meta.hpp

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#pragma once
 
/// @file userver/dump/meta.hpp
/// @brief Provides dump::kIsDumpable and includes userver/dump/fwd.hpp
 
#include <type_traits>
 
#include <userver/dump/fwd.hpp>
#include <userver/utils/meta_light.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace dump {
 
namespace impl {
 
template <typename T>
using WritableResult = decltype(Write(std::declval<Writer&>(), std::declval<const T&>()));
 
template <typename T>
using ReadableResult = decltype(Read(std::declval<Reader&>(), To<T>{}));
 
}  // namespace impl
 
/// Check if `writer.Write(T)` is available
template <typename T>
inline constexpr bool kIsWritable = std::is_same_v<meta::DetectedType<impl::WritableResult, T>, void>;
 
/// Check if `reader.Read<T>()` is available
template <typename T>
inline constexpr bool kIsReadable = std::is_same_v<meta::DetectedType<impl::ReadableResult, T>, std::remove_const_t<T>>;
 
/// Check if `T` is both writable and readable
template <typename T>
inline constexpr bool kIsDumpable = kIsWritable<T> && kIsReadable<T>;
 
template <typename T>
constexpr bool CheckDumpable() {
    static_assert(
        kIsDumpable<T>,
        "Type is not dumpable. Probably you forgot to include "
        "<userver/dump/common.hpp>, <userver/dump/common_containers.hpp> or "
        "other headers with Read and Write declarations"
    );
 
    return true;
}
 
}  // namespace dump
 
USERVER_NAMESPACE_END