tdesktop/Telegram/SourceFiles/rpl/conditional.h

53 lines
1.3 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.
For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#pragma once
#include "base/optional.h"
#include "base/variant.h"
#include <rpl/map.h>
#include <rpl/producer.h>
namespace rpl {
template <
typename Value,
typename Error,
typename GeneratorTest,
typename GeneratorA,
typename GeneratorB>
inline auto conditional(
rpl::producer<bool, Error, GeneratorTest> &&test,
rpl::producer<Value, Error, GeneratorA> &&a,
rpl::producer<Value, Error, GeneratorB> &&b) {
return rpl::combine(
std::move(test),
std::move(a),
std::move(b)
) | rpl::map([](bool test, Value &&a, Value &&b) {
return test ? std::move(a) : std::move(b);
});
//struct conditional_state {
// std::optional<Value> a;
// std::optional<Value> b;
// char state = -1;
// int working = 3;
//};
//return rpl::make_producer<Value, Error>([
// test = std::move(test),
// a = std::move(a),
// b = std::move(b)
//](const auto &consumer) mutable {
// auto result = lifetime();
// const auto state = result.make_state<conditional_state>();
// result.add(std::move(test).start())
// return result;
//});
}
} // namespace rpl