mirror of https://github.com/oxen-io/oxen-mq.git
113 lines
4.7 KiB
C++
113 lines
4.7 KiB
C++
// Copyright (c) 2019-2021, The Oxen Project
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#pragma once
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// This header is here to provide just the basic bt_value/bt_dict/bt_list definitions without
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// needing to include the full bt_serialize.h header.
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#include <map>
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#include <list>
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#include <cstdint>
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#include <variant>
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#include <string>
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#include <string_view>
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namespace oxenmq {
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struct bt_value;
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/// The type used to store dictionaries inside bt_value.
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using bt_dict = std::map<std::string, bt_value>; // NB: unordered_map doesn't work because it can't be used with a predeclared type
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/// The type used to store list items inside bt_value.
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using bt_list = std::list<bt_value>;
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/// The basic variant that can hold anything (recursively).
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using bt_variant = std::variant<
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std::string,
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std::string_view,
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int64_t,
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uint64_t,
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bt_list,
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bt_dict
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>;
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#ifdef __cpp_lib_remove_cvref // C++20
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using std::remove_cvref_t;
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#else
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template <typename T>
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using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
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#endif
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template <typename T, typename Variant>
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struct has_alternative;
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template <typename T, typename... V>
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struct has_alternative<T, std::variant<V...>> : std::bool_constant<(std::is_same_v<T, V> || ...)> {};
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template <typename T, typename Variant>
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constexpr bool has_alternative_v = has_alternative<T, Variant>::value;
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namespace detail {
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template <typename Tuple, size_t... Is>
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bt_list tuple_to_list(const Tuple& tuple, std::index_sequence<Is...>) {
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return {{bt_value{std::get<Is>(tuple)}...}};
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}
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template <typename T> constexpr bool is_tuple = false;
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template <typename... T> constexpr bool is_tuple<std::tuple<T...>> = true;
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template <typename S, typename T> constexpr bool is_tuple<std::pair<S, T>> = true;
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}
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/// Recursive generic type that can fully represent everything valid for a BT serialization.
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/// This is basically just an empty wrapper around the std::variant, except we add some extra
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/// converting constructors:
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/// - integer constructors so that any unsigned value goes to the uint64_t and any signed value goes
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/// to the int64_t.
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/// - std::tuple and std::pair constructors that build a bt_list out of the tuple/pair elements.
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struct bt_value : bt_variant {
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using bt_variant::bt_variant;
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using bt_variant::operator=;
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template <typename T, typename U = std::remove_reference_t<T>, std::enable_if_t<std::is_integral_v<U> && std::is_unsigned_v<U>, int> = 0>
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bt_value(T&& uint) : bt_variant{static_cast<uint64_t>(uint)} {}
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template <typename T, typename U = std::remove_reference_t<T>, std::enable_if_t<std::is_integral_v<U> && std::is_signed_v<U>, int> = 0>
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bt_value(T&& sint) : bt_variant{static_cast<int64_t>(sint)} {}
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template <typename... T>
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bt_value(const std::tuple<T...>& tuple) : bt_variant{detail::tuple_to_list(tuple, std::index_sequence_for<T...>{})} {}
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template <typename S, typename T>
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bt_value(const std::pair<S, T>& pair) : bt_variant{detail::tuple_to_list(pair, std::index_sequence_for<S, T>{})} {}
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template <typename T, typename U = std::remove_reference_t<T>, std::enable_if_t<!std::is_integral_v<U> && !detail::is_tuple<U>, int> = 0>
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bt_value(T&& v) : bt_variant{std::forward<T>(v)} {}
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bt_value(const char* s) : bt_value{std::string_view{s}} {}
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};
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}
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