mongodb: cursors.h Source File

00001 // cursors.h
00002 /*
00003  *    Copyright (C) 2010 10gen Inc.
00004  *
00005  *    This program is free software: you can redistribute it and/or  modify
00006  *    it under the terms of the GNU Affero General Public License, version 3,
00007  *    as published by the Free Software Foundation.
00008  *
00009  *    This program is distributed in the hope that it will be useful,
00010  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012  *    GNU Affero General Public License for more details.
00013  *
00014  *    You should have received a copy of the GNU Affero General Public License
00015  *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
00016  */
00017 
00018 
00019 #pragma once
00020 
00021 #include "../pch.h"
00022 
00023 #include "../db/jsobj.h"
00024 #include "../db/dbmessage.h"
00025 #include "../client/dbclient.h"
00026 #include "../client/parallel.h"
00027 
00028 #include "request.h"
00029 
00030 namespace mongo {
00031 
00032     class ShardedClientCursor : boost::noncopyable {
00033     public:
00034         ShardedClientCursor( QueryMessage& q , ClusteredCursor * cursor );
00035         virtual ~ShardedClientCursor();
00036 
00037         long long getId();
00038 
00042         bool sendNextBatch( Request& r ) { return sendNextBatch( r , _ntoreturn ); }
00043         bool sendNextBatch( Request& r , int ntoreturn );
00044 
00045         void accessed();
00047         long long idleTime( long long now );
00048 
00049     protected:
00050 
00051         ClusteredCursor * _cursor;
00052 
00053         int _skip;
00054         int _ntoreturn;
00055 
00056         int _totalSent;
00057         bool _done;
00058 
00059         long long _id;
00060         long long _lastAccessMillis; // 0 means no timeout
00061 
00062     };
00063 
00064     typedef boost::shared_ptr<ShardedClientCursor> ShardedClientCursorPtr;
00065 
00066     class CursorCache {
00067     public:
00068 
00069         static long long TIMEOUT;
00070 
00071         typedef map<long long,ShardedClientCursorPtr> MapSharded;
00072         typedef map<long long,string> MapNormal;
00073 
00074         CursorCache();
00075         ~CursorCache();
00076 
00077         ShardedClientCursorPtr get( long long id ) const;
00078         void store( ShardedClientCursorPtr cursor );
00079         void remove( long long id );
00080 
00081         void storeRef( const string& server , long long id );
00082 
00084         string getRef( long long id ) const ;
00085         
00086         void gotKillCursors(Message& m );
00087 
00088         void appendInfo( BSONObjBuilder& result ) const ;
00089 
00090         long long genId();
00091 
00092         void doTimeouts();
00093         void startTimeoutThread();
00094     private:
00095         mutable mongo::mutex _mutex;
00096 
00097         MapSharded _cursors;
00098         MapNormal _refs;
00099 
00100         long long _shardedTotal;
00101 
00102         static int _myLogLevel;
00103     };
00104 
00105     extern CursorCache cursorCache;
00106 }