From 34de75445d87df5e29b2b1e77fee86613c88c6d1 Mon Sep 17 00:00:00 2001
From: Eliot Horowitz <eliot@10gen.com>
Date: Fri, 21 Jan 2011 12:58:20 -0500
Subject: [PATCH] some BSONObjBuilder helpers for accessing data whilebuilding

---
 bson/bson-inl.h       | 28 ++++++++++++++++++++++++++++
 bson/bsonobjbuilder.h |  5 +++++
 2 files changed, 33 insertions(+)

diff --git a/bson/bson-inl.h b/bson/bson-inl.h
index cf52747b886..5b4c490ea74 100644
--- a/bson/bson-inl.h
+++ b/bson/bson-inl.h
@@ -121,6 +121,26 @@ namespace mongo {
         return *this;
     }
 
+    /* add all the fields from the object specified to this object if they don't exist */
+    inline BSONObjBuilder& BSONObjBuilder::appendElementsUnique(BSONObj x) {
+        set<string> have;
+        {
+            BSONObjIterator i = iterator();
+            while ( i.more() )
+                have.insert( i.next().fieldName() );
+        }
+        
+        BSONObjIterator it(x);
+        while ( it.more() ) {
+            BSONElement e = it.next();
+            if ( have.count( e.fieldName() ) )
+                continue;
+            append(e);
+        }
+        return *this;
+    }
+
+
     inline bool BSONObj::isValid() {
         int x = objsize();
         return x > 0 && x <= BSONObjMaxInternalSize;
@@ -205,6 +225,14 @@ namespace mongo {
         return BSONObjIterator( s , e );
     }
 
+    inline bool BSONObjBuilder::hasField( const StringData& name ) const {
+        BSONObjIterator i = iterator();
+        while ( i.more() )
+            if ( strcmp( name.data() , i.next().fieldName() ) == 0 )
+                return true;
+        return false;
+    }
+
     /* WARNING: nested/dotted conversions are not 100% reversible
      * nested2dotted(dotted2nested({a.b: {c:1}})) -> {a.b.c: 1}
      * also, dotted2nested ignores order
diff --git a/bson/bsonobjbuilder.h b/bson/bsonobjbuilder.h
index dda89c8e6ce..a39b529b74c 100644
--- a/bson/bsonobjbuilder.h
+++ b/bson/bsonobjbuilder.h
@@ -104,6 +104,9 @@ namespace mongo {
         /** add all the fields from the object specified to this object */
         BSONObjBuilder& appendElements(BSONObj x);
 
+        /** add all the fields from the object specified to this object if they don't exist already */
+        BSONObjBuilder& appendElementsUnique( BSONObj x );
+
         /** append element to the object we are building */
         BSONObjBuilder& append( const BSONElement& e) {
             assert( !e.eoo() ); // do not append eoo, that would corrupt us. the builder auto appends when done() is called.
@@ -616,6 +619,8 @@ namespace mongo {
 
         BSONObjIterator iterator() const ;
 
+        bool hasField( const StringData& name ) const ;
+
         int len() const { return _b.len(); }
 
     private: