File 004-Implement-client-to-server-clipboard-update-notification.patch of Package gtk-vnc
Subject: Implement client-to-server clipboard update notification
From: Lin Ma lma@suse.de Mon Jul 7 12:59:03 2025 +0800
Date: Sun Oct 12 16:55:56 2025 +0800:
Git: 348452c1007bbfd3575b94263d9e55b0e11b79db
This patch implements the mechanism for notifying the VNC server side
when the client's local clipboard content has changed.
On the VncDisplay (UI) layer:
- It detects local clipboard changes by listening to the 'owner-change'
signal on the GDK 'PRIMARY' selection.
- A 50ms timer is used to debounce events, filtering out transient,
invalid events caused by actions like double-clicks.
- When valid clipboard content is confirmed, it calls the underlying
VncConnection function.
On the VncConnection (protocol) layer:
- A new public function vnc_connection_handle_clipboard_change, is added
to serve as the entry point for triggering clipboard notifications from
the UI layer.
- The vnc_connection_write_clipboard_notify function is implemented to
construct and send an extended clipboard message with the NOTIFY action.
This patch completes the "announcement" phase of a client-side clipboard
update, laying the groundwork for the server to subsequently request the
data.
Signed-off-by: Lin Ma <lma@suse.de>
--- a/src/libgvnc_sym.version
+++ b/src/libgvnc_sym.version
@@ -95,6 +95,9 @@
vnc_connection_power_control;
vnc_connection_set_size;
+ vnc_connection_handle_clipboard_change;
+ vnc_connection_clear_pending_flag;
+
vnc_util_set_debug;
vnc_util_get_debug;
vnc_util_get_version;
--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -147,6 +147,10 @@ static void vnc_connection_handle_clipbo
const guint32 *lengths);
static void vnc_connection_handle_extended_clipboard(VncConnection *conn,
gint32 len);
+static void vnc_connection_write_clipboard_notify(VncConnection *conn,
+ guint32 flags);
+static void vnc_connection_announce_clipboard(VncConnection *conn,
+ gboolean available);
/*
* A special GSource impl which allows us to wait on a certain
@@ -276,6 +280,7 @@ struct _VncConnectionPrivate
gboolean has_extended_clipboard;
guint32 server_clipboard_flags;
guint32 server_clipboard_sizes[VNC_CLIPBOARD_MAX_FORMATS];
+ gboolean pendingClientClipboard;
};
G_DEFINE_TYPE_WITH_PRIVATE(VncConnection, vnc_connection, G_TYPE_OBJECT);
@@ -5619,6 +5624,7 @@ static void vnc_connection_init(VncConne
priv->has_extended_clipboard = FALSE;
priv->server_clipboard_flags = 0;
memset(priv->server_clipboard_sizes, 0, sizeof(priv->server_clipboard_sizes));
+ priv->pendingClientClipboard = FALSE;
}
@@ -6926,3 +6932,49 @@ vnc_connection_handle_extended_clipboard
return;
}
+
+static void vnc_connection_write_clipboard_notify(VncConnection *conn,
+ guint32 flags)
+{
+ guint8 pad[3] = {0};
+
+ vnc_connection_buffered_write_u8(conn, VNC_CONNECTION_CLIENT_MESSAGE_CUT_TEXT);
+ vnc_connection_buffered_write(conn, pad, 3);
+
+ /* Payload is flags(4). Negative length indicates extended message. */
+ vnc_connection_buffered_write_s32(conn, -4);
+
+ vnc_connection_buffered_write_u32(conn, flags | VNC_CLIPBOARD_ACTION_NOTIFY);
+
+ vnc_connection_buffered_flush(conn);
+}
+
+static void vnc_connection_announce_clipboard(VncConnection *conn,
+ gboolean available)
+{
+
+ if (!(conn->priv->server_clipboard_flags & VNC_CLIPBOARD_ACTION_NOTIFY)) {
+ vnc_connection_set_error(conn,
+ "Server does not support clipboard "
+ "'notify' action");
+ }
+
+ guint32 flags = available ? VNC_CLIPBOARD_FORMAT_UTF8 : 0;
+ vnc_connection_write_clipboard_notify(conn, flags);
+}
+
+void vnc_connection_handle_clipboard_change(VncConnection *conn)
+{
+ VncConnectionPrivate *priv = conn->priv;
+
+ priv->pendingClientClipboard = TRUE;
+
+ vnc_connection_announce_clipboard(conn, FALSE);
+}
+
+void vnc_connection_clear_pending_flag(VncConnection *conn)
+{
+ VncConnectionPrivate *priv = conn->priv;
+
+ priv->pendingClientClipboard = FALSE;
+}
--- a/src/vncconnection.h
+++ b/src/vncconnection.h
@@ -246,6 +246,9 @@ gboolean vnc_connection_has_error(VncCon
gboolean vnc_connection_set_framebuffer(VncConnection *conn,
VncFramebuffer *fb);
+void vnc_connection_handle_clipboard_change(VncConnection *conn);
+void vnc_connection_clear_pending_flag(VncConnection *conn);
+
const char *vnc_connection_get_name(VncConnection *conn);
int vnc_connection_get_width(VncConnection *conn);
int vnc_connection_get_height(VncConnection *conn);
--- a/src/vncdisplay.c
+++ b/src/vncdisplay.c
@@ -100,6 +100,8 @@ struct _VncDisplayPrivate
VncGrabSequence *vncgrabseq; /* the configured key sequence */
gboolean *vncactiveseq; /* the currently pressed keys */
+ guint primary_selection_timer_id;
+
#ifdef WIN32
HHOOK keyboard_hook;
#endif
@@ -1826,6 +1828,54 @@ static void on_auth_unsupported(VncConne
g_signal_emit(G_OBJECT(obj), signals[VNC_AUTH_UNSUPPORTED], 0, authType);
}
+static void handle_primary_received(GtkClipboard *clipboard G_GNUC_UNUSED,
+ const gchar *text,
+ gpointer opaque)
+{
+ VncDisplay *display = VNC_DISPLAY(opaque);
+ VncDisplayPrivate *priv = display->priv;
+
+ if (text != NULL && *text != '\0' && !priv->read_only) {
+ vnc_connection_handle_clipboard_change(priv->conn);
+ } else {
+ vnc_connection_clear_pending_flag(priv->conn);
+ }
+}
+
+static gboolean handle_primary_request(gpointer opaque)
+{
+ VncDisplay *display = VNC_DISPLAY(opaque);
+ VncDisplayPrivate *priv = display->priv;
+
+ GtkClipboard *clipboard = gtk_clipboard_get(GDK_SELECTION_PRIMARY);
+ gtk_clipboard_request_text(clipboard, handle_primary_received, opaque);
+
+ /* Returns FALSE to indicate that this timer will be executed only once and
+ * then automatically destroyed. */
+ priv->primary_selection_timer_id = 0;
+ return G_SOURCE_REMOVE;
+}
+
+static void on_primary_owner_change(GtkClipboard *clipboard G_GNUC_UNUSED,
+ GdkEventOwnerChange *event G_GNUC_UNUSED,
+ gpointer opaque)
+{
+ VncDisplay *display = VNC_DISPLAY(opaque);
+ VncDisplayPrivate *priv = display->priv;
+
+ /* If a timer is already running, cancel it first. */
+ if (priv->primary_selection_timer_id != 0) {
+ g_source_remove(priv->primary_selection_timer_id);
+ }
+
+ /* Start a new timer and execute the real request after 50 milliseconds,
+ * This delay is enough to filter out intermediate events generated by
+ * double clicks */
+ priv->primary_selection_timer_id = g_timeout_add(50,
+ handle_primary_request,
+ opaque);
+}
+
static void on_server_cut_text(VncConnection *conn G_GNUC_UNUSED,
const gchar *text,
gpointer opaque)
@@ -3003,6 +3053,8 @@ static void vnc_display_init(VncDisplay
G_CALLBACK(on_power_control_init), display);
g_signal_connect(G_OBJECT(priv->conn), "vnc-power-control-failed",
G_CALLBACK(on_power_control_fail), display);
+ g_signal_connect(gtk_clipboard_get(GDK_SELECTION_PRIMARY), "owner-change",
+ G_CALLBACK(on_primary_owner_change), display);
priv->keycode_map = vnc_display_keymap_gdk2rfb_table(&priv->keycode_maplen);
}
