// tail.cpp

/*    Copyright 2009 10gen Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

/* example of using a tailable cursor */

// It is the responsibility of the mongo client consumer to ensure that any necessary windows
// headers have already been included before including the driver facade headers.
#if defined(_WIN32)
#include <winsock2.h>
#include <windows.h>
#endif

#include "mongo/client/dbclient.h"
#include "mongo/util/goodies.h"

using namespace mongo;

void tail(DBClientBase& conn, const char* ns) {
    BSONElement lastId = minKey.firstElement();
    Query query = Query();

    auto_ptr<DBClientCursor> c = conn.query(ns, query, 0, 0, 0, QueryOption_CursorTailable);

    while (1) {
        if (!c->more()) {
            if (c->isDead()) {
                break;  // we need to requery
            }

            // all data (so far) exhausted, wait for more
            sleepsecs(1);
            continue;
        }
        BSONObj o = c->next();
        lastId = o["_id"];
        cout << o.toString() << endl;
    }
}
