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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/util/fail_point_service.h"
namespace mongo {
class BSONObj;
class LiteParsedQuery;
// Enabling this fail point will cause the getMore command to busy wait after pinning the cursor,
// until the fail point is disabled.
MONGO_FP_FORWARD_DECLARE(keepCursorPinnedDuringGetMore);
/**
* Suite of find/getMore related functions used in both the mongod and mongos query paths.
*/
class FindCommon {
public:
// The size threshold at which we stop adding result documents to a getMore response or a find
// response that has a batchSize set (i.e. once the sum of the document sizes in bytes exceeds
// this value, no further documents are added).
static const int kMaxBytesToReturnToClientAtOnce = 4 * 1024 * 1024;
// The initial size of the query response buffer.
static const int kInitReplyBufferSize = 32768;
/**
* Returns true if enough results have been prepared to stop adding more to the first batch.
*
* If 'pq' does not have a batchSize, the default batchSize is respected.
*/
static bool enoughForFirstBatch(const LiteParsedQuery& pq,
long long numDocs,
int bytesBuffered);
/**
* Returns true if enough results have been prepared to stop adding more to a getMore batch.
*
* An 'effectiveBatchSize' value of zero is interpreted as the absence of a batchSize;
* in this case, returns true only once the size threshold is exceeded. If 'effectiveBatchSize'
* is positive, returns true once either are added until we have either satisfied the batch size
* or exceeded the size threshold.
*/
static bool enoughForGetMore(long long effectiveBatchSize,
long long numDocs,
int bytesBuffered);
/**
* Transforms the raw sort spec into one suitable for use as the ordering specification in
* BSONObj::woCompare().
*
* In particular, eliminates text score meta-sort from 'sortSpec'.
*
* The input must be validated (each BSON element must be either a number or text score
* meta-sort specification).
*/
static BSONObj transformSortSpec(const BSONObj& sortSpec);
};
} // namespace mongo
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