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 }\r
  45 \r
  46 class executor : boost::noncopyable\r
  47 {\r
  48 public:\r
  49                 \r
  50         explicit executor(const std::wstring& name = L"executor") : name_(narrow(name))\r
  51         {\r
  52                 is_running_ = false;\r
  53         }\r
  54         \r
  55         virtual ~executor()\r
  56         {\r
  57                 stop();\r
  58                 clear();\r
  59                 if(boost::this_thread::get_id() != thread_.get_id())\r
  60                         thread_.join();\r
  61         }\r
  62 \r
  63         void set_capacity(size_t capacity)\r
  64         {\r
  65                 execution_queue_.set_capacity(capacity);\r
  66         }\r
  67 \r
  68         void start() // noexcept\r
  69         {\r
  70                 if(is_running_.fetch_and_store(true))\r
  71                         return;\r
  72                 clear();\r
  73                 thread_ = boost::thread([this]{run();});\r
  74         }\r
  75                         \r
  76         void stop() // noexcept\r
  77         {\r
  78                 is_running_ = false;    \r
  79                 execution_queue_.try_push([]{});\r
  80         }\r
  81         \r
  82         void clear()\r
  83         {\r
  84                 std::function<void()> func;\r
  85                 auto size = execution_queue_.size();\r
  86                 for(int n = 0; n < size; ++n)\r
  87                 {\r
  88                         try\r
  89                         {\r
  90                                 if(!execution_queue_.try_pop(func))\r
  91                                         return;\r
  92                         }\r
  93                         catch(boost::broken_promise&){}\r
  94                 }\r
  95         }\r
  96                         \r
  97         template<typename Func>\r
  98         auto begin_invoke(Func&& func) -> boost::unique_future<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                 auto future = task.get_future();\r
 104                 \r
 105                 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
 106                 {\r
 107                         try\r
 108                         {\r
 109                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 110                                         my_task();\r
 111                         }\r
 112                         catch(boost::task_already_started&){}\r
 113                 }));\r
 114                                 \r
 115                 struct task_adaptor_t\r
 116                 {\r
 117                         task_adaptor_t(const task_adaptor_t& other) : task(std::move(other.task)){}\r
 118                         task_adaptor_t(task_type&& task) : task(std::move(task)){}\r
 119                         void operator()() const { task(); }\r
 120                         mutable task_type task;\r
 121                 } task_adaptor(std::move(task));\r
 122 \r
 123                 execution_queue_.push([=]\r
 124                 {\r
 125                         try{task_adaptor();}\r
 126                         catch(boost::task_already_started&){}\r
 127                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 128                 });\r
 129 \r
 130                 return std::move(future);               \r
 131         }\r
 132         \r
 133         template<typename Func>\r
 134         auto invoke(Func&& func) -> decltype(func())\r
 135         {\r
 136                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 137                         return func();\r
 138                 \r
 139                 return begin_invoke(std::forward<Func>(func)).get();\r
 140         }\r
 141         \r
 142         tbb::concurrent_bounded_queue<std::function<void()>>::size_type capacity() const { return execution_queue_.capacity();  }\r
 143         tbb::concurrent_bounded_queue<std::function<void()>>::size_type size() const { return execution_queue_.size();  }\r
 144         bool empty() const              { return execution_queue_.empty();      }\r
 145         bool is_running() const { return is_running_;                           }       \r
 146                 \r
 147 private:\r
 148         \r
 149         void execute() // noexcept\r
 150         {\r
 151                 std::function<void()> func;\r
 152                 execution_queue_.pop(func);     \r
 153                 func();\r
 154         }\r
 155 \r
 156         void run() // noexcept\r
 157         {\r
 158                 win32_exception::install_handler();             \r
 159                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 160                 while(is_running_)\r
 161                         execute();\r
 162         }\r
 163         \r
 164         std::string name_;\r
 165         boost::thread thread_;\r
 166         tbb::atomic<bool> is_running_;\r
 167         tbb::concurrent_bounded_queue<std::function<void()>> execution_queue_;\r
 168 };\r
 169 \r
 170 }