72 lines
1.9 KiB
C++
72 lines
1.9 KiB
C++
/*
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This file is part of Telegram Desktop,
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the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
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https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
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#pragma once
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#include <rpl/producer.h>
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namespace rpl {
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namespace details {
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template <typename Value, typename Error, typename Generator>
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class then_helper {
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public:
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then_helper(producer<Value, Error, Generator> &&following)
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: _following(std::move(following)) {
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}
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template <
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typename OtherValue,
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typename OtherError,
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typename OtherGenerator,
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typename NewValue = superset_type_t<Value, OtherValue>,
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typename NewError = superset_type_t<Error, OtherError>>
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auto operator()(
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producer<OtherValue, OtherError, OtherGenerator> &&initial
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) {
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return make_producer<NewValue, NewError>([
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initial = std::move(initial),
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following = std::move(_following)
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](const auto &consumer) mutable {
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return std::move(initial).start(
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[consumer](auto &&value) {
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consumer.put_next_forward(
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std::forward<decltype(value)>(value));
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}, [consumer](auto &&error) {
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consumer.put_error_forward(
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std::forward<decltype(error)>(error));
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}, [
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consumer,
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following = std::move(following)
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]() mutable {
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consumer.add_lifetime(std::move(following).start(
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[consumer](auto &&value) {
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consumer.put_next_forward(
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std::forward<decltype(value)>(value));
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}, [consumer](auto &&error) {
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consumer.put_error_forward(
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std::forward<decltype(error)>(error));
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}, [consumer] {
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consumer.put_done();
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}));
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});
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});
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}
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private:
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producer<Value, Error, Generator> _following;
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};
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} // namespace details
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template <typename Value, typename Error, typename Generator>
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inline auto then(producer<Value, Error, Generator> &&following)
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-> details::then_helper<Value, Error, Generator> {
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return { std::move(following) };
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}
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} // namespace rpl
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