git.sesse.net Git - casparcg/blob - common/concurrency/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 "../log.h"\r
  26 #include "../enum_class.h"\r
  27 #include "../os/windows/windows.h"\r
  28 \r
  29 #include <tbb/atomic.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 namespace detail {\r
  39         \r
  40 template<typename T>\r
  41 struct move_on_copy\r
  42 {\r
  43         move_on_copy(const move_on_copy<T>& other) : value(std::move(other.value)){}\r
  44         move_on_copy(T&& value) : value(std::move(value)){}\r
  45         mutable T value;\r
  46 };\r
  47 \r
  48 template<typename T>\r
  49 move_on_copy<T> make_move_on_copy(T&& value)\r
  50 {\r
  51         return move_on_copy<T>(std::move(value));\r
  52 }\r
  53 \r
  54 }\r
  55         \r
  56 struct task_priority_def\r
  57 {\r
  58         enum type\r
  59         {\r
  60                 high_priority,\r
  61                 normal_priority,\r
  62                 priority_count\r
  63         };\r
  64 };\r
  65 typedef enum_class<task_priority_def> task_priority;\r
  66 \r
  67 struct thread_priority_def\r
  68 {\r
  69         enum type\r
  70         {\r
  71                 high_priority_class,\r
  72                 above_normal_priority_class,\r
  73                 normal_priority_class,\r
  74                 below_normal_priority_class\r
  75         };\r
  76 };\r
  77 typedef enum_class<thread_priority_def> thread_priority;\r
  78 \r
  79 class executor\r
  80 {\r
  81         executor(const executor&);\r
  82         executor& operator=(const executor&);\r
  83 \r
  84         const std::string name_;\r
  85         boost::thread thread_;\r
  86         tbb::atomic<bool> is_running_;\r
  87         \r
  88         typedef tbb::concurrent_bounded_queue<std::function<void()>> function_queue;\r
  89         function_queue execution_queue_[task_priority::priority_count];\r
  90                 \r
  91         template<typename Func>\r
  92         auto create_task(Func&& func) -> boost::packaged_task<decltype(func())> // noexcept\r
  93         {       \r
  94                 typedef boost::packaged_task<decltype(func())> task_type;\r
  95                                 \r
  96                 auto task = task_type(std::forward<Func>(func));\r
  97                 \r
  98                 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
  99                 {\r
 100                         try\r
 101                         {\r
 102                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 103                                         my_task();\r
 104                         }\r
 105                         catch(boost::task_already_started&){}\r
 106                 }));\r
 107                                 \r
 108                 return std::move(task);\r
 109         }\r
 110 \r
 111 public:\r
 112                 \r
 113         explicit executor(const std::wstring& name) : name_(u8(name)) // noexcept\r
 114         {\r
 115                 is_running_ = true;\r
 116                 thread_ = boost::thread([this]{run();});\r
 117         }\r
 118         \r
 119         virtual ~executor() // noexcept\r
 120         {\r
 121                 stop();\r
 122                 join();\r
 123         }\r
 124 \r
 125         void set_capacity(size_t capacity) // noexcept\r
 126         {\r
 127                 execution_queue_[task_priority::normal_priority].set_capacity(capacity);\r
 128         }\r
 129 \r
 130         void set_priority_class(thread_priority p)\r
 131         {\r
 132                 begin_invoke([=]\r
 133                 {\r
 134                         if(p == thread_priority::high_priority_class)\r
 135                                 SetThreadPriority(GetCurrentThread(), HIGH_PRIORITY_CLASS);\r
 136                         else if(p == thread_priority::above_normal_priority_class)\r
 137                                 SetThreadPriority(GetCurrentThread(), ABOVE_NORMAL_PRIORITY_CLASS);\r
 138                         else if(p == thread_priority::normal_priority_class)\r
 139                                 SetThreadPriority(GetCurrentThread(), NORMAL_PRIORITY_CLASS);\r
 140                         else if(p == thread_priority::below_normal_priority_class)\r
 141                                 SetThreadPriority(GetCurrentThread(), BELOW_NORMAL_PRIORITY_CLASS);\r
 142                 });\r
 143         }\r
 144         \r
 145         void clear()\r
 146         {               \r
 147                 std::function<void()> func;\r
 148                 while(execution_queue_[task_priority::normal_priority].try_pop(func));\r
 149                 while(execution_queue_[task_priority::high_priority].try_pop(func));\r
 150         }\r
 151                                 \r
 152         void stop() // noexcept\r
 153         {\r
 154                 is_running_ = false;    \r
 155                 execution_queue_[task_priority::normal_priority].try_push([]{}); // Wake the execution thread.\r
 156         }\r
 157 \r
 158         void wait() // noexcept\r
 159         {\r
 160                 invoke([]{});\r
 161         }\r
 162 \r
 163         void join()\r
 164         {\r
 165                 if(boost::this_thread::get_id() == thread_.get_id())\r
 166                         BOOST_THROW_EXCEPTION(invalid_operation());\r
 167 \r
 168                 thread_.join();\r
 169         }\r
 170                                 \r
 171         template<typename Func>\r
 172         auto begin_invoke(Func&& func, task_priority priority = task_priority::normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 173         {       \r
 174                 if(!is_running_)\r
 175                         BOOST_THROW_EXCEPTION(invalid_operation() << msg_info("executor not running."));\r
 176 \r
 177                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 178                 auto task_adaptor = detail::make_move_on_copy(create_task(func));\r
 179 \r
 180                 auto future = task_adaptor.value.get_future();\r
 181 \r
 182                 execution_queue_[priority.value()].push([=]\r
 183                 {\r
 184                         try\r
 185                         {\r
 186                                 task_adaptor.value();\r
 187                         }\r
 188                         catch(boost::task_already_started&)\r
 189                         {\r
 190                         }\r
 191                         catch(...)\r
 192                         {\r
 193                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 194                         }\r
 195                 });\r
 196 \r
 197                 if(priority != task_priority::normal_priority)\r
 198                         execution_queue_[task_priority::normal_priority].push(nullptr);\r
 199                                         \r
 200                 return std::move(future);               \r
 201         }\r
 202         \r
 203         template<typename Func>\r
 204         auto invoke(Func&& func, task_priority prioriy = task_priority::normal_priority) -> decltype(func()) // noexcept\r
 205         {\r
 206                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 207                         return func();\r
 208                 \r
 209                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 210         }\r
 211 \r
 212         void yield() // noexcept\r
 213         {\r
 214                 if(boost::this_thread::get_id() != thread_.get_id())\r
 215                         BOOST_THROW_EXCEPTION(invalid_operation() << msg_info("Executor can only yield inside of thread context."));\r
 216 \r
 217                 std::function<void()> func;\r
 218                 execution_queue_[task_priority::normal_priority].pop(func);     \r
 219                 \r
 220                 std::function<void()> func2;\r
 221                 while(execution_queue_[task_priority::high_priority].try_pop(func2))\r
 222                 {\r
 223                         if(func2)\r
 224                                 func2();\r
 225                 }       \r
 226 \r
 227                 if(func)\r
 228                         func();\r
 229         }\r
 230                 \r
 231         function_queue::size_type size() const /*noexcept*/\r
 232         {\r
 233                 return execution_queue_[task_priority::normal_priority].size() + execution_queue_[task_priority::high_priority].size(); \r
 234         }\r
 235                 \r
 236         bool is_running() const /*noexcept*/ { return is_running_; }    \r
 237                 \r
 238 private:        \r
 239 \r
 240         void run() // noexcept\r
 241         {\r
 242                 win32_exception::install_handler();             \r
 243                 //detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 244                 while(is_running_)\r
 245                 {\r
 246                         try\r
 247                         {\r
 248                                 yield();\r
 249                         }\r
 250                         catch(...)\r
 251                         {\r
 252                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 253                         }\r
 254                 }\r
 255         }       \r
 256 };\r
 257 \r
 258 }