ui/dbus: introduce "Interfaces" properties

This property is similar to ``org.freedesktop.DBus.Interfaces`` property
on the bus interface: it's an array of strings listing the extra
interfaces and capabilities available, in a convenient way.

Most interfaces are implicit, as they are required. For
``org/qemu/Display1_$id``, we can list the Keyboard And Mouse
interfaces. Those could be optional.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230606115658.677673-9-marcandre.lureau@redhat.com>

ui/dbus-console.c

@@ -537,6 +537,12 @@ dbus_display_console_new(DBusDisplay *display, QemuConsole *con)
     char device_addr[256] = "";
     DBusDisplayConsole *ddc;
     int idx, i;
+    const char *interfaces[] = {
+        "org.qemu.Display1.Keyboard",
+        "org.qemu.Display1.Mouse",
+        "org.qemu.Display1.MultiTouch",
+        NULL
+    };
 
     assert(display);
     assert(con);
@@ -561,6 +567,7 @@ dbus_display_console_new(DBusDisplay *display, QemuConsole *con)
         "width", qemu_console_get_width(con, 0),
         "height", qemu_console_get_height(con, 0),
         "device-address", device_addr,
+        "interfaces", interfaces,
         NULL);
     g_object_connect(ddc->iface,
         "swapped-signal::handle-register-listener",

ui/dbus-display1.xml

@@ -26,6 +26,20 @@
         The list of consoles available on ``/org/qemu/Display1/Console_$id``.
     -->
     <property name="ConsoleIDs" type="au" access="read"/>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/VM object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -127,12 +141,27 @@
         The device address (ex: "pci/0000/02.0").
     -->
     <property name="DeviceAddress" type="s" access="read"/>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        ``/org/qemu/Display1/Console_$id`` object, and can be used to detect the
+        capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
       org.qemu.Display1.Keyboard:
 
-      This interface in implemented on ``/org/qemu/Display1/Console_$id`` (see
+      This interface is optionally implemented on
+      ``/org/qemu/Display1/Console_$id`` (see
       :dbus:iface:`~org.qemu.Display1.Console`).
   -->
   <interface name="org.qemu.Display1.Keyboard">
@@ -171,7 +200,8 @@
   <!--
       org.qemu.Display1.Mouse:
 
-      This interface in implemented on ``/org/qemu/Display1/Console_$id`` (see
+      This interface is optionally implemented on
+      ``/org/qemu/Display1/Console_$id`` (see
       :dbus:iface:`~org.qemu.Display1.Console` documentation).
 
       .. _dbus-button-values:
@@ -425,6 +455,20 @@
         <annotation name="org.gtk.GDBus.C.ForceGVariant" value="true"/>
       </arg>
     </method>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/Listener object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -522,6 +566,20 @@
         <annotation name="org.gtk.GDBus.C.ForceGVariant" value="true"/>
       </arg>
     </method>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/Clipboard object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -571,6 +629,20 @@
       <arg type="h" name="listener" direction="in"/>
       <?endif?>
     </method>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/Audio object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -657,6 +729,20 @@
         <annotation name="org.gtk.GDBus.C.ForceGVariant" value="true"/>
       </arg>
     </method>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/AudioOutListener object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -745,6 +831,20 @@
         <annotation name="org.gtk.GDBus.C.ForceGVariant" value="true"/>
       </arg>
     </method>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        /org/qemu/Display1/AudioInListener object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 
   <!--
@@ -826,5 +926,19 @@
         The D-Bus unique name of the registered handler.
     -->
     <property name="Owner" type="s" access="read"/>
+
+    <!--
+        Interfaces:
+
+        This property lists extra interfaces provided by the
+        ``/org/qemu/Display1/Chardev_$i`` object, and can be used to detect
+        the capabilities with which they are communicating.
+
+        Unlike the standard D-Bus Introspectable interface, querying this
+        property does not require parsing XML.
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="Interfaces" type="as" access="read"/>
   </interface>
 </node>