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                 lower_priority = 1,\r
  43                 low_priority,\r
  44                 normal_priority,\r
  45                 high_priority,\r
  46                 higher_priority\r
  47         };\r
  48 };\r
  49 typedef enum_class<task_priority_def> task_priority;\r
  50 \r
  51 class executor\r
  52 {       \r
  53         struct priority_function\r
  54         {\r
  55                 int                                             priority;\r
  56                 std::function<void()>   func;\r
  57 \r
  58                 priority_function()\r
  59                 {\r
  60                 }\r
  61 \r
  62                 template<typename F>\r
  63                 priority_function(int priority, F&& func)\r
  64                         : priority(priority)\r
  65                         , func(std::forward<F>(func))\r
  66                 {\r
  67                 }\r
  68 \r
  69                 void operator()()\r
  70                 {\r
  71                         func();\r
  72                 }\r
  73 \r
  74                 bool operator<(const priority_function& other) const\r
  75                 {\r
  76                         return priority < other.priority;\r
  77                 }\r
  78         };\r
  79 \r
  80         executor(const executor&);\r
  81         executor& operator=(const executor&);\r
  82         \r
  83         typedef tbb::concurrent_priority_queue<priority_function>       function_queue_t;\r
  84 \r
  85         tbb::atomic<bool>                                                                                       is_running_;\r
  86         boost::thread                                                                                           thread_;        \r
  87         function_queue_t                                                                                        execution_queue_;\r
  88         tbb::concurrent_bounded_queue<int>                                                      semaphore_;\r
  89                 \r
  90 public:         \r
  91         executor(const std::wstring& name) // noexcept\r
  92         {\r
  93                 name; // TODO: Use to set thread name.\r
  94                 is_running_ = true;\r
  95                 thread_ = boost::thread([this]{run();});\r
  96         }\r
  97         \r
  98         virtual ~executor() // noexcept\r
  99         {\r
 100                 stop();\r
 101                 thread_.join();\r
 102         }\r
 103                                                 \r
 104         template<typename Func>\r
 105         auto begin_invoke(Func&& func, task_priority priority = task_priority::normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 106         {       \r
 107                 if(!is_running_)\r
 108                         BOOST_THROW_EXCEPTION(invalid_operation() << msg_info("executor not running."));\r
 109                                 \r
 110                 typedef typename std::remove_reference<Func>::type      function_type;\r
 111                 typedef decltype(func())                                                        result_type;\r
 112                 typedef boost::packaged_task<result_type>                       task_type;\r
 113                                                                 \r
 114                 std::unique_ptr<task_type> task;\r
 115 \r
 116                 // Use pointers since the boost thread library doesn't fully support move semantics.\r
 117 \r
 118                 auto raw_func2 = new function_type(std::forward<Func>(func));\r
 119                 try\r
 120                 {\r
 121                         task.reset(new task_type([raw_func2]() -> result_type\r
 122                         {\r
 123                                 std::unique_ptr<function_type> func2(raw_func2);\r
 124                                 return (*func2)();\r
 125                         }));\r
 126                 }\r
 127                 catch(...)\r
 128                 {\r
 129                         delete raw_func2;\r
 130                         throw;\r
 131                 }\r
 132                 \r
 133                 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
 134                 {\r
 135                         try\r
 136                         {\r
 137                                 if(is_current())  // Avoids potential deadlock.\r
 138                                         my_task();\r
 139                         }\r
 140                         catch(boost::task_already_started&){}\r
 141                 }));\r
 142                                 \r
 143                 auto future = task->get_future();\r
 144 \r
 145                 auto raw_task = task.release();\r
 146                 priority_function prio_func(priority.value(), [raw_task]\r
 147                 {\r
 148                         std::unique_ptr<task_type> task(raw_task);\r
 149                         try\r
 150                         {\r
 151                                 (*task)();\r
 152                         }\r
 153                         catch(boost::task_already_started&){}\r
 154                 });\r
 155 \r
 156                 execution_queue_.push(prio_func);\r
 157                 semaphore_.push(0);\r
 158                                                         \r
 159                 return std::move(future);               \r
 160         }\r
 161         \r
 162         template<typename Func>\r
 163         auto invoke(Func&& func, task_priority prioriy = task_priority::normal_priority) -> decltype(func()) // noexcept\r
 164         {\r
 165                 if(is_current())  // Avoids potential deadlock.\r
 166                         return func();\r
 167                 \r
 168                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 169         }\r
 170 \r
 171         void yield() // noexcept\r
 172         {\r
 173                 if(!is_current())\r
 174                         BOOST_THROW_EXCEPTION(invalid_operation() << msg_info("Executor can only yield inside of thread context."));\r
 175 \r
 176                 int dummy;\r
 177                 semaphore_.pop(dummy);\r
 178 \r
 179                 priority_function func;\r
 180                 if(execution_queue_.try_pop(func))\r
 181                         func();\r
 182         }\r
 183 \r
 184         void set_capacity(std::size_t capacity) // noexcept\r
 185         {\r
 186                 semaphore_.set_capacity(capacity);\r
 187         }\r
 188 \r
 189         std::size_t capacity() const\r
 190         {\r
 191                 return semaphore_.capacity();\r
 192         }\r
 193         \r
 194         void clear()\r
 195         {               \r
 196                 priority_function func;\r
 197                 while(execution_queue_.try_pop(func));\r
 198         }\r
 199                                 \r
 200         void stop()\r
 201         {\r
 202                 invoke([this]\r
 203                 {\r
 204                         is_running_ = false;\r
 205                 });\r
 206         }\r
 207 \r
 208         void wait()\r
 209         {\r
 210                 invoke([]{});\r
 211         }\r
 212                 \r
 213         function_queue_t::size_type size() const \r
 214         {\r
 215                 return execution_queue_.size(); \r
 216         }\r
 217                 \r
 218         bool is_running() const\r
 219         {\r
 220                 return is_running_; \r
 221         }       \r
 222 \r
 223         bool is_current() const\r
 224         {\r
 225                 return boost::this_thread::get_id() == thread_.get_id();\r
 226         }\r
 227                 \r
 228 private:        \r
 229 \r
 230         void run() // noexcept\r
 231         {\r
 232                 win32_exception::install_handler();             \r
 233                 while(is_running_)\r
 234                 {\r
 235                         try\r
 236                         {\r
 237                                 yield();\r
 238                         }\r
 239                         catch(...)\r
 240                         {\r
 241                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 242                         }\r
 243                 }\r
 244         }       \r
 245 };\r
 246 \r
 247 }