QueryResult* processGetMore(const char *ns, int ntoreturn, long long cursorid , CurOp& curop, int pass, bool& exhaust ) {
exhaust = false;
ClientCursor::Pointer p(cursorid);
ClientCursor *cc = p.c();
int bufSize = 512 + sizeof( QueryResult ) + MaxBytesToReturnToClientAtOnce;
BufBuilder b( bufSize );
b.skip(sizeof(QueryResult));
int resultFlags = ResultFlag_AwaitCapable;
int start = 0;
int n = 0;
if ( unlikely(!cc) ) {
LOGSOME << "getMore: cursorid not found " << ns << " " << cursorid << endl;
cursorid = 0;
resultFlags = ResultFlag_CursorNotFound;
}
else {
// check for spoofing of the ns such that it does not match the one originally there for the cursor
uassert(14833, "auth error", str::equals(ns, cc->ns().c_str()));
if ( pass == 0 )
cc->updateSlaveLocation( curop );
int queryOptions = cc->queryOptions();
curop.debug().query = cc->query();
start = cc->pos();
Cursor *c = cc->c();
c->recoverFromYield();
DiskLoc last;
scoped_ptr<Projection::KeyOnly> keyFieldsOnly;
if ( cc->modifiedKeys() == false && cc->isMultiKey() == false && cc->fields )
keyFieldsOnly.reset( cc->fields->checkKey( cc->indexKeyPattern() ) );
// This manager may be stale, but it's the state of chunking when the cursor was created.
ShardChunkManagerPtr manager = cc->getChunkManager();
while ( 1 ) {
if ( !c->ok() ) {
if ( c->tailable() ) {
/* when a tailable cursor hits "EOF", ok() goes false, and current() is null. however
advance() can still be retries as a reactivation attempt. when there is new data, it will
return true. that's what we are doing here.
*/
if ( c->advance() )
continue;
if( n == 0 && (queryOptions & QueryOption_AwaitData) && pass < 1000 ) {
return 0;
}
break;
}
p.release();
bool ok = ClientCursor::erase(cursorid);
verify(ok);
cursorid = 0;
cc = 0;
break;
}
// in some cases (clone collection) there won't be a matcher
if ( !c->currentMatches() ) {
}
else if ( manager && ! manager->belongsToMe( cc ) ){
LOG(2) << "cursor skipping document in un-owned chunk: " << c->current() << endl;
}
else {
if( c->getsetdup(c->currLoc()) ) {
//out() << " but it's a dup \n";
}
else {
last = c->currLoc();
n++;
if ( keyFieldsOnly ) {
fillQueryResultFromObj(b, 0, keyFieldsOnly->hydrate( c->currKey() ) );
}
else {
BSONObj js = c->current();
// show disk loc should be part of the main query, not in an $or clause, so this should be ok
fillQueryResultFromObj(b, cc->fields.get(), js, ( cc->pq.get() && cc->pq->showDiskLoc() ? &last : 0));
}
if ( ( ntoreturn && n >= ntoreturn ) || b.len() > MaxBytesToReturnToClientAtOnce ) {
c->advance();
cc->incPos( n );
break;
}
}
}
c->advance();
if ( ! cc->yieldSometimes( ClientCursor::MaybeCovered ) ) {
ClientCursor::erase(cursorid);
cursorid = 0;
cc = 0;
p.deleted();
break;
}
}
if ( cc ) {
if ( c->supportYields() ) {
ClientCursor::YieldData data;
verify( cc->prepareToYield( data ) );
}
else {
cc->c()->noteLocation();
}
cc->mayUpgradeStorage();
cc->storeOpForSlave( last );
exhaust = cc->queryOptions() & QueryOption_Exhaust;
}
}
QueryResult *qr = (QueryResult *) b.buf();
qr->len = b.len();
qr->setOperation(opReply);
qr->_resultFlags() = resultFlags;
qr->cursorId = cursorid;
qr->startingFrom = start;
qr->nReturned = n;
b.decouple();
return qr;
}
