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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.
*/
#pragma once
#include <string>
#include "mongo/base/disallow_copying.h"
#include "mongo/base/status.h"
#include "mongo/client/fetcher.h"
#include "mongo/stdx/functional.h"
namespace mongo {
struct HostAndPort;
class NamespaceString;
class BSONObj;
class BSONObjBuilder;
/**
* Follows the fetcher pattern for a find+getmore.
* QueryFetcher will continue to call getmore until an error or
* until the last batch of results.
*/
class QueryFetcher {
MONGO_DISALLOW_COPYING(QueryFetcher);
public:
using CallbackFn =
stdx::function<void (const Fetcher::QueryResponseStatus&, Fetcher::NextAction*)>;
QueryFetcher(executor::TaskExecutor* exec,
const HostAndPort& source,
const NamespaceString& nss,
const BSONObj& cmdBSON,
const QueryFetcher::CallbackFn& onBatchAvailable);
virtual ~QueryFetcher() = default;
bool isActive() const { return _fetcher.isActive(); }
Status schedule() { return _fetcher.schedule(); }
void cancel() { return _fetcher.cancel(); }
void wait() { if (_fetcher.isActive()) _fetcher.wait(); }
std::string getDiagnosticString() const;
protected:
int _getResponses() const;
void _onFetchCallback(const Fetcher::QueryResponseStatus& fetchResult,
Fetcher::NextAction* nextAction,
BSONObjBuilder* getMoreBob);
/**
* Called by _delegateCallback() to forward query results to '_work'.
*/
void _onQueryResponse(const Fetcher::QueryResponseStatus& fetchResult,
Fetcher::NextAction* nextAction);
virtual void _delegateCallback(const Fetcher::QueryResponseStatus& fetchResult,
Fetcher::NextAction* nextAction);
private:
executor::TaskExecutor* _exec;
Fetcher _fetcher;
int _responses;
const QueryFetcher::CallbackFn _work;
};
} // namespace mongo
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