1
0
Fork 0
arangodb/arangod/Aql/UnsortedGatherExecutor.h

104 lines
3.0 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// 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 Simon Grätzer
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_UNSORTED_GATHER_EXECUTOR_H
#define ARANGOD_AQL_UNSORTED_GATHER_EXECUTOR_H
#include "Aql/ClusterNodes.h"
#include "Aql/ExecutionState.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/InputAqlItemRow.h"
#include "Containers/SmallVector.h"
namespace arangodb {
namespace transaction {
class Methods;
}
namespace aql {
class MultiDependencySingleRowFetcher;
class NoStats;
class OutputAqlItemRow;
struct SortRegister;
class UnsortedGatherExecutorInfos : public ExecutorInfos {
public:
UnsortedGatherExecutorInfos(RegisterId nrInOutRegisters, std::unordered_set<RegisterId> registersToKeep,
std::unordered_set<RegisterId> registersToClear);
UnsortedGatherExecutorInfos() = delete;
UnsortedGatherExecutorInfos(UnsortedGatherExecutorInfos&&) = default;
UnsortedGatherExecutorInfos(UnsortedGatherExecutorInfos const&) = delete;
~UnsortedGatherExecutorInfos() = default;
};
class UnsortedGatherExecutor {
public:
public:
struct Properties {
static constexpr bool preservesOrder = true;
static constexpr BlockPassthrough allowsBlockPassthrough = BlockPassthrough::Disable;
static constexpr bool inputSizeRestrictsOutputSize = false;
};
using Fetcher = MultiDependencySingleRowFetcher;
using Infos = UnsortedGatherExecutorInfos;
using Stats = NoStats;
UnsortedGatherExecutor(Fetcher& fetcher, Infos& info);
~UnsortedGatherExecutor();
/**
* @brief produce the next Row of Aql Values.
*
* @return ExecutionState,
* if something was written output.hasValue() == true
*/
std::pair<ExecutionState, Stats> produceRows(OutputAqlItemRow& output);
std::tuple<ExecutionState, Stats, size_t> skipRows(size_t atMost);
private:
void initDependencies();
private:
Fetcher& _fetcher;
::arangodb::containers::SmallVector<ExecutionState>::allocator_type::arena_type _arena;
::arangodb::containers::SmallVector<ExecutionState> _upstream{_arena};
// Total Number of dependencies
size_t _numberDependencies;
size_t _currentDependency;
size_t _skipped;
};
} // namespace aql
} // namespace arangodb
#endif