1 // Support for concurrent programing -*- C++ -*- 2 3 // Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009 4 // Free Software Foundation, Inc. 5 // 6 // This file is part of the GNU ISO C++ Library. This library is free 7 // software; you can redistribute it and/or modify it under the 8 // terms of the GNU General Public License as published by the 9 // Free Software Foundation; either version 3, or (at your option) 10 // any later version. 11 12 // This library is distributed in the hope that it will be useful, 13 // but WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 // GNU General Public License for more details. 16 17 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 /** @file concurrence.h 27 * This is an internal header file, included by other library headers. 28 * You should not attempt to use it directly. 29 */ 30 31 #ifndef _CONCURRENCE_H 32 #define _CONCURRENCE_H 1 33 34 #include <exception> 35 #include <bits/gthr.h> 36 #include <bits/functexcept.h> 37 38 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 39 40 // Available locking policies: 41 // _S_single single-threaded code that doesn't need to be locked. 42 // _S_mutex multi-threaded code that requires additional support 43 // from gthr.h or abstraction layers in concurrence.h. 44 // _S_atomic multi-threaded code using atomic operations. 45 enum _Lock_policy { _S_single, _S_mutex, _S_atomic }; 46 47 // Compile time constant that indicates prefered locking policy in 48 // the current configuration. 49 static const _Lock_policy __default_lock_policy = 50 #ifdef __GTHREADS 51 #if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \ 52 && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) 53 _S_atomic; 54 #else 55 _S_mutex; 56 #endif 57 #else 58 _S_single; 59 #endif 60 61 // NB: As this is used in libsupc++, need to only depend on 62 // exception. No stdexception classes, no use of std::string. 63 class __concurrence_lock_error : public std::exception 64 { 65 public: 66 virtual char const* 67 what() const throw() 68 { return "__gnu_cxx::__concurrence_lock_error"; } 69 }; 70 71 class __concurrence_unlock_error : public std::exception 72 { 73 public: 74 virtual char const* 75 what() const throw() 76 { return "__gnu_cxx::__concurrence_unlock_error"; } 77 }; 78 79 class __concurrence_broadcast_error : public std::exception 80 { 81 public: 82 virtual char const* 83 what() const throw() 84 { return "__gnu_cxx::__concurrence_broadcast_error"; } 85 }; 86 87 class __concurrence_wait_error : public std::exception 88 { 89 public: 90 virtual char const* 91 what() const throw() 92 { return "__gnu_cxx::__concurrence_wait_error"; } 93 }; 94 95 // Substitute for concurrence_error object in the case of -fno-exceptions. 96 inline void 97 __throw_concurrence_lock_error() 98 { 99 #if __EXCEPTIONS 100 throw __concurrence_lock_error(); 101 #else 102 __builtin_abort(); 103 #endif 104 } 105 106 inline void 107 __throw_concurrence_unlock_error() 108 { 109 #if __EXCEPTIONS 110 throw __concurrence_unlock_error(); 111 #else 112 __builtin_abort(); 113 #endif 114 } 115 116 #ifdef __GTHREAD_HAS_COND 117 inline void 118 __throw_concurrence_broadcast_error() 119 { 120 #if __EXCEPTIONS 121 throw __concurrence_broadcast_error(); 122 #else 123 __builtin_abort(); 124 #endif 125 } 126 127 inline void 128 __throw_concurrence_wait_error() 129 { 130 #if __EXCEPTIONS 131 throw __concurrence_wait_error(); 132 #else 133 __builtin_abort(); 134 #endif 135 } 136 #endif 137 138 class __mutex 139 { 140 private: 141 __gthread_mutex_t _M_mutex; 142 143 __mutex(const __mutex&); 144 __mutex& operator=(const __mutex&); 145 146 public: 147 __mutex() 148 { 149 #if __GTHREADS 150 if (__gthread_active_p()) 151 { 152 #if defined __GTHREAD_MUTEX_INIT 153 __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT; 154 _M_mutex = __tmp; 155 #else 156 __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex); 157 #endif 158 } 159 #endif 160 } 161 162 void lock() 163 { 164 #if __GTHREADS 165 if (__gthread_active_p()) 166 { 167 if (__gthread_mutex_lock(&_M_mutex) != 0) 168 __throw_concurrence_lock_error(); 169 } 170 #endif 171 } 172 173 void unlock() 174 { 175 #if __GTHREADS 176 if (__gthread_active_p()) 177 { 178 if (__gthread_mutex_unlock(&_M_mutex) != 0) 179 __throw_concurrence_unlock_error(); 180 } 181 #endif 182 } 183 184 __gthread_mutex_t* gthread_mutex(void) 185 { return &_M_mutex; } 186 }; 187 188 class __recursive_mutex 189 { 190 private: 191 __gthread_recursive_mutex_t _M_mutex; 192 193 __recursive_mutex(const __recursive_mutex&); 194 __recursive_mutex& operator=(const __recursive_mutex&); 195 196 public: 197 __recursive_mutex() 198 { 199 #if __GTHREADS 200 if (__gthread_active_p()) 201 { 202 #if defined __GTHREAD_RECURSIVE_MUTEX_INIT 203 __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT; 204 _M_mutex = __tmp; 205 #else 206 __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex); 207 #endif 208 } 209 #endif 210 } 211 212 void lock() 213 { 214 #if __GTHREADS 215 if (__gthread_active_p()) 216 { 217 if (__gthread_recursive_mutex_lock(&_M_mutex) != 0) 218 __throw_concurrence_lock_error(); 219 } 220 #endif 221 } 222 223 void unlock() 224 { 225 #if __GTHREADS 226 if (__gthread_active_p()) 227 { 228 if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0) 229 __throw_concurrence_unlock_error(); 230 } 231 #endif 232 } 233 234 __gthread_recursive_mutex_t* gthread_recursive_mutex(void) 235 { return &_M_mutex; } 236 }; 237 238 /// Scoped lock idiom. 239 // Acquire the mutex here with a constructor call, then release with 240 // the destructor call in accordance with RAII style. 241 class __scoped_lock 242 { 243 public: 244 typedef __mutex __mutex_type; 245 246 private: 247 __mutex_type& _M_device; 248 249 __scoped_lock(const __scoped_lock&); 250 __scoped_lock& operator=(const __scoped_lock&); 251 252 public: 253 explicit __scoped_lock(__mutex_type& __name) : _M_device(__name) 254 { _M_device.lock(); } 255 256 ~__scoped_lock() throw() 257 { _M_device.unlock(); } 258 }; 259 260 #ifdef __GTHREAD_HAS_COND 261 class __cond 262 { 263 private: 264 __gthread_cond_t _M_cond; 265 266 __cond(const __cond&); 267 __cond& operator=(const __cond&); 268 269 public: 270 __cond() 271 { 272 #if __GTHREADS 273 if (__gthread_active_p()) 274 { 275 #if defined __GTHREAD_COND_INIT 276 __gthread_cond_t __tmp = __GTHREAD_COND_INIT; 277 _M_cond = __tmp; 278 #else 279 __GTHREAD_COND_INIT_FUNCTION(&_M_cond); 280 #endif 281 } 282 #endif 283 } 284 285 void broadcast() 286 { 287 #if __GTHREADS 288 if (__gthread_active_p()) 289 { 290 if (__gthread_cond_broadcast(&_M_cond) != 0) 291 __throw_concurrence_broadcast_error(); 292 } 293 #endif 294 } 295 296 void wait(__mutex *mutex) 297 { 298 #if __GTHREADS 299 { 300 if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0) 301 __throw_concurrence_wait_error(); 302 } 303 #endif 304 } 305 306 void wait_recursive(__recursive_mutex *mutex) 307 { 308 #if __GTHREADS 309 { 310 if (__gthread_cond_wait_recursive(&_M_cond, 311 mutex->gthread_recursive_mutex()) 312 != 0) 313 __throw_concurrence_wait_error(); 314 } 315 #endif 316 } 317 }; 318 #endif 319 320 _GLIBCXX_END_NAMESPACE 321 322 #endif 323