprt/gtk/class/application.zig

@@ -45,6 +45,7 @@ const CloseConfirmationDialog = @import("close_confirmation_dialog.zig").CloseCo
 const ConfigErrorsDialog = @import("config_errors_dialog.zig").ConfigErrorsDialog;
 const GlobalShortcuts = @import("global_shortcuts.zig").GlobalShortcuts;
 const OpenURI = @import("../portal.zig").OpenURI;
+const media = @import("../media.zig");
 
 const log = std.log.scoped(.gtk_ghostty_application);
 
@@ -223,6 +224,12 @@ pub const Application = extern struct {
 
         open_uri: OpenURI = undefined,
 
+        // The audio bell's MediaFile, reused across bells so we don't leak a
+        // GStreamer pipeline (and its GL threads) on every ring. Built lazily
+        // on the first audio bell and rebuilt when `bell-audio-path` changes;
+        // unref'd on dispose. See ringBell and media.zig.
+        bell_media: ?*gtk.MediaFile = null,
+
         pub var offset: c_int = 0;
     };
 
@@ -1478,6 +1485,7 @@ pub const Application = extern struct {
             .init("quit", actionQuit, null),
             .init("reload-config", actionReloadConfig, null),
             .init("toggle-quick-terminal", actionToggleQuickTerminal, null),
+            .init("ring-bell", actionRingBell, null),
         };
 
         ext.actions.add(Self, self, &actions);
@@ -1549,6 +1557,11 @@ pub const Application = extern struct {
             priv.signal_source = null;
         }
 
+        if (priv.bell_media) |v| {
+            v.unref();
+            priv.bell_media = null;
+        }
+
         gobject.Object.virtual_methods.dispose.call(
             Class.parent,
             self.as(Parent),
@@ -1948,6 +1961,40 @@ pub const Application = extern struct {
         );
     }
 
+    pub fn actionRingBell(
+        _: *gio.SimpleAction,
+        _: ?*glib.Variant,
+        self: *Self,
+    ) callconv(.c) void {
+        const priv: *Private = self.private();
+        const config = priv.config.get();
+
+        // Do our sound
+        if (config.@"bell-features".audio) audio: {
+            const config_path = config.@"bell-audio-path" orelse break :audio;
+            const path, const required = switch (config_path) {
+                .optional => |path| .{ path, false },
+                .required => |path| .{ path, true },
+            };
+
+            const volume = std.math.clamp(
+                config.@"bell-audio-volume",
+                0.0,
+                1.0,
+            );
+
+            // Reuse one MediaFile per application (rebuilt only when the path
+            // changes) so each bell replays the same pipeline instead of
+            // leaking a fresh one. Assign unconditionally: bellMediaFile frees
+            // any stale MediaFile and returns the current slot value (possibly
+            // null if the path is now inaccessible), so priv.bell_media never
+            // dangles.
+            priv.bell_media = media.bellMediaFile(priv.bell_media, path, required);
+            const media_file = priv.bell_media orelse break :audio;
+            media.playBell(media_file, volume);
+        }
+    }
+
     //----------------------------------------------------------------
     // Boilerplate/Noise
 

src/apprt/gtk/class/surface.zig

@@ -36,7 +36,6 @@ const Window = @import("window.zig").Window;
 const InspectorWindow = @import("inspector_window.zig").InspectorWindow;
 const SplitTree = @import("split_tree.zig").SplitTree;
 const i18n = @import("../../../os/i18n.zig");
-const media = @import("../media.zig");
 const global = @import("../../../global.zig");
 const gtk_version = @import("../gtk_version.zig");
 
@@ -677,12 +676,6 @@ pub const Surface = extern struct {
         // false by a parent widget.
         bell_ringing: bool = false,
 
-        // The audio bell's MediaFile, reused across bells so we don't leak a
-        // GStreamer pipeline (and its GL threads) on every ring. Built lazily
-        // on the first audio bell and rebuilt when `bell-audio-path` changes;
-        // unref'd on dispose. See ringBell and media.zig.
-        bell_media: ?*gtk.MediaFile = null,
-
         /// True if this surface is in an error state. This is currently
         /// a simple boolean with no additional information on WHAT the
         /// error state is, because we don't yet need it or use it. For now,
@@ -1880,11 +1873,6 @@ pub const Surface = extern struct {
             priv.config = null;
         }
 
-        if (priv.bell_media) |v| {
-            v.unref();
-            priv.bell_media = null;
-        }
-
         if (priv.vadj_signal_group) |group| {
             group.setTarget(null);
             group.as(gobject.Object).unref();
@@ -2544,8 +2532,6 @@ pub const Surface = extern struct {
     /// Handle bell features that need to happen every time a BEL is received
     /// Currently this is audio and system but this could change in the future.
     fn ringBell(self: *Self) void {
-        const priv = self.private();
-
         // Emit the signal
         signals.bell.impl.emit(
             self,
@@ -2557,33 +2543,7 @@ pub const Surface = extern struct {
         // Activate actions if they exist
         _ = self.as(gtk.Widget).activateAction("tab.ring-bell", null);
         _ = self.as(gtk.Widget).activateAction("win.ring-bell", null);
-
-        const config = if (priv.config) |c| c.get() else return;
-
-        // Do our sound
-        if (config.@"bell-features".audio) audio: {
-            const config_path = config.@"bell-audio-path" orelse break :audio;
-            const path, const required = switch (config_path) {
-                .optional => |path| .{ path, false },
-                .required => |path| .{ path, true },
-            };
-
-            const volume = std.math.clamp(
-                config.@"bell-audio-volume",
-                0.0,
-                1.0,
-            );
-
-            // Reuse one MediaFile per surface (rebuilt only when the path
-            // changes) so each bell replays the same pipeline instead of
-            // leaking a fresh one. Assign unconditionally: bellMediaFile frees
-            // any stale MediaFile and returns the current slot value (possibly
-            // null if the path is now inaccessible), so priv.bell_media never
-            // dangles.
-            priv.bell_media = media.bellMediaFile(priv.bell_media, path, required);
-            const media_file = priv.bell_media orelse break :audio;
-            media.playBell(media_file, volume);
-        }
+        _ = self.as(gtk.Widget).activateAction("app.ring-bell", null);
     }
 
     //---------------------------------------------------------------