rocksdb/utilities/merge_operators/string_append/stringappend2.h

52 lines
1.8 KiB
C++

/**
* A TEST MergeOperator for rocksdb/leveldb 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 "rocksdb/merge_operator.h"
#include "rocksdb/slice.h"
namespace leveldb {
class StringAppendTESTOperator : public MergeOperator {
public:
StringAppendTESTOperator(char delim_char); /// Constructor with delimiter
virtual bool FullMerge(const Slice& key,
const Slice* existing_value,
const std::deque<std::string>& operand_sequence,
std::string* new_value,
Logger* logger) const override;
virtual bool PartialMerge(const Slice& key,
const Slice& left_operand,
const Slice& right_operand,
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 _AssocPartialMerge(const Slice& key,
const Slice& left_operand,
const Slice& right_operand,
std::string* new_value,
Logger* logger) const;
char delim_; // The delimiter is inserted between elements
};
} // namespace leveldb