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arangodb/arangod/Aql/BlockCollector.cpp

94 lines
2.5 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// @brief Infrastructure for ExecutionPlans
///
/// DISCLAIMER
///
/// Copyright 2010-2014 triagens 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 triAGENS GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "BlockCollector.h"
#include "Aql/AqlItemBlock.h"
#include "Aql/AqlItemBlockManager.h"
#include "Aql/AqlItemBlockUtils.h"
#include "Basics/Exceptions.h"
using namespace arangodb::aql;
BlockCollector::BlockCollector(AqlItemBlockManager* blockManager)
: _blockManager(blockManager), _totalSize(0) {}
BlockCollector::~BlockCollector() { clear(); }
size_t BlockCollector::totalSize() const { return _totalSize; }
RegisterId BlockCollector::nrRegs() const {
TRI_ASSERT(_totalSize > 0);
TRI_ASSERT(!_blocks.empty());
return _blocks[0]->getNrRegs();
}
void BlockCollector::clear() {
for (auto& it : _blocks) {
it->destroy(); // overkill?
}
_blocks.clear();
_totalSize = 0;
}
void BlockCollector::add(SharedAqlItemBlockPtr block) {
TRI_ASSERT(block != nullptr);
TRI_ASSERT(block->size() > 0);
if (_blocks.capacity() == 0) {
_blocks.reserve(8);
}
_blocks.push_back(block);
_totalSize += block->size();
}
SharedAqlItemBlockPtr BlockCollector::steal() {
if (_blocks.empty()) {
return nullptr;
}
TRI_ASSERT(_totalSize > 0);
SharedAqlItemBlockPtr result{nullptr};
TRI_IF_FAILURE("BlockCollector::getOrSkipSomeConcatenate") {
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEBUG);
}
if (_blocks.size() == 1) {
// only got a single result. return it as it is
result = _blocks[0];
} else {
result = itemBlock::concatenate(*_blockManager, _blocks);
for (auto& it : _blocks) {
it->eraseAll();
}
}
// ownership is now passed to result
_totalSize = 0;
_blocks.clear();
return result;
}