fix the forwarder dead when st_thread interrupt at st_usleep, check thread->can_loop().

@@ -290,7 +290,7 @@ int SrsForwarder::forward()
 	
 	SrsPithyPrint pithy_print(SRS_STAGE_FORWARDER);
 
-	while (true) {
+	while (pthread->can_loop()) {
 		// switch to other st-threads.
 		st_usleep(0);
 

@@ -102,6 +102,11 @@ void SrsThread::stop()
 	}
 }
 
+bool SrsThread::can_loop()
+{
+	return loop;
+}
+
 void SrsThread::thread_cycle()
 {
 	int ret = ERROR_SUCCESS;

@@ -43,6 +43,23 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * when stop, the thread will interrupt the st_thread,
 * which will cause the socket to return error and 
 * terminate the cycle thread.
+*
+* when thread interrupt, the socket maybe not got EINT,
+* espectially on st_usleep(), so the cycle must check the loop,
+* when handler->cycle() has loop itself, for example:
+* 		handler->cycle() is:
+* 			while (true):
+* 				st_usleep(0);
+* 				if (read_from_socket(skt) < 0) break;
+* if thread stop when read_from_socket, it's ok, the loop will break,
+* but when thread stop interrupt the s_usleep(0), then the loop is
+* death loop.
+* in a word, the handler->cycle() must:
+*		handler->cycle() is:
+* 			while (pthread->can_loop()):
+*				st_usleep(0);
+* 				if (read_from_socket(skt) < 0) break;
+* check the loop, then it works.
 */
 class ISrsThreadHandler
 {
@@ -90,6 +107,12 @@ public:
 	* @remark user can stop multiple times, ignore if already stopped.
 	*/
 	virtual void stop();
+	/**
+	* whether the thread should loop,
+	* used for handler->cycle() which has a loop method,
+	* to check this method, break if false.
+	*/
+	virtual bool can_loop();
 private:
 	virtual void thread_cycle();
 	static void* thread_fun(void* arg);