gtk-ng: use WeakRef helper for type safety

src/apprt/gtk-ng/class/application.zig

@@ -133,7 +133,7 @@ pub const Application = extern struct {
         /// If non-null, we're currently showing a config errors dialog.
         /// This is a WeakRef because the dialog can close on its own
         /// outside of our own lifecycle and that's okay.
-        config_errors_dialog: WeakRef(ConfigErrorsDialog) = .{},
+        config_errors_dialog: WeakRef(ConfigErrorsDialog) = .empty,
 
         /// glib source for our signal handler.
         signal_source: ?c_uint = null,

src/apprt/gtk-ng/class/split_tree.zig

@@ -119,7 +119,7 @@ pub const SplitTree = extern struct {
 
         /// Last focused surface in the tree. We need this to handle various
         /// tree change states.
-        last_focused: WeakRef(Surface) = .{},
+        last_focused: WeakRef(Surface) = .empty,
 
         /// The source that we use to rebuild the tree. This is also
         /// used to debounce updates.

src/apprt/gtk-ng/class/window.zig

@@ -28,6 +28,7 @@ const Surface = @import("surface.zig").Surface;
 const Tab = @import("tab.zig").Tab;
 const DebugWarning = @import("debug_warning.zig").DebugWarning;
 const CommandPalette = @import("command_palette.zig").CommandPalette;
+const WeakRef = @import("../weak_ref.zig").WeakRef;
 
 const log = std.log.scoped(.gtk_ghostty_window);
 
@@ -249,7 +250,7 @@ pub const Window = extern struct {
         tab_overview_focus_timer: ?c_uint = null,
 
         /// A weak reference to a command palette.
-        command_palette: gobject.WeakRef = std.mem.zeroes(gobject.WeakRef),
+        command_palette: WeakRef(CommandPalette) = .empty,
 
         // Template bindings
         tab_overview: *adw.TabOverview,
@@ -1065,7 +1066,7 @@ pub const Window = extern struct {
     fn dispose(self: *Self) callconv(.c) void {
         const priv = self.private();
 
-        if (priv.command_palette.get()) |object| object.unref();
+        priv.command_palette.set(null);
 
         if (priv.config) |v| {
             v.unref();
@@ -1716,11 +1717,7 @@ pub const Window = extern struct {
         // Get a reference to a command palette. First check the weak reference
         // that we save to see if we already have one stored. If we don't then
         // create a new one.
-        const command_palette = command_palette: {
+        const command_palette = priv.command_palette.get() orelse command_palette: {
-            if (priv.command_palette.get()) |object| not_command_palette: {
-                break :command_palette gobject.ext.cast(CommandPalette, object) orelse break :not_command_palette;
-            }
-
             // Create a fresh command palette.
             const command_palette = CommandPalette.new();
 
@@ -1745,7 +1742,7 @@ pub const Window = extern struct {
 
             // Save a weak reference to the command palette. We use a weak reference to avoid
             // reference counting cycles that might cause problems later.
-            priv.command_palette.set(command_palette.as(gobject.Object));
+            priv.command_palette.set(command_palette);
 
             break :command_palette command_palette;
         };

src/apprt/gtk-ng/weak_ref.zig

@@ -10,6 +10,8 @@ pub fn WeakRef(comptime T: type) type {
 
         ref: gobject.WeakRef = std.mem.zeroes(gobject.WeakRef),
 
+        pub const empty: Self = .{};
+
         /// Set the weak reference to the given object. This will not
         /// increase the reference count of the object.
         pub fn set(self: *Self, v_: ?*T) void {
@@ -23,14 +25,9 @@ pub fn WeakRef(comptime T: type) type {
         /// Get a strong reference to the object, or null if the object
         /// has been finalized. This increases the reference count by one.
         pub fn get(self: *Self) ?*T {
-            // The GIR of g_weak_ref_get has a bug where the optional
-            // is not encoded. Or, it may be a bug in zig-gobject.
-            const obj_: ?*gobject.Object = @ptrCast(self.ref.get());
-            const obj = obj_ orelse return null;
-
             // We can't use `as` because `as` guarantees conversion and
             // that can't be statically guaranteed.
-            return gobject.ext.cast(T, obj);
+            return gobject.ext.cast(T, self.ref.get() orelse return null);
         }
     };
 }
@@ -38,7 +35,7 @@ pub fn WeakRef(comptime T: type) type {
 test WeakRef {
     const testing = std.testing;
 
-    var ref: WeakRef(gtk.TextBuffer) = .{};
+    var ref: WeakRef(gtk.TextBuffer) = .empty;
     const obj: *gtk.TextBuffer = .new(null);
     ref.set(obj);
     ref.get().?.unref(); // The "?" asserts non-null