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arangodb/arangod/Aql/MaterializeExecutor.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2019 ArangoDB GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Andrei Lobov
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_MATERIALIZE_EXECUTOR_H
#define ARANGOD_AQL_MATERIALIZE_EXECUTOR_H
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionBlockImpl.h"
#include "Aql/ExecutionState.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/OutputAqlItemRow.h"
#include "Aql/types.h"
#include "Indexes/IndexIterator.h"
#include "VocBase/LocalDocumentId.h"
#include "VocBase/LogicalCollection.h"
#include <iosfwd>
#include <memory>
namespace arangodb {
namespace aql {
class InputAqlItemRow;
class ExecutorInfos;
template <BlockPassthrough>
class SingleRowFetcher;
class NoStats;
template<typename T>
class MaterializerExecutorInfos : public ExecutorInfos {
public:
MaterializerExecutorInfos(RegisterId nrInputRegisters, RegisterId nrOutputRegisters,
std::unordered_set<RegisterId> registersToClear,
std::unordered_set<RegisterId> registersToKeep,
T collectionSource, RegisterId inNmDocId,
RegisterId outDocRegId, transaction::Methods* trx);
MaterializerExecutorInfos() = delete;
MaterializerExecutorInfos(MaterializerExecutorInfos&&) = default;
MaterializerExecutorInfos(MaterializerExecutorInfos const&) = delete;
~MaterializerExecutorInfos() = default;
RegisterId outputMaterializedDocumentRegId() const {
return _outMaterializedDocumentRegId;
}
RegisterId inputNonMaterializedDocRegId() const {
return _inNonMaterializedDocRegId;
}
transaction::Methods* trx() const {
return _trx;
}
T collectionSource() const {
return _collectionSource;
}
private:
std::shared_ptr<std::unordered_set<RegisterId>> getReadableInputRegisters(T const collectionSource, RegisterId inNmDocId) {
if constexpr (std::is_same<T, RegisterId>::value) {
return make_shared_unordered_set(std::initializer_list<RegisterId>({collectionSource, inNmDocId}));
} else {
return make_shared_unordered_set(std::initializer_list<RegisterId>({inNmDocId}));
}
}
/// @brief register to store raw collection pointer or collection name
T const _collectionSource;
/// @brief register to store local document id
RegisterId const _inNonMaterializedDocRegId;
/// @brief register to store materialized document
RegisterId const _outMaterializedDocumentRegId;
transaction::Methods* _trx;
};
template<typename T>
class MaterializeExecutor {
public:
struct Properties {
static constexpr bool preservesOrder = true;
static constexpr BlockPassthrough allowsBlockPassthrough = BlockPassthrough::Disable;
static constexpr bool inputSizeRestrictsOutputSize = false;
};
using Fetcher = SingleRowFetcher<Properties::allowsBlockPassthrough>;
using Infos = MaterializerExecutorInfos<T>;
using Stats = NoStats;
MaterializeExecutor(MaterializeExecutor&&) = default;
MaterializeExecutor(MaterializeExecutor const&) = delete;
MaterializeExecutor(Fetcher& fetcher, Infos& infos) : _readDocumentContext(infos), _infos(infos), _fetcher(fetcher) {}
std::pair<ExecutionState, Stats> produceRows(OutputAqlItemRow& output);
std::tuple<ExecutionState, Stats, size_t> skipRows(size_t toSkipRequested);
protected:
class ReadContext {
public:
explicit ReadContext(Infos& infos)
: _infos(&infos),
_inputRow(nullptr),
_outputRow(nullptr),
_callback(copyDocumentCallback(*this)) {}
ReadContext(ReadContext&&) = default;
const Infos* _infos;
const arangodb::aql::InputAqlItemRow* _inputRow;
arangodb::aql::OutputAqlItemRow* _outputRow;
arangodb::IndexIterator::DocumentCallback const _callback;
private:
static arangodb::IndexIterator::DocumentCallback copyDocumentCallback(ReadContext& ctx);
};
ReadContext _readDocumentContext;
Infos const& _infos;
Fetcher& _fetcher;
// for single collection case
LogicalCollection const* _collection = nullptr;
};
} // namespace aql
} // namespace arangodb
#endif