ClutterEvent: add API to query the full keyboard state when the event was generatedwip/wayland-compositor-help

When talking to other applications or serializing the modifier
state (and in particular when implementing a wayland compositor),
the effective modifier state alone is not sufficient, one needs
to know the base, latched and locked modifiers.

Previously one could do with backend specific functionality
such as clutter_device_manager_evdev_get_xkb_state(), but the
problem is that the internal data structures are updated as
soon as the events are fetched from the upstream source, but
the events are reported to the application some time later,
and thus the two can get out of sync.
This way, on the other hand, the information is cached in the
event, and provided to the application with the value that
was current when the event was generated.

https://bugzilla.gnome.org/show_bug.cgi?id=706494

10 files changed, 147 insertions, 53 deletions

diff --git a/clutter/clutter-event-private.h b/clutter/clutter-event-private.h
index eeb10800b..955db260e 100644
--- a/clutter/clutter-event-private.h
+++ b/clutter/clutter-event-private.h
@@ -19,6 +19,13 @@ void            _clutter_event_set_platform_data        (ClutterEvent       *eve
                                                          gpointer            data);
 gpointer        _clutter_event_get_platform_data        (const ClutterEvent *event);
 
+void            _clutter_event_set_state_full           (ClutterEvent        *event,
+							 ClutterModifierType  button_state,
+							 ClutterModifierType  base_state,
+							 ClutterModifierType  latched_state,
+							 ClutterModifierType  locked_state,
+							 ClutterModifierType  effective_state);
+
 void            _clutter_event_push                     (const ClutterEvent *event,
                                                          gboolean            do_copy);
 
diff --git a/clutter/clutter-event.c b/clutter/clutter-event.c
index 2547572ca..6b669128f 100644
--- a/clutter/clutter-event.c
+++ b/clutter/clutter-event.c
@@ -56,6 +56,11 @@ typedef struct _ClutterEventPrivate {
 
   gpointer platform_data;
 
+  ClutterModifierType button_state;
+  ClutterModifierType base_state;
+  ClutterModifierType latched_state;
+  ClutterModifierType locked_state;
+
   guint is_pointer_emulated : 1;
 } ClutterEventPrivate;
 
@@ -265,6 +270,61 @@ clutter_event_set_state (ClutterEvent        *event,
     }
 }
 
+void
+_clutter_event_set_state_full (ClutterEvent        *event,
+			       ClutterModifierType  button_state,
+			       ClutterModifierType  base_state,
+			       ClutterModifierType  latched_state,
+			       ClutterModifierType  locked_state,
+			       ClutterModifierType  effective_state)
+{
+  ClutterEventPrivate *private = (ClutterEventPrivate*) event;
+
+  private->button_state = button_state;
+  private->base_state = base_state;
+  private->latched_state = latched_state;
+  private->locked_state = locked_state;
+
+  clutter_event_set_state (event, effective_state);
+}
+
+/**
+ * clutter_event_get_state_full:
+ * @event: a #ClutterEvent
+ * @button_state: (out) (allow-none): the pressed buttons as a mask
+ * @base_state: (out) (allow-none): the regular pressed modifier keys
+ * @latched_state: (out) (allow-none): the latched modifier keys (currently released but still valid for one key press/release)
+ * @locked_state: (out) (allow-none): the locked modifier keys (valid until the lock key is pressed and released again)
+ * @effective_state: (out) (allow-none): the or of all the state bits above
+ *
+ * Retrieves the decomposition of the keyboard state into button, base,
+ * latched, locked and effective. This can be used to transmit to other
+ * applications, for example when implementing a wayland compositor.
+ */
+void
+clutter_event_get_state_full (const ClutterEvent  *event,
+			      ClutterModifierType *button_state,
+			      ClutterModifierType *base_state,
+			      ClutterModifierType *latched_state,
+			      ClutterModifierType *locked_state,
+			      ClutterModifierType *effective_state)
+{
+  const ClutterEventPrivate *private = (const ClutterEventPrivate*) event;
+
+  g_return_if_fail (event != NULL);
+
+  if (button_state)
+    *button_state = private->button_state;
+  if (base_state)
+    *base_state = private->base_state;
+  if (latched_state)
+    *latched_state = private->latched_state;
+  if (locked_state)
+    *locked_state = private->locked_state;
+  if (effective_state)
+    *effective_state = clutter_event_get_state (event);
+}
+
 /**
  * clutter_event_get_coords:
  * @event: a #ClutterEvent
diff --git a/clutter/clutter-event.h b/clutter/clutter-event.h
index 65ba1511f..83f6c7436 100644
--- a/clutter/clutter-event.h
+++ b/clutter/clutter-event.h
@@ -420,6 +420,12 @@ guint32                 clutter_event_get_time                  (const ClutterEv
 void                    clutter_event_set_state                 (ClutterEvent           *event,
                                                                  ClutterModifierType     state);
 ClutterModifierType     clutter_event_get_state                 (const ClutterEvent     *event);
+void                    clutter_event_get_state_full            (const ClutterEvent     *event,
+								 ClutterModifierType    *button_state,
+								 ClutterModifierType    *base_state,
+								 ClutterModifierType    *latched_state,
+								 ClutterModifierType    *locked_state,
+								 ClutterModifierType    *effective_state);
 void                    clutter_event_set_device                (ClutterEvent           *event,
                                                                  ClutterInputDevice     *device);
 ClutterInputDevice *    clutter_event_get_device                (const ClutterEvent     *event);
diff --git a/clutter/evdev/clutter-device-manager-evdev.c b/clutter/evdev/clutter-device-manager-evdev.c
index d4ff4b81b..1065472c1 100644
--- a/clutter/evdev/clutter-device-manager-evdev.c
+++ b/clutter/evdev/clutter-device-manager-evdev.c
@@ -273,8 +273,7 @@ notify_relative_motion (ClutterEventSource *source,
   event->motion.time = time_;
   event->motion.stage = stage;
   event->motion.device = manager_evdev->priv->core_pointer;
-  event->motion.modifier_state = xkb_state_serialize_mods (manager_evdev->priv->xkb, XKB_STATE_EFFECTIVE);
-  event->motion.modifier_state |= manager_evdev->priv->button_state;
+  _clutter_xkb_translate_state (event, manager_evdev->priv->xkb, manager_evdev->priv->button_state);
   event->motion.x = new_x;
   event->motion.y = new_y;
   clutter_event_set_source_device (event, input_device);
@@ -306,8 +305,7 @@ notify_scroll (ClutterEventSource *source,
   event->scroll.time = time_;
   event->scroll.stage = CLUTTER_STAGE (stage);
   event->scroll.device = manager_evdev->priv->core_pointer;
-  event->motion.modifier_state = xkb_state_serialize_mods (manager_evdev->priv->xkb, XKB_STATE_EFFECTIVE);
-  event->scroll.modifier_state |= manager_evdev->priv->button_state;
+  _clutter_xkb_translate_state (event, manager_evdev->priv->xkb, manager_evdev->priv->button_state);
   event->scroll.direction = value < 0 ? CLUTTER_SCROLL_DOWN : CLUTTER_SCROLL_UP;
   clutter_input_device_get_coords (manager_evdev->priv->core_pointer, NULL, &point);
   event->scroll.x = point.x;
@@ -385,8 +383,7 @@ notify_button (ClutterEventSource *source,
   event->button.time = time_;
   event->button.stage = CLUTTER_STAGE (stage);
   event->button.device = manager_evdev->priv->core_pointer;
-  event->motion.modifier_state = xkb_state_serialize_mods (manager_evdev->priv->xkb, XKB_STATE_EFFECTIVE);
-  event->button.modifier_state |= manager_evdev->priv->button_state;
+  _clutter_xkb_translate_state (event, manager_evdev->priv->xkb, manager_evdev->priv->button_state);
   event->button.button = button_nr;
   clutter_input_device_get_coords (manager_evdev->priv->core_pointer, NULL, &point);
   event->button.x = point.x;
diff --git a/clutter/evdev/clutter-xkb-utils.c b/clutter/evdev/clutter-xkb-utils.c
index 19d467048..eb84bf7b6 100644
--- a/clutter/evdev/clutter-xkb-utils.c
+++ b/clutter/evdev/clutter-xkb-utils.c
@@ -24,6 +24,7 @@
  */
 
 #include "clutter-keysyms.h"
+#include "clutter-event-private.h"
 #include "clutter-xkb-utils.h"
 
 /*
@@ -76,9 +77,7 @@ _clutter_key_event_new_from_evdev (ClutterInputDevice *device,
   event->key.device = core_device;
   event->key.stage = stage;
   event->key.time = _time;
-  event->key.modifier_state =
-    xkb_state_serialize_mods (xkb_state, XKB_STATE_EFFECTIVE);
-  event->key.modifier_state |= button_state;
+  _clutter_xkb_translate_state (event, xkb_state, button_state);
   event->key.hardware_keycode = key;
   event->key.keyval = sym;
   clutter_event_set_source_device (event, device);
@@ -142,3 +141,16 @@ _clutter_xkb_state_new (const gchar *model,
 
   return state;
 }
+
+void
+_clutter_xkb_translate_state (ClutterEvent     *event,
+			      struct xkb_state *state,
+			      uint32_t          button_state)
+{
+  _clutter_event_set_state_full (event,
+				 button_state,
+				 xkb_state_serialize_mods (state, XKB_STATE_MODS_DEPRESSED),
+				 xkb_state_serialize_mods (state, XKB_STATE_MODS_LATCHED),
+				 xkb_state_serialize_mods (state, XKB_STATE_MODS_LOCKED),
+				 xkb_state_serialize_mods (state, XKB_STATE_MODS_EFFECTIVE) | button_state);
+}
diff --git a/clutter/evdev/clutter-xkb-utils.h b/clutter/evdev/clutter-xkb-utils.h
index dd99b8721..ee3a66934 100644
--- a/clutter/evdev/clutter-xkb-utils.h
+++ b/clutter/evdev/clutter-xkb-utils.h
@@ -43,5 +43,8 @@ struct xkb_state * _clutter_xkb_state_new           (const gchar *model,
                                                      const gchar *layout,
                                                      const gchar *variant,
                                                      const gchar *options);
+void               _clutter_xkb_translate_state     (ClutterEvent       *event,
+						     struct xkb_state   *xkb_state,
+						     uint32_t            button_state);
 
 #endif /* __CLUTTER_XKB_UTILS_H__ */
diff --git a/clutter/wayland/clutter-input-device-wayland.c b/clutter/wayland/clutter-input-device-wayland.c
index 0effddff5..29c6caa5c 100644
--- a/clutter/wayland/clutter-input-device-wayland.c
+++ b/clutter/wayland/clutter-input-device-wayland.c
@@ -123,8 +123,7 @@ clutter_wayland_handle_button (void *data,
   event->button.time = _clutter_wayland_get_time();
   event->button.x = device->x;
   event->button.y = device->y;
-  event->button.modifier_state =
-    xkb_state_serialize_mods (device->xkb, XKB_STATE_EFFECTIVE);
+  _clutter_xkb_translate_state (event, device->xkb, 0);
 
   /* evdev button codes */
   switch (button) {
@@ -177,8 +176,7 @@ clutter_wayland_handle_axis (void *data,
     }
   clutter_event_set_scroll_delta (event, delta_x, delta_y);
 
-  event->scroll.modifier_state =
-    xkb_state_serialize_mods(device->xkb, XKB_STATE_EFFECTIVE);
+  _clutter_xkb_translate_state (event, device->xkb, 0);
 
   _clutter_event_push (event, FALSE);
 }
diff --git a/clutter/x11/clutter-device-manager-xi2.c b/clutter/x11/clutter-device-manager-xi2.c
index e5664d82d..1ee4fd9e7 100644
--- a/clutter/x11/clutter-device-manager-xi2.c
+++ b/clutter/x11/clutter-device-manager-xi2.c
@@ -821,8 +821,7 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
 
         event->key.time = xev->time;
         event->key.stage = stage;
-        event->key.modifier_state =
-          _clutter_input_device_xi2_translate_state (&xev->mods, &xev->buttons, &xev->group);
+	_clutter_input_device_xi2_translate_state (event, &xev->mods, &xev->buttons, &xev->group);
         event->key.hardware_keycode = xev->detail;
 
           /* keyval is the key ignoring all modifiers ('1' vs. '!') */
@@ -930,10 +929,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
             event->scroll.time = xev->time;
             event->scroll.x = xev->event_x;
             event->scroll.y = xev->event_y;
-            event->scroll.modifier_state =
-              _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                         &xev->buttons,
-                                                         &xev->group);
+	    _clutter_input_device_xi2_translate_state (event,
+						       &xev->mods,
+						       &xev->buttons,
+						       &xev->group);
 
             clutter_event_set_source_device (event, source_device);
             clutter_event_set_device (event, device);
@@ -979,10 +978,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
             event->button.x = xev->event_x;
             event->button.y = xev->event_y;
             event->button.button = xev->detail;
-            event->button.modifier_state =
-              _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                         &xev->buttons,
-                                                         &xev->group);
+	    _clutter_input_device_xi2_translate_state (event,
+						       &xev->mods,
+						       &xev->buttons,
+						       &xev->group);
 
             clutter_event_set_source_device (event, source_device);
             clutter_event_set_device (event, device);
@@ -1061,10 +1060,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
             event->scroll.time = xev->time;
             event->scroll.x = xev->event_x;
             event->scroll.y = xev->event_y;
-            event->scroll.modifier_state =
-              _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                         &xev->buttons,
-                                                         &xev->group);
+	    _clutter_input_device_xi2_translate_state (event,
+						       &xev->mods,
+						       &xev->buttons,
+						       &xev->group);
 
             clutter_event_set_scroll_delta (event, delta_x, delta_y);
             clutter_event_set_source_device (event, source_device);
@@ -1090,10 +1089,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
         event->motion.time = xev->time;
         event->motion.x = xev->event_x;
         event->motion.y = xev->event_y;
-        event->motion.modifier_state =
-          _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                     &xev->buttons,
-                                                     &xev->group);
+	_clutter_input_device_xi2_translate_state (event,
+						   &xev->mods,
+						   &xev->buttons,
+						   &xev->group);
 
         clutter_event_set_source_device (event, source_device);
         clutter_event_set_device (event, device);
@@ -1142,10 +1141,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
         event->touch.time = xev->time;
         event->touch.x = xev->event_x;
         event->touch.y = xev->event_y;
-        event->touch.modifier_state =
-          _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                     &xev->buttons,
-                                                     &xev->group);
+	_clutter_input_device_xi2_translate_state (event,
+						   &xev->mods,
+						   &xev->buttons,
+						   &xev->group);
 
         clutter_event_set_source_device (event, source_device);
 
@@ -1211,10 +1210,10 @@ clutter_device_manager_xi2_translate_event (ClutterEventTranslator *translator,
                                             stage_x11,
                                             &xev->valuators);
 
-        event->touch.modifier_state =
-          _clutter_input_device_xi2_translate_state (&xev->mods,
-                                                     &xev->buttons,
-                                                     &xev->group);
+	_clutter_input_device_xi2_translate_state (event,
+						   &xev->mods,
+						   &xev->buttons,
+						   &xev->group);
         event->touch.modifier_state |= CLUTTER_BUTTON1_MASK;
 
         if (xev->flags & XITouchEmulatingPointer)
diff --git a/clutter/x11/clutter-input-device-xi2.c b/clutter/x11/clutter-input-device-xi2.c
index b9e27a564..20ac71c44 100644
--- a/clutter/x11/clutter-input-device-xi2.c
+++ b/clutter/x11/clutter-input-device-xi2.c
@@ -27,6 +27,7 @@
 
 #include "clutter-debug.h"
 #include "clutter-device-manager-private.h"
+#include "clutter-event-private.h"
 #include "clutter-private.h"
 #include "clutter-stage-private.h"
 
@@ -94,15 +95,24 @@ clutter_input_device_xi2_init (ClutterInputDeviceXI2 *self)
 {
 }
 
-guint
-_clutter_input_device_xi2_translate_state (XIModifierState *modifiers_state,
+void
+_clutter_input_device_xi2_translate_state (ClutterEvent    *event,
+					   XIModifierState *modifiers_state,
                                            XIButtonState   *buttons_state,
                                            XIGroupState    *group_state)
 {
-  guint retval = 0;
+  guint button = 0;
+  guint base = 0;
+  guint latched = 0;
+  guint locked = 0;
+  guint effective;
 
   if (modifiers_state)
-    retval = (guint) modifiers_state->effective;
+    {
+      base = (guint) modifiers_state->base;
+      latched = (guint) modifiers_state->latched;
+      locked = (guint) modifiers_state->locked;
+    }
 
   if (buttons_state)
     {
@@ -118,23 +128,23 @@ _clutter_input_device_xi2_translate_state (XIModifierState *modifiers_state,
           switch (i)
             {
             case 1:
-              retval |= CLUTTER_BUTTON1_MASK;
+              button |= CLUTTER_BUTTON1_MASK;
               break;
 
             case 2:
-              retval |= CLUTTER_BUTTON2_MASK;
+              button |= CLUTTER_BUTTON2_MASK;
               break;
 
             case 3:
-              retval |= CLUTTER_BUTTON3_MASK;
+              button |= CLUTTER_BUTTON3_MASK;
               break;
 
             case 4:
-              retval |= CLUTTER_BUTTON4_MASK;
+              button |= CLUTTER_BUTTON4_MASK;
               break;
 
             case 5:
-              retval |= CLUTTER_BUTTON5_MASK;
+              button |= CLUTTER_BUTTON5_MASK;
               break;
 
             default:
@@ -143,8 +153,9 @@ _clutter_input_device_xi2_translate_state (XIModifierState *modifiers_state,
         }
     }
 
+  effective = button | base | latched | locked;
   if (group_state)
-    retval |= (group_state->effective) << 13;
+    effective |= (group_state->effective) << 13;
 
-  return retval;
+  _clutter_event_set_state_full (event, button, base, latched, locked, effective);
 }
diff --git a/clutter/x11/clutter-input-device-xi2.h b/clutter/x11/clutter-input-device-xi2.h
index b86401fb9..92dadc965 100644
--- a/clutter/x11/clutter-input-device-xi2.h
+++ b/clutter/x11/clutter-input-device-xi2.h
@@ -37,9 +37,10 @@ typedef struct _ClutterInputDeviceXI2           ClutterInputDeviceXI2;
 
 GType _clutter_input_device_xi2_get_type (void) G_GNUC_CONST;
 
-guint _clutter_input_device_xi2_translate_state (XIModifierState *modifiers_state,
-                                                 XIButtonState   *buttons_state,
-                                                 XIGroupState    *group_state);
+void  _clutter_input_device_xi2_translate_state (ClutterEvent    *event,
+						 XIModifierState *modifiers_state,
+						 XIButtonState   *buttons_state,
+						 XIGroupState    *group_state);
 
 G_END_DECLS