From 2af1da4ff46915256ff30a4f54f6ad0a41804aee Mon Sep 17 00:00:00 2001
From: ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
Date: Mon, 6 May 2024 09:29:32 +0200
Subject: [PATCH] Wayland: simpler implementation of "GTK Shell" protocol

---
 libdecor/build/fl_libdecor-plugins.c          | 55 +++----------------
 .../Wayland/Fl_Wayland_Screen_Driver.cxx      | 23 ++++++--
 2 files changed, 24 insertions(+), 54 deletions(-)

diff --git a/libdecor/build/fl_libdecor-plugins.c b/libdecor/build/fl_libdecor-plugins.c
index f04f8cf2c..4197ea8f0 100644
--- a/libdecor/build/fl_libdecor-plugins.c
+++ b/libdecor/build/fl_libdecor-plugins.c
@@ -301,52 +301,11 @@ unsigned char *fl_libdecor_titlebar_buffer(struct libdecor_frame *frame,
 }
 
 
-struct libdecor { // copied from libdecor.c, for libdecor versions > 0.2.2
-  int ref_count;
-  const struct libdecor_interface *iface;
-  void *user_data; // added after libdecor version 0.2.2
-  struct libdecor_plugin *plugin;
-  bool plugin_ready;
-  struct wl_display *wl_display;
-  struct wl_registry *wl_registry;
-  struct xdg_wm_base *xdg_wm_base;
-  struct zxdg_decoration_manager_v1 *decoration_manager;
-  struct wl_callback *init_callback;
-  bool init_done;
-  bool has_error;
-  struct wl_list frames;
-};
-
-struct libdecor_022 { // for libdecor versions ≤ 0.2.2
-  int ref_count;
-  const struct libdecor_interface *iface;
-  struct libdecor_plugin *plugin;
-  bool plugin_ready;
-  struct wl_display *wl_display;
-  struct wl_registry *wl_registry;
-  struct xdg_wm_base *xdg_wm_base;
-  struct zxdg_decoration_manager_v1 *decoration_manager;
-  struct wl_callback *init_callback;
-  bool init_done;
-  bool has_error;
-  struct wl_list frames;
-};
-
-
-/* Returns whether surface is a GTK-titlebar created by libdecor-gtk */
-bool fl_is_surface_gtk_titlebar(struct wl_surface *surface, struct libdecor *context,
-                                struct wl_display *wl_display) {
-  if (!context || get_plugin_kind(NULL) != GTK3) return false;
-  // loop over all decorations created by libdecor-gtk
-  struct libdecor_frame *frame;
-  struct wl_list *frames;
-  if (context->wl_display == wl_display) frames = &context->frames;
-  else if (((struct libdecor_022*)context)->wl_display == wl_display)
-    frames = &(((struct libdecor_022*)context)->frames);
-  else return false;
-  wl_list_for_each(frame, frames, link) {
-    struct libdecor_frame_gtk *frame_gtk = (struct libdecor_frame_gtk*)frame;
-    if (frame_gtk->headerbar.wl_surface == surface) return true;
-  }
-  return false;
+/* Returns whether surface is the libdecor-created GTK-titlebar of frame */
+bool fl_is_surface_from_GTK_titlebar (struct wl_surface *surface, struct libdecor_frame *frame,
+                                      bool *using_GTK) {
+  *using_GTK = (get_plugin_kind(NULL) == GTK3);
+  if (!*using_GTK) return false;
+  struct libdecor_frame_gtk *frame_gtk = (struct libdecor_frame_gtk*)frame;
+  return (frame_gtk->headerbar.wl_surface == surface);
 }
diff --git a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
index b2b9d1435..a0fc66f6f 100644
--- a/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Screen_Driver.cxx
@@ -47,7 +47,8 @@
 #include <string.h> // for strerror()
 extern "C" {
   bool libdecor_get_cursor_settings(char **theme, int *size);
-  bool fl_is_surface_gtk_titlebar(struct wl_surface *, struct libdecor *, struct wl_display *);
+  bool fl_is_surface_from_GTK_titlebar (struct wl_surface *surface, struct libdecor_frame *frame,
+                                        bool *using_GTK);
 }
 
 // set this to 1 for keyboard debug output, 0 for no debug output
@@ -204,11 +205,21 @@ static Fl_Window *event_coords_from_surface(struct wl_surface *surface,
 static void pointer_enter(void *data, struct wl_pointer *wl_pointer, uint32_t serial,
         struct wl_surface *surface, wl_fixed_t surface_x, wl_fixed_t surface_y) {
   Fl_Window *win = event_coords_from_surface(surface, surface_x, surface_y);
-  if (!win && gtk_shell) { // check that surface is the headerbar of a GTK-decorated window
-    Fl_Wayland_Screen_Driver *scr_driver = (Fl_Wayland_Screen_Driver*)Fl::screen_driver();
-    if (fl_is_surface_gtk_titlebar(surface, scr_driver->libdecor_context,
-                                   Fl_Wayland_Screen_Driver::wl_display)) {
-      gtk_shell_surface = surface;
+  if (!win && gtk_shell) { // check whether surface is the headerbar of a GTK-decorated window
+    Fl_X *xp = Fl_X::first;
+    bool using_GTK = true;
+    while (xp && using_GTK) { // all mapped windows
+      struct wld_window *xid = (struct wld_window*)xp->xid;
+      if (xid->kind == Fl_Wayland_Window_Driver::DECORATED &&
+          fl_is_surface_from_GTK_titlebar(surface, xid->frame, &using_GTK)) {
+        gtk_shell_surface = surface;
+        break;
+      }
+      xp = xp->next;
+    }
+    if (!using_GTK) {
+      gtk_shell1_destroy(gtk_shell);
+      gtk_shell = NULL;
     }
   }
   if (!win) return;