1 files changed, 23 insertions, 2 deletions
diff --git a/src/mongo/db/pipeline/document.h b/src/mongo/db/pipeline/document.h
index 5e5980f5a51..a8ebfd1c4d2 100644
--- a/src/mongo/db/pipeline/document.h
+++ b/src/mongo/db/pipeline/document.h
@@ -90,6 +90,12 @@ public:
         const Document& rhs;
     };
 
+    static constexpr StringData metaFieldTextScore = "$textScore"_sd;
+    static constexpr StringData metaFieldRandVal = "$randVal"_sd;
+    static constexpr StringData metaFieldSortKey = "$sortKey"_sd;
+
+    static const std::vector<StringData> allMetadataFieldNames;
+
     /// Empty Document (does no allocation)
     Document() {}
 
@@ -211,6 +217,12 @@ public:
      */
     static Document fromBsonWithMetaData(const BSONObj& bson);
 
+    /**
+     * Given a BSON object that may have metadata fields added as part of toBsonWithMetadata(),
+     * returns the same object without any of the metadata fields.
+     */
+    static BSONObj stripMetadataFields(const BSONObj& bsonWithMetadata);
+
     // Support BSONObjBuilder and BSONArrayBuilder "stream" API
     friend BSONObjBuilder& operator<<(BSONObjBuilderValueStream& builder, const Document& d);
 
@@ -233,7 +245,6 @@ public:
         return Document(storage().clone().get());
     }
 
-    static const StringData metaFieldTextScore;  // "$textScore"
     bool hasTextScore() const {
         return storage().hasTextScore();
     }
@@ -241,7 +252,6 @@ public:
         return storage().getTextScore();
     }
 
-    static const StringData metaFieldRandVal;  // "$randVal"
     bool hasRandMetaField() const {
         return storage().hasRandMetaField();
     }
@@ -249,6 +259,13 @@ public:
         return storage().getRandMetaField();
     }
 
+    bool hasSortKeyMetaField() const {
+        return storage().hasSortKeyMetaField();
+    }
+    BSONObj getSortKeyMetaField() const {
+        return storage().getSortKeyMetaField();
+    }
+
     /// members for Sorter
     struct SorterDeserializeSettings {};  // unused
     void serializeForSorter(BufBuilder& buf) const;
@@ -493,6 +510,10 @@ public:
         storage().setRandMetaField(val);
     }
 
+    void setSortKeyMetaField(BSONObj sortKey) {
+        storage().setSortKeyMetaField(sortKey);
+    }
+
     /** Convert to a read-only document and release reference.
      *
      *  Call this to indicate that you are done with this Document and will