1 files changed, 18 insertions, 0 deletions
diff --git a/Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h b/Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h
index ff8c9f9..c5eddc2 100644
--- a/Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h
+++ b/Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h
@@ -51,6 +51,7 @@ class TreeSortedMap : public SortedMapBase, private util::ComparatorHolder<C> {
    * The type of the node containing entries of value_type.
    */
   using node_type = LlrbNode<K, V>;
+  using const_iterator = typename node_type::const_iterator;
 
   /**
    * Creates an empty TreeSortedMap.
@@ -110,6 +111,23 @@ class TreeSortedMap : public SortedMapBase, private util::ComparatorHolder<C> {
     return root_;
   }
 
+  /**
+   * Returns a forward iterator pointing to the first entry in the map. If there
+   * are no entries in the map, begin() == end().
+   *
+   * See LlrbNodeIterator for details
+   */
+  const_iterator begin() const {
+    return const_iterator::Begin(&root_);
+  }
+
+  /**
+   * Returns an iterator pointing past the last entry in the map.
+   */
+  const_iterator end() const {
+    return const_iterator::End();
+  }
+
  private:
   TreeSortedMap(node_type&& root, const C& comparator) noexcept
       : util::ComparatorHolder<C>{comparator}, root_{std::move(root)} {