mirror of https://gitee.com/bigwinds/arangodb
114 lines
3.7 KiB
C++
114 lines
3.7 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS 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 Max Neunhoeffer
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_AQL_SUBQUERY_BLOCK_H
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#define ARANGOD_AQL_SUBQUERY_BLOCK_H 1
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#include "Aql/ExecutionBlock.h"
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#include "Aql/ExecutionNode.h"
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namespace arangodb {
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namespace aql {
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class AqlItemBlock;
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class ExecutionEngine;
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class SubqueryBlock final : public ExecutionBlock {
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public:
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SubqueryBlock(ExecutionEngine*, SubqueryNode const*, ExecutionBlock*);
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~SubqueryBlock() = default;
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/// @brief getSome
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std::pair<ExecutionState, std::unique_ptr<AqlItemBlock>> getSome(size_t atMost) override final;
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/// @brief shutdown, tell dependency and the subquery
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std::pair<ExecutionState, Result> shutdown(int errorCode) override final;
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/// @brief getter for the pointer to the subquery
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ExecutionBlock* getSubquery() { return _subquery; }
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private:
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/// @brief execute the subquery
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/// is repeatable in case of WAITING
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/// Fills result in _subqueryResults
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ExecutionState executeSubquery();
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/// @brief destroy the results of a subquery
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void destroySubqueryResults();
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/// @brief initialize the subquery,
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/// is repeatable in case of WAITING
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ExecutionState initSubquery(size_t position);
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/// @brief forward getSome to const subquery
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/// is repeatable in case of WAITING
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ExecutionState getSomeConstSubquery(size_t atMost);
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/// @brief forward getSome to non-const subquery
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/// is repeatable in case of WAITING
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ExecutionState getSomeNonConstSubquery(size_t atMost);
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private:
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/// @brief output register
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RegisterId _outReg;
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/// @brief we need to have an executionblock and where to write the result
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ExecutionBlock* _subquery;
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/// @brief whether the subquery is const and will always return the same
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/// values when invoked multiple times
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bool const _subqueryIsConst;
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/// @brief whether the subquery returns data
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bool const _subqueryReturnsData;
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/// @brief a unique_ptr to hold temporary results if thread gets suspended
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/// guaranteed to be cleared out after a DONE/HASMORE of get/skip-some
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std::unique_ptr<AqlItemBlock> _result;
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/// @brief the list of results from a single subquery
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/// NOTE: Responsibilty here is a bit tricky, it is handed over to the result
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std::unique_ptr<std::vector<std::unique_ptr<AqlItemBlock>>> _subqueryResults;
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/// @brief the current subquery in process, used if this thread gets suspended.
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size_t _subqueryPos;
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/// @brief track if we have already initialized this subquery.
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bool _subqueryInitialized;
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/// @brief track if we have completely executed the subquery.
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bool _subqueryCompleted;
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/// @brief track if we have completely shutdown the main query.
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bool _hasShutdownMainQuery;
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/// @brief result of the main query shutdown. is only valid if _hasShutdownMainQuery == true.
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Result _mainQueryShutdownResult;
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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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