rocksdb/utilities/cassandra/merge_operator.cc

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// Copyright (c) 2017-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 "merge_operator.h"
#include <memory>
#include <assert.h>
#include "rocksdb/slice.h"
#include "rocksdb/merge_operator.h"
#include "utilities/merge_operators.h"
#include "utilities/cassandra/format.h"
namespace rocksdb {
namespace cassandra {
// Implementation for the merge operation (merges two Cassandra values)
bool CassandraValueMergeOperator::FullMergeV2(
const MergeOperationInput& merge_in,
MergeOperationOutput* merge_out) const {
// Clear the *new_value for writing.
merge_out->new_value.clear();
if (merge_in.existing_value == nullptr && merge_in.operand_list.size() == 1) {
// Only one operand
merge_out->existing_operand = merge_in.operand_list.back();
return true;
}
std::vector<RowValue> row_values;
if (merge_in.existing_value) {
row_values.push_back(
RowValue::Deserialize(merge_in.existing_value->data(),
merge_in.existing_value->size()));
}
for (auto& operand : merge_in.operand_list) {
row_values.push_back(RowValue::Deserialize(operand.data(), operand.size()));
}
RowValue merged = RowValue::Merge(std::move(row_values));
merge_out->new_value.reserve(merged.Size());
merged.Serialize(&(merge_out->new_value));
return true;
}
bool CassandraValueMergeOperator::PartialMergeMulti(
const Slice& key,
const std::deque<Slice>& operand_list,
std::string* new_value,
Logger* logger) const {
// Clear the *new_value for writing.
assert(new_value);
new_value->clear();
std::vector<RowValue> row_values;
for (auto& operand : operand_list) {
row_values.push_back(RowValue::Deserialize(operand.data(), operand.size()));
}
RowValue merged = RowValue::Merge(std::move(row_values));
new_value->reserve(merged.Size());
merged.Serialize(new_value);
return true;
}
const char* CassandraValueMergeOperator::Name() const {
return "CassandraValueMergeOperator";
}
} // namespace cassandra
std::shared_ptr<MergeOperator>
MergeOperators::CreateCassandraMergeOperator() {
return std::make_shared<rocksdb::cassandra::CassandraValueMergeOperator>();
}
} // namespace rocksdb