readable.hpp

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#ifndef KAGOME_READABLE_HPP
#define KAGOME_READABLE_HPP

#include <outcome/outcome.hpp>

#include "storage/face/map_cursor.hpp"

namespace kagome::storage::face {

  template <typename K>
  struct ReadableBase {
    using Key = K;

    virtual ~ReadableBase() = default;

    virtual outcome::result<bool> contains(const Key &key) const = 0;

    virtual bool empty() const = 0;
  };

  template <typename K, typename V>
  struct ReadableMap : public ReadableBase<K> {
    using Key = K;
    using Value = V;
    using ValueView = std::reference_wrapper<V>;
    using ConstValueView = std::reference_wrapper<const V>;

    virtual ~ReadableMap() = default;

    virtual outcome::result<ConstValueView> get(const Key &key) const = 0;

    virtual outcome::result<std::optional<ConstValueView>> tryGet(
        const Key &key) const = 0;
  };

  template <typename K, typename V>
  struct ReadableStorage : public ReadableBase<K> {
    using Key = K;
    using Value = V;

    virtual ~ReadableStorage() = default;

    virtual outcome::result<V> load(const Key &key) const = 0;

    virtual outcome::result<std::optional<V>> tryLoad(const Key &key) const = 0;
  };

}  // namespace kagome::storage::face

#endif  // KAGOME_READABLE_HPP