Feature.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_PROTOCOL_FEATURE_H_INCLUDED
#define RIPPLE_PROTOCOL_FEATURE_H_INCLUDED
 
#include <xrpl/basics/base_uint.h>
 
#include <boost/container/flat_map.hpp>
 
#include <array>
#include <bitset>
#include <map>
#include <optional>
#include <string>
 
namespace ripple {
 
enum class VoteBehavior : int { Obsolete = -1, DefaultNo = 0, DefaultYes };
enum class AmendmentSupport : int { Retired = -1, Supported = 0, Unsupported };
 
std::map<std::string, AmendmentSupport> const&
allAmendments();
 
namespace detail {
 
// This value SHOULD be equal to the number of amendments registered in
// Feature.cpp. Because it's only used to reserve storage, and determine how
// large to make the FeatureBitset, it MAY be larger. It MUST NOT be less than
// the actual number of amendments. A LogicError on startup will verify this.
static constexpr std::size_t numFeatures = 88;
 
std::map<std::string, VoteBehavior> const&
supportedAmendments();
 
std::size_t
numDownVotedAmendments();
 
std::size_t
numUpVotedAmendments();
 
}  // namespace detail
 
std::optional<uint256>
getRegisteredFeature(std::string const& name);
 
size_t
featureToBitsetIndex(uint256 const& f);
 
uint256
bitsetIndexToFeature(size_t i);
 
std::string
featureToName(uint256 const& f);
 
class FeatureBitset : private std::bitset<detail::numFeatures>
{
    using base = std::bitset<detail::numFeatures>;
 
    template <class... Fs>
    void
    initFromFeatures(uint256 const& f, Fs&&... fs)
    {
        set(f);
        if constexpr (sizeof...(fs) > 0)
            initFromFeatures(std::forward<Fs>(fs)...);
    }
 
public:
    using base::bitset;
    using base::operator==;
 
    using base::all;
    using base::any;
    using base::count;
    using base::flip;
    using base::none;
    using base::reset;
    using base::set;
    using base::size;
    using base::test;
    using base::operator[];
    using base::to_string;
    using base::to_ullong;
    using base::to_ulong;
 
    FeatureBitset() = default;
 
    explicit FeatureBitset(base const& b) : base(b)
    {
        XRPL_ASSERT(
            b.count() == count(),
            "ripple::FeatureBitset::FeatureBitset(base) : count match");
    }
 
    template <class... Fs>
    explicit FeatureBitset(uint256 const& f, Fs&&... fs)
    {
        initFromFeatures(f, std::forward<Fs>(fs)...);
        XRPL_ASSERT(
            count() == (sizeof...(fs) + 1),
            "ripple::FeatureBitset::FeatureBitset(uint256) : count and "
            "sizeof... do match");
    }
 
    template <class Col>
    explicit FeatureBitset(Col const& fs)
    {
        for (auto const& f : fs)
            set(featureToBitsetIndex(f));
        XRPL_ASSERT(
            fs.size() == count(),
            "ripple::FeatureBitset::FeatureBitset(Container auto) : count and "
            "size do match");
    }
 
    auto
    operator[](uint256 const& f)
    {
        return base::operator[](featureToBitsetIndex(f));
    }
 
    auto
    operator[](uint256 const& f) const
    {
        return base::operator[](featureToBitsetIndex(f));
    }
 
    FeatureBitset&
    set(uint256 const& f, bool value = true)
    {
        base::set(featureToBitsetIndex(f), value);
        return *this;
    }
 
    FeatureBitset&
    reset(uint256 const& f)
    {
        base::reset(featureToBitsetIndex(f));
        return *this;
    }
 
    FeatureBitset&
    flip(uint256 const& f)
    {
        base::flip(featureToBitsetIndex(f));
        return *this;
    }
 
    FeatureBitset&
    operator&=(FeatureBitset const& rhs)
    {
        base::operator&=(rhs);
        return *this;
    }
 
    FeatureBitset&
    operator|=(FeatureBitset const& rhs)
    {
        base::operator|=(rhs);
        return *this;
    }
 
    FeatureBitset
    operator~() const
    {
        return FeatureBitset{base::operator~()};
    }
 
    friend FeatureBitset
    operator&(FeatureBitset const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{
            static_cast<base const&>(lhs) & static_cast<base const&>(rhs)};
    }
 
    friend FeatureBitset
    operator&(FeatureBitset const& lhs, uint256 const& rhs)
    {
        return lhs & FeatureBitset{rhs};
    }
 
    friend FeatureBitset
    operator&(uint256 const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{lhs} & rhs;
    }
 
    friend FeatureBitset
    operator|(FeatureBitset const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{
            static_cast<base const&>(lhs) | static_cast<base const&>(rhs)};
    }
 
    friend FeatureBitset
    operator|(FeatureBitset const& lhs, uint256 const& rhs)
    {
        return lhs | FeatureBitset{rhs};
    }
 
    friend FeatureBitset
    operator|(uint256 const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{lhs} | rhs;
    }
 
    friend FeatureBitset
    operator^(FeatureBitset const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{
            static_cast<base const&>(lhs) ^ static_cast<base const&>(rhs)};
    }
 
    friend FeatureBitset
    operator^(FeatureBitset const& lhs, uint256 const& rhs)
    {
        return lhs ^ FeatureBitset { rhs };
    }
 
    friend FeatureBitset
    operator^(uint256 const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{lhs} ^ rhs;
    }
 
    // set difference
    friend FeatureBitset
    operator-(FeatureBitset const& lhs, FeatureBitset const& rhs)
    {
        return lhs & ~rhs;
    }
 
    friend FeatureBitset
    operator-(FeatureBitset const& lhs, uint256 const& rhs)
    {
        return lhs - FeatureBitset{rhs};
    }
 
    friend FeatureBitset
    operator-(uint256 const& lhs, FeatureBitset const& rhs)
    {
        return FeatureBitset{lhs} - rhs;
    }
};
 
template <class F>
void
foreachFeature(FeatureBitset bs, F&& f)
{
    for (size_t i = 0; i < bs.size(); ++i)
        if (bs[i])
            f(bitsetIndexToFeature(i));
}
 
#pragma push_macro("XRPL_FEATURE")
#undef XRPL_FEATURE
#pragma push_macro("XRPL_FIX")
#undef XRPL_FIX
 
#define XRPL_FEATURE(name, supported, vote) extern uint256 const feature##name;
#define XRPL_FIX(name, supported, vote) extern uint256 const fix##name;
 
#include <xrpl/protocol/detail/features.macro>
 
#undef XRPL_FIX
#pragma pop_macro("XRPL_FIX")
#undef XRPL_FEATURE
#pragma pop_macro("XRPL_FEATURE")
 
}  // namespace ripple
 
#endif