ValueView.hpp

//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2024, the clio developers.
 
    Permission to use, copy, modify, and 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.
*/
//==============================================================================
 
#pragma once
 
#include "util/Assert.hpp"
#include "util/config/ConfigConstraints.hpp"
#include "util/config/ConfigValue.hpp"
#include "util/config/Types.hpp"
 
#include <fmt/format.h>
 
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <functional>
#include <optional>
#include <ostream>
#include <string>
#include <type_traits>
#include <utility>
 
namespace util::config {
 
class ClioConfigDefinition;

class ValueView {
public:
    ValueView(ConfigValue const& configVal);

    [[nodiscard]] std::string
    asString() const;

    [[nodiscard]] bool
    asBool() const;

    template <typename T>
    [[nodiscard]] T
    asIntType() const
    {
        if ((type() == ConfigType::Integer) && configVal_.get().hasValue()) {
            auto const val = std::get<int64_t>(configVal_.get().getValue());
            if (std::is_unsigned_v<T> && val < 0)
                ASSERT(false, "Int {} cannot be converted to the specified unsigned type", val);
 
            if (std::is_convertible_v<decltype(val), T>) {
                return static_cast<T>(val);
            }
        }
        ASSERT(false, "Value view is not of Int type");
        return 0;
    }

    [[nodiscard]] double
    asDouble() const;

    [[nodiscard]] float
    asFloat() const;

    [[nodiscard]] constexpr ConfigType
    type() const
    {
        return configVal_.get().type();
    }

    [[nodiscard]] bool constexpr hasValue() const
    {
        return configVal_.get().hasValue();
    }

    [[nodiscard]] bool constexpr isOptional() const
    {
        return configVal_.get().isOptional();
    }

    [[nodiscard]] constexpr std::optional<std::reference_wrapper<Constraint const>>
    getConstraint() const
    {
        return configVal_.get().getConstraint();
    }

    template <typename T>
    T
    getValueImpl() const
    {
        ASSERT(configVal_.get().hasValue(), "ConfigValue does not have a value");
        if constexpr (std::is_same_v<T, bool>) {
            ASSERT(type() == ConfigType::Boolean, "Value type is not a bool");
            return asBool();
        } else if constexpr (std::is_integral_v<T>) {
            ASSERT(type() == ConfigType::Integer, "Value type is not an int");
            return asIntType<T>();
        } else if constexpr (std::is_same_v<T, std::string>) {
            ASSERT(type() == ConfigType::String, "Value type is not a string");
            return asString();
        } else if constexpr (std::is_floating_point_v<T>) {
            ASSERT(
                type() == ConfigType::Double || type() == ConfigType::Integer,
                "Value type is not a floating point"
            );
            return asDouble();
        }
 
        std::unreachable();
    }

    template <typename T>
    std::optional<T>
    asOptional() const
    {
        ASSERT(isOptional(), "A Config Value is not an optional value");
        if (!hasValue())
            return std::nullopt;
 
        return std::make_optional(getValueImpl<T>());
    }

    friend std::ostream&
    operator<<(std::ostream& stream, ValueView value)
    {
        stream << value.configVal_;
        return stream;
    }
 
private:
    std::reference_wrapper<ConfigValue const> configVal_;
};
 
}  // namespace util::config