moving DBDirectClient to instance.* b/c it only make sense there and cleans linking

db/instance.cpp

@@ -505,3 +505,34 @@ void dbexit(int rc, const char *why) {
     log() << "  dbexit: really exiting now" << endl;
     exit(rc);
 }
+
+
+auto_ptr<DBClientCursor> DBDirectClient::query(const char *ns, BSONObj query, int nToReturn , int nToSkip ,
+                                               BSONObj *fieldsToReturn , int queryOptions ){
+    
+    auto_ptr<DBClientCursor> c( new DBClientCursor( new DirectConnector() , ns , 
+                                                    query , nToReturn , nToSkip , fieldsToReturn , queryOptions ));
+    if ( c->init() )
+        return c;
+
+    return auto_ptr< DBClientCursor >( 0 );
+}
+
+BSONObj DBDirectClient::findOne(const char *ns, BSONObj query, BSONObj *fieldsToReturn , int queryOptions ){
+    auto_ptr<DBClientCursor> c =
+        this->query(ns, query, 1, 0, fieldsToReturn, queryOptions);
+    
+    if ( ! c->more() )
+        return BSONObj();
+    
+    return c->next().copy();
+}
+
+
+bool DirectConnector::send( Message &toSend, Message &response, bool assertOk ){
+    DbResponse dbResponse;
+    assembleResponse( toSend, dbResponse );
+    assert( dbResponse.response );
+    response = *dbResponse.response;
+    return true;
+}