mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-30 04:41:49 +00:00
d616ebea23
Summary: Closes https://github.com/facebook/rocksdb/pull/2226 Differential Revision: D4967547 Pulled By: siying fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4
92 lines
3.3 KiB
C++
92 lines
3.3 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under the BSD-style license found in the
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
|
// of patent rights can be found in the PATENTS file in the same directory.
|
|
// This source code is also licensed under the GPLv2 license found in the
|
|
// COPYING file in the root directory of this source tree.
|
|
|
|
#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;
|
|
}
|
|
|
|
using MergeOperator::PartialMergeMulti;
|
|
virtual bool PartialMergeMulti(const Slice& key,
|
|
const std::deque<Slice>& operand_list,
|
|
std::string* new_value, Logger* logger) const
|
|
override {
|
|
new_value->assign(operand_list.back().data(), operand_list.back().size());
|
|
return true;
|
|
}
|
|
|
|
virtual const char* Name() const override {
|
|
return "PutOperator";
|
|
}
|
|
};
|
|
|
|
class PutOperatorV2 : public PutOperator {
|
|
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 {
|
|
assert(false);
|
|
return false;
|
|
}
|
|
|
|
virtual bool FullMergeV2(const MergeOperationInput& merge_in,
|
|
MergeOperationOutput* merge_out) const override {
|
|
// Put basically only looks at the current/latest value
|
|
assert(!merge_in.operand_list.empty());
|
|
merge_out->existing_operand = merge_in.operand_list.back();
|
|
return true;
|
|
}
|
|
};
|
|
|
|
} // end of anonymous namespace
|
|
|
|
namespace rocksdb {
|
|
|
|
std::shared_ptr<MergeOperator> MergeOperators::CreateDeprecatedPutOperator() {
|
|
return std::make_shared<PutOperator>();
|
|
}
|
|
|
|
std::shared_ptr<MergeOperator> MergeOperators::CreatePutOperator() {
|
|
return std::make_shared<PutOperatorV2>();
|
|
}
|
|
}
|