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arangodb/arangod/Aql/IdExecutor.h

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C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2018 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 Jan Christoph Uhde
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_ID_EXECUTOR_H
#define ARANGOD_AQL_ID_EXECUTOR_H
#include "Aql/ExecutionState.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/Stats.h"
#include "Aql/Variable.h"
#include "Aql/ExecutionBlockImpl.h"
namespace arangodb {
namespace transaction {
class Methods;
}
namespace aql {
class ConstFetcher;
class AqlItemMatrix;
class ExecutorInfos;
class NoStats;
class OutputAqlItemRow;
struct SortRegister;
class IdExecutorInfos : public ExecutorInfos {
public:
// whiteList will be used for slicing in the ExecutionBlockImpl
// whiteListClean is the same as our registersToKeep
IdExecutorInfos(RegisterId nrInOutRegisters, std::unordered_set<RegisterId> toKeep,
std::unordered_set<RegisterId> registersToClear);
IdExecutorInfos() = delete;
IdExecutorInfos(IdExecutorInfos&&) = default;
IdExecutorInfos(IdExecutorInfos const&) = delete;
~IdExecutorInfos() = default;
};
template <class UsedFetcher>
class IdExecutor {
public:
struct Properties {
static const bool preservesOrder = true;
static const bool allowsBlockPassthrough = true;
static const bool inputSizeRestrictsOutputSize = false;
};
// Only Supports SingleRowFetcher and ConstFetcher
using Fetcher = UsedFetcher;
using Infos = IdExecutorInfos;
using Stats = NoStats;
IdExecutor(Fetcher& fetcher, IdExecutorInfos&);
~IdExecutor();
/**
* @brief produce the next Row of Aql Values.
*
* @return ExecutionState,
* if something was written output.hasValue() == true
*/
std::pair<ExecutionState, Stats> produceRow(OutputAqlItemRow& output);
inline size_t numberOfRowsInFlight() const { return 0; }
private:
Fetcher& _fetcher;
};
} // namespace aql
} // namespace arangodb
#endif