mongodb/db/dbmessage.h

/**
*    Copyright (C) 2008 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/>.
*/

#include "storage.h"
#include "jsobj.h"
#include "namespace.h"

/* For the database/server protocol, these objects and functions encapsulate 
   the various messages transmitted over the connection.
*/

class DbMessage {
public:
	DbMessage(const Message& _m) : m(_m) {
		theEnd = _m.data->_data + _m.data->dataLen();
		int *r = (int *) _m.data->_data;
		reserved = *r;
		r++;
		data = (const char *) r;
		nextjsobj = data;
	}

	const char * getns() { return data; }
	void getns(Namespace& ns) {
		ns = data;
	}

	int pullInt() {
		if( nextjsobj == data )
			nextjsobj += strlen(data) + 1; // skip namespace
		int i = *((int *)nextjsobj);
		nextjsobj += 4;
		return i;
	}
	long long pullInt64() {
		if( nextjsobj == data )
			nextjsobj += strlen(data) + 1; // skip namespace
		long long i = *((long long *)nextjsobj);
		nextjsobj += 8;
		return i;
	}

	OID* getOID() {
		return (OID *) (data + strlen(data) + 1); // skip namespace
	}

	void getQueryStuff(const char *&query, int& ntoreturn) {
		int *i = (int *) (data + strlen(data) + 1);
		ntoreturn = *i;
		i++;
		query = (const char *) i;
	}

	/* for insert and update msgs */
	bool moreJSObjs() { return nextjsobj != 0; }
	BSONObj nextJsObj() {
		if( nextjsobj == data )
			nextjsobj += strlen(data) + 1; // skip namespace
		BSONObj js(nextjsobj);
                assert( js.objsize() < ( theEnd - data ) );
		if( js.objsize() <= 0 )
			nextjsobj = null;
		else {
			nextjsobj += js.objsize();
			if( nextjsobj >= theEnd )
				nextjsobj = 0;
		}
		return js;
	}

    const Message& msg() { return m; }

private:
	const Message& m;
	int reserved;
	const char *data;
	const char *nextjsobj;
	const char *theEnd;
};

/* a request to run a query, received from the database */
class QueryMessage { 
public:
    const char *ns;
    int ntoskip;
    int ntoreturn;
    int queryOptions;
    BSONObj query;
	auto_ptr< set<string> > fields;

    /* parses the message into the above fields */
    QueryMessage(DbMessage& d) { 
        ns = d.getns();
        ntoskip = d.pullInt();
        ntoreturn = d.pullInt();
        query = d.nextJsObj();
        if( d.moreJSObjs() ) { 
            fields = auto_ptr< set<string> >(new set<string>());
            d.nextJsObj().getFieldNames(*fields);
        }
        queryOptions = d.msg().data->dataAsInt();
    }
};

#include "../client/dbclient.h" 

inline void replyToQuery(MessagingPort& p, Message& requestMsg,
                         void *data, int size,
                         int nReturned, int startingFrom = 0, 
                         long long cursorId = 0
                         ) { 
    BufBuilder b(32768);
    b.skip(sizeof(QueryResult));
    b.append(data, size);
    QueryResult *qr = (QueryResult *) b.buf();
    qr->_data[0] = 0;
    qr->_data[1] = 0;
    qr->_data[2] = 0;
    qr->_data[3] = 0;
    qr->len = b.len();
    qr->setOperation(opReply);
    qr->cursorId = cursorId;
    qr->startingFrom = startingFrom;
    qr->nReturned = 1;
    b.decouple();
    Message *resp = new Message();
    resp->setData(qr, true); // transport will free
    p.reply(requestMsg, *resp, requestMsg.data->id);
}

//#include "bsonobj.h"

inline void replyToQuery(MessagingPort& p, Message& requestMsg,
                         BSONObj& responseObj) 
{
    replyToQuery(
        p, requestMsg, 
        (void *) responseObj.objdata(), responseObj.objsize(), 1);
}