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 class executor : boost::noncopyable\r
  72 {\r
  73         const std::string name_;\r
  74         boost::thread thread_;\r
  75         tbb::atomic<bool> is_running_;\r
  76         \r
  77         typedef tbb::concurrent_bounded_queue<std::function<void()>> function_queue;\r
  78         function_queue execution_queue_[priority_count];\r
  79         \r
  80 public:\r
  81                 \r
  82         explicit executor(const std::wstring& name) : name_(narrow(name)) // noexcept\r
  83         {\r
  84                 thread_ = boost::thread([this]{run();});\r
  85                 is_running_ = true;\r
  86         }\r
  87         \r
  88         virtual ~executor() // noexcept\r
  89         {\r
  90                 stop();\r
  91                 \r
  92                 std::function<void()> func;\r
  93                 while(execution_queue_[normal_priority].try_pop(func)){} // Wake all waiting push threads.\r
  94 \r
  95                 if(boost::this_thread::get_id() != thread_.get_id())\r
  96                         thread_.join();\r
  97         }\r
  98 \r
  99         void set_capacity(size_t capacity) // noexcept\r
 100         {\r
 101                 execution_queue_[normal_priority].set_capacity(capacity);\r
 102         }\r
 103                                 \r
 104         void stop() // noexcept\r
 105         {\r
 106                 is_running_ = false;    \r
 107                 execution_queue_[normal_priority].try_push([]{}); // Wake the execution thread.\r
 108         }\r
 109 \r
 110         void wait() // noexcept\r
 111         {\r
 112                 invoke([]{});\r
 113         }\r
 114                                 \r
 115         template<typename Func>\r
 116         auto begin_invoke(Func&& func, priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 117         {       \r
 118                 typedef boost::packaged_task<decltype(func())> task_type;\r
 119                                 \r
 120                 auto task = task_type(std::forward<Func>(func));\r
 121                 auto future = task.get_future();\r
 122                 \r
 123                 if(!is_running_)\r
 124                         return std::move(future);       \r
 125 \r
 126                 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
 127                 {\r
 128                         try\r
 129                         {\r
 130                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 131                                         my_task();\r
 132                         }\r
 133                         catch(boost::task_already_started&){}\r
 134                 }));\r
 135                                 \r
 136                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 137                 struct task_adaptor_t\r
 138                 {\r
 139                         task_adaptor_t(const task_adaptor_t& other) : task(std::move(other.task)){}\r
 140                         task_adaptor_t(task_type&& task) : task(std::move(task)){}\r
 141                         void operator()() const { task(); }\r
 142                         mutable task_type task;\r
 143                 } task_adaptor(std::move(task));\r
 144 \r
 145                 execution_queue_[priority].push([=]\r
 146                 {\r
 147                         try{task_adaptor();}\r
 148                         catch(boost::task_already_started&){}\r
 149                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 150                 });\r
 151 \r
 152                 if(priority != normal_priority)\r
 153                         execution_queue_[normal_priority].push(nullptr);\r
 154                                         \r
 155                 return std::move(future);               \r
 156         }\r
 157         \r
 158         template<typename Func>\r
 159         auto invoke(Func&& func, priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 160         {\r
 161                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 162                         return func();\r
 163                 \r
 164                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 165         }\r
 166 \r
 167         void yield() // noexcept\r
 168         {\r
 169                 if(boost::this_thread::get_id() != thread_.get_id())  // Only yield when calling from execution thread.\r
 170                         return;\r
 171 \r
 172                 std::function<void()> func;\r
 173                 while(execution_queue_[high_priority].try_pop(func))\r
 174                 {\r
 175                         if(func)\r
 176                                 func();\r
 177                 }       \r
 178         }\r
 179         \r
 180         function_queue::size_type capacity() const /*noexcept*/ { return execution_queue_[normal_priority].capacity();  }\r
 181         function_queue::size_type size() const /*noexcept*/ { return execution_queue_[normal_priority].size();  }\r
 182         bool empty() const /*noexcept*/ { return execution_queue_[normal_priority].empty();     }\r
 183         bool is_running() const /*noexcept*/ { return is_running_; }    \r
 184                 \r
 185 private:\r
 186         \r
 187         void execute() // noexcept\r
 188         {\r
 189                 std::function<void()> func;\r
 190                 execution_queue_[normal_priority].pop(func);    \r
 191 \r
 192                 yield();\r
 193 \r
 194                 if(func)\r
 195                         func();\r
 196         }\r
 197 \r
 198         void run() // noexcept\r
 199         {\r
 200                 win32_exception::install_handler();             \r
 201                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 202                 while(is_running_)\r
 203                         execute();\r
 204         }       \r
 205 };\r
 206 \r
 207 }