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 class executor : boost::noncopyable\r
  65 {\r
  66         const std::string name_;\r
  67         boost::thread thread_;\r
  68         tbb::atomic<bool> is_running_;\r
  69         tbb::concurrent_bounded_queue<std::function<void()>> execution_queue_;\r
  70 public:\r
  71                 \r
  72         explicit executor(const std::wstring& name) : name_(narrow(name)) // noexcept\r
  73         {\r
  74                 is_running_ = false;\r
  75         }\r
  76         \r
  77         virtual ~executor() // noexcept\r
  78         {\r
  79                 stop();\r
  80                 clear();\r
  81                 if(boost::this_thread::get_id() != thread_.get_id())\r
  82                         thread_.join();\r
  83         }\r
  84 \r
  85         void set_capacity(size_t capacity) // noexcept\r
  86         {\r
  87                 execution_queue_.set_capacity(capacity);\r
  88         }\r
  89                         \r
  90         void stop() // noexcept\r
  91         {\r
  92                 is_running_ = false;    \r
  93                 execution_queue_.try_push([]{});\r
  94         }\r
  95         \r
  96         void clear() // noexcept\r
  97         {\r
  98                 std::function<void()> func;\r
  99                 auto size = execution_queue_.size();\r
 100                 for(int n = 0; n < size; ++n)\r
 101                 {\r
 102                         try\r
 103                         {\r
 104                                 if(!execution_queue_.try_pop(func))\r
 105                                         return;\r
 106                         }\r
 107                         catch(boost::broken_promise&){}\r
 108                 }\r
 109         }\r
 110                         \r
 111         template<typename Func>\r
 112         auto begin_invoke(Func&& func) -> boost::unique_future<decltype(func())> // noexcept\r
 113         {       \r
 114                 if(!is_running_)\r
 115                         start();\r
 116 \r
 117                 typedef boost::packaged_task<decltype(func())> task_type;\r
 118                                 \r
 119                 auto task = task_type(std::forward<Func>(func));\r
 120                 auto future = task.get_future();\r
 121                 \r
 122                 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
 123                 {\r
 124                         try\r
 125                         {\r
 126                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 127                                         my_task();\r
 128                         }\r
 129                         catch(boost::task_already_started&){}\r
 130                 }));\r
 131                                 \r
 132                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 133                 struct task_adaptor_t\r
 134                 {\r
 135                         task_adaptor_t(const task_adaptor_t& other) : task(std::move(other.task)){}\r
 136                         task_adaptor_t(task_type&& task) : task(std::move(task)){}\r
 137                         void operator()() const { task(); }\r
 138                         mutable task_type task;\r
 139                 } task_adaptor(std::move(task));\r
 140 \r
 141                 execution_queue_.push([=]\r
 142                 {\r
 143                         try{task_adaptor();}\r
 144                         catch(boost::task_already_started&){}\r
 145                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 146                 });\r
 147                                         \r
 148                 return std::move(future);               \r
 149         }\r
 150         \r
 151         template<typename Func>\r
 152         auto invoke(Func&& func) -> decltype(func())\r
 153         {\r
 154                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 155                         return func();\r
 156                 \r
 157                 return begin_invoke(std::forward<Func>(func)).get();\r
 158         }\r
 159         \r
 160         tbb::concurrent_bounded_queue<std::function<void()>>::size_type capacity() const { return execution_queue_.capacity();  }\r
 161         tbb::concurrent_bounded_queue<std::function<void()>>::size_type size() const { return execution_queue_.size();  }\r
 162         bool empty() const              { return execution_queue_.empty();      }\r
 163         bool is_running() const { return is_running_;                           }       \r
 164                 \r
 165 private:\r
 166 \r
 167         void start() // noexcept\r
 168         {\r
 169                 if(is_running_.fetch_and_store(true))\r
 170                         return;\r
 171                 clear();\r
 172                 thread_ = boost::thread([this]{run();});\r
 173         }\r
 174         \r
 175         void execute() // noexcept\r
 176         {\r
 177                 std::function<void()> func;\r
 178                 execution_queue_.pop(func);     \r
 179                 func();\r
 180         }\r
 181 \r
 182         void run() // noexcept\r
 183         {\r
 184                 win32_exception::install_handler();             \r
 185                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 186                 while(is_running_)\r
 187                         execute();\r
 188         }       \r
 189 };\r
 190 \r
 191 }