1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_BASE_LOOKUP_SET_H_ 18 #define INCLUDE_PERFETTO_BASE_LOOKUP_SET_H_ 19 20 #include <set> 21 22 namespace perfetto { 23 namespace base { 24 25 // Set that allows lookup from const member of the object. 26 template <typename T, typename U, U T::*p> 27 class LookupSet { 28 public: Get(const U & key)29 T* Get(const U& key) { 30 // This will be nicer with C++14 transparent comparators. 31 // Then we will be able to look up by just the key using a sutiable 32 // comparator. 33 // 34 // For now we need to allow to construct a T from the key. 35 T node(key); 36 auto it = set_.find(node); 37 if (it == set_.end()) 38 return nullptr; 39 return const_cast<T*>(&(*it)); 40 } 41 42 template <typename... P> Emplace(P &&...args)43 T* Emplace(P&&... args) { 44 auto r = set_.emplace(std::forward<P>(args)...); 45 return const_cast<T*>(&(*r.first)); 46 } 47 Remove(const T & child)48 bool Remove(const T& child) { return set_.erase(child); } 49 50 static_assert(std::is_const<U>::value, "key must be const"); 51 52 private: 53 class Comparator { 54 public: operator()55 bool operator()(const T& one, const T& other) const { 56 return (&one)->*p < (&other)->*p; 57 } 58 }; 59 60 std::set<T, Comparator> set_; 61 }; 62 63 } // namespace base 64 } // namespace perfetto 65 66 #endif // INCLUDE_PERFETTO_BASE_LOOKUP_SET_H_ 67