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arangodb/arangod/Aql/CollectionScanner.h

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////////////////////////////////////////////////////////////////////////////////
/// 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 Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_COLLECTION_SCANNER_H
#define ARANGOD_AQL_COLLECTION_SCANNER_H 1
#include "Basics/Common.h"
#include "Utils/AqlTransaction.h"
#include "VocBase/document-collection.h"
#include "VocBase/transaction.h"
#include "VocBase/vocbase.h"
namespace arangodb {
namespace aql {
struct CollectionScanner {
CollectionScanner(arangodb::AqlTransaction*, TRI_transaction_collection_t*);
virtual ~CollectionScanner();
virtual int scan(std::vector<TRI_doc_mptr_copy_t>&, size_t) = 0;
virtual void reset() = 0;
//////////////////////////////////////////////////////////////////////////////
/// @brief forwards the cursor n elements. Does not read the data.
/// Will at most forward to the last element.
/// In the second parameter we add how many elements are
/// really skipped
//////////////////////////////////////////////////////////////////////////////
virtual int forward(size_t, size_t&) = 0;
arangodb::AqlTransaction* trx;
TRI_transaction_collection_t* trxCollection;
uint64_t totalCount;
arangodb::basics::BucketPosition position;
};
struct RandomCollectionScanner final : public CollectionScanner {
RandomCollectionScanner(arangodb::AqlTransaction*,
TRI_transaction_collection_t*);
int scan(std::vector<TRI_doc_mptr_copy_t>&, size_t) override;
void reset() override;
int forward(size_t, size_t&) override;
arangodb::basics::BucketPosition initialPosition;
uint64_t step;
};
struct LinearCollectionScanner final : public CollectionScanner {
LinearCollectionScanner(arangodb::AqlTransaction*,
TRI_transaction_collection_t*);
int scan(std::vector<TRI_doc_mptr_copy_t>&, size_t) override;
void reset() override;
int forward(size_t, size_t&) override;
};
}
}
#endif