tdesktop/Telegram/SourceFiles/rpl/deferred.h

40 lines
1.3 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop 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 3 of the License, or
(at your option) any later version.
It 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.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once
#include <rpl/producer.h>
namespace rpl {
template <
typename Creator,
typename Value = typename decltype(std::declval<Creator>()())::value_type,
typename Error = typename decltype(std::declval<Creator>()())::error_type>
inline auto deferred(Creator &&creator) {
return make_producer<Value, Error>([
creator = std::forward<Creator>(creator)
](const auto &consumer) mutable {
return std::move(creator)().start_existing(consumer);
});
}
} // namespace rpl