uORB print_message cleanup

 - indent field print with tabs instead of spaces
 - print a newline before printing a nested field
 - cmake add generator dependencies

msg/CMakeLists.txt

@@ -165,7 +165,10 @@ add_custom_command(OUTPUT ${uorb_headers}
 		-e templates/uorb
 		-t ${CMAKE_CURRENT_BINARY_DIR}/tmp/headers
 		-q
-	DEPENDS ${msg_files} templates/uorb/msg.h.template
+	DEPENDS
+		${msg_files}
+		templates/uorb/msg.h.template
+		tools/px_generate_uorb_topic_files.py
 	COMMENT "Generating uORB topic headers"
 	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 	VERBATIM
@@ -182,7 +185,10 @@ add_custom_command(OUTPUT ${uorb_sources}
 		-e templates/uorb
 		-t ${CMAKE_CURRENT_BINARY_DIR}/tmp/sources
 		-q
-	DEPENDS ${msg_files} templates/uorb/msg.cpp.template
+	DEPENDS
+		${msg_files}
+		templates/uorb/msg.cpp.template
+		tools/px_generate_uorb_topic_files.py
 	COMMENT "Generating uORB topic sources"
 	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 	VERBATIM

msg/templates/uorb/msg.cpp.template

@@ -80,9 +80,14 @@ ORB_DEFINE(@multi_topic, struct @uorb_struct, @(struct_size-padding_end_size), _
 
 void print_message(const @uorb_struct& message)
 {
-    printf(" @(uorb_struct)\n");
-	printf("\ttimestamp: %" PRIu64 " (%.6f seconds ago)\n", message.timestamp, hrt_elapsed_time(&message.timestamp) / 1e6);
+	printf(" @(uorb_struct)\n");
+	printf("\ttimestamp: %" PRIu64, message.timestamp);
+	if (message.timestamp != 0) {
+		printf(" (%.6f seconds ago)\n", hrt_elapsed_time(&message.timestamp) / 1e6);
+	} else {
+		printf("\n");
+	}
 @[for field in sorted_fields]@
-	@( print_field(field) )
-@[end for]
+	@( print_field(field) )@
+@[end for]@
 }
\ No newline at end of file

msg/tools/px_generate_uorb_topic_helper.py

@@ -205,7 +205,7 @@ def print_field(field):
 
         else:
             for i in range(array_length):
-                print("printf(\"   " + field.type + " " + field.name + "[" + str(i) + "]\");")
+                print("printf(\"\\t" + field.type + " " + field.name + "[" + str(i) + "]\");")
                 print(" print_message(message." + field.name + "[" + str(i) + "]);")
             return
 
@@ -236,11 +236,11 @@ def print_field(field):
                 field_name = "(double)" + field_name
 
         else:
-            print("printf(\"  " + field.name + "\");")
+            print("printf(\"\\n\\t" + field.name + "\");")
             print("\tprint_message(message."+ field.name + ");")
             return
 
-    print("printf(\"\t" + field.name + ": " + c_type + "\\n\", " + field_name + ");" )
+    print("printf(\"\\t" + field.name + ": " + c_type + "\\n\", " + field_name + ");" )
 
 
 def print_field_def(field):