File 008-Complete-server-to-client-data-sync-PROVIDE.patch of Package gtk-vnc
Subject: Complete server-to-client data sync (PROVIDE)
From: Lin Ma lma@suse.de Mon Jul 7 13:14:40 2025 +0800
Date: Sun Oct 12 16:55:56 2025 +0800:
Git: 6e6d5df86cb5b6fe032573e9fd4defe88f04a733
This patch implements the final stage of the server-to-client extended
clipboard synchronization, enabling the client to receive and process
the actual data sent by the server via 'VNC_CLIPBOARD_ACTION_PROVIDE'.
The main workflow is as follows:
1. Upon receiving a 'PROVIDE' message, VncConnection reads and
decompresses the data payload using zlib.
2. It parses the decompressed data, extracts the text content, and
handles any potential Unicode escape sequences.
3. After validating the data as legal UTF-8, it emits a new GObject
signal, 'vnc-clipboard-data-received', passing the text as an argument.
4. VncDisplay listens for this signal and, in its callback, sets the
received text to the local 'CLIPBOARD' and 'PRIMARY' selections.
Signed-off-by: Lin Ma <lma@suse.de>
--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -159,6 +159,9 @@ static void vnc_connection_write_clipboa
guint32 flags);
static void vnc_connection_handle_clipboard_notify(VncConnection *conn,
guint32 flags);
+static void vnc_connection_handle_clipboard_provide(VncConnection *conn,
+ guint32 flags,
+ gint32 len);
/*
* A special GSource impl which allows us to wait on a certain
@@ -320,6 +323,7 @@ enum {
VNC_ERROR,
VNC_CLIPBOARD_REQUEST, /* 20 */
+ VNC_CLIPBOARD_DATA_RECEIVED,
VNC_LAST_SIGNAL,
};
@@ -5625,6 +5629,16 @@ static void vnc_connection_class_init(Vn
g_cclosure_marshal_VOID__VOID,
G_TYPE_NONE,
0);
+ signals[VNC_CLIPBOARD_DATA_RECEIVED] =
+ g_signal_new("vnc-clipboard-data-received",
+ G_TYPE_FROM_CLASS(klass),
+ G_SIGNAL_RUN_LAST,
+ 0,
+ NULL, NULL,
+ g_cclosure_marshal_VOID__STRING,
+ G_TYPE_NONE,
+ 1,
+ G_TYPE_STRING);
}
@@ -6899,12 +6913,6 @@ vnc_connection_handle_extended_clipboard
len);
return;
}
- if (len > VNC_MAX_EXTENDED_CLIPBOARD_MSG_SIZE) {
- vnc_connection_set_error(conn,
- "Extended clipboard message too long (%d bytes).",
- len);
- return;
- }
flags = vnc_connection_read_u32(conn);
if (vnc_connection_has_error(conn))
@@ -6938,7 +6946,7 @@ vnc_connection_handle_extended_clipboard
vnc_connection_handle_clipboard_caps(conn, flags, lengths);
} else if (action == VNC_CLIPBOARD_ACTION_PROVIDE) {
- VNC_DEBUG("Received clipboard action 'provide', not implemented yet");
+ vnc_connection_handle_clipboard_provide(conn, flags, len);
} else if (action == VNC_CLIPBOARD_ACTION_REQUEST) {
vnc_connection_handle_clipboard_request(conn);
} else if (action == VNC_CLIPBOARD_ACTION_PEEK) {
@@ -7140,3 +7148,167 @@ vnc_connection_handle_clipboard_notify(V
}
}
}
+
+/**
+ * unescape_unicode_string:
+ * @escaped_text: A string that may contain \uXXXX escape sequences.
+ *
+ * This function parses a string containing C-style Unicode escapes
+ * (e.g., "\u4f60\u597d") and converts it back to a proper UTF-8
+ * encoded string (e.g., "你好").
+ *
+ * Returns: A new, g_malloc'd string with the unescaped UTF-8 content.
+ * The caller is responsible for freeing the returned string.
+ * Returns NULL on failure.
+ */
+static gchar*
+unescape_unicode_string(const gchar *escaped_text)
+{
+ if (!escaped_text)
+ return NULL;
+
+ GString *result = g_string_new("");
+ const gchar *p = escaped_text;
+
+ while (*p) {
+ if (p[0] == '\\' && p[1] == 'u' &&
+ g_ascii_isxdigit(p[2]) && g_ascii_isxdigit(p[3]) &&
+ g_ascii_isxdigit(p[4]) && g_ascii_isxdigit(p[5]))
+ {
+ gchar hex[5];
+ gunichar uc;
+
+ strncpy(hex, p + 2, 4);
+ hex[4] = '\0';
+ uc = g_ascii_strtoull(hex, NULL, 16);
+
+ g_string_append_unichar(result, uc);
+ p += 6;
+ } else {
+ g_string_append_c(result, *p);
+ p++;
+ }
+ }
+
+ return g_string_free(result, FALSE);
+}
+
+/*
+ * Handles the clipboard 'provide' action. It reads the compressed
+ * data from the connection, decompresses it, parses the content,
+ * and emits the "vnc-clipboard-data-received" signal if successful.
+ */
+static void
+vnc_connection_handle_clipboard_provide(VncConnection *conn, guint32 flags, gint32 len)
+{
+ guint8 *zlib_data = NULL;
+ guint8 *uncompressed_data = NULL;
+ GByteArray *out_array = NULL;
+ gchar *escaped_text = NULL;
+ gchar *text = NULL;
+ z_stream zst;
+ gboolean zst_initialized = FALSE;
+
+ gsize uncompressed_size = 0;
+ guint32 text_len = 0;
+
+ if (!(flags & VNC_CLIPBOARD_FORMAT_UTF8)) {
+ vnc_connection_set_error(conn, "%s", "Unsupported format UTF8.");
+ goto cleanup;
+ }
+
+ len -= 4;
+ // read the entire compressed data block from the network connection.
+ zlib_data = g_malloc(len);
+ if (!vnc_connection_read(conn, zlib_data, len)) {
+ vnc_connection_set_error(conn, "Failed to read clipboard provide data");
+ goto cleanup;
+ }
+
+ // Decompress the entire block of data.
+ zst.zalloc = Z_NULL;
+ zst.zfree = Z_NULL;
+ zst.opaque = Z_NULL;
+ zst.avail_in = len;
+ zst.next_in = zlib_data;
+
+ if (inflateInit(&zst) != Z_OK) {
+ vnc_connection_set_error(conn, "%s", "Failed to initialize zlib for decompression");
+ goto cleanup;
+ }
+ zst_initialized = TRUE;
+
+ out_array = g_byte_array_new();
+ guint8 temp_buf[4096];
+ int ret;
+
+ do {
+ zst.avail_out = sizeof(temp_buf);
+ zst.next_out = temp_buf;
+ ret = inflate(&zst, Z_NO_FLUSH);
+ if (ret != Z_OK && ret != Z_STREAM_END) {
+ vnc_connection_set_error(conn,
+ "Zlib decompression failed with code %d",
+ ret);
+ goto cleanup;
+ }
+ g_byte_array_append(out_array, temp_buf, sizeof(temp_buf) - zst.avail_out);
+ } while (zst.avail_out == 0 && ret != Z_STREAM_END);
+
+ uncompressed_data = g_byte_array_free(out_array, FALSE);
+ out_array = NULL;
+ uncompressed_size = zst.total_out;
+ inflateEnd(&zst);
+ zst_initialized = FALSE;
+
+ // parse [length][data] from the decompressed data.
+ if (uncompressed_size < 4) {
+ vnc_connection_set_error(conn,
+ "Invalid decompressed data: too short for "
+ "length field");
+ goto cleanup;
+ }
+
+ text_len = g_ntohl(*(guint32 *)uncompressed_data);
+
+ if (text_len > uncompressed_size - 4) {
+ vnc_connection_set_error(conn, "Invalid decompressed data: length mismatch");
+ goto cleanup;
+ }
+
+ if (text_len > VNC_MAX_EXTENDED_CLIPBOARD_MSG_SIZE) {
+ VNC_DEBUG("Clipboard data size (%u) exceeds maximum size (%u), ignoring.",
+ text_len,
+ VNC_MAX_EXTENDED_CLIPBOARD_MSG_SIZE);
+ goto cleanup;
+ }
+
+ escaped_text = g_strndup((const gchar *)(uncompressed_data + 4), text_len);
+ text = unescape_unicode_string(escaped_text);
+
+ if (!g_utf8_validate(text, -1, NULL)) {
+ VNC_DEBUG("Invalid UTF-8 sequence in clipboard data");
+ goto cleanup;
+ }
+
+ VNC_DEBUG("Successfully decoded clipboard text (len=%u), "
+ "emitting signal to UI layer.",
+ text_len);
+ g_signal_emit(conn, signals[VNC_CLIPBOARD_DATA_RECEIVED], 0, text);
+
+cleanup:
+ g_free(zlib_data);
+ g_free(uncompressed_data);
+ g_free(escaped_text);
+ g_free(text);
+
+ if (out_array) {
+ g_byte_array_free(out_array, TRUE);
+ }
+
+ if (zst_initialized) {
+ inflateEnd(&zst);
+ }
+
+ return;
+}
--- a/src/vncdisplay.c
+++ b/src/vncdisplay.c
@@ -360,6 +360,9 @@ static void on_clipboard_request(VncConn
static void send_primary_selection(GtkClipboard *clipboard G_GNUC_UNUSED,
const gchar *text,
gpointer user_data);
+static void on_clipboard_data_received(VncConnection *conn G_GNUC_UNUSED,
+ const gchar *text,
+ gpointer user_data);
#ifdef G_OS_WIN32
static HWND win32_window = NULL;
@@ -1557,6 +1560,23 @@ send_primary_selection(GtkClipboard *cli
}
}
+static void
+on_clipboard_data_received(VncConnection *conn G_GNUC_UNUSED,
+ const gchar *text,
+ gpointer user_data)
+{
+ VncDisplay *display = VNC_DISPLAY(user_data);
+ GtkClipboard *clipboard;
+
+ clipboard = gtk_widget_get_clipboard(GTK_WIDGET(display),
+ gdk_atom_intern("CLIPBOARD", FALSE));
+ gtk_clipboard_set_text(clipboard, text, -1);
+
+ clipboard = gtk_widget_get_clipboard(GTK_WIDGET(display),
+ GDK_SELECTION_PRIMARY);
+ gtk_clipboard_set_text(clipboard, text, -1);
+}
+
static void do_framebuffer_init(VncDisplay *obj,
const VncPixelFormat *remoteFormat,
@@ -3129,6 +3149,8 @@ static void vnc_display_init(VncDisplay
G_CALLBACK(on_primary_owner_change), display);
g_signal_connect(display, "focus-in-event",
G_CALLBACK(on_focus_in), display);
+ g_signal_connect(G_OBJECT(priv->conn), "vnc-clipboard-data-received",
+ G_CALLBACK(on_clipboard_data_received), display);
priv->keycode_map = vnc_display_keymap_gdk2rfb_table(&priv->keycode_maplen);
}
