Track the most-recently used device

Add a ::current-device property to GdkDeviceManager which tracks
the most recently used slave device.

3 files changed, 44 insertions, 2 deletions

diff --git a/gdk/gdkdevice.c b/gdk/gdkdevice.c
index 51c91721a5..d8b66f1a83 100644
--- a/gdk/gdkdevice.c
+++ b/gdk/gdkdevice.c
@@ -20,6 +20,7 @@
 #include <math.h>
 
 #include "gdkdeviceprivate.h"
+#include "gdkdevicemanagerprivate.h"
 #include "gdkdisplayprivate.h"
 #include "gdkinternals.h"
 #include "gdkintl.h"
@@ -1782,5 +1783,8 @@ _gdk_device_set_time (GdkDevice *device,
                       guint32    time)
 {
   if (time > device->time)
-    device->time = time;
+    {
+      device->time = time;
+      _gdk_device_manager_update_current_device (device->manager, device);
+    }
 }
diff --git a/gdk/gdkdevicemanager.c b/gdk/gdkdevicemanager.c
index 3da434d703..e7e16b546e 100644
--- a/gdk/gdkdevicemanager.c
+++ b/gdk/gdkdevicemanager.c
@@ -154,13 +154,15 @@ G_DEFINE_ABSTRACT_TYPE (GdkDeviceManager, gdk_device_manager, G_TYPE_OBJECT)
 
 enum {
   PROP_0,
-  PROP_DISPLAY
+  PROP_DISPLAY,
+  PROP_CURRENT_DEVICE
 };
 
 enum {
   DEVICE_ADDED,
   DEVICE_REMOVED,
   DEVICE_CHANGED,
+  CURRENT_DEVICE_CHANGED,
   LAST_SIGNAL
 };
 
@@ -184,6 +186,15 @@ gdk_device_manager_class_init (GdkDeviceManagerClass *klass)
                                                         G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
                                                         G_PARAM_STATIC_STRINGS));
 
+  g_object_class_install_property (object_class,
+                                   PROP_CURRENT_DEVICE,
+                                   g_param_spec_object ("current-device",
+                                                        P_("Current device"),
+                                                        P_("Most recently used device"),
+                                                        GDK_TYPE_DEVICE,
+                                                        G_PARAM_READABLE |
+                                                        G_PARAM_STATIC_STRINGS));
+
   /**
    * GdkDeviceManager::device-added:
    * @device_manager: the object on which the signal is emitted
@@ -283,6 +294,9 @@ gdk_device_manager_get_property (GObject      *object,
     case PROP_DISPLAY:
       g_value_set_object (value, GDK_DEVICE_MANAGER (object)->display);
       break;
+    case PROP_CURRENT_DEVICE:
+      g_value_set_object (value, GDK_DEVICE_MANAGER (object)->current_device);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -356,3 +370,22 @@ gdk_device_manager_get_client_pointer (GdkDeviceManager *device_manager)
 
   return GDK_DEVICE_MANAGER_GET_CLASS (device_manager)->get_client_pointer (device_manager);
 }
+
+void
+_gdk_device_manager_update_current_device (GdkDeviceManager *device_manager,
+                                           GdkDevice        *device)
+{
+  if (gdk_device_get_device_type (device) != GDK_DEVICE_TYPE_SLAVE)
+    return;
+
+  if (device_manager->current_device == device)
+    return;
+
+  if (device_manager->current_device == NULL ||
+      device == NULL ||
+      gdk_device_get_time (device) >= gdk_device_get_time (device_manager->current_device))
+    {
+      device_manager->current_device = device;
+      g_object_notify (G_OBJECT (device_manager), "current-device");
+    }
+}
diff --git a/gdk/gdkdevicemanagerprivate.h b/gdk/gdkdevicemanagerprivate.h
index c18d2cdd73..5ce6371af7 100644
--- a/gdk/gdkdevicemanagerprivate.h
+++ b/gdk/gdkdevicemanagerprivate.h
@@ -36,6 +36,7 @@ struct _GdkDeviceManager
 
   /*< private >*/
   GdkDisplay *display;
+  GdkDevice *current_device;
 };
 
 struct _GdkDeviceManagerClass
@@ -56,6 +57,10 @@ struct _GdkDeviceManagerClass
   GdkDevice * (* get_client_pointer) (GdkDeviceManager *device_manager);
 };
 
+void
+_gdk_device_manager_update_current_device (GdkDeviceManager *device_manager,
+                                           GdkDevice        *device);
+
 G_END_DECLS
 
 #endif