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arangodb/arangod/Utils/OperationCursor.cpp

67 lines
2.3 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 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 ArangoDB GmbH, Cologne, Germany
///
/// @author Michael Hackstein
////////////////////////////////////////////////////////////////////////////////
#include "OperationCursor.h"
using namespace arangodb;
//////////////////////////////////////////////////////////////////////////////
/// @brief Get next default batchSize many elements.
/// Check hasMore()==true before using this
/// NOTE: This will throw on OUT_OF_MEMORY
//////////////////////////////////////////////////////////////////////////////
int OperationCursor::getMore() {
return getMore(_batchSize);
}
//////////////////////////////////////////////////////////////////////////////
/// @brief Get next batchSize many elements.
/// Check hasMore()==true before using this
/// NOTE: This will throw on OUT_OF_MEMORY
//////////////////////////////////////////////////////////////////////////////
int OperationCursor::getMore(uint64_t batchSize) {
// This may throw out of memory
if (!hasMore()) {
TRI_ASSERT(false);
// You requested more even if you should have checked it before.
return TRI_ERROR_FORBIDDEN;
}
// We restart the builder
_builder.clear();
VPackArrayBuilder guard(&_builder);
TRI_doc_mptr_t* mptr = nullptr;
// TODO: Improve this for baby awareness
while (batchSize > 0 && _limit > 0 && (mptr = _indexIterator->next()) != nullptr) {
--batchSize;
--_limit;
_builder.add(VPackSlice(mptr->vpack()));
}
if (batchSize > 0 || _limit == 0) {
// Iterator empty, there is no more
_hasMore = false;
}
return TRI_ERROR_NO_ERROR;
}