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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MOJO_PUBLIC_CPP_BINDINGS_MAP_TRAITS_H_
#define MOJO_PUBLIC_CPP_BINDINGS_MAP_TRAITS_H_
#include "mojo/public/cpp/bindings/lib/template_util.h"
namespace mojo {
// This must be specialized for any type |T| to be serialized/deserialized as
// a mojom map.
//
// Usually you would like to do a partial specialization for a map template.
// Imagine you want to specialize it for CustomMap<>, you need to implement:
//
// template <typename K, typename V>
// struct MapTraits<CustomMap<K, V>> {
// using Key = K;
// using Value = V;
//
// // These two methods are optional. Please see comments in struct_traits.h
// // Note that unlike with StructTraits, IsNull() is called *twice* during
// // serialization for MapTraits.
// static bool IsNull(const CustomMap<K, V>& input);
// static void SetToNull(CustomMap<K, V>* output);
//
// static size_t GetSize(const CustomMap<K, V>& input);
//
// static CustomConstIterator GetBegin(const CustomMap<K, V>& input);
// static CustomIterator GetBegin(CustomMap<K, V>& input);
//
// static void AdvanceIterator(CustomConstIterator& iterator);
// static void AdvanceIterator(CustomIterator& iterator);
//
// static const K& GetKey(CustomIterator& iterator);
// static const K& GetKey(CustomConstIterator& iterator);
//
// static V& GetValue(CustomIterator& iterator);
// static const V& GetValue(CustomConstIterator& iterator);
//
// // Returning false results in deserialization failure and causes the
// // message pipe receiving it to be disconnected. |IK| and |IV| are
// // separate input key/value template parameters that allows for the
// // the key/value types to be forwarded.
// template <typename IK, typename IV>
// static bool Insert(CustomMap<K, V>& input,
// IK&& key,
// IV&& value);
//
// static void SetToEmpty(CustomMap<K, V>* output);
// };
//
template <typename T>
struct MapTraits {
static_assert(internal::AlwaysFalse<T>::value,
"Cannot find the mojo::MapTraits specialization. Did you "
"forget to include the corresponding header file?");
};
} // namespace mojo
#endif // MOJO_PUBLIC_CPP_BINDINGS_MAP_TRAITS_H_