gtk(adw): refactor version checks into readable functions

Doing `versionAtLeast(0, 0, 0)` to check for the existence of libadw
and `versionAtLeast(1, 4, 0)` wherever tab overviews are used gets old
after a while. We consolidate all of these checks (except for one
unconfirmed bugfix) into easily readable functions so that maintainers
don't have to memorize which libadw version added which functionality.

src/apprt/gtk/App.zig

@@ -288,9 +288,7 @@ pub fn init(core_app: *CoreApp, opts: Options) !App {
         });
 
         // If not libadwaita, create a standard GTK application.
-        if ((comptime !adwaita.versionAtLeast(0, 0, 0)) or
-            !adwaita.enabled(&config))
-        {
+        if ((comptime !adwaita.exists()) or !adwaita.enabled(&config)) {
             {
                 const provider = c.gtk_css_provider_new();
                 defer c.g_object_unref(provider);

src/apprt/gtk/Window.zig

@@ -123,7 +123,7 @@ pub fn init(self: *Window, app: *App) !void {
 
     // Create the window
     const window: *c.GtkWidget = window: {
-        if ((comptime adwaita.versionAtLeast(0, 0, 0)) and self.config.adw_enabled) {
+        if ((comptime adwaita.exists()) and self.config.adw_enabled) {
             const window = c.adw_application_window_new(app.app);
             c.gtk_widget_add_css_class(@ptrCast(window), "adw");
             break :window window;
@@ -265,7 +265,7 @@ pub fn init(self: *Window, app: *App) !void {
 
     // Setup our toast overlay if we have one
     self.toast_overlay = toast: {
-        if ((comptime !adwaita.versionAtLeast(0, 0, 0)) or !self.config.adw_enabled)
+        if ((comptime !adwaita.exists()) or !self.config.adw_enabled)
             break :toast null;
 
         const toast_overlay = c.adw_toast_overlay_new();
@@ -340,7 +340,7 @@ pub fn init(self: *Window, app: *App) !void {
         );
     } else tab_bar: {
         switch (self.notebook) {
-            .adw => |*adw| if (comptime adwaita.versionAtLeast(0, 0, 0)) {
+            .adw => |*adw| if (comptime adwaita.exists()) {
                 if (self.config.gtk_tabs_location == .hidden) break :tab_bar;
 
                 // In earlier adwaita versions, we need to add the tabbar manually since we do not use
@@ -370,8 +370,9 @@ pub fn init(self: *Window, app: *App) !void {
             .gtk => {},
         }
 
-        // The box is our main child
-        if ((comptime adwaita.versionAtLeast(0, 0, 0)) and !adwaita.supportsTabOverview() and self.config.adw_enabled) {
+        // If we're using an older version of libadwaita without support
+        // for tab overviews, we put the box directly as the main child
+        if ((comptime adwaita.exists()) and !adwaita.supportsTabOverview() and self.config.adw_enabled) {
             c.adw_application_window_set_content(@ptrCast(gtk_window), box);
         } else {
             c.gtk_window_set_titlebar(gtk_window, self.headerbar.asWidget());
@@ -665,7 +666,8 @@ pub fn onConfigReloaded(self: *Window) void {
 }
 
 pub fn sendToast(self: *Window, title: [:0]const u8) void {
-    if (comptime !adwaita.versionAtLeast(0, 0, 0)) return;
+    if (comptime !adwaita.exists()) return;
+
     const toast_overlay = self.toast_overlay orelse return;
     const toast = c.adw_toast_new(title);
     c.adw_toast_set_timeout(toast, 3);
@@ -890,7 +892,7 @@ fn gtkKeyPressed(
     //
     // If someone can confidently show or explain that this is not
     // necessary, please remove this check.
-    if (comptime adwaita.versionAtLeast(1, 4, 0)) {
+    if (comptime adwaita.supportsTabOverview()) {
         if (self.tab_overview) |tab_overview_widget| {
             const tab_overview: *c.AdwTabOverview = @ptrCast(@alignCast(tab_overview_widget));
             if (c.adw_tab_overview_get_open(tab_overview) == 0) return 0;

src/apprt/gtk/adwaita.zig

@@ -6,8 +6,7 @@ const Config = @import("../../config.zig").Config;
 /// Returns true if Ghostty is configured to build with libadwaita and
 /// the configuration has enabled adwaita.
 ///
-/// For a comptime version of this function, use `versionAtLeast` in
-/// a comptime context with all the version numbers set to 0.
+/// For a comptime version of this function, use `exists`.
 ///
 /// This must be `inline` so that the comptime check noops conditional
 /// paths that are not enabled.
@@ -74,17 +73,31 @@ test "versionAtLeast" {
     try testing.expect(versionAtLeast(c.ADW_MAJOR_VERSION, c.ADW_MINOR_VERSION - 1, c.ADW_MICRO_VERSION + 1));
 }
 
+/// Whether libadwaita exists at all.
+pub inline fn exists() bool {
+    return versionAtLeast(0, 0, 0);
+}
+
+/// Shortcuts for tab views is introduced in libadwaita 1.2.0.
+/// https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/NEWS?ref_type=heads#L1196
+pub inline fn supportsTabViewShortcuts() bool {
+    return versionAtLeast(1, 2, 0);
+}
+
 /// Banners are introduced in libadwaita 1.3.0.
+/// https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/NEWS?ref_type=heads#L1020
 pub inline fn supportsBanner() bool {
     return versionAtLeast(1, 3, 0);
 }
 
 /// Tab overviews are introduced in libadwaita 1.3.0.
+/// https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/NEWS?ref_type=heads#L1021
 pub inline fn supportsTabOverview() bool {
     return versionAtLeast(1, 3, 0);
 }
 
 /// About dialogs are introduced in libadwaita 1.5.0.
+/// https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/NEWS?ref_type=heads#L497
 pub inline fn supportsAboutDialog() bool {
     return versionAtLeast(1, 5, 0);
 }

src/apprt/gtk/headerbar.zig

@@ -13,7 +13,7 @@ pub const HeaderBar = union(enum) {
 
     pub fn init(self: *HeaderBar) void {
         const window: *Window = @fieldParentPtr("headerbar", self);
-        if ((comptime adwaita.versionAtLeast(1, 4, 0)) and adwaita.enabled(&window.app.config)) {
+        if ((comptime adwaita.exists()) and window.config.adw_enabled) {
             HeaderBarAdw.init(self);
         } else {
             HeaderBarGtk.init(self);

src/apprt/gtk/headerbar_adw.zig

@@ -8,8 +8,8 @@ const adwaita = @import("adwaita.zig");
 
 const HeaderBar = @import("headerbar.zig").HeaderBar;
 
-const AdwHeaderBar = if (adwaita.versionAtLeast(0, 0, 0)) c.AdwHeaderBar else anyopaque;
-const AdwWindowTitle = if (adwaita.versionAtLeast(0, 0, 0)) c.AdwWindowTitle else anyopaque;
+const AdwHeaderBar = if (adwaita.exists()) c.AdwHeaderBar else anyopaque;
+const AdwWindowTitle = if (adwaita.exists()) c.AdwWindowTitle else anyopaque;
 
 /// the window that this headerbar is attached to
 window: *Window,
@@ -19,7 +19,7 @@ headerbar: *AdwHeaderBar,
 title: *AdwWindowTitle,
 
 pub fn init(headerbar: *HeaderBar) void {
-    if (!adwaita.versionAtLeast(0, 0, 0)) return;
+    if (!adwaita.exists()) return;
 
     const window: *Window = @fieldParentPtr("headerbar", headerbar);
     headerbar.* = .{
@@ -47,32 +47,32 @@ pub fn asWidget(self: HeaderBarAdw) *c.GtkWidget {
 }
 
 pub fn packEnd(self: HeaderBarAdw, widget: *c.GtkWidget) void {
-    if (comptime adwaita.versionAtLeast(0, 0, 0)) {
-        c.adw_header_bar_pack_end(
-            @ptrCast(@alignCast(self.headerbar)),
-            widget,
-        );
-    }
+    if (comptime !adwaita.exists()) return;
+
+    c.adw_header_bar_pack_end(
+        @ptrCast(@alignCast(self.headerbar)),
+        widget,
+    );
 }
 
 pub fn packStart(self: HeaderBarAdw, widget: *c.GtkWidget) void {
-    if (comptime adwaita.versionAtLeast(0, 0, 0)) {
-        c.adw_header_bar_pack_start(
-            @ptrCast(@alignCast(self.headerbar)),
-            widget,
-        );
-    }
+    if (comptime !adwaita.exists()) return;
+
+    c.adw_header_bar_pack_start(
+        @ptrCast(@alignCast(self.headerbar)),
+        widget,
+    );
 }
 
 pub fn setTitle(self: HeaderBarAdw, title: [:0]const u8) void {
     c.gtk_window_set_title(self.window.window, title);
-    if (comptime adwaita.versionAtLeast(0, 0, 0)) {
+    if (comptime adwaita.exists()) {
         c.adw_window_title_set_title(self.title, title);
     }
 }
 
 pub fn setSubtitle(self: HeaderBarAdw, subtitle: [:0]const u8) void {
-    if (comptime adwaita.versionAtLeast(0, 0, 0)) {
+    if (comptime adwaita.exists()) {
         c.adw_window_title_set_subtitle(self.title, subtitle);
     }
 }

src/apprt/gtk/notebook.zig

@@ -10,7 +10,7 @@ const adwaita = @import("adwaita.zig");
 
 const log = std.log.scoped(.gtk);
 
-const AdwTabView = if (adwaita.versionAtLeast(0, 0, 0)) c.AdwTabView else anyopaque;
+const AdwTabView = if (adwaita.exists()) c.AdwTabView else anyopaque;
 
 /// An abstraction over the GTK notebook and Adwaita tab view to manage
 /// all the terminal tabs in a window.

src/apprt/gtk/notebook_adw.zig

@@ -10,8 +10,8 @@ const adwaita = @import("adwaita.zig");
 
 const log = std.log.scoped(.gtk);
 
-const AdwTabView = if (adwaita.versionAtLeast(0, 0, 0)) c.AdwTabView else anyopaque;
-const AdwTabPage = if (adwaita.versionAtLeast(0, 0, 0)) c.AdwTabPage else anyopaque;
+const AdwTabView = if (adwaita.exists()) c.AdwTabView else anyopaque;
+const AdwTabPage = if (adwaita.exists()) c.AdwTabPage else anyopaque;
 
 pub const NotebookAdw = struct {
     /// the tab view
@@ -33,7 +33,7 @@ pub const NotebookAdw = struct {
         const tab_view: *c.AdwTabView = c.adw_tab_view_new().?;
         c.gtk_widget_add_css_class(@ptrCast(@alignCast(tab_view)), "notebook");
 
-        if (comptime adwaita.versionAtLeast(1, 2, 0) and adwaita.versionAtLeast(1, 2, 0)) {
+        if ((comptime adwaita.supportsTabViewShortcuts()) and adwaita.supportsTabViewShortcuts()) {
             // Adwaita enables all of the shortcuts by default.
             // We want to manage keybindings ourselves.
             c.adw_tab_view_remove_shortcuts(tab_view, c.ADW_TAB_VIEW_SHORTCUT_ALL_SHORTCUTS);
@@ -56,23 +56,24 @@ pub const NotebookAdw = struct {
     }
 
     pub fn nPages(self: *NotebookAdw) c_int {
-        if (comptime adwaita.versionAtLeast(0, 0, 0))
-            return c.adw_tab_view_get_n_pages(self.tab_view)
-        else
-            unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
+        return c.adw_tab_view_get_n_pages(self.tab_view);
     }
 
     /// Returns the index of the currently selected page.
     /// Returns null if the notebook has no pages.
     pub fn currentPage(self: *NotebookAdw) ?c_int {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_selected_page(self.tab_view) orelse return null;
         return c.adw_tab_view_get_page_position(self.tab_view, page);
     }
 
     /// Returns the currently selected tab or null if there are none.
     pub fn currentTab(self: *NotebookAdw) ?*Tab {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_selected_page(self.tab_view) orelse return null;
         const child = c.adw_tab_page_get_child(page);
         return @ptrCast(@alignCast(
@@ -81,45 +82,51 @@ pub const NotebookAdw = struct {
     }
 
     pub fn gotoNthTab(self: *NotebookAdw, position: c_int) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page_to_select = c.adw_tab_view_get_nth_page(self.tab_view, position);
         c.adw_tab_view_set_selected_page(self.tab_view, page_to_select);
     }
 
     pub fn getTabPosition(self: *NotebookAdw, tab: *Tab) ?c_int {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_page(self.tab_view, @ptrCast(tab.box)) orelse return null;
         return c.adw_tab_view_get_page_position(self.tab_view, page);
     }
 
     pub fn reorderPage(self: *NotebookAdw, tab: *Tab, position: c_int) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_page(self.tab_view, @ptrCast(tab.box));
         _ = c.adw_tab_view_reorder_page(self.tab_view, page, position);
     }
 
     pub fn setTabLabel(self: *NotebookAdw, tab: *Tab, title: [:0]const u8) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_page(self.tab_view, @ptrCast(tab.box));
         c.adw_tab_page_set_title(page, title.ptr);
     }
 
     pub fn setTabTooltip(self: *NotebookAdw, tab: *Tab, tooltip: [:0]const u8) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const page = c.adw_tab_view_get_page(self.tab_view, @ptrCast(tab.box));
         c.adw_tab_page_set_tooltip(page, tooltip.ptr);
     }
 
     pub fn addTab(self: *NotebookAdw, tab: *Tab, position: c_int, title: [:0]const u8) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
+
         const box_widget: *c.GtkWidget = @ptrCast(tab.box);
         const page = c.adw_tab_view_insert(self.tab_view, box_widget, position);
         c.adw_tab_page_set_title(page, title.ptr);
         c.adw_tab_view_set_selected_page(self.tab_view, page);
     }
 
     pub fn closeTab(self: *NotebookAdw, tab: *Tab) void {
-        if (comptime !adwaita.versionAtLeast(0, 0, 0)) unreachable;
+        if (comptime !adwaita.exists()) unreachable;
 
         // closeTab always expects to close unconditionally so we mark this
         // as true so that the close_page call below doesn't request

src/apprt/gtk/winproto/x11.zig

@@ -176,8 +176,7 @@ pub const Window = struct {
         ) == 0) return error.NotX11Surface;
 
         const blur_region: Region = blur: {
-            if ((comptime !adwaita.versionAtLeast(0, 0, 0)) or
-                gtk_window.config.adw_enabled) break :blur .{};
+            if ((comptime !adwaita.exists()) or gtk_window.config.adw_enabled) break :blur .{};
 
             // NOTE(pluiedev): CSDs are a f--king mistake.
             // Please, GNOME, stop this nonsense of making a window ~30% bigger