rocksdb/utilities/merge_operators/put.cc
Dhruba Borthakur a143ef9b38 Change namespace from leveldb to rocksdb
Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.

Test Plan: compile rocksdb

Reviewers: emayanke

Reviewed By: emayanke

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13287
2013-10-04 11:59:26 -07:00

55 lines
1.7 KiB
C++

#include <memory>
#include "rocksdb/slice.h"
#include "rocksdb/merge_operator.h"
#include "utilities/merge_operators.h"
using namespace rocksdb;
namespace { // anonymous namespace
// A merge operator that mimics Put semantics
// Since this merge-operator will not be used in production,
// it is implemented as a non-associative merge operator to illustrate the
// new interface and for testing purposes. (That is, we inherit from
// the MergeOperator class rather than the AssociativeMergeOperator
// which would be simpler in this case).
//
// From the client-perspective, semantics are the same.
class PutOperator : public MergeOperator {
public:
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 {
// Put basically only looks at the current/latest value
assert(!operand_sequence.empty());
assert(new_value != nullptr);
new_value->assign(operand_sequence.back());
return true;
}
virtual bool PartialMerge(const Slice& key,
const Slice& left_operand,
const Slice& right_operand,
std::string* new_value,
Logger* logger) const override {
new_value->assign(right_operand.data(), right_operand.size());
return true;
}
virtual const char* Name() const override {
return "PutOperator";
}
};
} // end of anonymous namespace
namespace rocksdb {
std::shared_ptr<MergeOperator> MergeOperators::CreatePutOperator() {
return std::make_shared<PutOperator>();
}
}