remote-desktop: Add the ability to communicate via an EIS socket

This is intended as replacement for the NotifyFoo methods. libei
provides a more flexible and powerful method of sending input events to
the compositor.

A new method ConnectToEIS requests a file descriptor from the compositor
which can then be plugged into libei.

Once established, the communication between compositor and application
is direct, without the need to go through the portal process(es).

To avoid ambiguities between NotifyFoo and input events sent via libei,
any application that uses an EIS connection may not use the NotifyFoo
methods.

Co-authored-by: Olivier Fourdan <ofourdan@redhat.com>

data/org.freedesktop.impl.portal.RemoteDesktop.xml

@@ -350,6 +350,26 @@
       <arg type="a{sv}" name="options" direction="in"/>
       <arg type="u" name="slot" direction="in"/>
     </method>
+    <!--
+        ConnectToEIS:
+        @session_handle: Object path for the #org.freedesktop.portal.Session object
+        @app_id: App id of the application
+        @options: Vardict with optional further information
+        @fd: A file descriptor to an EIS implementation that can be passed to a
+        sender libei context
+
+        Request a connection to an EIS implementation.
+
+        This method is available in version 2 of this interface.
+    -->
+    <method name="ConnectToEIS">
+      <annotation name="org.gtk.GDBus.C.UnixFD" value="true"/>
+      <arg type="o" name="session_handle" direction="in"/>
+      <arg type="s" name="app_id" direction="in"/>
+      <annotation name="org.qtproject.QtDBus.QtTypeName.Out1" value="QVariantMap"/>
+      <arg type="a{sv}" name="options" direction="in"/>
+      <arg type="h" name="fd" direction="out"/>
+    </method>
     <!--
         AvailableDeviceTypes:
 

data/org.freedesktop.portal.RemoteDesktop.xml

@@ -396,6 +396,37 @@
       <arg type="a{sv}" name="options" direction="in"/>
       <arg type="u" name="slot" direction="in"/>
     </method>
+
+    <!--
+        ConnectToEIS:
+        @session_handle: Object path for the #org.freedesktop.portal.Session object
+        @options: Vardict with optional further information
+        @fd: A file descriptor to an EIS implementation that can be passed to a libei sender context
+
+        Request a connection to an EIS implementation. The returned handle can
+        be passed to ei_setup_backend_fd() for a libei sender context to
+        complete the connection. All information about available devices and the
+        event flow is subject to libei. Please see the libei documentation for details.
+
+        This method may only be called once per session, where the EIS
+        implementation disconnects the session should be closed.
+
+        This method must be called after #org.freedesktop.portal.RemoteDesktop.Start()
+
+        Once an EIS connection is established, input events must be sent exclusively via
+        the EIS connection. Any events submitted via NotifyPointerMotion,
+        NotifyKeyboardKeycode and other Notify* methods will return an error.
+
+        This method was added in version 2 of this interface.
+    -->
+    <method name="ConnectToEIS">
+      <annotation name="org.gtk.GDBus.C.Name" value="connect_to_eis"/>
+      <annotation name="org.gtk.GDBus.C.UnixFD" value="true"/>
+      <arg type="o" name="session_handle" direction="in"/>
+      <arg type="a{sv}" name="options" direction="in"/>
+      <arg type="h" name="fd" direction="out"/>
+    </method>
+
     <!--
         AvailableDeviceTypes:
 

src/remote-desktop.c

@@ -28,6 +28,7 @@
 #include "xdp-impl-dbus.h"
 #include "xdp-utils.h"
 
+#include <gio/gunixfdlist.h>
 #include <stdint.h>
 
 typedef struct _RemoteDesktop RemoteDesktop;
@@ -88,6 +89,8 @@ typedef struct _RemoteDesktopSession
   gboolean sources_selected;
 
   gboolean clipboard_enabled;
+
+  gboolean uses_eis;
 } RemoteDesktopSession;
 
 typedef struct _RemoteDesktopSessionClass
@@ -695,7 +698,7 @@ check_notify (Session *session,
 {
   RemoteDesktopSession *remote_desktop_session = (RemoteDesktopSession *)session;
 
-  if (!remote_desktop_session->devices_selected)
+  if (!remote_desktop_session->devices_selected || remote_desktop_session->uses_eis)
     return FALSE;
 
   switch (remote_desktop_session->state)
@@ -1357,6 +1360,105 @@ handle_notify_touch_up (XdpDbusRemoteDesktop *object,
   return G_DBUS_METHOD_INVOCATION_HANDLED;
 }
 
+static XdpOptionKey remote_desktop_connect_to_eis_options[] = {
+};
+
+static gboolean
+handle_connect_to_eis (XdpDbusRemoteDesktop *object,
+                       GDBusMethodInvocation *invocation,
+                       GUnixFDList *in_fd_list,
+                       const char *arg_session_handle,
+                       GVariant *arg_options)
+{
+  Call *call = call_from_invocation (invocation);
+  Session *session;
+  RemoteDesktopSession *remote_desktop_session;
+  g_autoptr(GUnixFDList) out_fd_list = NULL;
+  g_autoptr(GError) error = NULL;
+  GVariantBuilder options_builder;
+  GVariant *fd;
+
+  session = acquire_session_from_call (arg_session_handle, call);
+  if (!session)
+    {
+      g_dbus_method_invocation_return_error (invocation,
+                                             G_DBUS_ERROR,
+                                             G_DBUS_ERROR_ACCESS_DENIED,
+                                             "Invalid session");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  SESSION_AUTOLOCK_UNREF (session);
+
+  if (!is_remote_desktop_session (session))
+    {
+      g_dbus_method_invocation_return_error (invocation,
+                                             G_DBUS_ERROR,
+                                             G_DBUS_ERROR_ACCESS_DENIED,
+                                             "Invalid session");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  remote_desktop_session = (RemoteDesktopSession *)session;
+
+  if (remote_desktop_session->uses_eis)
+    {
+      g_dbus_method_invocation_return_error (invocation,
+                                             G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Session is already connected");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  switch (remote_desktop_session->state)
+    {
+    case REMOTE_DESKTOP_SESSION_STATE_STARTED:
+      break;
+    case REMOTE_DESKTOP_SESSION_STATE_INIT:
+      g_dbus_method_invocation_return_error (invocation,
+                                             G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Session is not ready");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    case REMOTE_DESKTOP_SESSION_STATE_CLOSED:
+      g_dbus_method_invocation_return_error (invocation,
+                                             G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Session is already closed");
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  g_variant_builder_init (&options_builder, G_VARIANT_TYPE_VARDICT);
+  if (!xdp_filter_options (arg_options, &options_builder,
+                           remote_desktop_connect_to_eis_options,
+                           G_N_ELEMENTS (remote_desktop_connect_to_eis_options),
+                           &error))
+    {
+      g_dbus_method_invocation_return_gerror (invocation, error);
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  if (!xdp_dbus_impl_remote_desktop_call_connect_to_eis_sync (impl,
+                                                             arg_session_handle,
+                                                             xdp_app_info_get_id (call->app_info),
+                                                             g_variant_builder_end (&options_builder),
+                                                             in_fd_list,
+                                                             &fd,
+                                                             &out_fd_list,
+                                                             NULL,
+                                                             &error))
+    {
+      g_warning ("Failed to ConnectToEIS: %s", error->message);
+      g_dbus_method_invocation_return_gerror (invocation, error);
+      return G_DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+  remote_desktop_session->uses_eis = TRUE;
+
+  xdp_dbus_remote_desktop_complete_connect_to_eis (object, invocation, out_fd_list, fd);
+  return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
 static void
 remote_desktop_iface_init (XdpDbusRemoteDesktopIface *iface)
 {
@@ -1374,6 +1476,8 @@ remote_desktop_iface_init (XdpDbusRemoteDesktopIface *iface)
   iface->handle_notify_touch_down = handle_notify_touch_down;
   iface->handle_notify_touch_motion = handle_notify_touch_motion;
   iface->handle_notify_touch_up = handle_notify_touch_up;
+
+  iface->handle_connect_to_eis = handle_connect_to_eis;
 }
 
 static void

src/xdg-desktop-portal.c

@@ -121,7 +121,7 @@ method_needs_request (GDBusMethodInvocation *invocation)
     }
   else if (strcmp (interface, "org.freedesktop.portal.RemoteDesktop") == 0)
     {
-      if (strstr (method, "Notify") == method)
+      if (strstr (method, "Notify") == method || strcmp (method, "ConnectToEIS") == 0)
         return FALSE;
       else
         return TRUE;

tests/templates/remotedesktop.py

@@ -5,6 +5,7 @@
 from tests.templates import Response, init_template_logger, ImplRequest, ImplSession
 import dbus
 import dbus.service
+import socket
 
 from gi.repository import GLib
 
@@ -29,6 +30,7 @@ def load(mock, parameters):
     mock.force_clipoboard_enabled: bool = parameters.get(
         "force-clipboard-enabled", False
     )
+    mock.fail_connect_to_eis: bool = parameters.get("fail-connect-to-eis", False)
     mock.AddProperties(
         MAIN_IFACE,
         dbus.Dictionary(
@@ -37,6 +39,7 @@ def load(mock, parameters):
             }
         ),
     )
+    mock.sessions: dict[str, ImplSession] = {}
 
 
 @dbus.service.method(
@@ -50,6 +53,7 @@ def CreateSession(self, handle, session_handle, app_id, options, cb_success, cb_
         logger.debug(f"CreateSession({handle}, {session_handle}, {app_id}, {options})")
 
         session = ImplSession(self, BUS_NAME, session_handle).export()
+        self.sessions[session_handle] = session
 
         response = Response(self.response, {"session_handle": session.handle})
 
@@ -85,6 +89,33 @@ def force_close():
         cb_error(e)
 
 
+@dbus.service.method(
+    MAIN_IFACE,
+    in_signature="oosa{sv}",
+    out_signature="ua{sv}",
+    async_callbacks=("cb_success", "cb_error"),
+)
+def SelectDevices(self, handle, session_handle, app_id, options, cb_success, cb_error):
+    try:
+        logger.debug(f"SelectDevices({handle}, {session_handle}, {app_id}, {options})")
+
+        assert session_handle in self.sessions
+        response = Response(self.response, {})
+        request = ImplRequest(self, BUS_NAME, handle)
+        request.export()
+
+        def reply():
+            logger.debug(f"SelectDevices with response {response}")
+            cb_success(response.response, response.results)
+
+        logger.debug(f"scheduling delay of {self.delay}")
+        GLib.timeout_add(self.delay, reply)
+
+    except Exception as e:
+        logger.critical(e)
+        cb_error(e)
+
+
 @dbus.service.method(
     MAIN_IFACE,
     in_signature="oossa{sv}",
@@ -99,6 +130,7 @@ def Start(
             f"Start({handle}, {session_handle}, {parent_window}, {app_id}, {options})"
         )
 
+        assert session_handle in self.sessions
         response = Response(self.response, {})
 
         if self.force_clipoboard_enabled:
@@ -127,3 +159,27 @@ def reply():
     except Exception as e:
         logger.critical(e)
         cb_error(e)
+
+
+@dbus.service.method(
+    MAIN_IFACE,
+    in_signature="osa{sv}",
+    out_signature="h",
+)
+def ConnectToEIS(self, session_handle, app_id, options):
+    try:
+        logger.debug(f"ConnectToEIS({session_handle}, {app_id}, {options})")
+
+        assert session_handle in self.sessions
+
+        if self.fail_connect_to_eis:
+            raise dbus.exceptions.DBusException(f"Purposely failing ConnectToEIS")
+
+        sockets = socket.socketpair()
+        self.eis_socket = sockets[0]
+        assert self.eis_socket.send(b"HELLO") == 5
+
+        return dbus.types.UnixFd(sockets[1])
+    except Exception as e:
+        logger.critical(e)
+        raise e