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// cursor_manager.h
/**
* Copyright (C) 2013 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 <boost/scoped_ptr.hpp>
#include "mongo/db/clientcursor.h"
#include "mongo/db/invalidation_type.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/record_id.h"
#include "mongo/platform/unordered_set.h"
#include "mongo/util/concurrency/mutex.h"
namespace mongo {
class OperationContext;
class PseudoRandom;
class PlanExecutor;
class CursorManager {
public:
CursorManager( StringData ns );
/**
* will kill() all PlanExecutor instances it has
*/
~CursorManager();
// -----------------
/**
* @param collectionGoingAway Pass as true if the Collection instance is going away.
* This could be because the db is being closed, or the
* collection/db is being dropped.
*/
void invalidateAll( bool collectionGoingAway );
/**
* Broadcast a document invalidation to all relevant PlanExecutor(s). invalidateDocument
* must called *before* the provided RecordId is about to be deleted or mutated.
*/
void invalidateDocument( OperationContext* txn,
const RecordId& dl,
InvalidationType type );
/*
* timesout cursors that have been idle for too long
* note: must have a readlock on the collection
* @return number timed out
*/
std::size_t timeoutCursors( int millisSinceLastCall );
// -----------------
/**
* Register an executor so that it can be notified of deletion/invalidation during yields.
* Must be called before an executor yields. If an executor is cached (inside a
* ClientCursor) it MUST NOT be registered; the two are mutually exclusive.
*/
void registerExecutor(PlanExecutor* exec);
/**
* Remove an executor from the registry.
*/
void deregisterExecutor(PlanExecutor* exec);
// -----------------
CursorId registerCursor( ClientCursor* cc );
void deregisterCursor( ClientCursor* cc );
bool eraseCursor(OperationContext* txn, CursorId id, bool checkAuth );
/**
* Returns true if the space of cursor ids that cursor manager is responsible for includes
* the given cursor id. Otherwise, returns false.
*
* The return value of this method does not indicate any information about whether or not a
* cursor actually exists with the given cursor id. Use the find() method for that purpose.
*/
bool ownsCursorId( CursorId cursorId ) const;
void getCursorIds( std::set<CursorId>* openCursors ) const;
std::size_t numCursors() const;
/**
* @param pin - if true, will try to pin cursor
* if pinned already, will assert
* otherwise will pin
*/
ClientCursor* find( CursorId id, bool pin );
void unpin( ClientCursor* cursor );
// ----------------------
static CursorManager* getGlobalCursorManager();
static int eraseCursorGlobalIfAuthorized(OperationContext* txn, int n,
const char* ids);
static bool eraseCursorGlobalIfAuthorized(OperationContext* txn, CursorId id);
static bool eraseCursorGlobal(OperationContext* txn, CursorId id);
/**
* @return number timed out
*/
static std::size_t timeoutCursorsGlobal(OperationContext* txn, int millisSinceLastCall);
private:
CursorId _allocateCursorId_inlock();
void _deregisterCursor_inlock( ClientCursor* cc );
NamespaceString _nss;
unsigned _collectionCacheRuntimeId;
boost::scoped_ptr<PseudoRandom> _random;
mutable SimpleMutex _mutex;
typedef unordered_set<PlanExecutor*> ExecSet;
ExecSet _nonCachedExecutors;
typedef std::map<CursorId,ClientCursor*> CursorMap;
CursorMap _cursors;
};
}
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