allow adding variable to global scope for M/R SERVER-449

db/mr.cpp

@@ -128,9 +128,11 @@ namespace mongo {
                     if ( cmdObj["mapparams"].type() == Array ){
                         mapparams = cmdObj["mapparams"].embeddedObjectUserCheck();
                     }
-                    else {
-                        mapparams = BSONObj();
+
+                    if ( cmdObj["scope"].type() == Object ){
+                        scopeSetup = cmdObj["scope"].embeddedObjectUserCheck();
                     }
+
                 }
 
                 { // query options
@@ -183,7 +185,8 @@ namespace mongo {
             string finalizeCode;
 
             BSONObj mapparams;
-
+            BSONObj scopeSetup;
+
             // output tables
             string incLong;
 
@@ -208,6 +211,9 @@ namespace mongo {
                 else
                     finalize = 0;
 
+                if ( ! setup.scopeSetup.isEmpty() )
+                    scope->init( &setup.scopeSetup );
+
                 db.dropCollection( setup.tempLong );
                 db.dropCollection( setup.incLong );
 

jstests/mr4.js

@@ -0,0 +1,45 @@
+
+t = db.mr4;
+t.drop();
+
+t.save( { x : 1 , tags : [ "a" , "b" ] } );
+t.save( { x : 2 , tags : [ "b" , "c" ] } );
+t.save( { x : 3 , tags : [ "c" , "a" ] } );
+t.save( { x : 4 , tags : [ "b" , "c" ] } );
+
+m = function(){
+    this.tags.forEach(
+        function(z){
+            emit( z , { count : xx } );
+        }
+    );
+};
+
+r = function( key , values ){
+    var total = 0;
+    for ( var i=0; i<values.length; i++ ){
+        total += values[i].count;
+    }
+    return { count : total };
+};
+
+res = t.mapReduce( m , r , { scope : { xx : 1 } } );
+z = res.convertToSingleObject()
+
+assert.eq( 3 , z.keySet().length , "A1" );
+assert.eq( 2 , z.a.count , "A2" );
+assert.eq( 3 , z.b.count , "A3" );
+assert.eq( 3 , z.c.count , "A4" );
+
+res.drop();
+
+
+res = t.mapReduce( m , r , { scope : { xx : 2 } } );
+z = res.convertToSingleObject()
+
+assert.eq( 3 , z.keySet().length , "A1" );
+assert.eq( 4 , z.a.count , "A2" );
+assert.eq( 6 , z.b.count , "A3" );
+assert.eq( 6 , z.c.count , "A4" );
+
+res.drop();