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