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| 1 //===------------------------- mutex.cpp ----------------------------------===// |
| 2 // |
| 3 // The LLVM Compiler Infrastructure |
| 4 // |
| 5 // This file is dual licensed under the MIT and the University of Illinois Open |
| 6 // Source Licenses. See LICENSE.TXT for details. |
| 7 // |
| 8 //===----------------------------------------------------------------------===// |
| 9 |
| 10 #define _LIBCPP_BUILDING_MUTEX |
| 11 #include "mutex" |
| 12 #include "limits" |
| 13 #include "system_error" |
| 14 #include "cassert" |
| 15 |
| 16 _LIBCPP_BEGIN_NAMESPACE_STD |
| 17 |
| 18 const defer_lock_t defer_lock = {}; |
| 19 const try_to_lock_t try_to_lock = {}; |
| 20 const adopt_lock_t adopt_lock = {}; |
| 21 |
| 22 mutex::~mutex() |
| 23 { |
| 24 pthread_mutex_destroy(&__m_); |
| 25 } |
| 26 |
| 27 void |
| 28 mutex::lock() |
| 29 { |
| 30 int ec = pthread_mutex_lock(&__m_); |
| 31 if (ec) |
| 32 __throw_system_error(ec, "mutex lock failed"); |
| 33 } |
| 34 |
| 35 bool |
| 36 mutex::try_lock() _NOEXCEPT |
| 37 { |
| 38 return pthread_mutex_trylock(&__m_) == 0; |
| 39 } |
| 40 |
| 41 void |
| 42 mutex::unlock() _NOEXCEPT |
| 43 { |
| 44 int ec = pthread_mutex_unlock(&__m_); |
| 45 (void)ec; |
| 46 assert(ec == 0); |
| 47 } |
| 48 |
| 49 // recursive_mutex |
| 50 |
| 51 recursive_mutex::recursive_mutex() |
| 52 { |
| 53 pthread_mutexattr_t attr; |
| 54 int ec = pthread_mutexattr_init(&attr); |
| 55 if (ec) |
| 56 goto fail; |
| 57 ec = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); |
| 58 if (ec) |
| 59 { |
| 60 pthread_mutexattr_destroy(&attr); |
| 61 goto fail; |
| 62 } |
| 63 ec = pthread_mutex_init(&__m_, &attr); |
| 64 if (ec) |
| 65 { |
| 66 pthread_mutexattr_destroy(&attr); |
| 67 goto fail; |
| 68 } |
| 69 ec = pthread_mutexattr_destroy(&attr); |
| 70 if (ec) |
| 71 { |
| 72 pthread_mutex_destroy(&__m_); |
| 73 goto fail; |
| 74 } |
| 75 return; |
| 76 fail: |
| 77 __throw_system_error(ec, "recursive_mutex constructor failed"); |
| 78 } |
| 79 |
| 80 recursive_mutex::~recursive_mutex() |
| 81 { |
| 82 int e = pthread_mutex_destroy(&__m_); |
| 83 (void)e; |
| 84 assert(e == 0); |
| 85 } |
| 86 |
| 87 void |
| 88 recursive_mutex::lock() |
| 89 { |
| 90 int ec = pthread_mutex_lock(&__m_); |
| 91 if (ec) |
| 92 __throw_system_error(ec, "recursive_mutex lock failed"); |
| 93 } |
| 94 |
| 95 void |
| 96 recursive_mutex::unlock() _NOEXCEPT |
| 97 { |
| 98 int e = pthread_mutex_unlock(&__m_); |
| 99 (void)e; |
| 100 assert(e == 0); |
| 101 } |
| 102 |
| 103 bool |
| 104 recursive_mutex::try_lock() _NOEXCEPT |
| 105 { |
| 106 return pthread_mutex_trylock(&__m_) == 0; |
| 107 } |
| 108 |
| 109 // timed_mutex |
| 110 |
| 111 timed_mutex::timed_mutex() |
| 112 : __locked_(false) |
| 113 { |
| 114 } |
| 115 |
| 116 timed_mutex::~timed_mutex() |
| 117 { |
| 118 lock_guard<mutex> _(__m_); |
| 119 } |
| 120 |
| 121 void |
| 122 timed_mutex::lock() |
| 123 { |
| 124 unique_lock<mutex> lk(__m_); |
| 125 while (__locked_) |
| 126 __cv_.wait(lk); |
| 127 __locked_ = true; |
| 128 } |
| 129 |
| 130 bool |
| 131 timed_mutex::try_lock() _NOEXCEPT |
| 132 { |
| 133 unique_lock<mutex> lk(__m_, try_to_lock); |
| 134 if (lk.owns_lock() && !__locked_) |
| 135 { |
| 136 __locked_ = true; |
| 137 return true; |
| 138 } |
| 139 return false; |
| 140 } |
| 141 |
| 142 void |
| 143 timed_mutex::unlock() _NOEXCEPT |
| 144 { |
| 145 lock_guard<mutex> _(__m_); |
| 146 __locked_ = false; |
| 147 __cv_.notify_one(); |
| 148 } |
| 149 |
| 150 // recursive_timed_mutex |
| 151 |
| 152 recursive_timed_mutex::recursive_timed_mutex() |
| 153 : __count_(0), |
| 154 __id_(0) |
| 155 { |
| 156 } |
| 157 |
| 158 recursive_timed_mutex::~recursive_timed_mutex() |
| 159 { |
| 160 lock_guard<mutex> _(__m_); |
| 161 } |
| 162 |
| 163 void |
| 164 recursive_timed_mutex::lock() |
| 165 { |
| 166 pthread_t id = pthread_self(); |
| 167 unique_lock<mutex> lk(__m_); |
| 168 if (pthread_equal(id, __id_)) |
| 169 { |
| 170 if (__count_ == numeric_limits<size_t>::max()) |
| 171 __throw_system_error(EAGAIN, "recursive_timed_mutex lock limit reach
ed"); |
| 172 ++__count_; |
| 173 return; |
| 174 } |
| 175 while (__count_ != 0) |
| 176 __cv_.wait(lk); |
| 177 __count_ = 1; |
| 178 __id_ = id; |
| 179 } |
| 180 |
| 181 bool |
| 182 recursive_timed_mutex::try_lock() _NOEXCEPT |
| 183 { |
| 184 pthread_t id = pthread_self(); |
| 185 unique_lock<mutex> lk(__m_, try_to_lock); |
| 186 if (lk.owns_lock() && (__count_ == 0 || pthread_equal(id, __id_))) |
| 187 { |
| 188 if (__count_ == numeric_limits<size_t>::max()) |
| 189 return false; |
| 190 ++__count_; |
| 191 __id_ = id; |
| 192 return true; |
| 193 } |
| 194 return false; |
| 195 } |
| 196 |
| 197 void |
| 198 recursive_timed_mutex::unlock() _NOEXCEPT |
| 199 { |
| 200 unique_lock<mutex> lk(__m_); |
| 201 if (--__count_ == 0) |
| 202 { |
| 203 __id_ = 0; |
| 204 lk.unlock(); |
| 205 __cv_.notify_one(); |
| 206 } |
| 207 } |
| 208 |
| 209 // If dispatch_once_f ever handles C++ exceptions, and if one can get to it |
| 210 // without illegal macros (unexpected macros not beginning with _UpperCase or |
| 211 // __lowercase), and if it stops spinning waiting threads, then call_once should |
| 212 // call into dispatch_once_f instead of here. Relevant radar this code needs to |
| 213 // keep in sync with: 7741191. |
| 214 |
| 215 static pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER; |
| 216 static pthread_cond_t cv = PTHREAD_COND_INITIALIZER; |
| 217 |
| 218 void |
| 219 __call_once(volatile unsigned long& flag, void* arg, void(*func)(void*)) |
| 220 { |
| 221 pthread_mutex_lock(&mut); |
| 222 while (flag == 1) |
| 223 pthread_cond_wait(&cv, &mut); |
| 224 if (flag == 0) |
| 225 { |
| 226 #ifndef _LIBCPP_NO_EXCEPTIONS |
| 227 try |
| 228 { |
| 229 #endif // _LIBCPP_NO_EXCEPTIONS |
| 230 flag = 1; |
| 231 pthread_mutex_unlock(&mut); |
| 232 func(arg); |
| 233 pthread_mutex_lock(&mut); |
| 234 flag = ~0ul; |
| 235 pthread_mutex_unlock(&mut); |
| 236 pthread_cond_broadcast(&cv); |
| 237 #ifndef _LIBCPP_NO_EXCEPTIONS |
| 238 } |
| 239 catch (...) |
| 240 { |
| 241 pthread_mutex_lock(&mut); |
| 242 flag = 0ul; |
| 243 pthread_mutex_unlock(&mut); |
| 244 pthread_cond_broadcast(&cv); |
| 245 throw; |
| 246 } |
| 247 #endif // _LIBCPP_NO_EXCEPTIONS |
| 248 } |
| 249 else |
| 250 pthread_mutex_unlock(&mut); |
| 251 } |
| 252 |
| 253 _LIBCPP_END_NAMESPACE_STD |
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