Evas: Add seat_event_filter_set()/get() API.

With this new API one can block or unblock keyboard, mouse and
focus events that was originated from a seat. This is useful to
create applications that wants to establish some kind of seat segregation.

src/lib/evas/canvas/efl_canvas_object.eo

@@ -666,5 +666,7 @@ abstract Efl.Canvas.Object (Efl.Object, Efl.Gfx, Efl.Gfx.Stack, Efl.Animator,
       Efl.Gfx.Size.Hint.hint_weight.get;
       Efl.Gfx.Map.map_enable.set;
       Efl.Gfx.Map.map_enable.get;
+      Efl.Input.Interface.seat_event_filter.set;
+      Efl.Input.Interface.seat_event_filter.get;
    }
 }

src/lib/evas/canvas/efl_input_interface.eo

@@ -79,6 +79,22 @@ interface Efl.Input.Interface ()
          }
          return: iterator<const(Efl.Input.Pointer)>; [[Iterator to pointer positions]]
       }
+      @property seat_event_filter {
+          set {
+             [[Add or remove a given seat to the filter list. If the filter list is empty this object
+               will report mouse, keyboard and focus events from any seat, otherwise those events will
+               only be reported if the event comes from a seat that is in the list.]]
+          }
+          get {
+             [[Check if input events from a given seat is enabled.]]
+          }
+          keys {
+             seat: Efl.Input.Device; [[The seat to act on.]]
+          }
+          values {
+             enable: bool; [[$true to enable events for a seat or $false otherwise.]]
+          }
+      }
    }
    events {
       pointer,move: Efl.Input.Pointer;   [[Main pointer move (current and previous positions are known).]]

src/lib/evas/canvas/evas_object_main.c

@@ -887,6 +887,52 @@ evas_object_del(Evas_Object *eo_obj)
    efl_del(eo_obj);
 }
 
+EOLIAN static Eina_Bool
+_efl_canvas_object_efl_input_interface_seat_event_filter_get(Eo *eo_obj EINA_UNUSED,
+                                                             Evas_Object_Protected_Data *obj,
+                                                             Efl_Input_Device *seat)
+{
+   //If the list is empty this object accept events from any seat.
+   if (!obj->events_whitelist)
+     return EINA_TRUE;
+   return eina_list_data_find(obj->events_whitelist, seat) ?
+     EINA_TRUE : EINA_FALSE;
+}
+
+static void
+_whitelist_events_device_remove_cb(void *data, const Efl_Event *event)
+{
+   Evas_Object_Protected_Data *obj = data;
+   obj->events_whitelist = eina_list_remove(obj->events_whitelist,
+                                            event->object);
+}
+
+EOLIAN static void
+_efl_canvas_object_efl_input_interface_seat_event_filter_set(Eo *eo_obj,
+                                                             Evas_Object_Protected_Data *obj,
+                                                             Efl_Input_Device *seat,
+                                                             Eina_Bool add)
+{
+   EINA_SAFETY_ON_NULL_RETURN(seat);
+
+   if (efl_input_device_type_get(seat) != EFL_INPUT_DEVICE_CLASS_SEAT) return;
+   if (add)
+     {
+        if (eina_list_data_find(obj->events_whitelist, seat)) return;
+        if (efl_canvas_object_seat_focus_check(eo_obj, seat))
+          efl_canvas_object_seat_focus_del(eo_obj, seat);
+        obj->events_whitelist = eina_list_append(obj->events_whitelist, seat);
+        efl_event_callback_add(seat, EFL_EVENT_DEL,
+                               _whitelist_events_device_remove_cb, obj);
+     }
+   else
+     {
+        obj->events_whitelist = eina_list_remove(obj->events_whitelist, seat);
+        efl_event_callback_del(seat, EFL_EVENT_DEL,
+                               _whitelist_events_device_remove_cb, obj);
+     }
+}
+
 EOLIAN static void
 _efl_canvas_object_efl_object_destructor(Eo *eo_obj, Evas_Object_Protected_Data *obj)
 {
@@ -914,6 +960,8 @@ _efl_canvas_object_efl_object_destructor(Eo *eo_obj, Evas_Object_Protected_Data
    evas_object_event_callback_call(eo_obj, obj, EVAS_CALLBACK_DEL, NULL, _evas_object_event_new(), NULL);
    if ((obj->layer) && (obj->layer->evas))
      _evas_post_event_callback_call(obj->layer->evas->evas, obj->layer->evas);
+   EINA_LIST_FREE(obj->events_whitelist, dev)
+     efl_event_callback_del(dev, EFL_EVENT_DEL, _whitelist_events_device_remove_cb, obj);
    if (obj->name) evas_object_name_set(eo_obj, NULL);
    if (!obj->layer)
      {

src/lib/evas/include/evas_private.h

@@ -1116,6 +1116,12 @@ struct _Evas_Object_Protected_Data
    Eina_List                  *grabs;
 
    Eina_Inlist                *callbacks;
+   /*
+      The list below contain the seats (Efl.Input.Devices) which this
+      object allows events to be reported (Mouse, Keybord and focus events).
+      If this list is empty, this object will allow events from any seat.
+    */
+   Eina_List                  *events_whitelist;
 
    struct {
       Eina_List               *clipees;