periodic msg source: add eof input

to stop non-GUI flow graphs

grc/foo_periodic_msg_source.xml

@@ -40,6 +40,12 @@
 		<type>int</type>
 	</param>
 
+	<sink>
+		<name>eof in</name>
+		<type>message</type>
+		<optional>1</optional>
+	</sink>
+
 	<source>
 		<name>out</name>
 		<type>message</type>

lib/periodic_msg_source_impl.cc

@@ -36,6 +36,10 @@ periodic_msg_source_impl::periodic_msg_source_impl(pmt::pmt_t msg,
 		d_finished(false) {
 
 	message_port_register_out(pmt::mp("out"));
+
+	message_port_register_in(pmt::mp("eof in"));
+	set_msg_handler(pmt::mp("eof in"), boost::bind(&periodic_msg_source_impl::eof_in, this, _1));
+
 	d_thread = boost::shared_ptr<boost::thread>(new boost::thread(boost::bind(&periodic_msg_source_impl::run, this, this)));
 }
 
@@ -45,10 +49,18 @@ periodic_msg_source_impl::~periodic_msg_source_impl() {
 	d_thread->join();
 }
 
+void
+periodic_msg_source_impl::eof_in (pmt::pmt_t msg) {
+	if(pmt::is_eof_object(msg)) {
+		detail().get()->set_done(true);
+		return;
+	} else {
+		dout << "non EOF message at eof port!" << std::endl;
+	}
+}
 
 void
 periodic_msg_source_impl::run(periodic_msg_source_impl *instance) {
-
 	// flow graph startup delay
 	boost::this_thread::sleep(boost::posix_time::milliseconds(500));
 

lib/periodic_msg_source_impl.h

@@ -25,6 +25,7 @@ namespace foo {
 	class periodic_msg_source_impl : public periodic_msg_source {
 		private:
 			void run(periodic_msg_source_impl *instance);
+			void eof_in(pmt::pmt_t msg);
 
 			int d_num_msg;
 			bool d_debug;