Implement wl_seat version 8

* 12to11.man:
* README: Update documentation.
* seat.c (MakeSeatForDevicePair): Support version 8.
(HandleRawButton): Minor markup changes.
(DispatchEntryExit): Send motion event for ungrab events.
(SendScrollAxis): Send value120 events when supported by the
client.
* subsurface.c (GetRootSurface): New function.
(GetSubsurface): Disallow invalid parent/child combinations.

12to11.man

@@ -199,7 +199,7 @@ wl_compositor	5
 wl_shm	1
 xdg_wm_base	5
 wl_subcompositor	1
-wl_seat	7
+wl_seat	8
 wl_data_device_manager	3
 zwp_linux_dmabuf_v1	4
 zwp_primary_selection_device_manager_v1	1

README

@@ -57,7 +57,7 @@ complete degree:
   'wl_shm',                                     version:  1
   'xdg_wm_base',                                version:  5
   'wl_subcompositor',                           version:  1
-  'wl_seat',                                    version:  7
+  'wl_seat',                                    version:  8
   'wl_data_device_manager',                     version:  3
   'zwp_linux_dmabuf_v1',                        version:  4
   'zwp_primary_selection_device_manager_v1',    version:  1

seat.c

@@ -1832,7 +1832,7 @@ MakeSeatForDevicePair (int master_keyboard, int master_pointer,
   seat->master_keyboard = master_keyboard;
   seat->master_pointer = master_pointer;
   seat->global = wl_global_create (compositor.wl_display,
-				   &wl_seat_interface, 7,
+				   &wl_seat_interface, 8,
 				   seat, HandleBind);
   seat->client_info.next = &seat->client_info;
   seat->client_info.last = &seat->client_info;
@@ -2542,9 +2542,10 @@ HandleRawButton (XIRawEvent *event)
 	  if (QueryPointer (seat, window, &win_x, &win_y))
 	    {
 	      /* Otherwise, the pointer is on a different screen!  */
-
 	      TransformToSurface (seat->last_seen_surface,
 				  win_x, win_y, &dispatch_x, &dispatch_y);
+
+	      /* And finally the button release.  */
 	      SendButton (seat, seat->last_seen_surface, event->time,
 			  button, WL_POINTER_BUTTON_STATE_RELEASED,
 			  dispatch_x, dispatch_y);
@@ -3639,6 +3640,12 @@ DispatchEntryExit (Subcompositor *subcompositor, XIEnterEvent *event)
 
       TransformToSurface (dispatch, event_x, event_y, &x, &y);
       EnteredSurface (seat, dispatch, event->time, x, y, False);
+
+      /* If this entry event was the result of a grab, also send
+	 motion now, as a corresponding XI_Motion will not arrive
+	 later.  */
+      if (event->mode == XINotifyUngrab)
+	SendMotion (seat, dispatch, x, y, event->time);
     }
 
   seat->last_motion_x = event->root_x;
@@ -3726,6 +3733,8 @@ SendScrollAxis (Seat *seat, Surface *surface, Time time,
 	  pointer->info->last_enter_serial = serial;
 	}
 
+      if (wl_resource_get_version (pointer->resource) < 8)
+	{
 	  if (axis_x != 0.0)
 	    wl_pointer_send_axis (pointer->resource, time,
 				  WL_POINTER_AXIS_HORIZONTAL_SCROLL,
@@ -3735,6 +3744,22 @@ SendScrollAxis (Seat *seat, Surface *surface, Time time,
 	    wl_pointer_send_axis (pointer->resource, time,
 				  WL_POINTER_AXIS_VERTICAL_SCROLL,
 				  wl_fixed_from_double (axis_y));
+	}
+      else
+        {
+	  /* Send value120 events if they are available; those events
+	     make more sense.  */
+
+	  if (axis_x != 0.0)
+	    wl_pointer_send_axis_value120 (pointer->resource,
+					   WL_POINTER_AXIS_HORIZONTAL_SCROLL,
+					   axis_x * 12);
+
+	  if (axis_y != 0.0)
+	    wl_pointer_send_axis_value120 (pointer->resource,
+					   WL_POINTER_AXIS_VERTICAL_SCROLL,
+					   axis_y * 12);
+	}
 
       if (axis_y == 0.0 && axis_x == 0.0)
 	{

subsurface.c

@@ -853,6 +853,22 @@ HandleSubsurfaceResourceDestroy (struct wl_resource *resource)
   DestroyBacking (subsurface);
 }
 
+static Surface *
+GetRootSurface (Surface *surface)
+{
+  Subsurface *subsurface;
+
+  if (surface->role_type != SubsurfaceType || !surface->role)
+    return surface;
+
+  subsurface = SubsurfaceFromRole (surface->role);
+
+  if (!subsurface->parent)
+    return surface;
+
+  return GetRootSurface (subsurface->parent);
+}
+
 static void
 GetSubsurface (struct wl_client *client, struct wl_resource *resource,
 	       uint32_t id, struct wl_resource *surface_resource,
@@ -870,11 +886,27 @@ GetSubsurface (struct wl_client *client, struct wl_resource *resource,
   if (surface->role || (surface->role_type != AnythingType
 			&& surface->role_type != SubsurfaceType))
     {
-      wl_resource_post_error (resource, WL_DISPLAY_ERROR_IMPLEMENTATION,
+      wl_resource_post_error (resource, WL_SUBCOMPOSITOR_ERROR_BAD_SURFACE,
 			      "trying to attach subsurface to surface with role");
       return;
     }
 
+  /* Check that a parent loop won't happen.  */
+
+  if (parent == surface)
+    {
+      wl_resource_post_error (resource, WL_SUBCOMPOSITOR_ERROR_BAD_PARENT,
+			      "trying to attach subsurface to itself");
+      return;
+    }
+
+  if (GetRootSurface (parent) == surface)
+    {
+      wl_resource_post_error (resource, WL_SUBCOMPOSITOR_ERROR_BAD_PARENT,
+			      "specified parent is ancestor of subsurface");
+      return;
+    }
+
   subsurface = XLSafeMalloc (sizeof *subsurface);
 
   if (!subsurface)