1 files changed, 74 insertions, 0 deletions
diff --git a/absl/container/btree_set.h b/absl/container/btree_set.h
index f587ca22..8c96e0ed 100644
--- a/absl/container/btree_set.h
+++ b/absl/container/btree_set.h
@@ -55,6 +55,17 @@
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
+namespace container_internal {
+
+template <typename Key>
+struct set_slot_policy;
+
+template <typename Key, typename Compare, typename Alloc, int TargetNodeSize,
+          bool Multi>
+struct set_params;
+
+}  // namespace container_internal
+
 // absl::btree_set<>
 //
 // An `absl::btree_set<K>` is an ordered associative container of unique key
@@ -724,6 +735,69 @@ void erase_if(btree_multiset<K, C, A> &set, Pred pred) {
   }
 }
 
+namespace container_internal {
+
+// This type implements the necessary functions from the
+// absl::container_internal::slot_type interface for btree_(multi)set.
+template <typename Key>
+struct set_slot_policy {
+  using slot_type = Key;
+  using value_type = Key;
+  using mutable_value_type = Key;
+
+  static value_type &element(slot_type *slot) { return *slot; }
+  static const value_type &element(const slot_type *slot) { return *slot; }
+
+  template <typename Alloc, class... Args>
+  static void construct(Alloc *alloc, slot_type *slot, Args &&...args) {
+    absl::allocator_traits<Alloc>::construct(*alloc, slot,
+                                             std::forward<Args>(args)...);
+  }
+
+  template <typename Alloc>
+  static void construct(Alloc *alloc, slot_type *slot, slot_type *other) {
+    absl::allocator_traits<Alloc>::construct(*alloc, slot, std::move(*other));
+  }
+
+  template <typename Alloc>
+  static void destroy(Alloc *alloc, slot_type *slot) {
+    absl::allocator_traits<Alloc>::destroy(*alloc, slot);
+  }
+
+  template <typename Alloc>
+  static void swap(Alloc * /*alloc*/, slot_type *a, slot_type *b) {
+    using std::swap;
+    swap(*a, *b);
+  }
+
+  template <typename Alloc>
+  static void move(Alloc * /*alloc*/, slot_type *src, slot_type *dest) {
+    *dest = std::move(*src);
+  }
+};
+
+// A parameters structure for holding the type parameters for a btree_set.
+// Compare and Alloc should be nothrow copy-constructible.
+template <typename Key, typename Compare, typename Alloc, int TargetNodeSize,
+          bool Multi>
+struct set_params : common_params<Key, Compare, Alloc, TargetNodeSize, Multi,
+                                  set_slot_policy<Key>> {
+  using value_type = Key;
+  using slot_type = typename set_params::common_params::slot_type;
+  using value_compare =
+      typename set_params::common_params::original_key_compare;
+  using is_map_container = std::false_type;
+
+  template <typename V>
+  static const V &key(const V &value) {
+    return value;
+  }
+  static const Key &key(const slot_type *slot) { return *slot; }
+  static const Key &key(slot_type *slot) { return *slot; }
+};
+
+}  // namespace container_internal
+
 ABSL_NAMESPACE_END
 }  // namespace absl