git.sesse.net Git - casparcg/blob - common/concurrency/executor.h

   1 #pragma once\r
   2 \r
   3 #include "../exception/win32_exception.h"\r
   4 #include "../log/log.h"\r
   5 \r
   6 #include <tbb/atomic.h>\r
   7 #include <tbb/concurrent_queue.h>\r
   8 \r
   9 #include <boost/thread.hpp>\r
  10 #include <boost/noncopyable.hpp>\r
  11 \r
  12 #include <functional>\r
  13 \r
  14 namespace caspar {\r
  15 \r
  16 namespace detail {\r
  17 \r
  18 typedef struct tagTHREADNAME_INFO\r
  19 {\r
  20         DWORD dwType; // must be 0x1000\r
  21         LPCSTR szName; // pointer to name (in user addr space)\r
  22         DWORD dwThreadID; // thread ID (-1=caller thread)\r
  23         DWORD dwFlags; // reserved for future use, must be zero\r
  24 } THREADNAME_INFO;\r
  25 \r
  26 inline void SetThreadName(DWORD dwThreadID, LPCSTR szThreadName)\r
  27 {\r
  28         THREADNAME_INFO info;\r
  29         {\r
  30                 info.dwType = 0x1000;\r
  31                 info.szName = szThreadName;\r
  32                 info.dwThreadID = dwThreadID;\r
  33                 info.dwFlags = 0;\r
  34         }\r
  35         __try\r
  36         {\r
  37                 RaiseException( 0x406D1388, 0, sizeof(info)/sizeof(DWORD), (DWORD*)&info );\r
  38         }\r
  39         __except (EXCEPTION_CONTINUE_EXECUTION){}       \r
  40 }\r
  41 \r
  42 }\r
  43 \r
  44 class executor : boost::noncopyable\r
  45 {\r
  46         const std::string name_;\r
  47         boost::thread thread_;\r
  48         tbb::atomic<bool> is_running_;\r
  49         tbb::concurrent_bounded_queue<std::function<void()>> execution_queue_;\r
  50 public:\r
  51                 \r
  52         explicit executor(const std::wstring& name = L"executor") : name_(narrow(name))\r
  53         {\r
  54                 is_running_ = false;\r
  55         }\r
  56         \r
  57         virtual ~executor()\r
  58         {\r
  59                 stop();\r
  60                 clear();\r
  61                 if(boost::this_thread::get_id() != thread_.get_id())\r
  62                         thread_.join();\r
  63         }\r
  64 \r
  65         void set_capacity(size_t capacity)\r
  66         {\r
  67                 execution_queue_.set_capacity(capacity);\r
  68         }\r
  69 \r
  70         void start() // noexcept\r
  71         {\r
  72                 if(is_running_.fetch_and_store(true))\r
  73                         return;\r
  74                 clear();\r
  75                 thread_ = boost::thread([this]{run();});\r
  76         }\r
  77                         \r
  78         void stop() // noexcept\r
  79         {\r
  80                 is_running_ = false;    \r
  81                 execution_queue_.try_push([]{});\r
  82         }\r
  83         \r
  84         void clear()\r
  85         {\r
  86                 std::function<void()> func;\r
  87                 auto size = execution_queue_.size();\r
  88                 for(int n = 0; n < size; ++n)\r
  89                 {\r
  90                         try\r
  91                         {\r
  92                                 if(!execution_queue_.try_pop(func))\r
  93                                         return;\r
  94                         }\r
  95                         catch(boost::broken_promise&){}\r
  96                 }\r
  97         }\r
  98                         \r
  99         template<typename Func>\r
 100         auto begin_invoke(Func&& func) -> boost::unique_future<decltype(func())> // noexcept\r
 101         {       \r
 102                 typedef boost::packaged_task<decltype(func())> task_type;\r
 103                                 \r
 104                 auto task = task_type(std::forward<Func>(func));\r
 105                 auto future = task.get_future();\r
 106                 \r
 107                 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
 108                 {\r
 109                         try\r
 110                         {\r
 111                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 112                                         my_task();\r
 113                         }\r
 114                         catch(boost::task_already_started&){}\r
 115                 }));\r
 116                                 \r
 117                 struct task_adaptor_t\r
 118                 {\r
 119                         task_adaptor_t(const task_adaptor_t& other) : task(std::move(other.task)){}\r
 120                         task_adaptor_t(task_type&& task) : task(std::move(task)){}\r
 121                         void operator()() const { task(); }\r
 122                         mutable task_type task;\r
 123                 } task_adaptor(std::move(task));\r
 124 \r
 125                 execution_queue_.push([=]\r
 126                 {\r
 127                         try{task_adaptor();}\r
 128                         catch(boost::task_already_started&){}\r
 129                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 130                 });\r
 131 \r
 132                 return std::move(future);               \r
 133         }\r
 134         \r
 135         template<typename Func>\r
 136         auto invoke(Func&& func) -> decltype(func())\r
 137         {\r
 138                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 139                         return func();\r
 140                 \r
 141                 return begin_invoke(std::forward<Func>(func)).get();\r
 142         }\r
 143         \r
 144         tbb::concurrent_bounded_queue<std::function<void()>>::size_type capacity() const { return execution_queue_.capacity();  }\r
 145         tbb::concurrent_bounded_queue<std::function<void()>>::size_type size() const { return execution_queue_.size();  }\r
 146         bool empty() const              { return execution_queue_.empty();      }\r
 147         bool is_running() const { return is_running_;                           }       \r
 148                 \r
 149 private:\r
 150         \r
 151         void execute() // noexcept\r
 152         {\r
 153                 std::function<void()> func;\r
 154                 execution_queue_.pop(func);     \r
 155                 func();\r
 156         }\r
 157 \r
 158         void run() // noexcept\r
 159         {\r
 160                 win32_exception::install_handler();             \r
 161                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 162                 while(is_running_)\r
 163                         execute();\r
 164         }       \r
 165 };\r
 166 \r
 167 }