Merge pull request #596 from Paciente8159/serial-multistream-guard-op…

…tion

added multistream parallel access guard option

uCNC/src/interface/serial.c

@@ -112,15 +112,26 @@ void stream_stdin(uint8_t *p)
 }
 #endif
 
-void serial_stream_change(serial_stream_t *stream)
+#ifdef ENABLE_MULTISTREAM_GUARD
+static bool serial_rx_busy;
+#endif
+
+bool serial_stream_change(serial_stream_t *stream)
 {
 #ifndef DISABLE_MULTISTREAM_SERIAL
 	uint8_t cleanup __attribute__((__cleanup__(stream_stdin))) = 0;
+
+#ifdef ENABLE_MULTISTREAM_GUARD
+	if (serial_rx_busy)
+	{
+		return false;
+	}
+#endif
 	serial_peek_buffer = 0;
 	if (stream != NULL)
 	{
 		current_stream = stream;
-		return;
+		return true;
 	}
 
 	// starts by the prioritary and test one by one until one that as characters available is found
@@ -130,6 +141,7 @@ void serial_stream_change(serial_stream_t *stream)
 	stream_available = mcu_available;
 	stream_clear = mcu_clear;
 #endif
+	return true;
 }
 
 void serial_stream_readonly(stream_getc_cb getc_cb, stream_available_cb available_cb, stream_clear_cb clear_cb)
@@ -156,6 +168,9 @@ void serial_stream_eeprom(uint16_t address)
 char serial_getc(void)
 {
 	uint8_t peek = serial_peek();
+#ifdef ENABLE_MULTISTREAM_GUARD
+	serial_rx_busy = (peek != EOL);
+#endif
 	serial_peek_buffer = 0;
 	return peek;
 }
@@ -217,6 +232,12 @@ uint8_t serial_available(void)
 	uint8_t count = stream_available();
 	if (!count)
 	{
+#ifdef ENABLE_MULTISTREAM_GUARD
+		if (serial_rx_busy)
+		{
+			return count;
+		}
+#endif
 		serial_stream_t *p = default_stream;
 		while (p != NULL)
 		{
@@ -237,7 +258,6 @@ uint8_t serial_available(void)
 			p = p->next;
 		}
 	}
-
 	return count;
 #else
 	return stream_available();

uCNC/src/interface/serial.h

@@ -56,7 +56,7 @@ extern "C"
 	void serial_init();
 
 	void serial_stream_register(serial_stream_t *stream);
-	void serial_stream_change(serial_stream_t *stream);
+	bool serial_stream_change(serial_stream_t *stream);
 	void serial_stream_readonly(stream_getc_cb getc_cb, stream_available_cb available_cb, stream_clear_cb clear_cb);
 	void serial_stream_eeprom(uint16_t address);