2 Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
4 This file is part of DCP-o-matic.
6 DCP-o-matic is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 DCP-o-matic is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
21 #ifndef DCPOMATIC_SIGNAL_MANAGER_H
22 #define DCPOMATIC_SIGNAL_MANAGER_H
24 #include <boost/asio.hpp>
25 #include <boost/thread.hpp>
26 #include <boost/noncopyable.hpp>
30 /** A class to allow signals to be emitted from non-UI threads and handled
33 class SignalManager : public boost::noncopyable
36 /** Create a SignalManager. Must be called from the UI thread */
40 _ui_thread = boost::this_thread::get_id ();
43 virtual ~SignalManager () {}
45 /* Do something next time the UI is idle */
47 void when_idle (T f) {
51 /** Call this in the UI when it is idle.
52 * @return Number of idle handlers that were executed.
55 /* This executes one of the functors that has been post()ed to _service */
56 return _service.poll_one ();
59 /** This should wake the UI and make it call ui_idle() */
60 virtual void wake_ui () {
61 /* This is only a sensible implementation when there is no GUI */
66 /** Emit a signal from any thread whose handlers will be called in the UI
67 * thread. Use something like:
69 * ui_signaller->emit (boost::bind (boost::ref (SomeSignal), parameter));
73 if (boost::this_thread::get_id() == _ui_thread) {
74 /* already in the UI thread */
77 /* non-UI thread; post to the service and wake up the UI */
83 friend class Signaller;
85 /** A io_service which is used as the conduit for messages */
86 boost::asio::io_service _service;
87 /** Object required to keep io_service from stopping when it has nothing to do */
88 boost::asio::io_service::work _work;
89 /** The UI thread's ID */
90 boost::thread::id _ui_thread;
93 extern SignalManager* signal_manager;