[mutter] remote-desktop: Add support for discovering supported device types

[Jonas Ådahl <jadahl src gnome org>]

commit 8dd377da384b308e87aee21cf50f4a9c6620aa0a
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Jan 29 14:51:01 2018 +0800

    remote-desktop: Add support for discovering supported device types
    
    This is so that application will not try to send touch events when
    touch is not supported.

 src/backends/meta-remote-desktop.c     | 34 ++++++++++++++++++++++++++++++++++
 src/org.gnome.Mutter.RemoteDesktop.xml | 11 +++++++++++
 2 files changed, 45 insertions(+)
---
diff --git a/src/backends/meta-remote-desktop.c b/src/backends/meta-remote-desktop.c
index 38dbb57ae..1282818c0 100644
--- a/src/backends/meta-remote-desktop.c
+++ b/src/backends/meta-remote-desktop.c
@@ -43,6 +43,14 @@
 #define META_REMOTE_DESKTOP_DBUS_SERVICE "org.gnome.Mutter.RemoteDesktop"
 #define META_REMOTE_DESKTOP_DBUS_PATH "/org/gnome/Mutter/RemoteDesktop"
 
+typedef enum _MetaRemoteDesktopDeviceTypes
+{
+  META_REMOTE_DESKTOP_DEVICE_TYPE_NONE = 0,
+  META_REMOTE_DESKTOP_DEVICE_TYPE_KEYBOARD = 1 << 0,
+  META_REMOTE_DESKTOP_DEVICE_TYPE_POINTER = 1 << 1,
+  META_REMOTE_DESKTOP_DEVICE_TYPE_TOUCHSCREEN = 1 << 2,
+} MetaRemoteDesktopDeviceTypes;
+
 struct _MetaRemoteDesktop
 {
   MetaDBusRemoteDesktopSkeleton parent;
@@ -224,10 +232,36 @@ meta_remote_desktop_new (MetaDbusSessionWatcher *session_watcher)
   return remote_desktop;
 }
 
+static MetaRemoteDesktopDeviceTypes
+calculate_supported_device_types (void)
+{
+  ClutterDeviceManager *device_manager =
+    clutter_device_manager_get_default ();
+  ClutterVirtualDeviceType device_types;
+  MetaRemoteDesktopDeviceTypes supported_devices =
+    META_REMOTE_DESKTOP_DEVICE_TYPE_NONE;
+
+  device_types =
+    clutter_device_manager_get_supported_virtual_device_types (device_manager);
+
+  if (device_types & CLUTTER_VIRTUAL_DEVICE_TYPE_KEYBOARD)
+    supported_devices |= META_REMOTE_DESKTOP_DEVICE_TYPE_KEYBOARD;
+  if (device_types & CLUTTER_VIRTUAL_DEVICE_TYPE_POINTER)
+    supported_devices |= META_REMOTE_DESKTOP_DEVICE_TYPE_POINTER;
+  if (device_types & CLUTTER_VIRTUAL_DEVICE_TYPE_TOUCHSCREEN)
+    supported_devices |= META_REMOTE_DESKTOP_DEVICE_TYPE_TOUCHSCREEN;
+
+  return supported_devices;
+}
+
 static void
 meta_remote_desktop_init (MetaRemoteDesktop *remote_desktop)
 {
   remote_desktop->sessions = g_hash_table_new (g_str_hash, g_str_equal);
+
+  meta_dbus_remote_desktop_set_supported_device_types (
+    META_DBUS_REMOTE_DESKTOP (remote_desktop),
+    calculate_supported_device_types ());
 }
 
 static void
diff --git a/src/org.gnome.Mutter.RemoteDesktop.xml b/src/org.gnome.Mutter.RemoteDesktop.xml
index dddc59a16..dc86cf342 100644
--- a/src/org.gnome.Mutter.RemoteDesktop.xml
+++ b/src/org.gnome.Mutter.RemoteDesktop.xml
@@ -17,6 +17,17 @@
       <arg name="session_path" type="o" direction="out" />
     </method>
 
+    <!--
+       SupportedDeviceTypes:
+       @short_description: Bit mask of supported device types
+
+       Device types:
+         1: keyboard
+         2: pointer
+         4: touchscreen
+    -->
+    <property name="SupportedDeviceTypes" type="u" access="read" />
+
   </interface>
 
   <!--