5d68243e61
Summary: Submitting on behalf of another employee. Closes https://github.com/facebook/rocksdb/pull/3557 Differential Revision: D7146025 Pulled By: ajkr fbshipit-source-id: 495ca5db5beec3789e671e26f78170957704e77e
78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
|
|
#include <memory>
|
|
|
|
#include "rocksdb/merge_operator.h"
|
|
#include "rocksdb/slice.h"
|
|
#include "utilities/merge_operators.h"
|
|
|
|
using rocksdb::Slice;
|
|
using rocksdb::Logger;
|
|
using rocksdb::MergeOperator;
|
|
|
|
namespace { // anonymous namespace
|
|
|
|
// Merge operator that picks the maximum operand, Comparison is based on
|
|
// Slice::compare
|
|
class MaxOperator : public MergeOperator {
|
|
public:
|
|
virtual bool FullMergeV2(const MergeOperationInput& merge_in,
|
|
MergeOperationOutput* merge_out) const override {
|
|
Slice& max = merge_out->existing_operand;
|
|
if (merge_in.existing_value) {
|
|
max = Slice(merge_in.existing_value->data(),
|
|
merge_in.existing_value->size());
|
|
} else if (max.data() == nullptr) {
|
|
max = Slice();
|
|
}
|
|
|
|
for (const auto& op : merge_in.operand_list) {
|
|
if (max.compare(op) < 0) {
|
|
max = op;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
virtual bool PartialMerge(const Slice& /*key*/, const Slice& left_operand,
|
|
const Slice& right_operand, std::string* new_value,
|
|
Logger* /*logger*/) const override {
|
|
if (left_operand.compare(right_operand) >= 0) {
|
|
new_value->assign(left_operand.data(), left_operand.size());
|
|
} else {
|
|
new_value->assign(right_operand.data(), right_operand.size());
|
|
}
|
|
return true;
|
|
}
|
|
|
|
virtual bool PartialMergeMulti(const Slice& /*key*/,
|
|
const std::deque<Slice>& operand_list,
|
|
std::string* new_value,
|
|
Logger* /*logger*/) const override {
|
|
Slice max;
|
|
for (const auto& operand : operand_list) {
|
|
if (max.compare(operand) < 0) {
|
|
max = operand;
|
|
}
|
|
}
|
|
|
|
new_value->assign(max.data(), max.size());
|
|
return true;
|
|
}
|
|
|
|
virtual const char* Name() const override { return "MaxOperator"; }
|
|
};
|
|
|
|
} // end of anonymous namespace
|
|
|
|
namespace rocksdb {
|
|
|
|
std::shared_ptr<MergeOperator> MergeOperators::CreateMaxOperator() {
|
|
return std::make_shared<MaxOperator>();
|
|
}
|
|
}
|