polkadot_codec.hpp

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#ifndef KAGOME_TRIE_POLKADOT_CODEC_IMPL_HPP
#define KAGOME_TRIE_POLKADOT_CODEC_IMPL_HPP

#include <memory>
#include <optional>
#include <string>

#include "storage/trie/codec.hpp"
#include "storage/trie/polkadot_trie/trie_node.hpp"
#include "storage/trie/serialization/buffer_stream.hpp"

namespace kagome::storage::trie {

  class PolkadotCodec : public Codec {
   public:
    using Buffer = common::Buffer;
    using BufferView = common::BufferView;

    enum class Error {
      SUCCESS = 0,
      TOO_MANY_NIBBLES,   
      UNKNOWN_NODE_TYPE,  
      INPUT_TOO_SMALL,    
      NO_NODE_VALUE       
    };

    ~PolkadotCodec() override = default;

    outcome::result<Buffer> encodeNodeAndStoreChildren(
        const Node &node, const StoreChildren &store_children) const override;

    outcome::result<std::shared_ptr<Node>> decodeNode(
        gsl::span<const uint8_t> encoded_data) const override;

    common::Buffer merkleValue(const BufferView &buf) const override;

    bool isMerkleHash(const common::BufferView &buf) const override;

    common::Hash256 hash256(const BufferView &buf) const override;

    outcome::result<Buffer> encodeHeader(const TrieNode &node) const;

   private:
    outcome::result<Buffer> encodeBranch(
        const BranchNode &node, const StoreChildren &store_children) const;
    outcome::result<Buffer> encodeLeaf(const LeafNode &node) const;

    outcome::result<std::pair<TrieNode::Type, size_t>> decodeHeader(
        BufferStream &stream) const;

    outcome::result<KeyNibbles> decodePartialKey(size_t nibbles_num,
                                                 BufferStream &stream) const;

    outcome::result<std::shared_ptr<Node>> decodeBranch(
        TrieNode::Type type,
        const KeyNibbles &partial_key,
        BufferStream &stream) const;
  };

}  // namespace kagome::storage::trie

OUTCOME_HPP_DECLARE_ERROR(kagome::storage::trie, PolkadotCodec::Error);

#endif  // KAGOME_TRIE_POLKADOT_CODEC_IMPL_HPP