+/*
+ Copyright (C) 2020 Carl Hetherington <cth@carlh.net>
+
+ This file is part of DCP-o-matic.
+
+ DCP-o-matic is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ DCP-o-matic is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "suspender.h"
+#include <boost/foreach.hpp>
+
+Suspender::Suspender(boost::function<void (int)> handler)
+ : _handler (handler)
+ , _count (0)
+{
+
+}
+
+Suspender::Block::Block (Suspender* s)
+ : _suspender (s)
+{
+ _suspender->increment ();
+}
+
+Suspender::Block::~Block ()
+{
+ _suspender->decrement ();
+}
+
+Suspender::Block
+Suspender::block ()
+{
+ return Block (this);
+}
+
+void
+Suspender::increment ()
+{
+ ++_count;
+}
+
+void
+Suspender::decrement ()
+{
+ --_count;
+ if (_count == 0) {
+ BOOST_FOREACH (int i, _pending) {
+ _handler (i);
+ }
+ _pending.clear ();
+ }
+}
+
+bool
+Suspender::check (int property)
+{
+ if (_count == 0) {
+ return false;
+ }
+
+ _pending.insert (property);
+ return true;
+}
+
+