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