include/google/protobuf/map_field_lite.h

// Protocol Buffers - Google's data interchange format
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#ifndef GOOGLE_PROTOBUF_MAP_FIELD_LITE_H__
#define GOOGLE_PROTOBUF_MAP_FIELD_LITE_H__

#include <google/protobuf/map.h>
#include <google/protobuf/map_entry_lite.h>
#include <google/protobuf/wire_format_lite.h>

namespace google {
namespace protobuf {
namespace internal {

// This class provides access to map field using generated api. It is used for
// internal generated message implentation only. Users should never use this
// directly.
template <typename Derived, typename Key, typename T,
          WireFormatLite::FieldType key_wire_type,
          WireFormatLite::FieldType value_wire_type, int default_enum_value = 0>
class MapFieldLite {
  // Define message type for internal repeated field.
  typedef Derived EntryType;

 public:
  typedef Map<Key, T> MapType;
  typedef EntryType EntryTypeTrait;

  MapFieldLite() : arena_(NULL) { SetDefaultEnumValue(); }

  explicit MapFieldLite(Arena* arena) : arena_(arena), map_(arena) {
    SetDefaultEnumValue();
  }

  // Accessors
  const Map<Key, T>& GetMap() const { return map_; }
  Map<Key, T>* MutableMap() { return &map_; }

  // Convenient methods for generated message implementation.
  int size() const { return static_cast<int>(map_.size()); }
  void Clear() { return map_.clear(); }
  void MergeFrom(const MapFieldLite& other) {
    for (typename Map<Key, T>::const_iterator it = other.map_.begin();
         it != other.map_.end(); ++it) {
      map_[it->first] = it->second;
    }
  }
  void Swap(MapFieldLite* other) { map_.swap(other->map_); }

  // Set default enum value only for proto2 map field whose value is enum type.
  void SetDefaultEnumValue() {
    MutableMap()->SetDefaultEnumValue(default_enum_value);
  }

  // Used in the implementation of parsing. Caller should take the ownership iff
  // arena_ is NULL.
  EntryType* NewEntry() const {
    if (arena_ == NULL) {
      return new EntryType();
    } else {
      return Arena::CreateMessage<EntryType>(arena_);
    }
  }
  // Used in the implementation of serializing enum value type. Caller should
  // take the ownership iff arena_ is NULL.
  EntryType* NewEnumEntryWrapper(const Key& key, const T t) const {
    return EntryType::EnumWrap(key, t, arena_);
  }
  // Used in the implementation of serializing other value types. Caller should
  // take the ownership iff arena_ is NULL.
  EntryType* NewEntryWrapper(const Key& key, const T& t) const {
    return EntryType::Wrap(key, t, arena_);
  }

 private:
  typedef void DestructorSkippable_;

  Arena* arena_;
  Map<Key, T> map_;

  friend class ::google::protobuf::Arena;
};

// True if IsInitialized() is true for value field in all elements of t. T is
// expected to be message.  It's useful to have this helper here to keep the
// protobuf compiler from ever having to emit loops in IsInitialized() methods.
// We want the C++ compiler to inline this or not as it sees fit.
template <typename Key, typename T>
bool AllAreInitialized(const Map<Key, T>& t) {
  for (typename Map<Key, T>::const_iterator it = t.begin(); it != t.end();
       ++it) {
    if (!it->second.IsInitialized()) return false;
  }
  return true;
}

template <typename MEntry>
struct MapEntryToMapField : MapEntryToMapField<typename MEntry::SuperType> {};

template <typename T, typename Key, typename Value,
          WireFormatLite::FieldType kKeyFieldType,
          WireFormatLite::FieldType kValueFieldType, int default_enum_value>
struct MapEntryToMapField<MapEntryLite<T, Key, Value, kKeyFieldType,
                                       kValueFieldType, default_enum_value> > {
  typedef MapFieldLite<MapEntryLite<T, Key, Value, kKeyFieldType,
                                    kValueFieldType, default_enum_value>,
                       Key, Value, kKeyFieldType, kValueFieldType,
                       default_enum_value>
      MapFieldType;
};

}  // namespace internal
}  // namespace protobuf

}  // namespace google
#endif  // GOOGLE_PROTOBUF_MAP_FIELD_LITE_H__