+class destroy_producer_proxy : public frame_producer\r
+{\r
+ std::shared_ptr<frame_producer> producer_;\r
+public:\r
+ destroy_producer_proxy(const std::shared_ptr<frame_producer>& producer) \r
+ : producer_(producer)\r
+ {\r
+ }\r
+\r
+ ~destroy_producer_proxy()\r
+ { \r
+ Concurrency::CurrentScheduler::ScheduleTask(destroy_producer, new destruction_context(std::move(producer_)));\r
+ }\r
+\r
+ virtual safe_ptr<basic_frame> receive(int hints) {return producer_->receive(hints);}\r
+ virtual safe_ptr<basic_frame> last_frame() const {return producer_->last_frame();}\r
+ virtual std::wstring print() const {return producer_->print();}\r
+ virtual void param(const std::wstring& str) {producer_->param(str);}\r
+ virtual safe_ptr<frame_producer> get_following_producer() const {return producer_->get_following_producer();}\r
+ virtual void set_leading_producer(const safe_ptr<frame_producer>& producer) {producer_->set_leading_producer(producer);}\r
+ virtual int64_t nb_frames() const {return producer_->nb_frames();}\r
+};\r
+\r
+class last_frame_producer : public frame_producer\r
+{\r
+ const std::wstring print_;\r
+ const safe_ptr<basic_frame> frame_;\r
+ const int64_t nb_frames_;\r
+public:\r
+ last_frame_producer(const safe_ptr<frame_producer>& producer) \r
+ : print_(producer->print())\r
+ , frame_(producer->last_frame() != basic_frame::eof() ? producer->last_frame() : basic_frame::empty())\r
+ , nb_frames_(producer->nb_frames())\r
+ {\r
+ }\r
+ \r
+ virtual safe_ptr<basic_frame> receive(int){return frame_;}\r
+ virtual safe_ptr<core::basic_frame> last_frame() const{return frame_;}\r
+ virtual std::wstring print() const{return L"dummy[" + print_ + L"]";}\r
+ virtual int64_t nb_frames() const {return nb_frames_;} \r
+};\r
+\r
+struct empty_frame_producer : public frame_producer\r
+{\r
+ virtual safe_ptr<basic_frame> receive(int){return basic_frame::empty();}\r
+ virtual safe_ptr<basic_frame> last_frame() const{return basic_frame::empty();}\r
+ virtual void set_frame_factory(const safe_ptr<frame_factory>&){}\r
+ virtual int64_t nb_frames() const {return 0;}\r
+ virtual std::wstring print() const { return L"empty";}\r
+};\r
+\r
+const safe_ptr<frame_producer>& frame_producer::empty() // nothrow\r
+{\r
+ static safe_ptr<frame_producer> producer = make_safe<empty_frame_producer>();\r
+ return producer;\r
+} \r
+\r
+safe_ptr<basic_frame> receive_and_follow(safe_ptr<frame_producer>& producer, int hints)\r
+{ \r
+ auto frame = producer->receive(hints);\r