585 lines
17 KiB
C++
585 lines
17 KiB
C++
// This file Copyright © Mnemosyne LLC.
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// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
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// or any future license endorsed by Mnemosyne LLC.
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// License text can be found in the licenses/ folder.
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#pragma once
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#include <algorithm> // std::move()
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#include <cstddef> // size_t
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#include <cstdint> // int64_t
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#include <optional>
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#include <string>
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#include <string_view>
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#include <type_traits> // std::is_same_v
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#include <utility> // std::pair
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#include <variant>
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#include <vector>
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#include "libtransmission/error.h"
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#include "libtransmission/quark.h"
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#include "libtransmission/tr-macros.h" // TR_CONSTEXPR20
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/**
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* A variant that holds typical benc/json types: bool, int,
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* double, string, vectors of variants, and maps of variants.
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* Useful when serializing / deserializing benc/json data.
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*
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* @see tr_variant_serde
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*/
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struct tr_variant
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{
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public:
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enum Type : size_t
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{
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NoneIndex = 0,
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BoolIndex = 1,
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IntIndex = 2,
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DoubleIndex = 3,
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StringIndex = 4,
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VectorIndex = 5,
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MapIndex = 6
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};
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using Vector = std::vector<tr_variant>;
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class Map
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{
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public:
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Map() = default;
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Map(size_t const n_reserve)
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{
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vec_.reserve(n_reserve);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto begin() noexcept
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{
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return std::begin(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto begin() const noexcept
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{
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return std::cbegin(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto cbegin() const noexcept
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{
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return std::cbegin(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto end() noexcept
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{
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return std::end(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto end() const noexcept
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{
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return std::cend(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto cend() const noexcept
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{
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return std::cend(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto find(tr_quark const key) noexcept
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{
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auto const predicate = [key](auto const& item)
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{
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return item.first == key;
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};
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return std::find_if(std::begin(vec_), std::end(vec_), predicate);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto find(tr_quark const key) const noexcept
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{
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auto const predicate = [key](auto const& item)
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{
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return item.first == key;
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};
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return std::find_if(std::cbegin(vec_), std::cend(vec_), predicate);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto size() const noexcept
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{
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return std::size(vec_);
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}
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[[nodiscard]] TR_CONSTEXPR20 auto empty() const noexcept
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{
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return std::empty(vec_);
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}
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void reserve(size_t const new_cap)
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{
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vec_.reserve(std::max(new_cap, size_t{ 16U }));
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}
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auto erase(tr_quark const key)
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{
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if (auto iter = find(key); iter != end())
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{
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vec_.erase(iter);
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return 1U;
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}
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return 0U;
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}
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[[nodiscard]] tr_variant& operator[](tr_quark const& key)
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{
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if (auto const iter = find(key); iter != end())
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{
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return iter->second;
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}
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return vec_.emplace_back(key, tr_variant{}).second;
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}
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template<typename Val>
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std::pair<tr_variant&, bool> try_emplace(tr_quark const key, Val&& val)
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{
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if (auto iter = find(key); iter != end())
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{
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return { iter->second, false };
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}
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return { vec_.emplace_back(key, tr_variant{ std::forward<Val>(val) }).second, true };
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}
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// --- custom functions
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template<typename Type>
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[[nodiscard]] TR_CONSTEXPR20 auto find_if(tr_quark const key) const noexcept
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{
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auto const iter = find(key);
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return iter != end() ? iter->second.get_if<Type>() : nullptr;
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}
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template<typename Type>
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[[nodiscard]] std::optional<Type> value_if(tr_quark const key) const noexcept
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{
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if (auto it = find(key); it != end())
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{
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return it->second.value_if<Type>();
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}
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return {};
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}
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private:
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using Vector = std::vector<std::pair<tr_quark, tr_variant>>;
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Vector vec_;
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};
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constexpr tr_variant() noexcept = default;
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tr_variant(tr_variant const&) = delete;
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tr_variant(tr_variant&& that) noexcept = default;
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tr_variant& operator=(tr_variant const&) = delete;
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tr_variant& operator=(tr_variant&& that) noexcept = default;
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template<typename Val>
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tr_variant(Val&& value)
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{
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*this = std::forward<Val>(value);
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}
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[[nodiscard]] static auto make_map(size_t const n_reserve = 0U) noexcept
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{
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auto ret = tr_variant{};
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ret.val_.emplace<Map>(n_reserve);
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return ret;
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}
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[[nodiscard]] static auto make_vector(size_t const n_reserve = 0U)
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{
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auto ret = tr_variant{};
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ret.val_.emplace<Vector>().reserve(n_reserve);
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return ret;
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}
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[[nodiscard]] static auto make_raw(void const* value, size_t n_bytes)
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{
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return tr_variant{ std::string{ static_cast<char const*>(value), n_bytes } };
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}
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template<typename CharSpan>
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[[nodiscard]] static auto make_raw(CharSpan const& value)
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{
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static_assert(sizeof(CharSpan::value_type) == 1U);
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return make_raw(std::data(value), std::size(value));
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}
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[[nodiscard]] static tr_variant unmanaged_string(std::string_view val)
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{
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auto ret = tr_variant{};
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ret.val_.emplace<StringHolder>().set_unmanaged(val);
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return ret;
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}
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template<typename Val>
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tr_variant& operator=(Val value)
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{
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if constexpr (std::is_same_v<Val, std::string_view>)
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{
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val_.emplace<StringHolder>(std::string{ value });
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}
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// note: std::is_integral_v<bool> is true, so this check
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// must come first to prevent bools from being stored as ints
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else if constexpr (std::is_same_v<Val, bool>)
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{
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val_.emplace<bool>(value);
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}
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else if constexpr (std::is_integral_v<Val> || std::is_enum_v<Val>)
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{
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val_ = static_cast<int64_t>(value);
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}
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else
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{
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val_ = std::move(value);
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}
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return *this;
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}
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tr_variant& operator=(std::string&& value)
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{
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val_.emplace<StringHolder>(std::move(value));
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return *this;
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}
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tr_variant& operator=(std::string const& value)
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{
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*this = std::string{ value };
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return *this;
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}
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tr_variant& operator=(char const* const value)
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{
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*this = std::string{ value != nullptr ? value : "" };
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return *this;
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}
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[[nodiscard]] constexpr auto index() const noexcept
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{
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return val_.index();
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}
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[[nodiscard]] constexpr auto has_value() const noexcept
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{
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return index() != NoneIndex;
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}
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template<typename Val>
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[[nodiscard]] constexpr auto* get_if() noexcept
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{
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if constexpr (std::is_same_v<Val, std::string_view>)
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{
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auto const* const val = std::get_if<StringHolder>(&val_);
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return val != nullptr ? &val->sv_ : nullptr;
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}
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else
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{
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return std::get_if<Val>(&val_);
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}
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}
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template<typename Val>
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[[nodiscard]] constexpr auto const* get_if() const noexcept
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{
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return const_cast<tr_variant*>(this)->get_if<Val>();
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}
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template<size_t Index>
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[[nodiscard]] constexpr auto* get_if() noexcept
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{
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if constexpr (Index == StringIndex)
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{
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auto const* const val = std::get_if<StringIndex>(&val_);
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return val != nullptr ? &val->sv_ : nullptr;
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}
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else
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{
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return std::get_if<Index>(&val_);
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}
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}
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template<size_t Index>
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[[nodiscard]] constexpr auto const* get_if() const noexcept
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{
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return const_cast<tr_variant*>(this)->get_if<Index>();
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}
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template<typename Val>
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[[nodiscard]] constexpr std::optional<Val> value_if() noexcept
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{
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if (auto const* const val = get_if<Val>())
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{
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return *val;
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}
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return {};
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}
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template<typename Val>
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[[nodiscard]] std::optional<Val> value_if() const noexcept
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{
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return const_cast<tr_variant*>(this)->value_if<Val>();
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}
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template<typename Val>
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[[nodiscard]] constexpr bool holds_alternative() const noexcept
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{
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if constexpr (std::is_same_v<Val, std::string_view>)
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{
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return std::holds_alternative<StringHolder>(val_);
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}
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else
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{
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return std::holds_alternative<Val>(val_);
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}
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}
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void clear()
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{
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val_.emplace<std::monostate>();
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}
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tr_variant& merge(tr_variant const& that)
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{
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std::visit(Merge{ *this }, that.val_);
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return *this;
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}
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private:
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// Holds a string_view to either an unmanaged/external string or to
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// one owned by the class. If the string is unmanaged, only sv_ is used.
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// If we own the string, then sv_ points to the managed str_.
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class StringHolder
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{
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public:
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StringHolder() = default;
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explicit StringHolder(std::string&& str) noexcept;
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explicit StringHolder(StringHolder&& that) noexcept;
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void set_unmanaged(std::string_view sv);
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StringHolder& operator=(StringHolder&& that) noexcept;
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std::string_view sv_;
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private:
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std::string str_;
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};
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class Merge
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{
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public:
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explicit Merge(tr_variant& tgt);
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void operator()(std::monostate const& src);
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void operator()(bool const& src);
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void operator()(int64_t const& src);
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void operator()(double const& src);
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void operator()(tr_variant::StringHolder const& src);
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void operator()(tr_variant::Vector const& src);
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void operator()(tr_variant::Map const& src);
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private:
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tr_variant& tgt_;
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};
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std::variant<std::monostate, bool, int64_t, double, StringHolder, Vector, Map> val_;
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};
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template<>
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[[nodiscard]] std::optional<int64_t> tr_variant::value_if() noexcept;
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template<>
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[[nodiscard]] std::optional<bool> tr_variant::value_if() noexcept;
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template<>
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[[nodiscard]] std::optional<double> tr_variant::value_if() noexcept;
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// --- Strings
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bool tr_variantGetStrView(tr_variant const* variant, std::string_view* setme);
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bool tr_variantGetRaw(tr_variant const* variant, std::byte const** setme_raw, size_t* setme_len);
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bool tr_variantGetRaw(tr_variant const* variant, uint8_t const** setme_raw, size_t* setme_len);
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// --- Real Numbers
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bool tr_variantGetReal(tr_variant const* variant, double* value_setme);
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// --- Booleans
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bool tr_variantGetBool(tr_variant const* variant, bool* setme);
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// --- Ints
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bool tr_variantGetInt(tr_variant const* var, int64_t* setme);
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// --- Lists
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void tr_variantInitList(tr_variant* initme, size_t n_reserve);
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void tr_variantListReserve(tr_variant* var, size_t n_reserve);
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tr_variant* tr_variantListAdd(tr_variant* var);
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tr_variant* tr_variantListAddBool(tr_variant* var, bool value);
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tr_variant* tr_variantListAddInt(tr_variant* var, int64_t value);
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tr_variant* tr_variantListAddReal(tr_variant* var, double value);
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tr_variant* tr_variantListAddStr(tr_variant* var, std::string_view value);
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tr_variant* tr_variantListAddStrView(tr_variant* var, std::string_view value);
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tr_variant* tr_variantListAddRaw(tr_variant* var, void const* value, size_t n_bytes);
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tr_variant* tr_variantListAddList(tr_variant* var, size_t n_reserve);
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tr_variant* tr_variantListAddDict(tr_variant* var, size_t n_reserve);
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tr_variant* tr_variantListChild(tr_variant* var, size_t pos);
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bool tr_variantListRemove(tr_variant* var, size_t pos);
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[[nodiscard]] constexpr size_t tr_variantListSize(tr_variant const* const var)
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{
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if (var != nullptr)
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{
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if (auto const* const vec = var->get_if<tr_variant::Vector>(); vec != nullptr)
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{
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return std::size(*vec);
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}
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}
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return {};
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}
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// --- Dictionaries
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void tr_variantInitDict(tr_variant* initme, size_t n_reserve);
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void tr_variantDictReserve(tr_variant* var, size_t n_reserve);
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bool tr_variantDictRemove(tr_variant* var, tr_quark key);
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tr_variant* tr_variantDictAdd(tr_variant* var, tr_quark key);
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tr_variant* tr_variantDictAddReal(tr_variant* var, tr_quark key, double value);
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tr_variant* tr_variantDictAddInt(tr_variant* var, tr_quark key, int64_t value);
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tr_variant* tr_variantDictAddBool(tr_variant* var, tr_quark key, bool value);
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tr_variant* tr_variantDictAddStr(tr_variant* var, tr_quark key, std::string_view value);
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tr_variant* tr_variantDictAddStrView(tr_variant* var, tr_quark key, std::string_view value);
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tr_variant* tr_variantDictAddList(tr_variant* var, tr_quark key, size_t n_reserve);
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tr_variant* tr_variantDictAddDict(tr_variant* var, tr_quark key, size_t n_reserve);
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tr_variant* tr_variantDictAddRaw(tr_variant* var, tr_quark key, void const* value, size_t n_bytes);
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bool tr_variantDictChild(tr_variant* var, size_t pos, tr_quark* setme_key, tr_variant** setme_value);
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tr_variant* tr_variantDictFind(tr_variant* var, tr_quark key);
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bool tr_variantDictFindList(tr_variant* var, tr_quark key, tr_variant** setme);
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bool tr_variantDictFindDict(tr_variant* var, tr_quark key, tr_variant** setme_value);
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bool tr_variantDictFindInt(tr_variant* var, tr_quark key, int64_t* setme);
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bool tr_variantDictFindReal(tr_variant* var, tr_quark key, double* setme);
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bool tr_variantDictFindBool(tr_variant* var, tr_quark key, bool* setme);
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bool tr_variantDictFindStrView(tr_variant* var, tr_quark key, std::string_view* setme);
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bool tr_variantDictFindRaw(tr_variant* var, tr_quark key, uint8_t const** setme_raw, size_t* setme_len);
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bool tr_variantDictFindRaw(tr_variant* var, tr_quark key, std::byte const** setme_raw, size_t* setme_len);
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/* this is only quasi-supported. don't rely on it too heavily outside of libT */
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void tr_variantMergeDicts(tr_variant* tgt, tr_variant const* src);
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/**
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* Helper class for serializing and deserializing benc/json data.
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*
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* @see tr_variant
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*/
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class tr_variant_serde
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{
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public:
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[[nodiscard]] static tr_variant_serde benc() noexcept
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{
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return tr_variant_serde{ Type::Benc };
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}
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[[nodiscard]] static tr_variant_serde json() noexcept
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{
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return tr_variant_serde{ Type::Json };
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}
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// Serialize data as compactly as possible, e.g.
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// omit pretty-printing JSON whitespace
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constexpr tr_variant_serde& compact() noexcept
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{
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compact_ = true;
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return *this;
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}
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// When set, assumes that the `input` passed to parse() is valid
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// for the lifespan of the variant and we can use string_views of
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// `input` instead of cloning new strings.
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constexpr tr_variant_serde& inplace() noexcept
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{
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parse_inplace_ = true;
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return *this;
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}
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// ---
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[[nodiscard]] std::optional<tr_variant> parse(std::string_view input);
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template<typename CharSpan>
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[[nodiscard]] std::optional<tr_variant> parse(CharSpan const& input)
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{
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return parse(std::string_view{ std::data(input), std::size(input) });
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}
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[[nodiscard]] std::optional<tr_variant> parse_file(std::string_view filename);
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[[nodiscard]] constexpr char const* end() const noexcept
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{
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return end_;
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}
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// ---
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[[nodiscard]] std::string to_string(tr_variant const& var) const;
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bool to_file(tr_variant const& var, std::string_view filename);
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|
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// ---
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|
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|
// Tracks errors when parsing / saving
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|
tr_error error_ = {};
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|
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|
private:
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|
friend tr_variant;
|
|
|
|
enum class Type
|
|
{
|
|
Benc,
|
|
Json
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|
};
|
|
|
|
struct WalkFuncs
|
|
{
|
|
void (*int_func)(tr_variant const& var, int64_t val, void* user_data);
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|
void (*bool_func)(tr_variant const& var, bool val, void* user_data);
|
|
void (*double_func)(tr_variant const& var, double val, void* user_data);
|
|
void (*string_func)(tr_variant const& var, std::string_view val, void* user_data);
|
|
void (*dict_begin_func)(tr_variant const& var, void* user_data);
|
|
void (*list_begin_func)(tr_variant const& var, void* user_data);
|
|
void (*container_end_func)(tr_variant const& var, void* user_data);
|
|
};
|
|
|
|
tr_variant_serde(Type type)
|
|
: type_{ type }
|
|
{
|
|
}
|
|
|
|
[[nodiscard]] std::optional<tr_variant> parse_json(std::string_view input);
|
|
[[nodiscard]] std::optional<tr_variant> parse_benc(std::string_view input);
|
|
|
|
[[nodiscard]] std::string to_json_string(tr_variant const& var) const;
|
|
[[nodiscard]] static std::string to_benc_string(tr_variant const& var);
|
|
|
|
static void walk(tr_variant const& top, WalkFuncs const& walk_funcs, void* user_data, bool sort_dicts);
|
|
|
|
Type type_;
|
|
|
|
bool compact_ = false;
|
|
|
|
bool parse_inplace_ = false;
|
|
|
|
// This is set to the first unparsed character after `parse()`.
|
|
char const* end_ = nullptr;
|
|
};
|
|
|
|
/* @} */
|