//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under both the GPLv2 (found in the

//  COPYING file in the root directory) and Apache 2.0 License

//  (found in the LICENSE.Apache file in the root directory).

//

#pragma once

#include "db/dbformat.h"

#include "rocksdb/slice.h"

#include "rocksdb/status.h"

namespace ROCKSDB_NAMESPACE {

// A class that validates key/value that is inserted to an SST file.

// Pass every key/value of the file using OutputValidator::Add()

// and the class validates key order and optionally calculate a hash

// of all the key and value.

class OutputValidator {

 public:

  explicit OutputValidator(const InternalKeyComparator& icmp, bool enable_hash,

                           uint64_t precalculated_hash = 0)

      : icmp_(icmp),

        paranoid_hash_(precalculated_hash),

        enable_hash_(enable_hash) {}

  // Add a key to the KV sequence, and return whether the key follows

  // criteria, e.g. key is ordered.

  Status Add(const Slice& key, const Slice& value);

  // Compare result of two key orders are the same. It can be used

  // to compare the keys inserted into a file, and what is read back.

  // Return true if the validation passes.

  bool CompareValidator(const OutputValidator& other_validator) {

    return GetHash() == other_validator.GetHash();

  }

  // Not (yet) intended to be persisted, so subject to change

  // without notice between releases.

  uint64_t GetHash() const { return paranoid_hash_; }

 private:

  const InternalKeyComparator& icmp_;

  std::string prev_key_;

  uint64_t paranoid_hash_ = 0;

  bool enable_hash_;

};

}  // namespace ROCKSDB_NAMESPACE