Add WeakFilm and WeakConstFilm and use them a bit.

[dcpomatic.git] / src / lib / weak_film.h

diff --git a/src/lib/weak_film.h b/src/lib/weak_film.h
new file mode 100644 (file)
index 0000000..7311014
--- /dev/null
+++ b/src/lib/weak_film.h
@@ -0,0 +1,57 @@
+/*
+    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/>.
+
+*/
+
+
+#ifndef DCPOMATIC_WEAK_FILM_H
+#define DCPOMATIC_WEAK_FILM_H
+
+
+#include "dcpomatic_assert.h"
+#include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
+
+
+class Film;
+
+
+template <class T>
+class WeakFilmTemplate
+{
+public:
+       WeakFilmTemplate (boost::weak_ptr<T> f)
+               : _film(f)
+       {}
+
+protected:
+       boost::weak_ptr<T> _film;
+
+       boost::shared_ptr<T> film () const {
+               boost::shared_ptr<T> f = _film.lock();
+               DCPOMATIC_ASSERT (f);
+               return f;
+       }
+};
+
+
+typedef WeakFilmTemplate<const Film> WeakConstFilm;
+typedef WeakFilmTemplate<Film> WeakFilm;
+
+
+#endif