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/**
* A MergeOperator for rocksdb that implements string append.
* @author Deon Nicholas (dnicholas@fb.com)
* Copyright 2013 Facebook
*/
#pragma once
#include "rocksdb/merge_operator.h"
#include "rocksdb/slice.h"
namespace ROCKSDB_NAMESPACE {
class StringAppendOperator : public AssociativeMergeOperator {
public:
// Constructor: specify delimiter
explicit StringAppendOperator(char delim_char);
explicit StringAppendOperator(const std::string& delim);
virtual bool Merge(const Slice& key, const Slice* existing_value,
const Slice& value, std::string* new_value,
Logger* logger) const override;
static const char* kClassName() { return "StringAppendOperator"; }
static const char* kNickName() { return "stringappend"; }
virtual const char* Name() const override { return kClassName(); }
virtual const char* NickName() const override { return kNickName(); }
private:
std::string delim_; // The delimiter is inserted between elements
};
} // namespace ROCKSDB_NAMESPACE
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