[geary] Add menu setting to decoration-layout if it is missing

[Michael Gratton <mjog src gnome org>]

commit 67cf38a6779eb39cb87db4a3d9c2a161bc461ec6
Author: Kacper Bielecki <kazjote gmail com>
Date:   Sun Oct 9 19:06:48 2016 +0200

    Add menu setting to decoration-layout if it is missing
    
    Bug 770617
    
    Check if gtk_decoration_layout contains menu setting.
    
    Add it to the left if it is missing. This will force displaying menu for
    clients having both:
    
     * disabled Gtk/ShellShowsAppMenu setting
     * no 'menu' setting in Gtk/DecorationLayout
    
    which would have no possibility of using menu otherwise.

 src/client/application/geary-controller.vala |   27 ++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
---
diff --git a/src/client/application/geary-controller.vala b/src/client/application/geary-controller.vala
index 0e85cf4..2be739f 100644
--- a/src/client/application/geary-controller.vala
+++ b/src/client/application/geary-controller.vala
@@ -176,6 +176,8 @@ public class GearyController : Geary.BaseObject {
         // Ensure all geary windows have an icon
         Gtk.Window.set_default_icon_name("geary");
 
+        apply_app_menu_fix();
+
         // Setup actions.
         setup_actions();
         this.application.load_ui_resource("accelerators.ui");
@@ -400,6 +402,31 @@ public class GearyController : Geary.BaseObject {
             accelerator, action);
     }
 
+    // Fix for clients having both:
+    //   * disabled Gtk/ShellShowsAppMenu setting
+    //   * no 'menu' setting in Gtk/DecorationLayout
+    // See https://bugzilla.gnome.org/show_bug.cgi?id=770617
+    private void apply_app_menu_fix() {
+        Gtk.Settings? settings = Gtk.Settings.get_default();
+
+        if (settings == null) {
+            warning("Couldn't fetch Gtk default settings");
+            return ;
+        }
+
+        string? decoration_layout = settings.gtk_decoration_layout;
+
+        if (decoration_layout == null) decoration_layout = "";
+
+        if (!decoration_layout.contains("menu")) {
+            string prefix = "menu:";
+            if (decoration_layout.contains(":")) {
+                prefix = (decoration_layout.has_prefix(":")) ? "menu" : "menu,";
+            }
+            settings.gtk_decoration_layout = prefix + settings.gtk_decoration_layout;
+        }
+    }
+
     private Gtk.ActionEntry[] create_actions() {
         Gtk.ActionEntry[] entries = new Gtk.ActionEntry[0];