backends: Add MetaInputDevice derivable class

This class sits between ClutterInputDevice and the backend implementations,
it will be the despositary of features we need across both backends, but
don't need to offer through Clutter's API.

As a first thing to have there, add a getter for a WacomDevice. This is
something scattered across and somewhat inconsistent (eg. different places
of the code create wacom devices for different device types). Just make it
here for all devices, so users can pick.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1109

src/backends/meta-backend-private.h

@@ -182,4 +182,8 @@ void meta_backend_add_gpu (MetaBackend *backend,
 META_EXPORT_TEST
 GList * meta_backend_get_gpus (MetaBackend *backend);
 
+#ifdef HAVE_LIBWACOM
+WacomDeviceDatabase * meta_backend_get_wacom_database (MetaBackend *backend);
+#endif
+
 #endif /* META_BACKEND_PRIVATE_H */

src/backends/meta-backend.c

@@ -134,6 +134,10 @@ struct _MetaBackendPrivate
   MetaProfiler *profiler;
 #endif
 
+#ifdef HAVE_LIBWACOM
+  WacomDeviceDatabase *wacom_db;
+#endif
+
   ClutterBackend *clutter_backend;
   ClutterActor *stage;
 
@@ -199,6 +203,10 @@ meta_backend_finalize (GObject *object)
   g_clear_object (&priv->remote_access_controller);
 #endif
 
+#ifdef HAVE_LIBWACOM
+  g_clear_pointer (&priv->wacom_db, libwacom_database_destroy);
+#endif
+
   if (priv->sleep_signal_id)
     g_dbus_connection_signal_unsubscribe (priv->system_bus, priv->sleep_signal_id);
   if (priv->upower_watch_id)
@@ -715,6 +723,15 @@ meta_backend_constructed (GObject *object)
   MetaBackendClass *backend_class =
    META_BACKEND_GET_CLASS (backend);
 
+#ifdef HAVE_LIBWACOM
+  priv->wacom_db = libwacom_database_new ();
+  if (!priv->wacom_db)
+    {
+      g_warning ("Could not create database of Wacom devices, "
+                 "expect tablets to misbehave");
+    }
+#endif
+
   if (backend_class->is_lid_closed != meta_backend_real_is_lid_closed)
     return;
 
@@ -1442,3 +1459,13 @@ meta_backend_get_gpus (MetaBackend *backend)
 
   return priv->gpus;
 }
+
+#ifdef HAVE_LIBWACOM
+WacomDeviceDatabase *
+meta_backend_get_wacom_database (MetaBackend *backend)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+
+  return priv->wacom_db;
+}
+#endif

src/backends/meta-input-device-private.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright © 2020  Red Hat Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Carlos Garnacho <carlosg@gnome.org>
+ */
+#ifndef META_INPUT_DEVICE_H
+#define META_INPUT_DEVICE_H
+
+#include <glib-object.h>
+
+#ifdef HAVE_LIBWACOM
+#include <libwacom/libwacom.h>
+#endif
+
+#include "clutter/clutter-mutter.h"
+
+typedef struct _MetaInputDeviceClass MetaInputDeviceClass;
+typedef struct _MetaInputDevice MetaInputDevice;
+
+struct _MetaInputDeviceClass
+{
+  ClutterInputDeviceClass parent_class;
+};
+
+#define META_TYPE_INPUT_DEVICE (meta_input_device_get_type ())
+G_DECLARE_DERIVABLE_TYPE (MetaInputDevice,
+			  meta_input_device,
+			  META, INPUT_DEVICE,
+			  ClutterInputDevice)
+
+#ifdef HAVE_LIBWACOM
+WacomDevice * meta_input_device_get_wacom_device (MetaInputDevice *input_device);
+#endif
+
+#endif /* META_INPUT_DEVICE_H */

src/backends/meta-input-device.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright © 2020  Red Hat Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Carlos Garnacho <carlosg@gnome.org>
+ */
+
+#include "config.h"
+
+#include "backends/meta-backend-private.h"
+#include "meta-input-device-private.h"
+
+typedef struct _MetaInputDevicePrivate MetaInputDevicePrivate;
+
+struct _MetaInputDevicePrivate
+{
+#ifdef HAVE_LIBWACOM
+  WacomDevice *wacom_device;
+#else
+  /* Just something to have non-zero sized struct otherwise */
+  gpointer wacom_device;
+#endif
+};
+
+enum
+{
+  PROP_WACOM_DEVICE = 1,
+  N_PROPS
+};
+
+static GParamSpec *props[N_PROPS] = { 0 };
+
+G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (MetaInputDevice,
+                                     meta_input_device,
+                                     CLUTTER_TYPE_INPUT_DEVICE)
+
+static void
+meta_input_device_init (MetaInputDevice *input_device)
+{
+}
+
+static void
+meta_input_device_constructed (GObject *object)
+{
+  MetaInputDevice *input_device = META_INPUT_DEVICE (object);
+#ifdef HAVE_LIBWACOM
+  WacomDeviceDatabase *wacom_db;
+  MetaInputDevicePrivate *priv;
+  const char *node;
+#endif
+
+  G_OBJECT_CLASS (meta_input_device_parent_class)->constructed (object);
+
+#ifdef HAVE_LIBWACOM
+  priv = meta_input_device_get_instance_private (input_device);
+  wacom_db = meta_backend_get_wacom_database (meta_get_backend ());
+  node = clutter_input_device_get_device_node (CLUTTER_INPUT_DEVICE (input_device));
+  priv->wacom_device = libwacom_new_from_path (wacom_db, node,
+                                               WFALLBACK_NONE, NULL);
+#endif /* HAVE_LIBWACOM */
+}
+
+static void
+meta_input_device_finalize (GObject *object)
+{
+#ifdef HAVE_LIBWACOM
+  MetaInputDevicePrivate *priv;
+
+  priv = meta_input_device_get_instance_private (META_INPUT_DEVICE (object));
+
+  g_clear_pointer (&priv->wacom_device, libwacom_destroy);
+#endif /* HAVE_LIBWACOM */
+
+  G_OBJECT_CLASS (meta_input_device_parent_class)->finalize (object);
+}
+
+static void
+meta_input_device_get_property (GObject    *object,
+                                guint       prop_id,
+                                GValue     *value,
+                                GParamSpec *pspec)
+{
+  MetaInputDevicePrivate *priv;
+
+  priv = meta_input_device_get_instance_private (META_INPUT_DEVICE (object));
+
+  switch (prop_id)
+    {
+    case PROP_WACOM_DEVICE:
+      g_value_set_pointer (value, priv->wacom_device);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+meta_input_device_class_init (MetaInputDeviceClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = meta_input_device_constructed;
+  object_class->finalize = meta_input_device_finalize;
+  object_class->get_property = meta_input_device_get_property;
+
+  props[PROP_WACOM_DEVICE] =
+    g_param_spec_pointer ("wacom-device",
+                          "Wacom device",
+                          "Wacom device",
+                          G_PARAM_READABLE);
+
+  g_object_class_install_properties (object_class, N_PROPS, props);
+}
+
+#ifdef HAVE_LIBWACOM
+WacomDevice *
+meta_input_device_get_wacom_device (MetaInputDevice *input_device)
+{
+  MetaInputDevicePrivate *priv;
+
+  priv = meta_input_device_get_instance_private (input_device);
+
+  return priv->wacom_device;
+}
+#endif /* HAVE_LIBWACOM */

src/backends/native/meta-input-device-native.c

@@ -31,7 +31,7 @@
 
 G_DEFINE_TYPE (MetaInputDeviceNative,
                meta_input_device_native,
-               CLUTTER_TYPE_INPUT_DEVICE)
+               META_TYPE_INPUT_DEVICE)
 
 enum
 {

src/backends/native/meta-input-device-native.h

@@ -28,6 +28,7 @@
 
 #include <glib-object.h>
 
+#include "backends/meta-input-device-private.h"
 #include "backends/native/meta-seat-native.h"
 #include "clutter/clutter-mutter.h"
 

src/backends/x11/meta-input-device-x11.c

@@ -52,7 +52,7 @@ struct _MetaInputDeviceX11Class
 
 G_DEFINE_TYPE (MetaInputDeviceX11,
                meta_input_device_x11,
-               CLUTTER_TYPE_INPUT_DEVICE)
+               META_TYPE_INPUT_DEVICE)
 
 static void
 meta_input_device_x11_constructed (GObject *object)

src/backends/x11/meta-input-device-x11.h

@@ -26,6 +26,7 @@
 #include <libwacom/libwacom.h>
 #endif
 
+#include "backends/meta-input-device-private.h"
 #include "clutter/clutter.h"
 
 G_BEGIN_DECLS

src/meson.build

@@ -190,6 +190,7 @@ mutter_sources = [
   'backends/meta-idle-monitor-dbus.c',
   'backends/meta-idle-monitor-dbus.h',
   'backends/meta-idle-monitor-private.h',
+  'backends/meta-input-device.c',
   'backends/meta-input-mapper.c',
   'backends/meta-input-mapper-private.h',
   'backends/meta-input-settings.c',