1 /* 2 * Copyright (C) 2016 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 #ifndef ANDROID_HIDL_CONCURRENT_MAP_H 17 #define ANDROID_HIDL_CONCURRENT_MAP_H 18 19 #include <mutex> 20 #include <map> 21 22 namespace android { 23 namespace hardware { 24 25 template<typename K, typename V> 26 class ConcurrentMap { 27 private: 28 using size_type = typename std::map<K, V>::size_type; 29 using iterator = typename std::map<K, V>::iterator; 30 using const_iterator = typename std::map<K, V>::const_iterator; 31 32 public: set(K && k,V && v)33 void set(K &&k, V &&v) { 34 std::unique_lock<std::mutex> _lock(mMutex); 35 mMap[std::forward<K>(k)] = std::forward<V>(v); 36 } 37 38 // get with the given default value. get(const K & k,const V & def)39 const V &get(const K &k, const V &def) const { 40 std::unique_lock<std::mutex> _lock(mMutex); 41 const_iterator iter = mMap.find(k); 42 if (iter == mMap.end()) { 43 return def; 44 } 45 return iter->second; 46 } 47 erase(const K & k)48 size_type erase(const K &k) { 49 std::unique_lock<std::mutex> _lock(mMutex); 50 return mMap.erase(k); 51 } 52 eraseIfEqual(const K & k,const V & v)53 size_type eraseIfEqual(const K& k, const V& v) { 54 std::unique_lock<std::mutex> _lock(mMutex); 55 const_iterator iter = mMap.find(k); 56 if (iter == mMap.end()) { 57 return 0; 58 } 59 if (iter->second == v) { 60 mMap.erase(iter); 61 return 1; 62 } else { 63 return 0; 64 } 65 } 66 lock()67 std::unique_lock<std::mutex> lock() { return std::unique_lock<std::mutex>(mMutex); } 68 setLocked(K && k,V && v)69 void setLocked(K&& k, V&& v) { mMap[std::forward<K>(k)] = std::forward<V>(v); } setLocked(K && k,const V & v)70 void setLocked(K&& k, const V& v) { mMap[std::forward<K>(k)] = v; } 71 getLocked(const K & k,const V & def)72 const V& getLocked(const K& k, const V& def) const { 73 const_iterator iter = mMap.find(k); 74 if (iter == mMap.end()) { 75 return def; 76 } 77 return iter->second; 78 } 79 eraseLocked(const K & k)80 size_type eraseLocked(const K& k) { return mMap.erase(k); } 81 82 // the concurrent map must be locked in order to iterate over it begin()83 iterator begin() { return mMap.begin(); } end()84 iterator end() { return mMap.end(); } begin()85 const_iterator begin() const { return mMap.begin(); } end()86 const_iterator end() const { return mMap.end(); } 87 88 private: 89 mutable std::mutex mMutex; 90 std::map<K, V> mMap; 91 }; 92 93 namespace details { 94 95 // TODO(b/69122224): remove this type and usages of it 96 // DO NOT ADD USAGES 97 template <typename T> 98 class DoNotDestruct { 99 public: DoNotDestruct()100 DoNotDestruct() { new (buffer) T(); } get()101 T& get() { return *reinterpret_cast<T*>(buffer); } 102 T* operator->() { return reinterpret_cast<T*>(buffer); } 103 104 private: 105 alignas(T) char buffer[sizeof(T)]; 106 }; 107 108 } // namespace details 109 110 } // namespace hardware 111 } // namespace android 112 113 114 #endif // ANDROID_HIDL_CONCURRENT_MAP_H 115