Greg Hartman | a4ff248 | 2017-10-03 16:35:00 -0700 | [diff] [blame^] | 1 | #pragma once |
Tomasz Wiszkowski | a449e9c | 2017-05-25 14:30:56 -0700 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (C) 2016 The Android Open Source Project |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | */ |
Tomasz Wiszkowski | a449e9c | 2017-05-25 14:30:56 -0700 | [diff] [blame] | 17 | |
| 18 | // Concurreny classess for Cloud Android projects. |
| 19 | // |
| 20 | // These more or less mimic the interface of the C++ classes: |
| 21 | // Mutex is similar to std::mutex |
| 22 | // ConditionVariable is similar to std::condition_variable |
| 23 | // LockGuard is similar to std::lock_guard |
| 24 | // |
| 25 | // There are some extensions: |
| 26 | // ScopedThread creates a Thread and joins it when the class is destroyed |
| 27 | // This comes in handy during unit tests. It should be used cautiously, if |
| 28 | // at all, in production code because thread creation isn't free. |
| 29 | |
| 30 | #include <stdint.h> |
| 31 | #include <pthread.h> |
| 32 | #include "common/libs/time/monotonic_time.h" |
| 33 | |
| 34 | namespace avd { |
| 35 | |
| 36 | class Mutex { |
| 37 | friend class ConditionVariable; |
| 38 | |
| 39 | public: |
| 40 | Mutex() { |
| 41 | pthread_mutex_init(&mutex_, NULL); |
| 42 | } |
| 43 | |
| 44 | ~Mutex() { |
| 45 | pthread_mutex_destroy(&mutex_); |
| 46 | } |
| 47 | |
| 48 | void Lock() { |
| 49 | pthread_mutex_lock(&mutex_); |
| 50 | } |
| 51 | |
| 52 | void Unlock() { |
| 53 | pthread_mutex_unlock(&mutex_); |
| 54 | } |
| 55 | |
| 56 | // TODO(ghartman): Add TryLock if and only if there's a good use case. |
| 57 | |
| 58 | protected: |
| 59 | |
| 60 | pthread_mutex_t* GetMutex() { |
| 61 | return &mutex_; |
| 62 | } |
| 63 | |
| 64 | pthread_mutex_t mutex_; |
| 65 | |
| 66 | private: |
| 67 | Mutex(const Mutex&); |
| 68 | Mutex& operator= (const Mutex&); |
| 69 | }; |
| 70 | |
| 71 | class ConditionVariable { |
| 72 | public: |
| 73 | explicit ConditionVariable(Mutex* mutex) : mutex_(mutex) { |
| 74 | pthread_condattr_t attr; |
| 75 | pthread_condattr_init(&attr); |
| 76 | pthread_condattr_setclock(&attr, CLOCK_MONOTONIC); |
| 77 | pthread_cond_init(&cond_, &attr); |
| 78 | pthread_condattr_destroy(&attr); |
| 79 | } |
| 80 | |
| 81 | ~ConditionVariable() { |
| 82 | pthread_cond_destroy(&cond_); |
| 83 | } |
| 84 | |
| 85 | int NotifyOne() { |
| 86 | return pthread_cond_signal(&cond_); |
| 87 | } |
| 88 | |
| 89 | int NotifyAll() { |
| 90 | return pthread_cond_broadcast(&cond_); |
| 91 | } |
| 92 | |
| 93 | int Wait() { |
| 94 | return pthread_cond_wait(&cond_, mutex_->GetMutex()); |
| 95 | } |
| 96 | |
| 97 | int WaitUntil(const avd::time::MonotonicTimePoint& tp) { |
| 98 | struct timespec ts; |
| 99 | tp.ToTimespec(&ts); |
| 100 | return pthread_cond_timedwait(&cond_, mutex_->GetMutex(), &ts); |
| 101 | } |
| 102 | |
| 103 | protected: |
| 104 | Mutex* mutex_; |
| 105 | pthread_cond_t cond_; |
| 106 | |
| 107 | private: |
| 108 | ConditionVariable(const ConditionVariable&); |
| 109 | ConditionVariable& operator= (const ConditionVariable&); |
| 110 | }; |
| 111 | |
| 112 | template <typename M> class LockGuard { |
| 113 | public: |
| 114 | explicit LockGuard(M& mutex) : mutex_(mutex) { |
| 115 | mutex_.Lock(); |
| 116 | } |
| 117 | |
| 118 | ~LockGuard() { |
| 119 | mutex_.Unlock(); |
| 120 | } |
| 121 | |
| 122 | private: |
| 123 | M& mutex_; |
| 124 | |
| 125 | LockGuard(const LockGuard&); |
| 126 | LockGuard& operator= (const LockGuard&); |
| 127 | }; |
| 128 | |
| 129 | // Use only in cases where the mutex can't be upgraded to a Mutex. |
| 130 | template<> class LockGuard<pthread_mutex_t> { |
| 131 | public: |
| 132 | explicit LockGuard(pthread_mutex_t& mutex) : mutex_(mutex), unlock_(false) { |
| 133 | unlock_ = (pthread_mutex_lock(&mutex_) == 0); |
| 134 | } |
| 135 | |
| 136 | ~LockGuard() { |
| 137 | if (unlock_) { |
| 138 | pthread_mutex_unlock(&mutex_); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | private: |
| 143 | pthread_mutex_t& mutex_; |
| 144 | bool unlock_; |
| 145 | |
| 146 | LockGuard(const LockGuard&); |
| 147 | LockGuard& operator= (const LockGuard&); |
| 148 | }; |
| 149 | |
| 150 | class ScopedThread { |
| 151 | public: |
| 152 | ScopedThread(void* (*start)(void*), void* arg) { |
| 153 | pthread_create(&thread_, NULL, start, arg); |
| 154 | } |
| 155 | |
| 156 | ~ScopedThread() { |
| 157 | void* value; |
| 158 | pthread_join(thread_, &value); |
| 159 | } |
| 160 | |
| 161 | protected: |
| 162 | pthread_t thread_; |
| 163 | |
| 164 | private: |
| 165 | ScopedThread(const ScopedThread&); |
| 166 | ScopedThread& operator= (const ScopedThread&); |
| 167 | }; |
| 168 | |
| 169 | } // namespace avd |