2 Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef DCPOMATIC_UI_SIGNALLER_H
21 #define DCPOMATIC_UI_SIGNALLER_H
23 #include <boost/bind.hpp>
24 #include <boost/asio.hpp>
25 #include <boost/thread.hpp>
29 /** A class to allow signals to be emitted from non-UI threads and handled
32 class UISignaller : public boost::noncopyable
35 /** Create a UISignaller. Must be called from the UI thread */
39 _ui_thread = boost::this_thread::get_id ();
42 /* Do something next time the UI is idle */
44 void when_idle (T f) {
48 /** Call this in the UI when it is idle */
50 /* This executes any functors that have been post()ed to _service */
51 return _service.poll ();
54 /** This should wake the UI and make it call ui_idle() */
55 virtual void wake_ui () {
56 /* This is only a sensible implementation when there is no GUI... */
61 /** Emit a signal from any thread whose handlers will be called in the UI
62 * thread. Use something like:
64 * ui_signaller->emit (boost::bind (boost::ref (SomeSignal), parameter));
68 if (boost::this_thread::get_id() == _ui_thread) {
69 /* already in the UI thread */
72 /* non-UI thread; post to the service and wake up the UI */
78 friend class Signaller;
80 /** A io_service which is used as the conduit for messages */
81 boost::asio::io_service _service;
82 /** Object required to keep io_service from stopping when it has nothing to do */
83 boost::asio::io_service::work _work;
84 /** The UI thread's ID */
85 boost::thread::id _ui_thread;
88 extern UISignaller* ui_signaller;