mirror of https://gitee.com/bigwinds/arangodb
106 lines
2.9 KiB
C++
106 lines
2.9 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2018 ArangoDB GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Daniel Larkin
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/// @author Jan Christoph Uhde
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_AQL_CONSTRAINED_SORT_EXECUTOR_H
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#define ARANGOD_AQL_CONSTRAINED_SORT_EXECUTOR_H
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#include "Aql/ExecutionState.h"
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#include "Aql/ExecutorInfos.h"
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#include "Aql/OutputAqlItemRow.h"
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#include "Aql/SortExecutor.h"
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#include "Aql/SortNode.h"
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#include "AqlValue.h"
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#include <memory>
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namespace arangodb {
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namespace transaction {
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class Methods;
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}
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namespace aql {
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template <bool>
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class SingleRowFetcher;
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class AqlItemMatrix;
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class ConstrainedLessThan;
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class ExecutorInfos;
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class InputAqlItemRow;
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class NoStats;
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class OutputAqlItemRow;
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struct SortRegister;
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/**
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* @brief Implementation of Sort Node
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*/
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class ConstrainedSortExecutor {
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public:
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friend class Sorter;
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struct Properties {
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static const bool preservesOrder = false;
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static const bool allowsBlockPassthrough = false;
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static const bool inputSizeRestrictsOutputSize = true;
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};
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using Fetcher = SingleRowFetcher<Properties::allowsBlockPassthrough>;
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using Infos = SortExecutorInfos;
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using Stats = NoStats;
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ConstrainedSortExecutor(Fetcher& fetcher, Infos&);
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~ConstrainedSortExecutor();
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/**
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* @brief produce the next Row of Aql Values.
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*
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* @return ExecutionState,
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* if something was written output.hasValue() == true
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*/
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std::pair<ExecutionState, Stats> produceRows(OutputAqlItemRow& output);
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/**
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* @brief This Executor knows how many rows it will produce and most by itself
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* It also knows that it could produce less if the upstream only has fewer rows.
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*/
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std::pair<ExecutionState, size_t> expectedNumberOfRows(size_t atMost) const;
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private:
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bool compareInput(size_t const& rosPos, InputAqlItemRow& row) const;
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arangodb::Result pushRow(InputAqlItemRow& row);
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private:
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Infos& _infos;
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Fetcher& _fetcher;
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ExecutionState _state;
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size_t _returnNext;
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std::vector<size_t> _rows;
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size_t _rowsPushed;
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SharedAqlItemBlockPtr _heapBuffer;
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std::unique_ptr<ConstrainedLessThan> _cmpHeap; // in pointer to avoid
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OutputAqlItemRow _heapOutputRow;
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};
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} // namespace aql
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} // namespace arangodb
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#endif
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