Return NodePointer instead of iterator in find/emplace.

tdutils/td/utils/FlatHashTable.h

@@ -136,6 +136,64 @@ class FlatHashTable {
   using iterator = Iterator;
   using const_iterator = ConstIterator;
 
+  struct NodePointer {
+    value_type &operator*() {
+      return it_->get_public();
+    }
+    const value_type &operator*() const {
+      return it_->get_public();
+    }
+    value_type *operator->() {
+      return &it_->get_public();
+    }
+    const value_type *operator->() const {
+      return &it_->get_public();
+    }
+
+    NodeT *get() {
+      return it_;
+    }
+
+    bool operator==(const EndSentinel &other) const {
+      return it_ == nullptr;
+    }
+    bool operator!=(const EndSentinel &other) const {
+      return it_ != nullptr;
+    }
+
+    explicit NodePointer(NodeT *it) : it_(it) {
+    }
+
+   private:
+    NodeT *it_ = nullptr;
+  };
+
+  struct ConstNodePointer {
+    const value_type &operator*() const {
+      return it_->get_public();
+    }
+    const value_type *operator->() const {
+      return &it_->get_public();
+    }
+
+    bool operator==(const EndSentinel &other) const {
+      return it_ == nullptr;
+    }
+    bool operator!=(const EndSentinel &other) const {
+      return it_ != nullptr;
+    }
+
+    const NodeT *get() const {
+      return it_;
+    }
+
+    explicit ConstNodePointer(const NodeT *it) : it_(it) {
+    }
+
+   private:
+    const NodeT *it_ = nullptr;
+  };
+
   FlatHashTable() = default;
   FlatHashTable(const FlatHashTable &other) {
     assign(other);
@@ -205,12 +263,12 @@ class FlatHashTable {
     return bucket_count_;
   }
 
-  Iterator find(const KeyT &key) {
-    return create_iterator(find_impl(key));
+  NodePointer find(const KeyT &key) {
+    return NodePointer(find_impl(key));
   }
 
-  ConstIterator find(const KeyT &key) const {
-    return ConstIterator(const_cast<FlatHashTable *>(this)->find(key));
+  ConstNodePointer find(const KeyT &key) const {
+    return ConstNodePointer(const_cast<FlatHashTable *>(this)->find_impl(key));
   }
 
   size_t size() const {
@@ -244,25 +302,25 @@ class FlatHashTable {
   }
 
   template <class... ArgsT>
-  std::pair<Iterator, bool> emplace(KeyT key, ArgsT &&...args) {
+  std::pair<NodePointer, bool> emplace(KeyT key, ArgsT &&...args) {
     try_grow();
     CHECK(!is_hash_table_key_empty(key));
     auto bucket = calc_bucket(key);
     while (true) {
       auto &node = nodes_[bucket];
       if (EqT()(node.key(), key)) {
-        return {create_iterator(&node), false};
+        return {NodePointer(&node), false};
       }
       if (node.empty()) {
         node.emplace(std::move(key), std::forward<ArgsT>(args)...);
         used_node_count_++;
-        return {create_iterator(&node), true};
+        return {NodePointer(&node), true};
       }
       next_bucket(bucket);
     }
   }
 
-  std::pair<Iterator, bool> insert(KeyT key) {
+  std::pair<NodePointer, bool> insert(KeyT key) {
     return emplace(std::move(key));
   }
 
@@ -305,6 +363,12 @@ class FlatHashTable {
     try_shrink();
   }
 
+  void erase(NodePointer it) {
+    DCHECK(it != end());
+    erase_node(it.get());
+    try_shrink();
+  }
+
   template <class F>
   void remove_if(F &&f) {
     if (empty()) {

tdutils/td/utils/MapNode.h

@@ -34,6 +34,10 @@ struct MapNode {
     return *this;
   }
 
+  const MapNode &get_public() const {
+    return *this;
+  }
+
   MapNode() {
   }
   MapNode(KeyT key, ValueT value) : first(std::move(key)) {

tdutils/td/utils/SetNode.h

@@ -14,7 +14,7 @@ namespace td {
 template <class KeyT>
 struct SetNode {
   using public_key_type = KeyT;
-  using public_type = KeyT;
+  using public_type = const KeyT;
   using second_type = KeyT;  // TODO: remove second_type?
 
   KeyT first{};
@@ -23,7 +23,7 @@ struct SetNode {
     return first;
   }
 
-  KeyT &get_public() {
+  const KeyT &get_public() {
     return first;
   }