// strategy.h
/*
 *    Copyright (C) 2010 10gen 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
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 */


#pragma once

#include "mongo/pch.h"
#include "chunk.h"
#include "request.h"

namespace mongo {

    class Strategy {
    public:
        Strategy() {}
        virtual ~Strategy() {}
        virtual void queryOp( Request& r ) = 0;
        virtual void getMore( Request& r ) = 0;
        virtual void writeOp( int op , Request& r ) = 0;

        void insert( const Shard& shard , const char * ns , const BSONObj& obj , int flags=0 , bool safe=false );

        struct CommandResult {
            Shard shardTarget;
            ConnectionString target;
            BSONObj result;
        };

        virtual void commandOp( const string& db,
                                const BSONObj& command,
                                int options,
                                const string& versionedNS,
                                const BSONObj& targetingQuery,
                                vector<CommandResult>* results )
        {
            // Only call this from sharded, for now.
            // TODO:  Refactor all this.
            verify( false );
        }

        // These interfaces will merge soon, so make it easy to share logic
        friend class ShardStrategy;
        friend class SingleStrategy;

    protected:
        void doWrite( int op , Request& r , const Shard& shard , bool checkVersion = true );
        void doIndexQuery( Request& r , const Shard& shard );
        void broadcastWrite(int op, Request& r); // Sends to all shards in cluster. DOESN'T CHECK VERSION

        void insert( const Shard& shard , const char * ns , const vector<BSONObj>& v , int flags=0 , bool safe=false );
        void update( const Shard& shard , const char * ns , const BSONObj& query , const BSONObj& toupdate , int flags=0, bool safe=false );

    };

    extern Strategy * SINGLE;
    extern Strategy * SHARDED;

}