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