SERVER-6400 FieldRef has a equalsDottedField to compare it to a full string

1 files changed, 29 insertions, 0 deletions

diff --git a/src/mongo/db/field_ref.cpp b/src/mongo/db/field_ref.cpp
index c3dbc47ed5d..68ab798b320 100644
--- a/src/mongo/db/field_ref.cpp
+++ b/src/mongo/db/field_ref.cpp
@@ -16,6 +16,7 @@
 
 #include "mongo/db/field_ref.h"
 
+#include "mongo/util/log.h"
 #include "mongo/util/assert_util.h"
 
 namespace mongo {
@@ -115,6 +116,34 @@ namespace mongo {
         return res;
     }
 
+    bool FieldRef::equalsDottedField( const StringData& other ) const {
+        StringData rest = other;
+
+
+        for ( size_t i = 0; i < _size; i++ ) {
+
+            StringData part = getPart( i );
+
+            if ( !rest.startsWith( part ) )
+                return false;
+
+            if ( i == _size - 1 )
+                return rest.size() == part.size();
+
+            // make sure next thing is a dot
+            if ( rest.size() == part.size() )
+                return false;
+
+            if ( rest[part.size()] != '.' )
+                return false;
+
+            rest = rest.substr( part.size() + 1 );
+        }
+
+        return false;
+    }
+
+
     size_t FieldRef::numReplaced() const {
         size_t res = 0;
         for (size_t i = 0; i < _replacements.size(); i++) {