Skip unknown fields while decoding FieldValue proto objects. (#1354)

2 files changed, 17 insertions, 0 deletions

diff --git a/Firestore/core/src/firebase/firestore/nanopb/reader.cc b/Firestore/core/src/firebase/firestore/nanopb/reader.cc
index ec4282d..69e3d83 100644
--- a/Firestore/core/src/firebase/firestore/nanopb/reader.cc
+++ b/Firestore/core/src/firebase/firestore/nanopb/reader.cc
@@ -136,6 +136,14 @@ std::string Reader::ReadString() {
   return result;
 }
 
+void Reader::SkipField(const Tag& tag) {
+  if (!status_.ok()) return;
+
+  if (!pb_skip_field(&stream_, tag.wire_type)) {
+    status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
+  }
+}
+
 }  // namespace nanopb
 }  // namespace firestore
 }  // namespace firebase
diff --git a/Firestore/core/src/firebase/firestore/nanopb/reader.h b/Firestore/core/src/firebase/firestore/nanopb/reader.h
index 930211a..2c16ec4 100644
--- a/Firestore/core/src/firebase/firestore/nanopb/reader.h
+++ b/Firestore/core/src/firebase/firestore/nanopb/reader.h
@@ -89,6 +89,15 @@ class Reader {
   template <typename T>
   T ReadNestedMessage(const std::function<T(Reader*)>& read_message_fn);
 
+  /**
+   * Discards the bytes associated with the given tag.
+   *
+   * @param tag The tag associated with the field that is otherwise about to be
+   * read. This method uses the tag to determine how many bytes should be
+   * discarded.
+   */
+  void SkipField(const Tag& tag);
+
   size_t bytes_left() const {
     return stream_.bytes_left;
   }