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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 <memory>
#include <queue>
#include "mongo/executor/task_executor.h"
#include "mongo/s/query/cluster_client_cursor.h"
#include "mongo/s/query/cluster_client_cursor_params.h"
#include "mongo/s/query/router_exec_stage.h"
#include "mongo/util/net/hostandport.h"
namespace mongo {
class RouterStageMock;
/**
* An RAII object which owns a ClusterClientCursor and kills the cursor if it is not explicitly
* released.
*/
class ClusterClientCursorGuard final {
MONGO_DISALLOW_COPYING(ClusterClientCursorGuard);
public:
ClusterClientCursorGuard(std::unique_ptr<ClusterClientCursor> ccc);
/**
* If a cursor is owned, safely destroys the cursor, cleaning up remote cursor state if
* necessary. May block waiting for remote cursor cleanup.
*
* If no cursor is owned, does nothing.
*/
~ClusterClientCursorGuard();
#if defined(_MSC_VER) && _MSC_VER < 1900
ClusterClientCursorGuard(ClusterClientCursorGuard&&);
ClusterClientCursorGuard& operator=(ClusterClientCursorGuard&&);
#else
ClusterClientCursorGuard(ClusterClientCursorGuard&&) = default;
ClusterClientCursorGuard& operator=(ClusterClientCursorGuard&&) = default;
#endif
/**
* Returns a pointer to the underlying cursor.
*/
ClusterClientCursor* operator->();
/**
* Transfers ownership of the underlying cursor to the caller.
*/
std::unique_ptr<ClusterClientCursor> releaseCursor();
private:
std::unique_ptr<ClusterClientCursor> _ccc;
};
class ClusterClientCursorImpl final : public ClusterClientCursor {
MONGO_DISALLOW_COPYING(ClusterClientCursorImpl);
public:
/**
* Constructs a CCC whose safe cleanup is ensured by an RAII object.
*/
static ClusterClientCursorGuard make(executor::TaskExecutor* executor,
ClusterClientCursorParams&& params);
/**
* Constructs a CCC whose result set is generated by a mock execution stage.
*/
ClusterClientCursorImpl(std::unique_ptr<RouterStageMock> root);
StatusWith<boost::optional<BSONObj>> next() final;
void kill() final;
bool isTailable() const final;
long long getNumReturnedSoFar() const final;
void queueResult(const BSONObj& obj) final;
bool remotesExhausted() final;
Status setAwaitDataTimeout(Milliseconds awaitDataTimeout) final;
private:
/**
* Constructs a cluster client cursor.
*/
ClusterClientCursorImpl(executor::TaskExecutor* executor, ClusterClientCursorParams&& params);
/**
* Constructs the pipeline of MergerPlanStages which will be used to answer the query.
*/
std::unique_ptr<RouterExecStage> buildMergerPlan(executor::TaskExecutor* executor,
ClusterClientCursorParams&& params);
bool _isTailable = false;
// Number of documents already returned by next().
long long _numReturnedSoFar = 0;
// The root stage of the pipeline used to return the result set, merged from the remote nodes.
std::unique_ptr<RouterExecStage> _root;
// Stores documents queued by queueResult(). Stashed BSONObjs must be owned.
std::queue<BSONObj> _stash;
};
} // namespace mongo
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