[connections] vnc-connection: Add shared clipboard support

[Felipe Borges <felipeborges src gnome org>]

commit 0e909160d4920885323dc7295059df5e2770b9c3
Author: Manuel Wassermann <manuel wassermann97 gmail com>
Date:   Wed Jul 7 12:49:28 2021 +0200

    vnc-connection: Add shared clipboard support
    
    Fixes: #14

 src/vnc-connection.vala | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
---
diff --git a/src/vnc-connection.vala b/src/vnc-connection.vala
index 4befaa0..59a6f54 100644
--- a/src/vnc-connection.vala
+++ b/src/vnc-connection.vala
@@ -24,6 +24,7 @@ using Vnc;
 namespace Connections {
     private class VncConnection : Connection {
         private Gtk.Window window;
+        private Gtk.Clipboard clipboard;
 
         private Vnc.Display display;
         public override Gtk.Widget widget {
@@ -93,10 +94,14 @@ namespace Connections {
             window.add (display);
             display.realize ();
 
+            clipboard = Gtk.Clipboard.get_default(window.get_display ());
+
             display.vnc_initialized.connect (() => { show (); });
             display.vnc_auth_credential.connect (on_vnc_auth_credential_cb);
             display.vnc_auth_failure.connect (on_vnc_auth_failure_cb);
             display.size_allocate.connect (scale);
+            display.vnc_server_cut_text.connect (on_vnc_server_cut_text_cb);
+            clipboard.owner_change.connect (on_owner_change_cb);
 
             notify["scale-mode"].connect (scale);
         }
@@ -207,6 +212,22 @@ namespace Connections {
             auth_failed (reason);
         }
 
+        private void on_vnc_server_cut_text_cb (string message) {
+            if (view_only)
+                return;
+
+            clipboard.set_text (message, message.length);
+            clipboard.store ();
+        }
+
+        private void on_owner_change_cb () {
+            if (view_only)
+                return;
+
+            string message = clipboard.wait_for_text ();
+            display.client_cut_text (message);
+        }
+
         public void scale () {
             if (!display.is_open ())
                 return;