MAVExplorer: revert paramfiles, early return, flake8

MAVProxy/tools/MAVExplorer.py

@@ -340,15 +340,12 @@ def load_graphs():
             if filename.lower().endswith('.xml'):
                 gfiles.append(os.path.join(dirname, filename))
 
-    # list of parameter files to be skipped when loading graph XML
-    paramfiles = ["ArduSub.xml", "ArduPlane.xml", "APMrover2.xml", "ArduCopter.xml", "AntennaTracker.xml", "Blimp.xml", "Rover.xml"]
-    # loop though files
     for file in gfiles:
         if not os.path.exists(file):
             continue
         # skip parameter files.  They specify an encoding, and under
         # Python3 this leads to a warning from etree
-        if os.path.basename(file) in paramfiles:
+        if os.path.basename(file) in ["ArduSub.xml", "ArduPlane.xml", "APMrover2.xml", "ArduCopter.xml", "AntennaTracker.xml", "Blimp.xml", "Rover.xml"]:
             continue
         graphs = load_graph_xml(open(file).read(), file)
         if graphs:
@@ -1183,41 +1180,48 @@ def cmd_paramchange(args):
         vmap[pname] = pvalue
     mestate.mlog.rewind()
 
+
 def cmd_logmessage(args):
     '''show log message information'''
     mlog = mestate.mlog
     usage = "Usage: logmessage <help|download>"
+    # Print usage and return, if we have no arguments
     if len(args) <= 0:
         print(usage)
         return
-
-        if args[0] == 'help':
-            if len(args) < 2:
-                print(usage)
-                return
-            if hasattr(mlog,'metadata'):
-                mlog.metadata.print_help(args[1])
-            return
-        if args[0] == 'download':
-            # download XML files for log messages
-            folder = mp_util.dot_mavproxy("LogMessages")
-            mp_util.mkdir_p(folder)
-            files = []
-            for vehicle in ['Rover', 'Copter', 'Plane', 'Tracker', 'Blimp', 'Sub']:
-                url = 'http://autotest.ardupilot.org/LogMessages/%s/LogMessages.xml.gz' % vehicle
-                path = os.path.join(folder,"%s.xml" % vehicle)
-                files.append((url, path))
-            try:
-                child = multiproc.Process(target=mp_util.download_files, args=(files,))
-                child.start()
-            except Exception as e:
-                print(e)
-            if hasattr(mlog,'metadata'):
-                mlog.metadata.reset()
+    # help: print help for the requested log message
+    if args[0] == 'help':
+        if len(args) < 2:
+            print(usage)
             return
+        if hasattr(mlog, 'metadata'):
+            mlog.metadata.print_help(args[1])
+        elif isinstance(mlog, mavutil.mavlogfile):
+            print("logmessage help is not supported for telemetry log files")
+        else:
+            print("Incompatible pymavlink; upgrade pymavlink?")
+        return
+    # download: download XML files for log messages
+    if args[0] == 'download':
+        folder = mp_util.dot_mavproxy("LogMessages")
+        mp_util.mkdir_p(folder)
+        files = []
+        for vehicle in ['Rover', 'Copter', 'Plane', 'Tracker', 'Blimp', 'Sub']:
+            url = 'http://autotest.ardupilot.org/LogMessages/%s/LogMessages.xml.gz' % vehicle
+            path = os.path.join(folder, "%s.xml" % vehicle)
+            files.append((url, path))
+        try:
+            child = multiproc.Process(target=mp_util.download_files, args=(files,))
+            child.start()
+        except Exception as e:
+            print(e)
+        if hasattr(mlog, 'metadata'):
+            mlog.metadata.reset()
+        return
     # Print usage if we've dropped through the ifs
     print(usage)
 
+
 def cmd_mission(args):
     '''show mission'''
     if (len(args) == 1):