rocksdb/utilities/merge_operators/string_append/stringappend2.h

50 lines
1.7 KiB
C++

// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
/**
* A TEST MergeOperator for rocksdb that implements string append.
* It is built using the MergeOperator interface rather than the simpler
* AssociativeMergeOperator interface. This is useful for testing/benchmarking.
* While the two operators are semantically the same, all production code
* should use the StringAppendOperator defined in stringappend.{h,cc}. The
* operator defined in the present file is primarily for testing.
*
* @author Deon Nicholas (dnicholas@fb.com)
* Copyright 2013 Facebook
*/
#pragma once
#include <deque>
#include <string>
#include "rocksdb/merge_operator.h"
#include "rocksdb/slice.h"
namespace rocksdb {
class StringAppendTESTOperator : public MergeOperator {
public:
// Constructor with delimiter
explicit StringAppendTESTOperator(char delim_char);
virtual bool FullMergeV2(const MergeOperationInput& merge_in,
MergeOperationOutput* merge_out) const override;
virtual bool PartialMergeMulti(const Slice& key,
const std::deque<Slice>& operand_list,
std::string* new_value, Logger* logger) const
override;
virtual const char* Name() const override;
private:
// A version of PartialMerge that actually performs "partial merging".
// Use this to simulate the exact behaviour of the StringAppendOperator.
bool _AssocPartialMergeMulti(const Slice& key,
const std::deque<Slice>& operand_list,
std::string* new_value, Logger* logger) const;
char delim_; // The delimiter is inserted between elements
};
} // namespace rocksdb