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arangodb/arangod/Aql/OutputAqlItemRow.cpp

116 lines
3.9 KiB
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 Tobias Gödderz
/// @author Michael Hackstein
/// @author Heiko Kernbach
/// @author Jan Christoph Uhde
////////////////////////////////////////////////////////////////////////////////
#include "OutputAqlItemRow.h"
#include "Aql/AqlItemBlock.h"
#include "Aql/AqlItemBlockShell.h"
#include "Aql/AqlValue.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/InputAqlItemRow.h"
using namespace arangodb;
using namespace arangodb::aql;
OutputAqlItemRow::OutputAqlItemRow(
std::shared_ptr<AqlItemBlockShell> blockShell,
std::shared_ptr<std::unordered_set<RegisterId> const> outputRegisters,
std::shared_ptr<std::unordered_set<RegisterId> const> registersToKeep,
std::shared_ptr<std::unordered_set<RegisterId> const> registersToClear,
CopyRowBehaviour copyRowBehaviour)
: _blockShell(std::move(blockShell)),
_baseIndex(0),
_lastBaseIndex(0),
_inputRowCopied(false),
_lastSourceRow{CreateInvalidInputRowHint{}},
_numValuesWritten(0),
_doNotCopyInputRow(copyRowBehaviour == CopyRowBehaviour::DoNotCopyInputRows),
_outputRegisters(std::move(outputRegisters)),
_registersToKeep(std::move(registersToKeep)),
_registersToClear(std::move(registersToClear))
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
,
_setBaseIndexNotUsed(true)
#endif
{
TRI_ASSERT(_blockShell != nullptr);
}
void OutputAqlItemRow::doCopyRow(InputAqlItemRow const& sourceRow, bool ignoreMissing) {
// Note that _lastSourceRow is invalid right after construction. However, when
// _baseIndex > 0, then we must have seen one row already.
TRI_ASSERT(!_doNotCopyInputRow);
TRI_ASSERT(_baseIndex == 0 || _lastSourceRow.isInitialized());
bool mustClone = _baseIndex == 0 || _lastSourceRow != sourceRow;
if (mustClone) {
for (auto itemId : registersToKeep()) {
TRI_ASSERT(sourceRow.isInitialized());
if (ignoreMissing && itemId >= sourceRow.getNrRegisters()) {
continue;
}
auto const& value = sourceRow.getValue(itemId);
if (!value.isEmpty()) {
AqlValue clonedValue = value.clone();
AqlValueGuard guard(clonedValue, true);
TRI_IF_FAILURE("OutputAqlItemRow::copyRow") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
TRI_IF_FAILURE("ExecutionBlock::inheritRegisters") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
block().setValue(_baseIndex, itemId, clonedValue);
guard.steal();
}
}
} else {
TRI_ASSERT(_baseIndex > 0);
block().copyValuesFromRow(_baseIndex, registersToKeep(), _lastBaseIndex);
}
_lastBaseIndex = _baseIndex;
_inputRowCopied = true;
_lastSourceRow = sourceRow;
}
std::unique_ptr<AqlItemBlock> OutputAqlItemRow::stealBlock() {
std::unique_ptr<AqlItemBlock> block = blockShell().stealBlockCompat();
if (numRowsWritten() == 0) {
// blocks may not be empty
block.reset();
} else {
// numRowsWritten() returns the exact number of rows that were fully
// written and takes into account whether the current row was written.
block->shrink(numRowsWritten());
if (_doNotCopyInputRow) {
block->clearRegisters(registersToClear());
}
}
return block;
}