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/** @file oplogreader.h */
#pragma once
#include "../client/dbclient.h"
#include "../client/constants.h"
#include "dbhelpers.h"
namespace mongo {
/* started abstracting out the querying of the primary/master's oplog
still fairly awkward but a start.
*/
class OplogReader {
shared_ptr<DBClientConnection> _conn;
shared_ptr<DBClientCursor> cursor;
public:
OplogReader() { }
~OplogReader() { }
void resetCursor() { cursor.reset(); }
void resetConnection() {
cursor.reset();
_conn.reset();
}
DBClientConnection* conn() { return _conn.get(); }
BSONObj findOne(const char *ns, const Query& q) {
return conn()->findOne(ns, q, 0, QueryOption_SlaveOk);
}
BSONObj getLastOp(const char *ns) {
return findOne(ns, Query().sort(reverseNaturalObj));
}
/* ok to call if already connected */
bool connect(string hostname);
bool connect(const BSONObj& rid, const int from, const string& to);
void tailCheck() {
if( cursor.get() && cursor->isDead() ) {
log() << "repl: old cursor isDead, will initiate a new one" << endl;
resetCursor();
}
}
bool haveCursor() { return cursor.get() != 0; }
/** this is ok but commented out as when used one should consider if QueryOption_OplogReplay
is needed; if not fine, but if so, need to change.
*//*
void query(const char *ns, const BSONObj& query) {
assert( !haveCursor() );
cursor.reset( _conn->query(ns, query, 0, 0, 0, QueryOption_SlaveOk).release() );
}*/
/** this can be used; it is commented out as it does not indicate
QueryOption_OplogReplay and that is likely important. could be uncommented
just need to add that.
*/
/*
void queryGTE(const char *ns, OpTime t) {
BSONObjBuilder q;
q.appendDate("$gte", t.asDate());
BSONObjBuilder q2;
q2.append("ts", q.done());
query(ns, q2.done());
}
*/
void tailingQuery(const char *ns, const BSONObj& query, const BSONObj* fields=0) {
assert( !haveCursor() );
log(2) << "repl: " << ns << ".find(" << query.toString() << ')' << endl;
cursor.reset( _conn->query( ns, query, 0, 0, fields,
QueryOption_CursorTailable | QueryOption_SlaveOk | QueryOption_OplogReplay |
/* TODO: slaveOk maybe shouldn't use? */
QueryOption_AwaitData
).release() );
}
void tailingQueryGTE(const char *ns, OpTime t, const BSONObj* fields=0) {
BSONObjBuilder q;
q.appendDate("$gte", t.asDate());
BSONObjBuilder query;
query.append("ts", q.done());
tailingQuery(ns, query.done(), fields);
}
/* Do a tailing query, but only send the ts field back. */
void ghostQueryGTE(const char *ns, OpTime t) {
const BSONObj fields = BSON("ts" << 1 << "_id" << 0);
return tailingQueryGTE(ns, t, &fields);
}
bool more() {
uassert( 15910, "Doesn't have cursor for reading oplog", cursor.get() );
return cursor->more();
}
bool moreInCurrentBatch() {
uassert( 15911, "Doesn't have cursor for reading oplog", cursor.get() );
return cursor->moreInCurrentBatch();
}
/* old mongod's can't do the await flag... */
bool awaitCapable() {
return cursor->hasResultFlag(ResultFlag_AwaitCapable);
}
void peek(vector<BSONObj>& v, int n) {
if( cursor.get() )
cursor->peek(v,n);
}
BSONObj nextSafe() { return cursor->nextSafe(); }
BSONObj next() { return cursor->next(); }
void putBack(BSONObj op) { cursor->putBack(op); }
private:
bool commonConnect(const string& hostName);
bool passthroughHandshake(const BSONObj& rid, const int f);
};
}
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