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

   1 /*\r
   2 * Copyright (c) 2011 Sveriges Television AB <info@casparcg.com>\r
   3 *\r
   4 * This file is part of CasparCG (www.casparcg.com).\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 * Author: Robert Nagy, ronag89@gmail.com\r
  20 */\r
  21 \r
  22 #pragma once\r
  23 \r
  24 #include "except.h"\r
  25 #include "enum_class.h"\r
  26 #include "log.h"\r
  27 \r
  28 #include <tbb/atomic.h>\r
  29 #include <tbb/concurrent_priority_queue.h>\r
  30 #include <tbb/concurrent_queue.h>\r
  31 \r
  32 #include <boost/thread.hpp>\r
  33 \r
  34 #include <functional>\r
  35 \r
  36 namespace caspar {\r
  37                 \r
  38 struct task_priority_def\r
  39 {\r
  40         enum type\r
  41         {\r
  42                 lowest_priority = 0,\r
  43                 lower_priority,\r
  44                 low_priority,\r
  45                 normal_priority,\r
  46                 high_priority,\r
  47                 higher_priority\r
  48         };\r
  49 };\r
  50 typedef enum_class<task_priority_def> task_priority;\r
  51 \r
  52 class executor sealed\r
  53 {       \r
  54         struct priority_function\r
  55         {\r
  56                 int                                             priority;\r
  57                 std::function<void()>   func;\r
  58 \r
  59                 priority_function()\r
  60                 {\r
  61                 }\r
  62 \r
  63                 template<typename F>\r
  64                 priority_function(int priority, F&& func)\r
  65                         : priority(priority)\r
  66                         , func(std::forward<F>(func))\r
  67                 {\r
  68                 }\r
  69 \r
  70                 void operator()()\r
  71                 {\r
  72                         func();\r
  73                 }\r
  74 \r
  75                 bool operator<(const priority_function& other) const\r
  76                 {\r
  77                         return priority < other.priority;\r
  78                 }\r
  79         };\r
  80 \r
  81         executor(const executor&);\r
  82         executor& operator=(const executor&);\r
  83         \r
  84         typedef tbb::concurrent_priority_queue<priority_function>       function_queue_t;\r
  85         \r
  86         const std::wstring                                                                                      name_;\r
  87         tbb::atomic<bool>                                                                                       is_running_;\r
  88         boost::thread                                                                                           thread_;        \r
  89         function_queue_t                                                                                        execution_queue_;\r
  90         tbb::concurrent_bounded_queue<int>                                                      semaphore_;\r
  91                 \r
  92 public:         \r
  93         executor(const std::wstring& name)\r
  94                 : name_(name)\r
  95         {\r
  96                 is_running_ = true;\r
  97                 set_capacity(512);\r
  98                 thread_ = boost::thread([this]{run();});\r
  99         }\r
 100         \r
 101         ~executor()\r
 102         {\r
 103                 try\r
 104                 {\r
 105                         internal_begin_invoke([=]\r
 106                         {\r
 107                                 is_running_ = false;\r
 108                         }).wait();\r
 109                 }\r
 110                 catch(...)\r
 111                 {\r
 112                         CASPAR_LOG_CURRENT_EXCEPTION();\r
 113                 }\r
 114                 \r
 115                 thread_.join();\r
 116         }\r
 117                                                 \r
 118         template<typename Func>\r
 119         auto begin_invoke(Func&& func, task_priority priority = task_priority::normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 120         {       \r
 121                 if(!is_running_)\r
 122                         CASPAR_THROW_EXCEPTION(invalid_operation() << msg_info("executor not running.") << source_info(name_));\r
 123                                 \r
 124                 return internal_begin_invoke(std::forward<Func>(func), priority);       \r
 125         }\r
 126         \r
 127         template<typename Func>\r
 128         auto invoke(Func&& func, task_priority prioriy = task_priority::normal_priority) -> decltype(func()) // noexcept\r
 129         {\r
 130                 if(is_current())  // Avoids potential deadlock.\r
 131                         return func();\r
 132                 \r
 133                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 134         }\r
 135 \r
 136         void yield()\r
 137         {\r
 138                 if(!is_current())\r
 139                         CASPAR_THROW_EXCEPTION(invalid_operation() << msg_info("Executor can only yield inside of thread context.")  << source_info(name_));\r
 140 \r
 141                 int dummy;\r
 142                 if(!semaphore_.try_pop(dummy))\r
 143                         return;\r
 144 \r
 145                 priority_function func;\r
 146                 if(execution_queue_.try_pop(func))\r
 147                         func();\r
 148         }\r
 149 \r
 150         void set_capacity(std::size_t capacity)\r
 151         {\r
 152                 semaphore_.set_capacity(capacity);\r
 153         }\r
 154 \r
 155         std::size_t capacity() const\r
 156         {\r
 157                 return semaphore_.capacity();\r
 158         }\r
 159         \r
 160         void clear()\r
 161         {               \r
 162                 priority_function func;\r
 163                 while(execution_queue_.try_pop(func));\r
 164         }\r
 165                                 \r
 166         void stop()\r
 167         {\r
 168                 invoke([this]\r
 169                 {\r
 170                         is_running_ = false;\r
 171                 });\r
 172         }\r
 173 \r
 174         void wait()\r
 175         {\r
 176                 invoke([]{}, task_priority::lowest_priority);\r
 177         }\r
 178                 \r
 179         function_queue_t::size_type size() const \r
 180         {\r
 181                 return execution_queue_.size(); \r
 182         }\r
 183                 \r
 184         bool is_running() const\r
 185         {\r
 186                 return is_running_; \r
 187         }       \r
 188 \r
 189         bool is_current() const\r
 190         {\r
 191                 return boost::this_thread::get_id() == thread_.get_id();\r
 192         }\r
 193                 \r
 194 private:        \r
 195         \r
 196         template<typename Func>\r
 197         auto internal_begin_invoke(Func&& func, task_priority priority = task_priority::normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 198         {                                       \r
 199                 typedef typename std::remove_reference<Func>::type      function_type;\r
 200                 typedef decltype(func())                                                        result_type;\r
 201                 typedef boost::packaged_task<result_type>                       task_type;\r
 202                                                                 \r
 203                 std::unique_ptr<task_type> task;\r
 204 \r
 205                 // Use pointers since the boost thread library doesn't fully support move semantics.\r
 206 \r
 207                 auto raw_func2 = new function_type(std::forward<Func>(func));\r
 208                 try\r
 209                 {\r
 210                         task.reset(new task_type([raw_func2]() -> result_type\r
 211                         {\r
 212                                 std::unique_ptr<function_type> func2(raw_func2);\r
 213                                 return (*func2)();\r
 214                         }));\r
 215                 }\r
 216                 catch(...)\r
 217                 {\r
 218                         delete raw_func2;\r
 219                         throw;\r
 220                 }\r
 221                 \r
 222                 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
 223                 {\r
 224                         try\r
 225                         {\r
 226                                 if(is_current())  // Avoids potential deadlock.\r
 227                                         my_task();\r
 228                         }\r
 229                         catch(boost::task_already_started&){}\r
 230                 }));\r
 231                                 \r
 232                 auto future = task->get_future();\r
 233 \r
 234                 auto raw_task = task.release();\r
 235                 priority_function prio_func(priority.value(), [raw_task]\r
 236                 {\r
 237                         std::unique_ptr<task_type> task(raw_task);\r
 238                         try\r
 239                         {\r
 240                                 (*task)();\r
 241                         }\r
 242                         catch(boost::task_already_started&){}\r
 243                 });\r
 244 \r
 245                 execution_queue_.push(prio_func);\r
 246                 semaphore_.push(0);\r
 247                                                         \r
 248                 return std::move(future);               \r
 249         }\r
 250 \r
 251         void run() // noexcept\r
 252         {\r
 253                 win32_exception::install_handler();             \r
 254                 while(is_running_)\r
 255                 {\r
 256                         try\r
 257                         {\r
 258                                 int dummy;\r
 259                                 semaphore_.pop(dummy);\r
 260 \r
 261                                 priority_function func;\r
 262                                 if(execution_queue_.try_pop(func))\r
 263                                         func();\r
 264                         }\r
 265                         catch(...)\r
 266                         {\r
 267                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 268                         }\r
 269                 }\r
 270         }       \r
 271 };\r
 272 \r
 273 }