File 007-Implement-handling-of-server-clipboard-NOTIFY-action.patch of Package gtk-vnc

Subject: Implement handling of server clipboard NOTIFY action
From: Lin Ma lma@suse.de Mon Jul 7 13:11:06 2025 +0800
Date: Sun Oct 12 16:55:56 2025 +0800:
Git: b9150485968c771bdb32dc8a95560f6baa3c91eb

This patch implements the first step in the server-to-client clipboard
synchronization flow: the client's response to a server update
notification.

The specific changes are as follows:
- When VncConnection receives a message from the server with the
  'VNC_CLIPBOARD_ACTION_NOTIFY' flag, the new
  'vnc_connection_handle_clipboard_notify' function is called.
- Within this function, the client checks if the server supports the
  'REQUEST' action. If so, the client immediately sends back a 'REQUEST'
  message, asking the server to provide its clipboard data.
- Additionally, upon receiving a notification from the server, any
  pending client-to-server clipboard update ('pendingClientClipboard')
  is cancelled. This ensures correct clipboard state synchronization.

This commit establishes the "Notify -> Request" interaction, laying the
groundwork for the client to receive clipboard data from the server.

Signed-off-by: Lin Ma <lma@suse.de>

--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -155,6 +155,10 @@ static void vnc_connection_write_clipboa
                                                    guint32 flags,
                                                    const gchar *text);
 static void vnc_connection_handle_clipboard_request(VncConnection *conn);
+static void vnc_connection_write_clipboard_request(VncConnection *conn,
+                                                   guint32 flags);
+static void vnc_connection_handle_clipboard_notify(VncConnection *conn,
+                                                   guint32 flags);
 
 /*
  * A special GSource impl which allows us to wait on a certain
@@ -6940,7 +6944,7 @@ vnc_connection_handle_extended_clipboard
     } else if (action == VNC_CLIPBOARD_ACTION_PEEK) {
         VNC_DEBUG("Received clipboard action 'peek', not implemented yet");
     } else if (action == VNC_CLIPBOARD_ACTION_NOTIFY) {
-        VNC_DEBUG("Received clipboard action 'notify', not implemented yet");
+        vnc_connection_handle_clipboard_notify(conn, flags);
     } else {
         VNC_DEBUG("Unknown extended clipboard action 0x%x", action);
     }
@@ -7091,3 +7095,48 @@ void vnc_connection_send_clipboard_data(
                                  "action, can not send clipboard data.");
     }
 }
+
+static void
+vnc_connection_write_clipboard_request(VncConnection *conn, guint32 flags)
+{
+    VncConnectionPrivate *priv = conn->priv;
+    guint8 pad[3] = {0};
+
+    if (!(priv->server_clipboard_flags & VNC_CLIPBOARD_ACTION_REQUEST)) {
+        vnc_connection_set_error(conn,
+                                 "Server does not support clipboard 'request'"
+                                 "action.");
+        return;
+    }
+
+    VNC_DEBUG("Sending clipboard request to server for format flags 0x%x", flags);
+
+    vnc_connection_buffered_write_u8(conn, VNC_CONNECTION_CLIENT_MESSAGE_CUT_TEXT);
+    vnc_connection_buffered_write(conn, pad, 3);
+
+    vnc_connection_buffered_write_s32(conn, -4);
+    vnc_connection_buffered_write_u32(conn, flags | VNC_CLIPBOARD_ACTION_REQUEST);
+
+    vnc_connection_buffered_flush(conn);
+}
+
+static void
+vnc_connection_handle_clipboard_notify(VncConnection *conn, guint32 flags)
+{
+    VncConnectionPrivate *priv = conn->priv;
+
+    if (flags & VNC_CLIPBOARD_FORMAT_UTF8) {
+        priv->pendingClientClipboard = FALSE;
+
+        VNC_DEBUG("Received notification of new clipboard data on server.");
+
+        if (priv->server_clipboard_flags & VNC_CLIPBOARD_ACTION_REQUEST) {
+            vnc_connection_write_clipboard_request(conn, VNC_CLIPBOARD_FORMAT_UTF8);
+        } else {
+            VNC_DEBUG("Server does not support clipboard request, not requesting data.");
+            vnc_connection_set_error(conn,
+                                     "Server does not support clipboard "
+                                     "'notify' action.");
+        }
+    }
+}