tdesktop/Telegram/SourceFiles/rpl/after_next.h

72 lines
2.1 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 {
namespace details {
template <typename SideEffect>
class after_next_helper {
public:
template <typename OtherSideEffect>
after_next_helper(OtherSideEffect &&method)
: _method(std::forward<OtherSideEffect>(method)) {
}
template <typename Value, typename Error, typename Generator>
auto operator()(producer<Value, Error, Generator> &&initial) {
return make_producer<Value, Error>([
initial = std::move(initial),
method = std::move(_method)
](const auto &consumer) mutable {
return std::move(initial).start(
[method = std::move(method), consumer](auto &&value) {
auto copy = method;
consumer.put_next_copy(value);
std::move(copy)(
std::forward<decltype(value)>(value));
}, [consumer](auto &&error) {
consumer.put_error_forward(
std::forward<decltype(error)>(error));
}, [consumer] {
consumer.put_done();
});
});
}
private:
SideEffect _method;
};
} // namespace details
template <typename SideEffect>
inline auto after_next(SideEffect &&method)
-> details::after_next_helper<std::decay_t<SideEffect>> {
return details::after_next_helper<std::decay_t<SideEffect>>(
std::forward<SideEffect>(method));
}
} // namespace rpl