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 "../utility/move_on_copy.h"\r
  25 #include "../log/log.h"\r
  26 \r
  27 #include <tbb/atomic.h>\r
  28 #include <tbb/concurrent_queue.h>\r
  29 \r
  30 #include <boost/thread.hpp>\r
  31 #include <boost/noncopyable.hpp>\r
  32 \r
  33 #include <functional>\r
  34 \r
  35 namespace caspar {\r
  36 \r
  37 namespace detail {\r
  38 \r
  39 typedef struct tagTHREADNAME_INFO\r
  40 {\r
  41         DWORD dwType; // must be 0x1000\r
  42         LPCSTR szName; // pointer to name (in user addr space)\r
  43         DWORD dwThreadID; // thread ID (-1=caller thread)\r
  44         DWORD dwFlags; // reserved for future use, must be zero\r
  45 } THREADNAME_INFO;\r
  46 \r
  47 inline void SetThreadName(DWORD dwThreadID, LPCSTR szThreadName)\r
  48 {\r
  49         THREADNAME_INFO info;\r
  50         {\r
  51                 info.dwType = 0x1000;\r
  52                 info.szName = szThreadName;\r
  53                 info.dwThreadID = dwThreadID;\r
  54                 info.dwFlags = 0;\r
  55         }\r
  56         __try\r
  57         {\r
  58                 RaiseException( 0x406D1388, 0, sizeof(info)/sizeof(DWORD), (DWORD*)&info );\r
  59         }\r
  60         __except (EXCEPTION_CONTINUE_EXECUTION){}       \r
  61 }\r
  62 \r
  63 }\r
  64 \r
  65 enum task_priority\r
  66 {\r
  67         high_priority,\r
  68         normal_priority,\r
  69         priority_count\r
  70 };\r
  71 \r
  72 enum thread_priority\r
  73 {\r
  74         high_priority_class,\r
  75         above_normal_priority_class,\r
  76         normal_priority_class,\r
  77         below_normal_priority_class\r
  78 };\r
  79 \r
  80 class executor : boost::noncopyable\r
  81 {\r
  82         const std::string name_;\r
  83         boost::thread thread_;\r
  84         tbb::atomic<bool> is_running_;\r
  85         \r
  86         typedef tbb::concurrent_bounded_queue<std::function<void()>> function_queue;\r
  87         function_queue execution_queue_[priority_count];\r
  88                 \r
  89         template<typename Func>\r
  90         auto create_task(Func&& func) -> boost::packaged_task<decltype(func())> // noexcept\r
  91         {       \r
  92                 typedef boost::packaged_task<decltype(func())> task_type;\r
  93                                 \r
  94                 auto task = task_type(std::forward<Func>(func));\r
  95                 \r
  96                 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
  97                 {\r
  98                         try\r
  99                         {\r
 100                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 101                                         my_task();\r
 102                         }\r
 103                         catch(boost::task_already_started&){}\r
 104                 }));\r
 105                                 \r
 106                 return std::move(task);\r
 107         }\r
 108 \r
 109 public:\r
 110                 \r
 111         explicit executor(const std::wstring& name) : name_(narrow(name)) // noexcept\r
 112         {\r
 113                 thread_ = boost::thread([this]{run();});\r
 114                 is_running_ = true;\r
 115         }\r
 116         \r
 117         virtual ~executor() // noexcept\r
 118         {\r
 119                 stop();\r
 120                 join();\r
 121         }\r
 122 \r
 123         void set_capacity(size_t capacity) // noexcept\r
 124         {\r
 125                 execution_queue_[normal_priority].set_capacity(capacity);\r
 126         }\r
 127 \r
 128         void set_priority_class(thread_priority p)\r
 129         {\r
 130                 begin_invoke([=]\r
 131                 {\r
 132                         if(p == high_priority_class)\r
 133                                 SetThreadPriority(GetCurrentThread(), HIGH_PRIORITY_CLASS);\r
 134                         if(p == above_normal_priority_class)\r
 135                                 SetThreadPriority(GetCurrentThread(), ABOVE_NORMAL_PRIORITY_CLASS);\r
 136                         else if(p == normal_priority_class)\r
 137                                 SetThreadPriority(GetCurrentThread(), NORMAL_PRIORITY_CLASS);\r
 138                         else if(p == below_normal_priority_class)\r
 139                                 SetThreadPriority(GetCurrentThread(), BELOW_NORMAL_PRIORITY_CLASS);\r
 140                 });\r
 141         }\r
 142                                 \r
 143         void stop() // noexcept\r
 144         {\r
 145                 is_running_ = false;    \r
 146                 execution_queue_[normal_priority].try_push([]{}); // Wake the execution thread.\r
 147         }\r
 148 \r
 149         void wait() // noexcept\r
 150         {\r
 151                 invoke([]{});\r
 152         }\r
 153 \r
 154         void join()\r
 155         {\r
 156                 if(boost::this_thread::get_id() != thread_.get_id())\r
 157                         thread_.join();\r
 158         }\r
 159                                 \r
 160         template<typename Func>\r
 161         auto begin_invoke(Func&& func, task_priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 162         {       \r
 163                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 164                 auto task_adaptor = make_move_on_copy(create_task(func));\r
 165 \r
 166                 auto future = task_adaptor.value.get_future();\r
 167 \r
 168                 execution_queue_[priority].push([=]\r
 169                 {\r
 170                         try{task_adaptor.value();}\r
 171                         catch(boost::task_already_started&){}\r
 172                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 173                 });\r
 174 \r
 175                 if(priority != normal_priority)\r
 176                         execution_queue_[normal_priority].push(nullptr);\r
 177                                         \r
 178                 return std::move(future);               \r
 179         }\r
 180 \r
 181         template<typename Func>\r
 182         auto try_begin_invoke(Func&& func, task_priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 183         {\r
 184                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 185                 auto task_adaptor = make_move_on_copy(create_task(func));\r
 186                 \r
 187                 auto future = task_adaptor.value.get_future();\r
 188 \r
 189                 if(priority == normal_priority || execution_queue_[normal_priority].try_push(nullptr))\r
 190                 {                       \r
 191                         execution_queue_[priority].try_push([=]\r
 192                         {\r
 193                                 try{task_adaptor.value();}\r
 194                                 catch(boost::task_already_started&){}\r
 195                                 catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 196                         });\r
 197                 }\r
 198                 \r
 199                 return std::move(future);                       \r
 200         }\r
 201 \r
 202         template<typename Func>\r
 203         auto invoke(Func&& func, task_priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 204         {\r
 205                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 206                         return func();\r
 207                 \r
 208                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 209         }\r
 210 \r
 211         template<typename Func>\r
 212         auto try_invoke(Func&& func, task_priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 213         {\r
 214                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 215                         return func();\r
 216                 \r
 217                 return try_begin_invoke(std::forward<Func>(func), prioriy).get();\r
 218         }\r
 219 \r
 220         void yield() // noexcept\r
 221         {\r
 222                 if(boost::this_thread::get_id() != thread_.get_id())  // Only yield when calling from execution thread.\r
 223                         return;\r
 224 \r
 225                 std::function<void()> func;\r
 226                 while(execution_queue_[high_priority].try_pop(func))\r
 227                 {\r
 228                         if(func)\r
 229                                 func();\r
 230                 }       \r
 231         }\r
 232         \r
 233         function_queue::size_type capacity() const /*noexcept*/ { return execution_queue_[normal_priority].capacity();  }\r
 234         function_queue::size_type size() const /*noexcept*/ { return execution_queue_[normal_priority].size();  }\r
 235         bool empty() const /*noexcept*/ { return execution_queue_[normal_priority].empty();     }\r
 236         bool is_running() const /*noexcept*/ { return is_running_; }    \r
 237                 \r
 238 private:\r
 239         \r
 240         void execute() // noexcept\r
 241         {\r
 242                 std::function<void()> func;\r
 243                 execution_queue_[normal_priority].pop(func);    \r
 244 \r
 245                 yield();\r
 246 \r
 247                 if(func)\r
 248                         func();\r
 249         }\r
 250 \r
 251         void run() // noexcept\r
 252         {\r
 253                 win32_exception::install_handler();             \r
 254                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 255                 while(is_running_)\r
 256                 {\r
 257                         try\r
 258                         {\r
 259                                 execute();\r
 260                         }\r
 261                         catch(...)\r
 262                         {\r
 263                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 264                         }\r
 265                 }\r
 266         }       \r
 267 };\r
 268 \r
 269 }