1 files changed, 14 insertions, 3 deletions
diff --git a/src/google/protobuf/util/field_comparator.h b/src/google/protobuf/util/field_comparator.h
index 26a7ba4d..63e89fb7 100644
--- a/src/google/protobuf/util/field_comparator.h
+++ b/src/google/protobuf/util/field_comparator.h
@@ -35,6 +35,7 @@
 
 #include <map>
 #include <string>
+#include <vector>
 
 #include <google/protobuf/stubs/common.h>
 
@@ -48,6 +49,7 @@ class FieldDescriptor;
 namespace util {
 
 class FieldContext;
+class MessageDifferencer;
 
 // Base class specifying the interface for comparing protocol buffer fields.
 // Regular users should consider using or subclassing DefaultFieldComparator
@@ -108,14 +110,14 @@ class LIBPROTOBUF_EXPORT DefaultFieldComparator : public FieldComparator {
   // Creates new comparator with float comparison set to EXACT.
   DefaultFieldComparator();
 
-  virtual ~DefaultFieldComparator();
+  ~DefaultFieldComparator() override;
 
-  virtual ComparisonResult Compare(
+  ComparisonResult Compare(
       const google::protobuf::Message& message_1,
       const google::protobuf::Message& message_2,
       const google::protobuf::FieldDescriptor* field,
       int index_1, int index_2,
-      const google::protobuf::util::FieldContext* field_context);
+      const google::protobuf::util::FieldContext* field_context) override;
 
   void set_float_comparison(FloatComparison float_comparison) {
     float_comparison_ = float_comparison;
@@ -153,6 +155,15 @@ class LIBPROTOBUF_EXPORT DefaultFieldComparator : public FieldComparator {
   // REQUIRES: float_comparison_ == APPROXIMATE
   void SetDefaultFractionAndMargin(double fraction, double margin);
 
+ protected:
+  // Compare using the provided message_differencer. For example, a subclass can
+  // use this method to compare some field in a certain way using the same
+  // message_differencer instance and the field context.
+  bool Compare(MessageDifferencer* differencer,
+               const google::protobuf::Message& message1,
+               const google::protobuf::Message& message2,
+               const google::protobuf::util::FieldContext* field_context);
+
  private:
   // Defines the tolerance for floating point comparison (fraction and margin).
   struct Tolerance {