Mathias Agopian | 2bd9959 | 2012-02-25 23:02:14 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2007 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 _LIBS_UTILS_MUTEX_H |
| 18 | #define _LIBS_UTILS_MUTEX_H |
| 19 | |
| 20 | #include <stdint.h> |
| 21 | #include <sys/types.h> |
| 22 | #include <time.h> |
| 23 | |
| 24 | #if defined(HAVE_PTHREADS) |
| 25 | # include <pthread.h> |
| 26 | #endif |
| 27 | |
| 28 | #include <utils/Errors.h> |
| 29 | |
| 30 | // --------------------------------------------------------------------------- |
| 31 | namespace android { |
| 32 | // --------------------------------------------------------------------------- |
| 33 | |
| 34 | class Condition; |
| 35 | |
| 36 | /* |
| 37 | * Simple mutex class. The implementation is system-dependent. |
| 38 | * |
| 39 | * The mutex must be unlocked by the thread that locked it. They are not |
| 40 | * recursive, i.e. the same thread can't lock it multiple times. |
| 41 | */ |
| 42 | class Mutex { |
| 43 | public: |
| 44 | enum { |
| 45 | PRIVATE = 0, |
| 46 | SHARED = 1 |
| 47 | }; |
| 48 | |
| 49 | Mutex(); |
| 50 | Mutex(const char* name); |
| 51 | Mutex(int type, const char* name = NULL); |
| 52 | ~Mutex(); |
| 53 | |
| 54 | // lock or unlock the mutex |
| 55 | status_t lock(); |
| 56 | void unlock(); |
| 57 | |
| 58 | // lock if possible; returns 0 on success, error otherwise |
| 59 | status_t tryLock(); |
| 60 | |
| 61 | // Manages the mutex automatically. It'll be locked when Autolock is |
| 62 | // constructed and released when Autolock goes out of scope. |
| 63 | class Autolock { |
| 64 | public: |
| 65 | inline Autolock(Mutex& mutex) : mLock(mutex) { mLock.lock(); } |
| 66 | inline Autolock(Mutex* mutex) : mLock(*mutex) { mLock.lock(); } |
| 67 | inline ~Autolock() { mLock.unlock(); } |
| 68 | private: |
| 69 | Mutex& mLock; |
| 70 | }; |
| 71 | |
| 72 | private: |
| 73 | friend class Condition; |
| 74 | |
| 75 | // A mutex cannot be copied |
| 76 | Mutex(const Mutex&); |
| 77 | Mutex& operator = (const Mutex&); |
| 78 | |
| 79 | #if defined(HAVE_PTHREADS) |
| 80 | pthread_mutex_t mMutex; |
| 81 | #else |
| 82 | void _init(); |
| 83 | void* mState; |
| 84 | #endif |
| 85 | }; |
| 86 | |
| 87 | // --------------------------------------------------------------------------- |
| 88 | |
| 89 | #if defined(HAVE_PTHREADS) |
| 90 | |
| 91 | inline Mutex::Mutex() { |
| 92 | pthread_mutex_init(&mMutex, NULL); |
| 93 | } |
Igor Murashkin | a27c1e0 | 2012-12-05 16:10:26 -0800 | [diff] [blame] | 94 | inline Mutex::Mutex(__attribute__((unused)) const char* name) { |
Mathias Agopian | 2bd9959 | 2012-02-25 23:02:14 -0800 | [diff] [blame] | 95 | pthread_mutex_init(&mMutex, NULL); |
| 96 | } |
Igor Murashkin | a27c1e0 | 2012-12-05 16:10:26 -0800 | [diff] [blame] | 97 | inline Mutex::Mutex(int type, __attribute__((unused)) const char* name) { |
Mathias Agopian | 2bd9959 | 2012-02-25 23:02:14 -0800 | [diff] [blame] | 98 | if (type == SHARED) { |
| 99 | pthread_mutexattr_t attr; |
| 100 | pthread_mutexattr_init(&attr); |
| 101 | pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED); |
| 102 | pthread_mutex_init(&mMutex, &attr); |
| 103 | pthread_mutexattr_destroy(&attr); |
| 104 | } else { |
| 105 | pthread_mutex_init(&mMutex, NULL); |
| 106 | } |
| 107 | } |
| 108 | inline Mutex::~Mutex() { |
| 109 | pthread_mutex_destroy(&mMutex); |
| 110 | } |
| 111 | inline status_t Mutex::lock() { |
| 112 | return -pthread_mutex_lock(&mMutex); |
| 113 | } |
| 114 | inline void Mutex::unlock() { |
| 115 | pthread_mutex_unlock(&mMutex); |
| 116 | } |
| 117 | inline status_t Mutex::tryLock() { |
| 118 | return -pthread_mutex_trylock(&mMutex); |
| 119 | } |
| 120 | |
| 121 | #endif // HAVE_PTHREADS |
| 122 | |
| 123 | // --------------------------------------------------------------------------- |
| 124 | |
| 125 | /* |
| 126 | * Automatic mutex. Declare one of these at the top of a function. |
| 127 | * When the function returns, it will go out of scope, and release the |
| 128 | * mutex. |
| 129 | */ |
| 130 | |
| 131 | typedef Mutex::Autolock AutoMutex; |
| 132 | |
| 133 | // --------------------------------------------------------------------------- |
| 134 | }; // namespace android |
| 135 | // --------------------------------------------------------------------------- |
| 136 | |
| 137 | #endif // _LIBS_UTILS_MUTEX_H |