| 1 | // Support for concurrent programing -*- C++ -*- |
|---|---|
| 2 | |
| 3 | // Copyright (C) 2003-2017 Free Software Foundation, Inc. |
| 4 | // |
| 5 | // This file is part of the GNU ISO C++ Library. This library is free |
| 6 | // software; you can redistribute it and/or modify it under the |
| 7 | // terms of the GNU General Public License as published by the |
| 8 | // Free Software Foundation; either version 3, or (at your option) |
| 9 | // any later version. |
| 10 | |
| 11 | // This library is distributed in the hope that it will be useful, |
| 12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | // GNU General Public License for more details. |
| 15 | |
| 16 | // Under Section 7 of GPL version 3, you are granted additional |
| 17 | // permissions described in the GCC Runtime Library Exception, version |
| 18 | // 3.1, as published by the Free Software Foundation. |
| 19 | |
| 20 | // You should have received a copy of the GNU General Public License and |
| 21 | // a copy of the GCC Runtime Library Exception along with this program; |
| 22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| 23 | // <http://www.gnu.org/licenses/>. |
| 24 | |
| 25 | /** @file ext/concurrence.h |
| 26 | * This file is a GNU extension to the Standard C++ Library. |
| 27 | */ |
| 28 | |
| 29 | #ifndef _CONCURRENCE_H |
| 30 | #define _CONCURRENCE_H 1 |
| 31 | |
| 32 | #pragma GCC system_header |
| 33 | |
| 34 | #include <exception> |
| 35 | #include <bits/gthr.h> |
| 36 | #include <bits/functexcept.h> |
| 37 | #include <bits/cpp_type_traits.h> |
| 38 | #include <ext/type_traits.h> |
| 39 | |
| 40 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
| 41 | { |
| 42 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| 43 | |
| 44 | // Available locking policies: |
| 45 | // _S_single single-threaded code that doesn't need to be locked. |
| 46 | // _S_mutex multi-threaded code that requires additional support |
| 47 | // from gthr.h or abstraction layers in concurrence.h. |
| 48 | // _S_atomic multi-threaded code using atomic operations. |
| 49 | enum _Lock_policy { _S_single, _S_mutex, _S_atomic }; |
| 50 | |
| 51 | // Compile time constant that indicates prefered locking policy in |
| 52 | // the current configuration. |
| 53 | static const _Lock_policy __default_lock_policy = |
| 54 | #ifdef __GTHREADS |
| 55 | #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \ |
| 56 | && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) |
| 57 | _S_atomic; |
| 58 | #else |
| 59 | _S_mutex; |
| 60 | #endif |
| 61 | #else |
| 62 | _S_single; |
| 63 | #endif |
| 64 | |
| 65 | // NB: As this is used in libsupc++, need to only depend on |
| 66 | // exception. No stdexception classes, no use of std::string. |
| 67 | class __concurrence_lock_error : public std::exception |
| 68 | { |
| 69 | public: |
| 70 | virtual char const* |
| 71 | what() const throw() |
| 72 | { return "__gnu_cxx::__concurrence_lock_error"; } |
| 73 | }; |
| 74 | |
| 75 | class __concurrence_unlock_error : public std::exception |
| 76 | { |
| 77 | public: |
| 78 | virtual char const* |
| 79 | what() const throw() |
| 80 | { return "__gnu_cxx::__concurrence_unlock_error"; } |
| 81 | }; |
| 82 | |
| 83 | class __concurrence_broadcast_error : public std::exception |
| 84 | { |
| 85 | public: |
| 86 | virtual char const* |
| 87 | what() const throw() |
| 88 | { return "__gnu_cxx::__concurrence_broadcast_error"; } |
| 89 | }; |
| 90 | |
| 91 | class __concurrence_wait_error : public std::exception |
| 92 | { |
| 93 | public: |
| 94 | virtual char const* |
| 95 | what() const throw() |
| 96 | { return "__gnu_cxx::__concurrence_wait_error"; } |
| 97 | }; |
| 98 | |
| 99 | // Substitute for concurrence_error object in the case of -fno-exceptions. |
| 100 | inline void |
| 101 | __throw_concurrence_lock_error() |
| 102 | { _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); } |
| 103 | |
| 104 | inline void |
| 105 | __throw_concurrence_unlock_error() |
| 106 | { _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); } |
| 107 | |
| 108 | #ifdef __GTHREAD_HAS_COND |
| 109 | inline void |
| 110 | __throw_concurrence_broadcast_error() |
| 111 | { _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); } |
| 112 | |
| 113 | inline void |
| 114 | __throw_concurrence_wait_error() |
| 115 | { _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); } |
| 116 | #endif |
| 117 | |
| 118 | class __mutex |
| 119 | { |
| 120 | private: |
| 121 | #if __GTHREADS && defined __GTHREAD_MUTEX_INIT |
| 122 | __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT; |
| 123 | #else |
| 124 | __gthread_mutex_t _M_mutex; |
| 125 | #endif |
| 126 | |
| 127 | __mutex(const __mutex&); |
| 128 | __mutex& operator=(const __mutex&); |
| 129 | |
| 130 | public: |
| 131 | __mutex() |
| 132 | { |
| 133 | #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT |
| 134 | if (__gthread_active_p()) |
| 135 | __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); |
| 136 | #endif |
| 137 | } |
| 138 | |
| 139 | #if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT |
| 140 | ~__mutex() |
| 141 | { |
| 142 | if (__gthread_active_p()) |
| 143 | __gthread_mutex_destroy(&_M_mutex); |
| 144 | } |
| 145 | #endif |
| 146 | |
| 147 | void lock() |
| 148 | { |
| 149 | #if __GTHREADS |
| 150 | if (__gthread_active_p()) |
| 151 | { |
| 152 | if (__gthread_mutex_lock(&_M_mutex) != 0) |
| 153 | __throw_concurrence_lock_error(); |
| 154 | } |
| 155 | #endif |
| 156 | } |
| 157 | |
| 158 | void unlock() |
| 159 | { |
| 160 | #if __GTHREADS |
| 161 | if (__gthread_active_p()) |
| 162 | { |
| 163 | if (__gthread_mutex_unlock(&_M_mutex) != 0) |
| 164 | __throw_concurrence_unlock_error(); |
| 165 | } |
| 166 | #endif |
| 167 | } |
| 168 | |
| 169 | __gthread_mutex_t* gthread_mutex(void) |
| 170 | { return &_M_mutex; } |
| 171 | }; |
| 172 | |
| 173 | class __recursive_mutex |
| 174 | { |
| 175 | private: |
| 176 | #if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT |
| 177 | __gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT; |
| 178 | #else |
| 179 | __gthread_recursive_mutex_t _M_mutex; |
| 180 | #endif |
| 181 | |
| 182 | __recursive_mutex(const __recursive_mutex&); |
| 183 | __recursive_mutex& operator=(const __recursive_mutex&); |
| 184 | |
| 185 | public: |
| 186 | __recursive_mutex() |
| 187 | { |
| 188 | #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT |
| 189 | if (__gthread_active_p()) |
| 190 | __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); |
| 191 | #endif |
| 192 | } |
| 193 | |
| 194 | #if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT |
| 195 | ~__recursive_mutex() |
| 196 | { |
| 197 | if (__gthread_active_p()) |
| 198 | __gthread_recursive_mutex_destroy(&_M_mutex); |
| 199 | } |
| 200 | #endif |
| 201 | |
| 202 | void lock() |
| 203 | { |
| 204 | #if __GTHREADS |
| 205 | if (__gthread_active_p()) |
| 206 | { |
| 207 | if (__gthread_recursive_mutex_lock(&_M_mutex) != 0) |
| 208 | __throw_concurrence_lock_error(); |
| 209 | } |
| 210 | #endif |
| 211 | } |
| 212 | |
| 213 | void unlock() |
| 214 | { |
| 215 | #if __GTHREADS |
| 216 | if (__gthread_active_p()) |
| 217 | { |
| 218 | if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0) |
| 219 | __throw_concurrence_unlock_error(); |
| 220 | } |
| 221 | #endif |
| 222 | } |
| 223 | |
| 224 | __gthread_recursive_mutex_t* gthread_recursive_mutex(void) |
| 225 | { return &_M_mutex; } |
| 226 | }; |
| 227 | |
| 228 | /// Scoped lock idiom. |
| 229 | // Acquire the mutex here with a constructor call, then release with |
| 230 | // the destructor call in accordance with RAII style. |
| 231 | class __scoped_lock |
| 232 | { |
| 233 | public: |
| 234 | typedef __mutex __mutex_type; |
| 235 | |
| 236 | private: |
| 237 | __mutex_type& _M_device; |
| 238 | |
| 239 | __scoped_lock(const __scoped_lock&); |
| 240 | __scoped_lock& operator=(const __scoped_lock&); |
| 241 | |
| 242 | public: |
| 243 | explicit __scoped_lock(__mutex_type& __name) : _M_device(__name) |
| 244 | { _M_device.lock(); } |
| 245 | |
| 246 | ~__scoped_lock() throw() |
| 247 | { _M_device.unlock(); } |
| 248 | }; |
| 249 | |
| 250 | #ifdef __GTHREAD_HAS_COND |
| 251 | class __cond |
| 252 | { |
| 253 | private: |
| 254 | #if __GTHREADS && defined __GTHREAD_COND_INIT |
| 255 | __gthread_cond_t _M_cond = __GTHREAD_COND_INIT; |
| 256 | #else |
| 257 | __gthread_cond_t _M_cond; |
| 258 | #endif |
| 259 | |
| 260 | __cond(const __cond&); |
| 261 | __cond& operator=(const __cond&); |
| 262 | |
| 263 | public: |
| 264 | __cond() |
| 265 | { |
| 266 | #if __GTHREADS && ! defined __GTHREAD_COND_INIT |
| 267 | if (__gthread_active_p()) |
| 268 | __GTHREAD_COND_INIT_FUNCTION(&_M_cond); |
| 269 | #endif |
| 270 | } |
| 271 | |
| 272 | #if __GTHREADS && ! defined __GTHREAD_COND_INIT |
| 273 | ~__cond() |
| 274 | { |
| 275 | if (__gthread_active_p()) |
| 276 | __gthread_cond_destroy(&_M_cond); |
| 277 | } |
| 278 | #endif |
| 279 | |
| 280 | void broadcast() |
| 281 | { |
| 282 | #if __GTHREADS |
| 283 | if (__gthread_active_p()) |
| 284 | { |
| 285 | if (__gthread_cond_broadcast(&_M_cond) != 0) |
| 286 | __throw_concurrence_broadcast_error(); |
| 287 | } |
| 288 | #endif |
| 289 | } |
| 290 | |
| 291 | void wait(__mutex *mutex) |
| 292 | { |
| 293 | #if __GTHREADS |
| 294 | { |
| 295 | if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0) |
| 296 | __throw_concurrence_wait_error(); |
| 297 | } |
| 298 | #endif |
| 299 | } |
| 300 | |
| 301 | void wait_recursive(__recursive_mutex *mutex) |
| 302 | { |
| 303 | #if __GTHREADS |
| 304 | { |
| 305 | if (__gthread_cond_wait_recursive(&_M_cond, |
| 306 | mutex->gthread_recursive_mutex()) |
| 307 | != 0) |
| 308 | __throw_concurrence_wait_error(); |
| 309 | } |
| 310 | #endif |
| 311 | } |
| 312 | }; |
| 313 | #endif |
| 314 | |
| 315 | _GLIBCXX_END_NAMESPACE_VERSION |
| 316 | } // namespace |
| 317 | |
| 318 | #endif |
| 319 |