From 6f1c32b3eb8d6beadab1df0aa923b8f8b78354c0 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Mon, 22 Apr 2019 15:22:33 +0000
Subject: [PATCH] x11: Implement popup surfaces

Make them use o-r windows, and move
with their parent.

We do a sort-of ok job on stacking order
here - whenever the parent window gets a
ConfigureNotify, we just restack all popups
directly on top of their parent. This is good
enough to keep popups on top of their parent
while we drag it around, and it gets the popup
to disappear when raising another window on
top of the parent.
---
 gdk/x11/gdkdisplay-x11.c | 10 ++++--
 gdk/x11/gdkprivate-x11.h |  2 ++
 gdk/x11/gdksurface-x11.c | 78 ++++++++++++++++++++++++++++++++--------
 gdk/x11/gdksurface-x11.h |  5 +++
 4 files changed, 79 insertions(+), 16 deletions(-)

diff --git a/gdk/x11/gdkdisplay-x11.c b/gdk/x11/gdkdisplay-x11.c
index 95ca2211f3..62de7d39e9 100644
--- a/gdk/x11/gdkdisplay-x11.c
+++ b/gdk/x11/gdkdisplay-x11.c
@@ -985,8 +985,12 @@ gdk_x11_display_translate_event (GdkEventTranslator *translator,
 	    }
 	  if (!is_substructure)
 	    {
-	      surface->x = event->configure.x;
-	      surface->y = event->configure.y;
+              if (surface->x != event->configure.x ||
+                  surface->y != event->configure.y)
+                {
+                  surface->x = event->configure.x;
+                  surface->y = event->configure.y;
+                }
 
               if (surface_impl->unscaled_width != xevent->xconfigure.width ||
                   surface_impl->unscaled_height != xevent->xconfigure.height)
@@ -1007,6 +1011,8 @@ gdk_x11_display_translate_event (GdkEventTranslator *translator,
 		  if (surface->resize_count == 0)
 		    _gdk_x11_moveresize_configure_done (display, surface);
 		}
+
+              gdk_x11_surface_update_popups (surface);
 	    }
         }
       break;
diff --git a/gdk/x11/gdkprivate-x11.h b/gdk/x11/gdkprivate-x11.h
index 05b8c1f7df..ff32ea7642 100644
--- a/gdk/x11/gdkprivate-x11.h
+++ b/gdk/x11/gdkprivate-x11.h
@@ -223,6 +223,8 @@ void _gdk_x11_cursor_display_finalize (GdkDisplay *display);
 
 void _gdk_x11_surface_register_dnd (GdkSurface *window);
 
+void gdk_x11_surface_update_popups (GdkSurface *surface);
+
 GdkDrag        * _gdk_x11_surface_drag_begin (GdkSurface          *window,
                                               GdkDevice          *device,
                                               GdkContentProvider *content,
diff --git a/gdk/x11/gdksurface-x11.c b/gdk/x11/gdksurface-x11.c
index 0643948ec2..1d6dee093a 100644
--- a/gdk/x11/gdksurface-x11.c
+++ b/gdk/x11/gdksurface-x11.c
@@ -425,12 +425,20 @@ gdk_x11_surface_end_frame (GdkSurface *surface)
 static void
 gdk_x11_surface_finalize (GObject *object)
 {
+  GdkSurface *surface;
   GdkX11Surface *impl;
 
   g_return_if_fail (GDK_IS_X11_SURFACE (object));
 
+  surface = GDK_SURFACE (object);
   impl = GDK_X11_SURFACE (object);
 
+  if (surface->parent)
+    {
+      GdkX11Surface *parent_impl = GDK_X11_SURFACE (surface->parent);
+      parent_impl->popups = g_list_remove (parent_impl->popups, surface);
+    }
+
   if (impl->toplevel->in_frame)
     unhook_surface_changed (GDK_SURFACE (impl));
 
@@ -842,7 +850,8 @@ _gdk_x11_display_create_surface (GdkDisplay     *display,
   xattributes.colormap = gdk_x11_display_get_window_colormap (display_x11);
   xattributes_mask |= CWColormap;
 
-  if (surface->surface_type == GDK_SURFACE_TEMP)
+  if (surface->surface_type == GDK_SURFACE_TEMP ||
+      surface->surface_type == GDK_SURFACE_POPUP)
     {
       xattributes.save_under = True;
       xattributes.override_redirect = True;
@@ -899,6 +908,12 @@ _gdk_x11_display_create_surface (GdkDisplay     *display,
 
   gdk_surface_freeze_toplevel_updates (surface);
 
+  if (parent)
+    {
+      GdkX11Surface *parent_impl = GDK_X11_SURFACE (parent);
+      parent_impl->popups = g_list_prepend (parent_impl->popups, surface);
+    }
+
   return surface;
 }
 
@@ -1231,8 +1246,8 @@ gdk_x11_surface_hide (GdkSurface *surface)
 
 static inline void
 x11_surface_move (GdkSurface *surface,
-                 gint       x,
-                 gint       y)
+                  gint        x,
+                  gint        y)
 {
   GdkX11Surface *impl = GDK_X11_SURFACE (surface);
 
@@ -1244,6 +1259,12 @@ x11_surface_move (GdkSurface *surface,
     {
       surface->x = x;
       surface->y = y;
+
+      if (surface->parent)
+        {
+          impl->offset_x = surface->x - surface->parent->x;
+          impl->offset_y = surface->y - surface->parent->y;
+        }
     }
 }
 
@@ -1283,10 +1304,10 @@ x11_surface_resize (GdkSurface *surface,
 
 static inline void
 x11_surface_move_resize (GdkSurface *surface,
-                        gint       x,
-                        gint       y,
-                        gint       width,
-                        gint       height)
+                         gint        x,
+                         gint        y,
+                         gint        width,
+                         gint        height)
 {
   GdkX11Surface *impl = GDK_X11_SURFACE (surface);
 
@@ -1314,6 +1335,12 @@ x11_surface_move_resize (GdkSurface *surface,
       surface->height = height;
 
       _gdk_x11_surface_update_size (GDK_X11_SURFACE (surface));
+
+      if (surface->parent)
+        {
+          impl->offset_x = surface->x - surface->parent->x;
+          impl->offset_y = surface->y - surface->parent->y;
+        }
     }
   else
     {
@@ -1324,11 +1351,11 @@ x11_surface_move_resize (GdkSurface *surface,
 
 static void
 gdk_x11_surface_move_resize (GdkSurface *surface,
-                            gboolean   with_move,
-                            gint       x,
-                            gint       y,
-                            gint       width,
-                            gint       height)
+                             gboolean    with_move,
+                             gint        x,
+                             gint        y,
+                             gint        width,
+                             gint        height)
 {
   if (with_move && (width < 0 && height < 0))
     x11_surface_move (surface, x, y);
@@ -1341,6 +1368,29 @@ gdk_x11_surface_move_resize (GdkSurface *surface,
     }
 }
 
+static void gdk_x11_surface_restack_toplevel (GdkSurface *surface,
+                                              GdkSurface *sibling,
+                                              gboolean    above);
+
+void
+gdk_x11_surface_update_popups (GdkSurface *parent)
+{
+  GdkX11Surface *impl = GDK_X11_SURFACE (parent);
+  GList *l;
+
+  for (l = impl->popups; l; l = l->next)
+    {
+      GdkX11Surface *popup_impl = l->data;
+      GdkSurface *popup = GDK_SURFACE (popup_impl);
+      int new_x = parent->x + popup_impl->offset_x;
+      int new_y = parent->y + popup_impl->offset_y;
+
+      if (new_x != popup->x || new_y != popup->y)
+        x11_surface_move (popup, new_x, new_y);
+      gdk_x11_surface_restack_toplevel (popup, parent, TRUE);
+    }
+}
+
 void
 _gdk_x11_surface_set_surface_scale (GdkSurface *surface,
 				  int scale)
@@ -1390,8 +1440,8 @@ gdk_x11_surface_raise (GdkSurface *surface)
 
 static void
 gdk_x11_surface_restack_toplevel (GdkSurface *surface,
-				 GdkSurface *sibling,
-				 gboolean   above)
+                                  GdkSurface *sibling,
+                                  gboolean    above)
 {
   XWindowChanges changes;
 
diff --git a/gdk/x11/gdksurface-x11.h b/gdk/x11/gdksurface-x11.h
index 6ffdbf24e6..c051d10d82 100644
--- a/gdk/x11/gdksurface-x11.h
+++ b/gdk/x11/gdksurface-x11.h
@@ -75,6 +75,11 @@ struct _GdkX11Surface
 #if defined (HAVE_XCOMPOSITE) && defined(HAVE_XDAMAGE) && defined (HAVE_XFIXES)
   Damage damage;
 #endif
+
+  int offset_x;
+  int offset_y;
+
+  GList *popups;
 };
  
 struct _GdkX11SurfaceClass