Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 1 | // -*- C++ -*- |
| 2 | //===------------------------ shared_mutex --------------------------------===// |
| 3 | // |
| 4 | // The LLVM Compiler Infrastructure |
| 5 | // |
| 6 | // This file is dual licensed under the MIT and the University of Illinois Open |
| 7 | // Source Licenses. See LICENSE.TXT for details. |
| 8 | // |
| 9 | //===----------------------------------------------------------------------===// |
| 10 | |
| 11 | #ifndef _LIBCPP_SHARED_MUTEX |
| 12 | #define _LIBCPP_SHARED_MUTEX |
| 13 | |
| 14 | /* |
| 15 | shared_mutex synopsis |
| 16 | |
| 17 | // C++1y |
| 18 | |
| 19 | namespace std |
| 20 | { |
| 21 | |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 22 | class shared_timed_mutex |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 23 | { |
| 24 | public: |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 25 | shared_timed_mutex(); |
| 26 | ~shared_timed_mutex(); |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 27 | |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 28 | shared_timed_mutex(const shared_timed_mutex&) = delete; |
| 29 | shared_timed_mutex& operator=(const shared_timed_mutex&) = delete; |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 30 | |
| 31 | // Exclusive ownership |
| 32 | void lock(); // blocking |
| 33 | bool try_lock(); |
| 34 | template <class Rep, class Period> |
| 35 | bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
| 36 | template <class Clock, class Duration> |
| 37 | bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
| 38 | void unlock(); |
| 39 | |
| 40 | // Shared ownership |
| 41 | void lock_shared(); // blocking |
| 42 | bool try_lock_shared(); |
| 43 | template <class Rep, class Period> |
| 44 | bool |
| 45 | try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time); |
| 46 | template <class Clock, class Duration> |
| 47 | bool |
| 48 | try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time); |
| 49 | void unlock_shared(); |
| 50 | }; |
| 51 | |
| 52 | template <class Mutex> |
| 53 | class shared_lock |
| 54 | { |
| 55 | public: |
| 56 | typedef Mutex mutex_type; |
| 57 | |
| 58 | // Shared locking |
| 59 | shared_lock() noexcept; |
| 60 | explicit shared_lock(mutex_type& m); // blocking |
| 61 | shared_lock(mutex_type& m, defer_lock_t) noexcept; |
| 62 | shared_lock(mutex_type& m, try_to_lock_t); |
| 63 | shared_lock(mutex_type& m, adopt_lock_t); |
| 64 | template <class Clock, class Duration> |
| 65 | shared_lock(mutex_type& m, |
| 66 | const chrono::time_point<Clock, Duration>& abs_time); |
| 67 | template <class Rep, class Period> |
| 68 | shared_lock(mutex_type& m, |
| 69 | const chrono::duration<Rep, Period>& rel_time); |
| 70 | ~shared_lock(); |
| 71 | |
| 72 | shared_lock(shared_lock const&) = delete; |
| 73 | shared_lock& operator=(shared_lock const&) = delete; |
| 74 | |
| 75 | shared_lock(shared_lock&& u) noexcept; |
| 76 | shared_lock& operator=(shared_lock&& u) noexcept; |
| 77 | |
| 78 | void lock(); // blocking |
| 79 | bool try_lock(); |
| 80 | template <class Rep, class Period> |
| 81 | bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
| 82 | template <class Clock, class Duration> |
| 83 | bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
| 84 | void unlock(); |
| 85 | |
| 86 | // Setters |
| 87 | void swap(shared_lock& u) noexcept; |
| 88 | mutex_type* release() noexcept; |
| 89 | |
| 90 | // Getters |
| 91 | bool owns_lock() const noexcept; |
| 92 | explicit operator bool () const noexcept; |
| 93 | mutex_type* mutex() const noexcept; |
| 94 | }; |
| 95 | |
| 96 | template <class Mutex> |
| 97 | void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept; |
| 98 | |
| 99 | } // std |
| 100 | |
| 101 | */ |
| 102 | |
| 103 | #include <__config> |
| 104 | |
| 105 | #if _LIBCPP_STD_VER > 11 || defined(_LIBCPP_BUILDING_SHARED_MUTEX) |
| 106 | |
| 107 | #include <__mutex_base> |
| 108 | |
| 109 | #include <__undef_min_max> |
| 110 | |
| 111 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 112 | #pragma GCC system_header |
| 113 | #endif |
| 114 | |
| 115 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 116 | |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 117 | class _LIBCPP_TYPE_VIS shared_timed_mutex |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 118 | { |
| 119 | mutex __mut_; |
| 120 | condition_variable __gate1_; |
| 121 | condition_variable __gate2_; |
| 122 | unsigned __state_; |
| 123 | |
| 124 | static const unsigned __write_entered_ = 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1); |
| 125 | static const unsigned __n_readers_ = ~__write_entered_; |
| 126 | public: |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 127 | shared_timed_mutex(); |
| 128 | _LIBCPP_INLINE_VISIBILITY ~shared_timed_mutex() = default; |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 129 | |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 130 | shared_timed_mutex(const shared_timed_mutex&) = delete; |
| 131 | shared_timed_mutex& operator=(const shared_timed_mutex&) = delete; |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 132 | |
| 133 | // Exclusive ownership |
| 134 | void lock(); |
| 135 | bool try_lock(); |
| 136 | template <class _Rep, class _Period> |
| 137 | _LIBCPP_INLINE_VISIBILITY |
| 138 | bool |
| 139 | try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time) |
| 140 | { |
| 141 | return try_lock_until(chrono::steady_clock::now() + __rel_time); |
| 142 | } |
| 143 | template <class _Clock, class _Duration> |
| 144 | bool |
| 145 | try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time); |
| 146 | void unlock(); |
| 147 | |
| 148 | // Shared ownership |
| 149 | void lock_shared(); |
| 150 | bool try_lock_shared(); |
| 151 | template <class _Rep, class _Period> |
| 152 | _LIBCPP_INLINE_VISIBILITY |
| 153 | bool |
| 154 | try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time) |
| 155 | { |
| 156 | return try_lock_shared_until(chrono::steady_clock::now() + __rel_time); |
| 157 | } |
| 158 | template <class _Clock, class _Duration> |
| 159 | bool |
| 160 | try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time); |
| 161 | void unlock_shared(); |
| 162 | }; |
| 163 | |
| 164 | template <class _Clock, class _Duration> |
| 165 | bool |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 166 | shared_timed_mutex::try_lock_until( |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 167 | const chrono::time_point<_Clock, _Duration>& __abs_time) |
| 168 | { |
| 169 | unique_lock<mutex> __lk(__mut_); |
| 170 | if (__state_ & __write_entered_) |
| 171 | { |
| 172 | while (true) |
| 173 | { |
| 174 | cv_status __status = __gate1_.wait_until(__lk, __abs_time); |
| 175 | if ((__state_ & __write_entered_) == 0) |
| 176 | break; |
| 177 | if (__status == cv_status::timeout) |
| 178 | return false; |
| 179 | } |
| 180 | } |
| 181 | __state_ |= __write_entered_; |
| 182 | if (__state_ & __n_readers_) |
| 183 | { |
| 184 | while (true) |
| 185 | { |
| 186 | cv_status __status = __gate2_.wait_until(__lk, __abs_time); |
| 187 | if ((__state_ & __n_readers_) == 0) |
| 188 | break; |
| 189 | if (__status == cv_status::timeout) |
| 190 | { |
| 191 | __state_ &= ~__write_entered_; |
| 192 | return false; |
| 193 | } |
| 194 | } |
| 195 | } |
| 196 | return true; |
| 197 | } |
| 198 | |
| 199 | template <class _Clock, class _Duration> |
| 200 | bool |
David Majnemer | f9f95be | 2014-03-17 20:19:44 +0000 | [diff] [blame] | 201 | shared_timed_mutex::try_lock_shared_until( |
Howard Hinnant | ba898e4 | 2013-09-21 01:49:28 +0000 | [diff] [blame] | 202 | const chrono::time_point<_Clock, _Duration>& __abs_time) |
| 203 | { |
| 204 | unique_lock<mutex> __lk(__mut_); |
| 205 | if ((__state_ & __write_entered_) || (__state_ & __n_readers_) == __n_readers_) |
| 206 | { |
| 207 | while (true) |
| 208 | { |
| 209 | cv_status status = __gate1_.wait_until(__lk, __abs_time); |
| 210 | if ((__state_ & __write_entered_) == 0 && |
| 211 | (__state_ & __n_readers_) < __n_readers_) |
| 212 | break; |
| 213 | if (status == cv_status::timeout) |
| 214 | return false; |
| 215 | } |
| 216 | } |
| 217 | unsigned __num_readers = (__state_ & __n_readers_) + 1; |
| 218 | __state_ &= ~__n_readers_; |
| 219 | __state_ |= __num_readers; |
| 220 | return true; |
| 221 | } |
| 222 | |
| 223 | template <class _Mutex> |
| 224 | class shared_lock |
| 225 | { |
| 226 | public: |
| 227 | typedef _Mutex mutex_type; |
| 228 | |
| 229 | private: |
| 230 | mutex_type* __m_; |
| 231 | bool __owns_; |
| 232 | |
| 233 | public: |
| 234 | _LIBCPP_INLINE_VISIBILITY |
| 235 | shared_lock() noexcept |
| 236 | : __m_(nullptr), |
| 237 | __owns_(false) |
| 238 | {} |
| 239 | |
| 240 | _LIBCPP_INLINE_VISIBILITY |
| 241 | explicit shared_lock(mutex_type& __m) |
| 242 | : __m_(&__m), |
| 243 | __owns_(true) |
| 244 | {__m_->lock_shared();} |
| 245 | |
| 246 | _LIBCPP_INLINE_VISIBILITY |
| 247 | shared_lock(mutex_type& __m, defer_lock_t) noexcept |
| 248 | : __m_(&__m), |
| 249 | __owns_(false) |
| 250 | {} |
| 251 | |
| 252 | _LIBCPP_INLINE_VISIBILITY |
| 253 | shared_lock(mutex_type& __m, try_to_lock_t) |
| 254 | : __m_(&__m), |
| 255 | __owns_(__m.try_lock_shared()) |
| 256 | {} |
| 257 | |
| 258 | _LIBCPP_INLINE_VISIBILITY |
| 259 | shared_lock(mutex_type& __m, adopt_lock_t) |
| 260 | : __m_(&__m), |
| 261 | __owns_(true) |
| 262 | {} |
| 263 | |
| 264 | template <class _Clock, class _Duration> |
| 265 | _LIBCPP_INLINE_VISIBILITY |
| 266 | shared_lock(mutex_type& __m, |
| 267 | const chrono::time_point<_Clock, _Duration>& __abs_time) |
| 268 | : __m_(&__m), |
| 269 | __owns_(__m.try_lock_shared_until(__abs_time)) |
| 270 | {} |
| 271 | |
| 272 | template <class _Rep, class _Period> |
| 273 | _LIBCPP_INLINE_VISIBILITY |
| 274 | shared_lock(mutex_type& __m, |
| 275 | const chrono::duration<_Rep, _Period>& __rel_time) |
| 276 | : __m_(&__m), |
| 277 | __owns_(__m.try_lock_shared_for(__rel_time)) |
| 278 | {} |
| 279 | |
| 280 | _LIBCPP_INLINE_VISIBILITY |
| 281 | ~shared_lock() |
| 282 | { |
| 283 | if (__owns_) |
| 284 | __m_->unlock_shared(); |
| 285 | } |
| 286 | |
| 287 | shared_lock(shared_lock const&) = delete; |
| 288 | shared_lock& operator=(shared_lock const&) = delete; |
| 289 | |
| 290 | _LIBCPP_INLINE_VISIBILITY |
| 291 | shared_lock(shared_lock&& __u) noexcept |
| 292 | : __m_(__u.__m_), |
| 293 | __owns_(__u.__owns_) |
| 294 | { |
| 295 | __u.__m_ = nullptr; |
| 296 | __u.__owns_ = false; |
| 297 | } |
| 298 | |
| 299 | _LIBCPP_INLINE_VISIBILITY |
| 300 | shared_lock& operator=(shared_lock&& __u) noexcept |
| 301 | { |
| 302 | if (__owns_) |
| 303 | __m_->unlock_shared(); |
| 304 | __m_ = nullptr; |
| 305 | __owns_ = false; |
| 306 | __m_ = __u.__m_; |
| 307 | __owns_ = __u.__owns_; |
| 308 | __u.__m_ = nullptr; |
| 309 | __u.__owns_ = false; |
| 310 | return *this; |
| 311 | } |
| 312 | |
| 313 | void lock(); |
| 314 | bool try_lock(); |
| 315 | template <class Rep, class Period> |
| 316 | bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
| 317 | template <class Clock, class Duration> |
| 318 | bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
| 319 | void unlock(); |
| 320 | |
| 321 | // Setters |
| 322 | _LIBCPP_INLINE_VISIBILITY |
| 323 | void swap(shared_lock& __u) noexcept |
| 324 | { |
| 325 | _VSTD::swap(__m_, __u.__m_); |
| 326 | _VSTD::swap(__owns_, __u.__owns_); |
| 327 | } |
| 328 | |
| 329 | _LIBCPP_INLINE_VISIBILITY |
| 330 | mutex_type* release() noexcept |
| 331 | { |
| 332 | mutex_type* __m = __m_; |
| 333 | __m_ = nullptr; |
| 334 | __owns_ = false; |
| 335 | return __m; |
| 336 | } |
| 337 | |
| 338 | // Getters |
| 339 | _LIBCPP_INLINE_VISIBILITY |
| 340 | bool owns_lock() const noexcept {return __owns_;} |
| 341 | |
| 342 | _LIBCPP_INLINE_VISIBILITY |
| 343 | explicit operator bool () const noexcept {return __owns_;} |
| 344 | |
| 345 | _LIBCPP_INLINE_VISIBILITY |
| 346 | mutex_type* mutex() const noexcept {return __m_;} |
| 347 | }; |
| 348 | |
| 349 | template <class _Mutex> |
| 350 | void |
| 351 | shared_lock<_Mutex>::lock() |
| 352 | { |
| 353 | if (__m_ == nullptr) |
| 354 | __throw_system_error(EPERM, "shared_lock::lock: references null mutex"); |
| 355 | if (__owns_) |
| 356 | __throw_system_error(EDEADLK, "shared_lock::lock: already locked"); |
| 357 | __m_->lock_shared(); |
| 358 | __owns_ = true; |
| 359 | } |
| 360 | |
| 361 | template <class _Mutex> |
| 362 | bool |
| 363 | shared_lock<_Mutex>::try_lock() |
| 364 | { |
| 365 | if (__m_ == nullptr) |
| 366 | __throw_system_error(EPERM, "shared_lock::try_lock: references null mutex"); |
| 367 | if (__owns_) |
| 368 | __throw_system_error(EDEADLK, "shared_lock::try_lock: already locked"); |
| 369 | __owns_ = __m_->try_lock_shared(); |
| 370 | return __owns_; |
| 371 | } |
| 372 | |
| 373 | template <class _Mutex> |
| 374 | template <class _Rep, class _Period> |
| 375 | bool |
| 376 | shared_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d) |
| 377 | { |
| 378 | if (__m_ == nullptr) |
| 379 | __throw_system_error(EPERM, "shared_lock::try_lock_for: references null mutex"); |
| 380 | if (__owns_) |
| 381 | __throw_system_error(EDEADLK, "shared_lock::try_lock_for: already locked"); |
| 382 | __owns_ = __m_->try_lock_shared_for(__d); |
| 383 | return __owns_; |
| 384 | } |
| 385 | |
| 386 | template <class _Mutex> |
| 387 | template <class _Clock, class _Duration> |
| 388 | bool |
| 389 | shared_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t) |
| 390 | { |
| 391 | if (__m_ == nullptr) |
| 392 | __throw_system_error(EPERM, "shared_lock::try_lock_until: references null mutex"); |
| 393 | if (__owns_) |
| 394 | __throw_system_error(EDEADLK, "shared_lock::try_lock_until: already locked"); |
| 395 | __owns_ = __m_->try_lock_shared_until(__t); |
| 396 | return __owns_; |
| 397 | } |
| 398 | |
| 399 | template <class _Mutex> |
| 400 | void |
| 401 | shared_lock<_Mutex>::unlock() |
| 402 | { |
| 403 | if (!__owns_) |
| 404 | __throw_system_error(EPERM, "shared_lock::unlock: not locked"); |
| 405 | __m_->unlock_shared(); |
| 406 | __owns_ = false; |
| 407 | } |
| 408 | |
| 409 | template <class _Mutex> |
| 410 | inline _LIBCPP_INLINE_VISIBILITY |
| 411 | void |
| 412 | swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) noexcept |
| 413 | {__x.swap(__y);} |
| 414 | |
| 415 | _LIBCPP_END_NAMESPACE_STD |
| 416 | |
| 417 | #endif // _LIBCPP_STD_VER > 11 |
| 418 | |
| 419 | #endif // _LIBCPP_SHARED_MUTEX |