device: Make InputDevice an object and subclass it for X11

ClutterInputDevice should be a type that we can subclass per-backend
to add functionality.

clutter/clutter-input-device.h

@@ -0,0 +1,64 @@
+#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
+#error "Only <clutter/clutter.h> can be included directly."
+#endif
+
+#ifndef __CLUTTER_INPUT_DEVICE_H__
+#define __CLUTTER_INPUT_DEVICE_H__
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define CLUTTER_TYPE_INPUT_DEVICE               (clutter_input_device_get_type ())
+#define CLUTTER_INPUT_DEVICE(obj)               (G_TYPE_CHECK_INSTANCE_CAST ((obj), CLUTTER_TYPE_INPUT_DEVICE, ClutterInputDevice))
+#define CLUTTER_IS_INPUT_DEVICE(obj)            (G_TYPE_CHECK_INSTANCE_TYPE ((obj), CLUTTER_TYPE_INPUT_DEVICE))
+#define CLUTTER_INPUT_DEVICE_CLASS(klass)       (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_INPUT_DEVICE, ClutterInputDeviceClass))
+#define CLUTTER_IS_INPUT_DEVICE_CLASS(klass)    (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_INPUT_DEVICE))
+#define CLUTTER_INPUT_DEVICE_GET_CLASS(obj)     (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_INPUT_DEVICE, ClutterInputDeviceClass))
+
+/**
+ * ClutterInputDevice:
+ *
+ * Generic representation of an input device. The
+ * actual contents of this structure depend on the
+ * backend used.
+ */
+typedef struct _ClutterInputDevice      ClutterInputDevice;
+typedef struct _ClutterInputDeviceClass ClutterInputDeviceClass;
+
+/**
+ * ClutterInputDeviceType:
+ * @CLUTTER_POINTER_DEVICE: A pointer device
+ * @CLUTTER_KEYBOARD_DEVICE: A keyboard device
+ * @CLUTTER_EXTENSION_DEVICE: A generic extension device
+ * @CLUTTER_N_DEVICE_TYPES: The number of device types
+ *
+ * The types of input devices available.
+ *
+ * The #ClutterInputDeviceType enumeration can be extended at later
+ * date; not every platform supports every input device type.
+ *
+ * Since: 1.0
+ */
+typedef enum {
+  CLUTTER_POINTER_DEVICE,
+  CLUTTER_KEYBOARD_DEVICE,
+  CLUTTER_EXTENSION_DEVICE,
+
+  CLUTTER_N_DEVICE_TYPES
+} ClutterInputDeviceType;
+
+struct _ClutterInputDeviceClass
+{
+  /*< private >*/
+  GObjectClass parent_class;
+};
+
+GType clutter_input_device_get_type (void) G_GNUC_CONST;
+
+ClutterInputDeviceType clutter_input_device_get_device_type (ClutterInputDevice *device);
+gint                   clutter_input_device_get_device_id   (ClutterInputDevice *device);
+
+G_END_DECLS
+
+#endif /* __CLUTTER_INPUT_DEVICE_H__ */