removing duplicate logic

client/parallel.cpp

@@ -140,10 +140,16 @@ namespace mongo {
         _advance();
         return ret;
     }
+
+    BSONObj FilteringClientCursor::peek(){
+        if ( _next.isEmpty() )
+            _advance();
+        return _next;
+    }
     
     void FilteringClientCursor::_advance(){
         assert( _next.isEmpty() );
-        if ( ! _cursor.get() )
+        if ( ! _cursor.get() || _done )
             return;
         
         while ( _cursor->more() ){
@@ -215,7 +221,6 @@ namespace mongo {
     void ParallelSortClusteredCursor::_init(){
         _numServers = _servers.size();
         _cursors = new FilteringClientCursor[_numServers];
-        _nexts = new BSONObj[_numServers];
             
         // TODO: parellize
         int num = 0;
@@ -228,14 +233,10 @@ namespace mongo {
     
     ParallelSortClusteredCursor::~ParallelSortClusteredCursor(){
         delete [] _cursors;
-        delete [] _nexts;
     }
 
     bool ParallelSortClusteredCursor::more(){
         for ( int i=0; i<_numServers; i++ ){
-            if ( ! _nexts[i].isEmpty() )
-                return true;
-
             if ( _cursors[i].more() )
                 return true;
         }
@@ -243,53 +244,35 @@ namespace mongo {
     }
         
     BSONObj ParallelSortClusteredCursor::next(){
-        advance();
-            
         BSONObj best = BSONObj();
         int bestFrom = -1;
             
         for ( int i=0; i<_numServers; i++){
-            if ( _nexts[i].isEmpty() )
+            if ( ! _cursors[i].more() )
                 continue;
+            
+            BSONObj me = _cursors[i].peek();
 
             if ( best.isEmpty() ){
-                best = _nexts[i];
+                best = me;
                 bestFrom = i;
                 continue;
             }
                 
-            int comp = best.woSortOrder( _nexts[i] , _sortKey );
+            int comp = best.woSortOrder( me , _sortKey );
             if ( comp < 0 )
                 continue;
                 
-            best = _nexts[i];
+            best = me;
             bestFrom = i;
         }
-            
+        
         uassert( 10019 ,  "no more elements" , ! best.isEmpty() );
-        _nexts[bestFrom] = BSONObj();
+        _cursors[bestFrom].next();
             
         return best;
     }
 
-    void ParallelSortClusteredCursor::advance(){
-        for ( int i=0; i<_numServers; i++ ){
-
-            if ( ! _nexts[i].isEmpty() ){
-                // already have a good object there
-                continue;
-            }
-                
-            if ( ! _cursors[i].more() ){
-                // cursor is dead, oh well
-                continue;
-            }
-
-            _nexts[i] = _cursors[i].next();
-        }
-            
-    }
-
     // -----------------
     // ---- Future -----
     // -----------------