File 006-Implement-response-to-server-clipboard-REQUEST-action.patch of Package gtk-vnc
Subject: Implement response to server clipboard REQUEST action
From: Lin Ma lma@suse.de Mon Jul 7 13:05:22 2025 +0800
Date: Sun Oct 12 16:55:56 2025 +0800:
Git: e5ecf1243b7b7ac274681567ed9bb1b596967b28
This patch implements the full logic for the client to handle a server's
VNC_CLIPBOARD_ACTION_REQUEST and send back the clipboard data.
When the VncConnection receives a data request from the server, it now:
1. Emits a new GObject signal, 'clipboard-request', to propagate the
protocol event to the upper VncDisplay layer.
2. VncDisplay, upon catching this signal, asynchronously requests the
text content of the 'PRIMARY' selection from GTK.
3. After successfully fetching the text, it passes the data back to the
VncConnection via the public API vnc_connection_send_clipboard_data.
4. The VncConnection then compresses the data using zlib and sends it
to the server side.
This implementation handles the decoupling of the protocol and UI layers,
manages GTK's asynchronous clipboard operations, and completes the
request-response loop for client-to-server data synchronization.
Signed-off-by: Lin Ma <lma@suse.de>
--- a/src/libgvnc_sym.version
+++ b/src/libgvnc_sym.version
@@ -98,6 +98,7 @@
vnc_connection_handle_clipboard_change;
vnc_connection_clear_pending_flag;
vnc_connection_flush_pending_clipboard;
+ vnc_connection_send_clipboard_data;
vnc_util_set_debug;
vnc_util_get_debug;
--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -151,6 +151,10 @@ static void vnc_connection_write_clipboa
guint32 flags);
static void vnc_connection_announce_clipboard(VncConnection *conn,
gboolean available);
+static void vnc_connection_write_clipboard_provide(VncConnection *conn,
+ guint32 flags,
+ const gchar *text);
+static void vnc_connection_handle_clipboard_request(VncConnection *conn);
/*
* A special GSource impl which allows us to wait on a certain
@@ -311,6 +315,8 @@ enum {
VNC_DISCONNECTED,
VNC_ERROR,
+ VNC_CLIPBOARD_REQUEST, /* 20 */
+
VNC_LAST_SIGNAL,
};
@@ -5606,6 +5612,15 @@ static void vnc_connection_class_init(Vn
G_TYPE_NONE,
1,
G_TYPE_STRING);
+ signals[VNC_CLIPBOARD_REQUEST] =
+ g_signal_new ("clipboard-request",
+ G_OBJECT_CLASS_TYPE (object_class),
+ G_SIGNAL_RUN_FIRST,
+ G_STRUCT_OFFSET (VncConnectionClass, vnc_clipboard_request),
+ NULL, NULL,
+ g_cclosure_marshal_VOID__VOID,
+ G_TYPE_NONE,
+ 0);
}
@@ -6921,7 +6936,7 @@ vnc_connection_handle_extended_clipboard
} else if (action == VNC_CLIPBOARD_ACTION_PROVIDE) {
VNC_DEBUG("Received clipboard action 'provide', not implemented yet");
} else if (action == VNC_CLIPBOARD_ACTION_REQUEST) {
- VNC_DEBUG("Received clipboard action 'request', not implemented yet");
+ vnc_connection_handle_clipboard_request(conn);
} else if (action == VNC_CLIPBOARD_ACTION_PEEK) {
VNC_DEBUG("Received clipboard action 'peek', not implemented yet");
} else if (action == VNC_CLIPBOARD_ACTION_NOTIFY) {
@@ -6987,3 +7002,92 @@ void vnc_connection_flush_pending_clipbo
vnc_connection_announce_clipboard(conn, TRUE);
priv->pendingClientClipboard = FALSE;
}
+
+static void
+vnc_connection_write_clipboard_provide(VncConnection *conn,
+ guint32 flags,
+ const gchar *text)
+{
+ guint8 pad[3] = {0};
+ z_stream zst;
+ GByteArray *uncompressed_payload = NULL;
+ guchar *compressed_buf = NULL;
+ gsize compressed_size = 0;
+ gulong text_len = strlen(text) + 1;
+ guint32 text_len_net;
+ gulong dest_len;
+
+ uncompressed_payload = g_byte_array_new();
+
+ text_len_net = g_htonl(text_len);
+ g_byte_array_append(uncompressed_payload,
+ (const guint8 *)&text_len_net,
+ sizeof(text_len_net));
+
+ g_byte_array_append(uncompressed_payload, (const guint8 *)text, text_len);
+
+ dest_len = compressBound(uncompressed_payload->len);
+ compressed_buf = g_malloc(dest_len);
+
+ zst.zalloc = Z_NULL;
+ zst.zfree = Z_NULL;
+ zst.opaque = Z_NULL;
+
+ if (deflateInit(&zst, Z_DEFAULT_COMPRESSION) != Z_OK) {
+ vnc_connection_set_error(conn,
+ "Failed to initialize zlib for compression");
+ g_free(compressed_buf);
+ g_byte_array_free(uncompressed_payload, TRUE);
+ return;
+ }
+
+ zst.avail_in = uncompressed_payload->len;
+ zst.next_in = uncompressed_payload->data;
+ zst.avail_out = dest_len;
+ zst.next_out = compressed_buf;
+
+ if (deflate(&zst, Z_FINISH) != Z_STREAM_END) {
+ vnc_connection_set_error(conn, "%s", "Zlib compression failed");
+ goto cleanup;
+ }
+ compressed_size = zst.total_out;
+
+ VNC_DEBUG("Sending clipboard provide, payload size %u, compressed size %lu",
+ uncompressed_payload->len, (gulong)compressed_size);
+
+ 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 + compressed_size));
+ vnc_connection_buffered_write_u32(conn, flags | VNC_CLIPBOARD_ACTION_PROVIDE);
+
+ vnc_connection_buffered_write(conn, compressed_buf, compressed_size);
+
+ vnc_connection_buffered_flush(conn);
+
+cleanup:
+ deflateEnd(&zst);
+ g_free(compressed_buf);
+ g_byte_array_free(uncompressed_payload, TRUE);
+}
+
+static void vnc_connection_handle_clipboard_request(VncConnection *conn)
+{
+ g_signal_emit(conn, signals[VNC_CLIPBOARD_REQUEST], 0);
+}
+
+void vnc_connection_send_clipboard_data(VncConnection *conn,
+ const gchar *text)
+{
+ VncConnectionPrivate *priv = conn->priv;
+
+ if (priv->server_clipboard_flags & VNC_CLIPBOARD_ACTION_PROVIDE) {
+ vnc_connection_write_clipboard_provide(conn,
+ VNC_CLIPBOARD_FORMAT_UTF8,
+ text);
+ } else {
+ vnc_connection_set_error(conn,
+ "Server does not support clipboard 'provide'"
+ "action, can not send clipboard data.");
+ }
+}
--- a/src/vncconnection.h
+++ b/src/vncconnection.h
@@ -83,6 +83,7 @@ struct _VncConnectionClass
void (*vnc_power_control_initialized)(VncConnection *conn);
void (*vnc_power_control_failed)(VncConnection *conn);
void (*vnc_desktop_rename)(VncConnection *conn, const char *name);
+ void (*vnc_clipboard_request) (VncConnection *conn);
/*
* If adding fields to this struct, remove corresponding
@@ -249,6 +250,7 @@ gboolean vnc_connection_set_framebuffer(
void vnc_connection_handle_clipboard_change(VncConnection *conn);
void vnc_connection_clear_pending_flag(VncConnection *conn);
void vnc_connection_flush_pending_clipboard(VncConnection *conn);
+void vnc_connection_send_clipboard_data(VncConnection *conn, const gchar *text);
const char *vnc_connection_get_name(VncConnection *conn);
int vnc_connection_get_width(VncConnection *conn);
--- a/src/vncdisplay.c
+++ b/src/vncdisplay.c
@@ -356,6 +356,11 @@ static GdkCursor *create_default_cursor(
return cursor;
}
+static void on_clipboard_request(VncConnection *conn, VncDisplay *display);
+static void send_primary_selection(GtkClipboard *clipboard G_GNUC_UNUSED,
+ const gchar *text,
+ gpointer user_data);
+
#ifdef G_OS_WIN32
static HWND win32_window = NULL;
@@ -1347,6 +1352,11 @@ static void realize_event(GtkWidget *wid
gdk_window_set_cursor(gtk_widget_get_window(GTK_WIDGET(obj)),
priv->remote_cursor ? priv->remote_cursor : priv->null_cursor);
+
+ if (priv->conn) {
+ g_signal_connect(priv->conn, "clipboard-request",
+ G_CALLBACK(on_clipboard_request), obj);
+ }
}
static void get_preferred_width(GtkWidget *widget,
@@ -1501,6 +1511,53 @@ static void on_framebuffer_update(VncCon
}
+/**
+ * on_clipboard_request:
+ *
+ * This function is called when the VncConnection receives a clipboard
+ * request from the server. Its job is to start the *asynchronous*
+ * process of getting the local PRIMARY selection text from GTK.
+ */
+static void
+on_clipboard_request(VncConnection *conn G_GNUC_UNUSED, VncDisplay *display)
+{
+ GtkClipboard *primary_clipboard;
+
+ VNC_DEBUG("Handling 'clipboard-request' signal, asking GTK for PRIMARY selection.");
+
+ primary_clipboard = gtk_widget_get_clipboard(GTK_WIDGET(display),
+ GDK_SELECTION_PRIMARY);
+
+ /*
+ * This is an asynchronous operation. GTK will fetch the text
+ * and call send_primary_selection() when it's done.
+ */
+ gtk_clipboard_request_text(primary_clipboard,
+ send_primary_selection,
+ display);
+}
+
+/**
+ * send_primary_selection:
+ *
+ * GTK calls this function after it has successfully fetched the PRIMARY
+ * selection text. We now have the data and can send it to the server.
+ */
+static void
+send_primary_selection(GtkClipboard *clipboard G_GNUC_UNUSED,
+ const gchar *text,
+ gpointer user_data)
+{
+ VncDisplay *display = VNC_DISPLAY(user_data);
+ VncConnection *conn = vnc_display_get_connection(display);
+
+ if (conn && text != NULL && *text != '\0') {
+ VNC_DEBUG("Got PRIMARY selection asynchronously, sending to server.");
+ vnc_connection_send_clipboard_data(conn, text);
+ }
+}
+
+
static void do_framebuffer_init(VncDisplay *obj,
const VncPixelFormat *remoteFormat,
int width, int height, gboolean quiet)
