apprt/gtk: move adw enabling and version checks into shared file

src/apprt/gtk/Window.zig

@@ -21,6 +21,7 @@ const Color = configpkg.Config.Color;
 const Surface = @import("Surface.zig");
 const Tab = @import("Tab.zig");
 const c = @import("c.zig").c;
+const adwaita = @import("adwaita.zig");
 const Notebook = @import("./notebook.zig").Notebook;
 
 const log = std.log.scoped(.gtk);
@@ -59,10 +60,11 @@ pub fn init(self: *Window, app: *App) !void {
         .context_menu = undefined,
     };
 
-    const adwaita = build_options.libadwaita and app.config.@"gtk-adwaita";
-
     // Create the window
-    const adw_window = adwaita and app.config.@"gtk-titlebar" and c.ADW_MINOR_VERSION >= 4;
+    const adw_window = adwaita.enabled(&app.config) and
+        app.config.@"gtk-titlebar" and
+        comptime adwaita.versionAtLeast(1, 4, 0) and
+        adwaita.versionAtLeast(1, 4, 0);
     const window: *c.GtkWidget = if (adw_window)
         c.adw_application_window_new(app.app)
     else
@@ -125,7 +127,10 @@ pub fn init(self: *Window, app: *App) !void {
     // This is a really common issue where people build from source in debug and performance is really bad.
     if (comptime std.debug.runtime_safety) {
         const warning_text = "⚠️ You're running a debug build of Ghostty! Performance will be degraded.";
-        if (adwaita and c.ADW_MINOR_VERSION >= 3) {
+        if (adwaita.enabled(&app.config) and
+            comptime adwaita.versionAtLeast(1, 3, 0) and
+            adwaita.versionAtLeast(1, 3, 0))
+        {
             const banner = c.adw_banner_new(warning_text);
             c.gtk_box_append(@ptrCast(box), @ptrCast(banner));
         } else {
@@ -155,7 +160,12 @@ pub fn init(self: *Window, app: *App) !void {
     // Our actions for the menu
     initActions(self);
 
-    if (build_options.libadwaita and app.config.@"gtk-adwaita" and app.config.@"gtk-titlebar" and header != null and c.ADW_MINOR_VERSION >= 4) {
+    if (adwaita.enabled(&app.config) and
+        app.config.@"gtk-titlebar" and
+        header != null and
+        comptime adwaita.versionAtLeast(1, 4, 0) and
+        adwaita.versionAtLeast(1, 4, 0))
+    {
         const toolbar_view: *c.AdwToolbarView = @ptrCast(c.adw_toolbar_view_new());
 
         const header_widget: *c.GtkWidget = @ptrCast(@alignCast(header.?));

src/apprt/gtk/adwaita.zig

@@ -0,0 +1,46 @@
+const std = @import("std");
+const c = @import("c.zig").c;
+const build_options = @import("build_options");
+const Config = @import("../../config.zig").Config;
+
+/// Returns true if Ghostty is configured to build with libadwaita and
+/// the configuration has enabled adwaita.
+pub fn enabled(config: *const Config) bool {
+    return build_options.libadwaita and
+        config.@"gtk-adwaita";
+}
+
+/// Verifies that the running libadwaita version is at least the given
+/// version. This will return false if Ghostty is configured to
+/// not build with libadwaita.
+///
+/// This can be run in both a comptime and runtime context. If it
+/// is run in a comptime context, it will only check the version
+/// in the headers. If it is run in a runtime context, it will
+/// check the actual version of the library we are linked against.
+/// So generally  you probably want to do both checks!
+pub fn versionAtLeast(
+    comptime major: u16,
+    comptime minor: u16,
+    comptime micro: u16,
+) bool {
+    if (comptime !build_options.libadwaita) return false;
+
+    // If our header has lower versions than the given version,
+    // we can return false immediately. This prevents us from
+    // compiling against unknown symbols and makes runtime checks
+    // very slightly faster.
+    if (comptime c.ADW_MAJOR_VERSION < major or
+        c.ADW_MINOR_VERSION < minor or
+        c.ADW_MICRO_VERSION < micro) return false;
+
+    // If we're in comptime then we can't check the runtime version.
+    if (@inComptime()) return true;
+
+    // We use the functions instead of the constants such as
+    // c.ADW_MINOR_VERSION because the function gets the actual
+    // runtime version.
+    return c.adw_get_major_version() >= major and
+        c.adw_get_minor_version() >= minor and
+        c.adw_get_micro_version() >= micro;
+}