meta_containers.hpp

#pragma once
 
#include <iterator>
#include <map>
#include <set>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
 
#include <userver/dump/meta.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace dump {
 
/// @{
/// Customization point: insert an element into a container
template <typename T, typename Alloc>
void Insert(std::vector<T, Alloc>& cont, T&& elem) {
  cont.push_back(std::forward<T>(elem));
}
 
template <typename K, typename V, typename Comp, typename Alloc>
void Insert(std::map<K, V, Comp, Alloc>& cont, std::pair<const K, V>&& elem) {
  cont.insert(std::move(elem));
}
 
template <typename K, typename V, typename Hash, typename Eq, typename Alloc>
void Insert(std::unordered_map<K, V, Hash, Eq, Alloc>& cont,
            std::pair<const K, V>&& elem) {
  cont.insert(std::move(elem));
}
 
template <typename T, typename Comp, typename Alloc>
void Insert(std::set<T, Comp, Alloc>& cont, T&& elem) {
  cont.insert(std::forward<T>(elem));
}
 
template <typename T, typename Hash, typename Eq, typename Alloc>
void Insert(std::unordered_set<T, Hash, Eq, Alloc>& cont, T&& elem) {
  cont.insert(std::forward<T>(elem));
}
/// @}
 
namespace impl {
 
template <typename T>
using InsertResult = decltype(dump::Insert(
    std::declval<T&>(), std::declval<meta::RangeValueType<T>&&>()));
 
}  // namespace impl
 
/// Check if a range is a container
template <typename T>
inline constexpr bool kIsContainer =
    meta::kIsRange<T> && std::is_default_constructible_v<T> &&
    meta::kIsSizable<T> && meta::kIsDetected<impl::InsertResult, T>;
 
}  // namespace dump
 
USERVER_NAMESPACE_END