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diff --git a/src/seastar/include/seastar/util/indirect.hh b/src/seastar/include/seastar/util/indirect.hh
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+/*
+ * This file is open source software, licensed to you under the terms
+ * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership.  You may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Copyright (C) 2016 ScyllaDB
+ */
+
+#pragma once
+
+#include <memory>
+
+namespace seastar {
+
+// This header defines functors for comparing and hashing pointers by pointed-to values instead of pointer addresses.
+//
+// Examples:
+//
+//  std::multiset<shared_ptr<sstring>, indirect_less<shared_ptr<sstring>>> _multiset;
+//
+//  std::unordered_map<shared_ptr<sstring>, bool,
+//      indirect_hash<shared_ptr<sstring>>, indirect_equal_to<shared_ptr<sstring>>> _unordered_map;
+//
+
+template<typename Pointer, typename Equal = std::equal_to<typename std::pointer_traits<Pointer>::element_type>>
+struct indirect_equal_to {
+    Equal _eq;
+    indirect_equal_to(Equal eq = Equal()) : _eq(std::move(eq)) {}
+    bool operator()(const Pointer& i1, const Pointer& i2) const {
+        if (bool(i1) ^ bool(i2)) {
+            return false;
+        }
+        return !i1 || _eq(*i1, *i2);
+    }
+};
+
+template<typename Pointer, typename Less = std::less<typename std::pointer_traits<Pointer>::element_type>>
+struct indirect_less {
+    Less _cmp;
+    indirect_less(Less cmp = Less()) : _cmp(std::move(cmp)) {}
+    bool operator()(const Pointer& i1, const Pointer& i2) const {
+        if (i1 && i2) {
+            return _cmp(*i1, *i2);
+        }
+        return !i1 && i2;
+    }
+};
+
+template<typename Pointer, typename Hash = std::hash<typename std::pointer_traits<Pointer>::element_type>>
+struct indirect_hash {
+    Hash _h;
+    indirect_hash(Hash h = Hash()) : _h(std::move(h)) {}
+    size_t operator()(const Pointer& p) const {
+        if (p) {
+            return _h(*p);
+        }
+        return 0;
+    }
+};
+
+}