git.sesse.net Git - casparcg/blob - common/concurrency/executor.h

   1 /*\r
   2 * copyright (c) 2010 Sveriges Television AB <info@casparcg.com>\r
   3 *\r
   4 *  This file is part of CasparCG.\r
   5 *\r
   6 *    CasparCG is free software: you can redistribute it and/or modify\r
   7 *    it under the terms of the GNU General Public License as published by\r
   8 *    the Free Software Foundation, either version 3 of the License, or\r
   9 *    (at your option) any later version.\r
  10 *\r
  11 *    CasparCG is distributed in the hope that it will be useful,\r
  12 *    but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14 *    GNU General Public License for more details.\r
  15 \r
  16 *    You should have received a copy of the GNU General Public License\r
  17 *    along with CasparCG.  If not, see <http://www.gnu.org/licenses/>.\r
  18 *\r
  19 */\r
  20 #pragma once\r
  21 \r
  22 #include "../exception/win32_exception.h"\r
  23 #include "../utility/string.h"\r
  24 #include "../log/log.h"\r
  25 \r
  26 #include <tbb/atomic.h>\r
  27 #include <tbb/concurrent_queue.h>\r
  28 \r
  29 #include <boost/thread.hpp>\r
  30 #include <boost/noncopyable.hpp>\r
  31 \r
  32 #include <functional>\r
  33 \r
  34 namespace caspar {\r
  35 \r
  36 namespace detail {\r
  37 \r
  38 typedef struct tagTHREADNAME_INFO\r
  39 {\r
  40         DWORD dwType; // must be 0x1000\r
  41         LPCSTR szName; // pointer to name (in user addr space)\r
  42         DWORD dwThreadID; // thread ID (-1=caller thread)\r
  43         DWORD dwFlags; // reserved for future use, must be zero\r
  44 } THREADNAME_INFO;\r
  45 \r
  46 inline void SetThreadName(DWORD dwThreadID, LPCSTR szThreadName)\r
  47 {\r
  48         THREADNAME_INFO info;\r
  49         {\r
  50                 info.dwType = 0x1000;\r
  51                 info.szName = szThreadName;\r
  52                 info.dwThreadID = dwThreadID;\r
  53                 info.dwFlags = 0;\r
  54         }\r
  55         __try\r
  56         {\r
  57                 RaiseException( 0x406D1388, 0, sizeof(info)/sizeof(DWORD), (DWORD*)&info );\r
  58         }\r
  59         __except (EXCEPTION_CONTINUE_EXECUTION){}       \r
  60 }\r
  61 \r
  62 }\r
  63 \r
  64 enum task_priority\r
  65 {\r
  66         high_priority,\r
  67         normal_priority,\r
  68         priority_count\r
  69 };\r
  70 \r
  71 enum thread_priority\r
  72 {\r
  73         high_priority_class,\r
  74         above_normal_priority_class,\r
  75         normal_priority_class,\r
  76         below_normal_priority_class\r
  77 };\r
  78 \r
  79 namespace internal\r
  80 {\r
  81         template<typename T>\r
  82         struct move_on_copy\r
  83         {\r
  84                 move_on_copy(const move_on_copy<T>& other) : value(std::move(other.value)){}\r
  85                 move_on_copy(T&& value) : value(std::move(value)){}\r
  86                 mutable T value;\r
  87         };\r
  88 \r
  89         template<typename T>\r
  90         move_on_copy<T> make_move_on_copy(T&& value)\r
  91         {\r
  92                 return move_on_copy<T>(std::move(value));\r
  93         }\r
  94 }\r
  95 \r
  96 class executor : boost::noncopyable\r
  97 {\r
  98         const std::string name_;\r
  99         boost::thread thread_;\r
 100         tbb::atomic<bool> is_running_;\r
 101         \r
 102         typedef tbb::concurrent_bounded_queue<std::function<void()>> function_queue;\r
 103         function_queue execution_queue_[priority_count];\r
 104                 \r
 105         template<typename Func>\r
 106         auto create_task(Func&& func) -> boost::packaged_task<decltype(func())> // noexcept\r
 107         {       \r
 108                 typedef boost::packaged_task<decltype(func())> task_type;\r
 109                                 \r
 110                 auto task = task_type(std::forward<Func>(func));\r
 111                 \r
 112                 task.set_wait_callback(std::function<void(task_type&)>([=](task_type& my_task) // The std::function wrapper is required in order to add ::result_type to functor class.\r
 113                 {\r
 114                         try\r
 115                         {\r
 116                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 117                                         my_task();\r
 118                         }\r
 119                         catch(boost::task_already_started&){}\r
 120                 }));\r
 121                                 \r
 122                 return std::move(task);\r
 123         }\r
 124 \r
 125 public:\r
 126                 \r
 127         explicit executor(const std::wstring& name) : name_(narrow(name)) // noexcept\r
 128         {\r
 129                 thread_ = boost::thread([this]{run();});\r
 130                 is_running_ = true;\r
 131         }\r
 132         \r
 133         virtual ~executor() // noexcept\r
 134         {\r
 135                 stop();\r
 136                 join();\r
 137         }\r
 138 \r
 139         void set_capacity(size_t capacity) // noexcept\r
 140         {\r
 141                 execution_queue_[normal_priority].set_capacity(capacity);\r
 142         }\r
 143 \r
 144         void set_priority_class(thread_priority p)\r
 145         {\r
 146                 begin_invoke([=]\r
 147                 {\r
 148                         if(p == high_priority_class)\r
 149                                 SetThreadPriority(GetCurrentThread(), HIGH_PRIORITY_CLASS);\r
 150                         if(p == above_normal_priority_class)\r
 151                                 SetThreadPriority(GetCurrentThread(), ABOVE_NORMAL_PRIORITY_CLASS);\r
 152                         else if(p == normal_priority_class)\r
 153                                 SetThreadPriority(GetCurrentThread(), NORMAL_PRIORITY_CLASS);\r
 154                         else if(p == below_normal_priority_class)\r
 155                                 SetThreadPriority(GetCurrentThread(), BELOW_NORMAL_PRIORITY_CLASS);\r
 156                 });\r
 157         }\r
 158                                 \r
 159         void stop() // noexcept\r
 160         {\r
 161                 is_running_ = false;    \r
 162                 execution_queue_[normal_priority].try_push([]{}); // Wake the execution thread.\r
 163         }\r
 164 \r
 165         void wait() // noexcept\r
 166         {\r
 167                 invoke([]{});\r
 168         }\r
 169 \r
 170         void join()\r
 171         {\r
 172                 if(boost::this_thread::get_id() != thread_.get_id())\r
 173                         thread_.join();\r
 174         }\r
 175                                 \r
 176         template<typename Func>\r
 177         auto begin_invoke(Func&& func, task_priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 178         {       \r
 179                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 180                 auto task_adaptor = internal::make_move_on_copy(create_task(func));\r
 181 \r
 182                 auto future = task_adaptor.value.get_future();\r
 183 \r
 184                 execution_queue_[priority].push([=]\r
 185                 {\r
 186                         try{task_adaptor.value();}\r
 187                         catch(boost::task_already_started&){}\r
 188                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 189                 });\r
 190 \r
 191                 if(priority != normal_priority)\r
 192                         execution_queue_[normal_priority].push(nullptr);\r
 193                                         \r
 194                 return std::move(future);               \r
 195         }\r
 196 \r
 197         template<typename Func>\r
 198         auto try_begin_invoke(Func&& func, task_priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 199         {\r
 200                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 201                 auto task_adaptor = internal::make_move_on_copy(create_task(func));\r
 202                 \r
 203                 auto future = task_adaptor.value.get_future();\r
 204 \r
 205                 if(priority == normal_priority || execution_queue_[normal_priority].try_push(nullptr))\r
 206                 {                       \r
 207                         execution_queue_[priority].try_push([=]\r
 208                         {\r
 209                                 try{task_adaptor.value();}\r
 210                                 catch(boost::task_already_started&){}\r
 211                                 catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 212                         });\r
 213                 }\r
 214                 \r
 215                 return std::move(future);                       \r
 216         }\r
 217 \r
 218         template<typename Func>\r
 219         auto invoke(Func&& func, task_priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 220         {\r
 221                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 222                         return func();\r
 223                 \r
 224                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 225         }\r
 226 \r
 227         template<typename Func>\r
 228         auto try_invoke(Func&& func, task_priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 229         {\r
 230                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 231                         return func();\r
 232                 \r
 233                 return try_begin_invoke(std::forward<Func>(func), prioriy).get();\r
 234         }\r
 235 \r
 236         void yield() // noexcept\r
 237         {\r
 238                 if(boost::this_thread::get_id() != thread_.get_id())  // Only yield when calling from execution thread.\r
 239                         return;\r
 240 \r
 241                 std::function<void()> func;\r
 242                 while(execution_queue_[high_priority].try_pop(func))\r
 243                 {\r
 244                         if(func)\r
 245                                 func();\r
 246                 }       \r
 247         }\r
 248         \r
 249         function_queue::size_type capacity() const /*noexcept*/ { return execution_queue_[normal_priority].capacity();  }\r
 250         function_queue::size_type size() const /*noexcept*/ { return execution_queue_[normal_priority].size();  }\r
 251         bool empty() const /*noexcept*/ { return execution_queue_[normal_priority].empty();     }\r
 252         bool is_running() const /*noexcept*/ { return is_running_; }    \r
 253                 \r
 254 private:\r
 255         \r
 256         void execute() // noexcept\r
 257         {\r
 258                 std::function<void()> func;\r
 259                 execution_queue_[normal_priority].pop(func);    \r
 260 \r
 261                 yield();\r
 262 \r
 263                 if(func)\r
 264                         func();\r
 265         }\r
 266 \r
 267         void run() // noexcept\r
 268         {\r
 269                 win32_exception::install_handler();             \r
 270                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 271                 while(is_running_)\r
 272                 {\r
 273                         try\r
 274                         {\r
 275                                 execute();\r
 276                         }\r
 277                         catch(...)\r
 278                         {\r
 279                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 280                         }\r
 281                 }\r
 282         }       \r
 283 };\r
 284 \r
 285 }