[plugins/mousepad]: Add support for the persistence feature of the RemoteDesktop portal

This allows us to avoid asking the user for permission for remote control on Wayland every time kdeconnectd is restarted for whatever reason (for example logging out or rebooting), at least in theory. The idea is that the SelectDevices call now also accepts a restore token, and if the user grants permission to persist a restore token will be returned in the response of the Start call.

Currently https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/merge_requests/265 is required for this to work at all with Plasma 6, and even then persistence only works in the same session (for example if I restart kdeconnectd then I only get the notification instead of the permissions prompt), if I reboot the system then the token gets invalidated and the permissions dialog appears again, not sure if the issue is with what I'm doing here or if that's a bug in the portal.

Things that need to be checked:
- What happens if the portal implementation only has v1 of the protocol and not v2 (the one with persistence)?
  - In particular what happens for the SelectDevices call if a restore token is given despite the portal not supporting it
    - Seems fine with xdg-desktop-portal 1.14.4 at least
  - For the Start call we'll need to handle the case of the user denying the persistence request anyway
- Where and how should the restore token be stored?
  - ~~I used KConfig just so I have something to test, but the restore token isn't really a setting~~
    - Updated to use `KSharedConfig::openStateConfig`
  - Most of KDE Connect's settings and data appear to be for each connected device
  - The device name is a global setting, but it's implemented using QSettings rather than KConfig, and currently only setName and getName is exposed in `core/kdeconnectconfig.h`

BUG: 479013
(cherry picked from commit 383ad27b59)

interfaces/systeminterfaces/org.freedesktop.portal.RemoteDesktop.xml

@@ -1,14 +1,17 @@
 <?xml version="1.0"?>
 <!--
  Copyright (C) 2017-2018 Red Hat, Inc.
+
  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/>.
 -->
@@ -17,22 +20,34 @@
   <!--
       org.freedesktop.portal.RemoteDesktop:
       @short_description: Remote desktop portal
+
       The Remote desktop portal allows to create remote desktop sessions.
-      This documentation describes version 1 of this interface.
+
+      This documentation describes version 2 of this interface.
   -->
   <interface name="org.freedesktop.portal.RemoteDesktop">
     <!--
         CreateSession:
         @options: Vardict with optional further information
         @handle: Object path for the #org.freedesktop.portal.Request object representing this call
+
         Create a remote desktop session.
+
         A remote desktop session is used to allow remote controlling a desktop
-        session. It can also be used together with a screen cast session (see
+        session.
-        org.freedesktop.portal.ScreenCast), but may only be started and stopped
+
-        with this interface.
+        A remote desktop session may only be started and stopped with this interface,
-        To also get a screen content, call the
+        but you can use the #org.freedesktop.portal.Session object created with this
-        #org.freedesktop.ScreenCast.SelectSources with the
+        method together with certain methods on the #org.freedesktop.portal.ScreenCast and
-        #org.freedesktop.Session object created with this method.
+        #org.freedesktop.portal.Clipboard interfaces. Specifically, you can call
+        org.freedesktop.portal.ScreenCast.SelectSources() to also get screen content,
+        and org.freedesktop.portal.ScreenCast.OpenPipeWireRemote() to acquire a file
+        descriptor for a PipeWire remote. See #org.freedesktop.portal.ScreenCast for
+        more information on how to use those methods. To capture clipboard content,
+        you can call org.freedesktop.portal.Clipboard.RequestClipboard(). See
+        #org.freedesktop.portal.Clipboard for more information on the clipboard
+        integration.
+
         Supported keys in the @options vardict include:
         <variablelist>
           <varlistentry>
@@ -75,7 +90,9 @@
         @session_handle: Object path for the #org.freedesktop.portal.Session object
         @options: Vardict with optional further information
         @handle: Object path for the #org.freedesktop.portal.Request object representing this call
+
         Select input devices to remote control.
+
         Supported keys in the @options vardict include:
         <variablelist>
           <varlistentry>
@@ -87,14 +104,50 @@
             </para></listitem>
           </varlistentry>
           <varlistentry>
-            <term>type u</term>
+            <term>types u</term>
             <listitem><para>
               Bitmask of what device types to request remote controlling of.
               Default is all.
             </para></listitem>
           </varlistentry>
+          <varlistentry>
+            <term>restore_token s</term>
+            <listitem><para>
+              The token to restore a previous session.
+
+              If the stored session cannot be restored, this value is ignored
+              and the user will be prompted normally. This may happen when, for
+              example, the session contains a monitor or a window that is not
+              available anymore, or when the stored permissions are withdrawn.
+
+              The restore token is invalidated after using it once. To restore
+              the same session again, use the new restore token sent in response
+              to starting this session.
+
+              This option was added in version 2 of this interface.
+            </para></listitem>
+          </varlistentry>
+          <varlistentry>
+            <term>persist_mode u</term>
+            <listitem><para>
+              How this session should persist. Default is 0. Accepted values are:
+
+              <simplelist>
+                <member>0: Do not persist (default)</member>
+                <member>1: Permissions persist as long as the application is running</member>
+                <member>2: Permissions persist until explicitly revoked</member>
+              </simplelist>
+
+              If the permission for the session to persist is granted, a restore token will
+              be returned via the #org.freedesktop.portal.Request::Response signal of the
+              start method used to start the session.
+
+              This option was added in version 2 of this interface.
+            </para></listitem>
+          </varlistentry>
         </variablelist>
-        For available source types, see the AvailableDeviceTypes property.
+
+        For available device types, see the AvailableDeviceTypes property.
     -->
     <method name="SelectDevices">
       <arg type="o" name="session_handle" direction="in"/>
@@ -108,10 +161,12 @@
         @parent_window: Identifier for the application window, see <link linkend="parent_window">Common Conventions</link>
         @options: Vardict with optional further information
         @handle: Object path for the #org.freedesktop.portal.Request object representing this call
+
         Start the remote desktop session. This will typically result in the portal
         presenting a dialog letting the user select what to share, including
         devices and optionally screen content if screen cast sources was
         selected.
+
         Supported keys in the @options vardict include:
         <variablelist>
           <varlistentry>
@@ -123,6 +178,7 @@
             </para></listitem>
           </varlistentry>
         </variablelist>
+
         The following results get returned via the
         #org.freedesktop.portal.Request::Response signal:
         <variablelist>
@@ -132,7 +188,26 @@
               A bitmask of the devices selected by the user.
             </para></listitem>
           </varlistentry>
+          <varlistentry>
+            <term>clipboard_enabled b</term>
+            <listitem><para>
+              A boolean for whether the clipboard was enabled ('true') or not ('false').
+              See the #org.freedesktop.portal.Clipboard documentation for more information.
+              Since version 2.
+            </para></listitem>
+          </varlistentry>
+          <varlistentry>
+            <term>restore_token s</term>
+            <listitem><para>
+              The restore token. This token is a single use token that can later
+              be used to restore a session. See
+              org.freedesktop.portal.RemoteDesktop.SelectDevices() for details.
+
+              This response option was added in version 2 of this interface.
+            </para></listitem>
+          </varlistentry>
         </variablelist>
+
         If a screen cast source was selected, the results of the
         #org.freedesktop.portal.ScreenCast.Start response signal may be
         included.
@@ -150,6 +225,7 @@
         @options: Vardict with optional further information
         @dx: Relative movement on the x axis
         @dy: Relative movement on the y axis
+
         Notify about a new relative pointer motion event. The (dx, dy) vector
         represents the new pointer position in the streams logical coordinate
         space.
@@ -168,6 +244,7 @@
         @stream: The PipeWire stream node the coordinate is relative to
         @x: Pointer motion x coordinate
         @y: Pointer motion y coordinate
+
         Notify about a new absolute pointer motion event. The (x, y) position
         represents the new pointer position in the streams logical coordinate
         space (see the logical_size stream property in
@@ -187,9 +264,12 @@
         @options: Vardict with optional further information
         @button: The pointer button was pressed or released
         @state: The new state of the button
+
         The pointer button is encoded according to Linux Evdev button codes.
+
         May only be called if POINTER access was provided after starting the
         session.
+
         Available button states:
         <simplelist>
           <member>0: Released</member>
@@ -209,11 +289,14 @@
         @options: Vardict with optional further information
         @dx: Relative axis movement on the x axis
         @dy: Relative axis movement on the y axis
+
         The axis movement from a 'smooth scroll' device, such as a touchpad.
         When applicable, the size of the motion delta should be equivalent to
         the motion vector of a pointer motion done using the same advice.
+
         May only be called if POINTER access was provided after starting the
         session.
+
         Supported keys in the @options vardict include:
         <variablelist>
           <varlistentry>
@@ -239,8 +322,10 @@
         @options: Vardict with optional further information
         @axis: The axis that was scrolled
         @steps: The number of steps scrolled
+
         May only be called if POINTER access was provided after starting the
         session.
+
         Available axes:
         <simplelist>
           <member>0: Vertical scroll</member>
@@ -259,10 +344,12 @@
         @session_handle: Object path for the #org.freedesktop.portal.Session object
         @options: Vardict with optional further information
         @keycode: Keyboard code that was pressed or released
-        @state: New state of keyboard keysym
+        @state: New state of keyboard keycode
+
         May only be called if KEYBOARD access was provided after starting the
         session.
-        Available keyboard keysym states:
+
+        Available keyboard keycode states:
         <simplelist>
           <member>0: Released</member>
           <member>1: Pressed</member>
@@ -281,8 +368,10 @@
         @options: Vardict with optional further information
         @keysym: Keyboard symbol that was pressed or released
         @state: New state of keyboard keysym
+
         May only be called if KEYBOARD access was provided after starting the
         session.
+
         Available keyboard keysym states:
         <simplelist>
           <member>0: Released</member>
@@ -304,8 +393,10 @@
         @slot: Touch slot where touch point appeared
         @x: Touch down x coordinate
         @y: Touch down y coordinate
+
         May only be called if TOUCHSCREEN access was provided after starting the
         session.
+
         Notify about a new touch down event. The (x, y) position
         represents the new touch point position in the streams logical
         coordinate space (see the logical_size stream property in
@@ -328,8 +419,10 @@
         @slot: Touch slot where touch point appeared
         @x: Touch motion x coordinate
         @y: Touch motion y coordinate
+
         May only be called if TOUCHSCREEN access was provided after starting the
         session.
+
         Notify about a new touch motion event. The (x, y) position
         represents where the touch point position in the streams logical
         coordinate space moved (see the logical_size stream property in
@@ -349,8 +442,10 @@
         @session_handle: Object path for the #org.freedesktop.portal.Session object
         @options: Vardict with optional further information
         @slot: Touch slot where touch point appeared
+
         May only be called if TOUCHSCREEN access was provided after starting the
         session.
+
         Notify about a new touch up event.
     -->
     <method name="NotifyTouchUp">
@@ -359,9 +454,47 @@
       <annotation name="org.qtproject.QtDBus.QtTypeName.In1" value="QVariantMap"/>
       <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.
+
+        To see how to pair a PipeWire stream with a libei device region, see the
+        documentation for the mapping_id stream property in
+        #org.freedesktop.portal.RemoteDesktop.Start().
+
+        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"/>
+      <annotation name="org.qtproject.QtDBus.QtTypeName.In1" value="QVariantMap"/>
+      <arg type="h" name="fd" direction="out"/>
+    </method>
+
     <!--
         AvailableDeviceTypes:
+
         A bitmask of available source types. Currently defined types are:
+
         <simplelist>
           <member>1: KEYBOARD</member>
           <member>2: POINTER</member>

plugins/mousepad/waylandremoteinput.cpp

@@ -10,7 +10,9 @@
 #include <QDebug>
 #include <QSizeF>
 
+#include <KConfigGroup>
 #include <KLocalizedString>
+#include <KSharedConfig>
 #include <QDBusPendingCallWatcher>
 
 #include <linux/input.h>
@@ -106,13 +108,21 @@ void RemoteDesktopSession::handleXdpSessionCreated(uint code, const QVariantMap
         qCWarning(KDECONNECT_PLUGIN_MOUSEPAD) << "Failed to create session with code" << code << results;
         return;
     }
+
     m_connecting = false;
     m_xdpPath = QDBusObjectPath(results.value(QLatin1String("session_handle")).toString());
-    const QVariantMap startParameters = {
+    QVariantMap startParameters = {
         {QLatin1String("handle_token"), QStringLiteral("kdeconnect%1").arg(QRandomGenerator::global()->generate())},
         {QStringLiteral("types"), QVariant::fromValue<uint>(7)}, // request all (KeyBoard, Pointer, TouchScreen)
+        {QLatin1String("persist_mode"), QVariant::fromValue<uint>(2)}, // Persist permission until explicitly revoked by user
     };
 
+    KConfigGroup stateConfig = KSharedConfig::openStateConfig()->group(QStringLiteral("mousepad"));
+    QString restoreToken = stateConfig.readEntry(QStringLiteral("RestoreToken"), QString());
+    if (restoreToken.length() > 0) {
+        startParameters[QLatin1String("restore_token")] = restoreToken;
+    }
+
     QDBusConnection::sessionBus().connect(QString(),
                                           m_xdpPath.path(),
                                           QLatin1String("org.freedesktop.portal.Session"),
@@ -158,10 +168,28 @@ void RemoteDesktopSession::handleXdpSessionConfigured(uint code, const QVariantM
         if (reply.isError()) {
             qCWarning(KDECONNECT_PLUGIN_MOUSEPAD) << "Could not start the remote control session" << reply.error();
             m_connecting = false;
+            return;
         }
+
+        bool b = QDBusConnection::sessionBus().connect(QString(),
+                                                       reply.value().path(),
+                                                       QLatin1String("org.freedesktop.portal.Request"),
+                                                       QLatin1String("Response"),
+                                                       this,
+                                                       SLOT(handleXdpSessionStarted(uint, QVariantMap)));
+        Q_ASSERT(b);
+        qCDebug(KDECONNECT_PLUGIN_MOUSEPAD) << "starting" << reply.value().path();
     });
 }
 
+void RemoteDesktopSession::handleXdpSessionStarted(uint code, const QVariantMap &results)
+{
+    Q_UNUSED(code);
+
+    KConfigGroup stateConfig = KSharedConfig::openStateConfig()->group(QStringLiteral("mousepad"));
+    stateConfig.writeEntry(QStringLiteral("RestoreToken"), results[QStringLiteral("restore_token")].toString());
+}
+
 void RemoteDesktopSession::handleXdpSessionFinished(uint /*code*/, const QVariantMap & /*results*/)
 {
     m_xdpPath = {};

plugins/mousepad/waylandremoteinput.h

@@ -30,6 +30,7 @@ public:
 private Q_SLOTS:
     void handleXdpSessionCreated(uint code, const QVariantMap &results);
     void handleXdpSessionConfigured(uint code, const QVariantMap &results);
+    void handleXdpSessionStarted(uint code, const QVariantMap &results);
     void handleXdpSessionFinished(uint code, const QVariantMap &results);
 
 private: