Convert monitor.event_queue to a queue.Queue.

* We now use event_queue.empty() to see if it is indeed empty.
* Changed AppWindow.journal_event() to also use .empty() rather than
  `while True`.  Keeping the `'if not entry'` check just in case.
  This prevents it from calling monitor.get_entry() when the prior run
  through the loop has just emptied the queue.  Thus we'll only log when
  it genuinely IS unexpectedly empty.
* During *game* Shutdown we can send the synthetic 'Shutdown' event
  through, and then find and append the actual game 'Shutdown' event
  (i.e. this wasn't a crash, which is what the synthetic event is meant
  to react to).  But AppWindow.journal_event() loop picks up both events
  in one call, so the second <<JournalEvent>> sends it working on an
  empty queue.
  Thus we log in monitor.get_entry() only if the queue is empty *and*
  the game is still running.
* NB: Also adds 'Component' to the OTHER place montitor.state is
  initialised.

EDMarketConnector.py

@@ -891,7 +891,7 @@ class AppWindow(object):
             logger.debug('monitor.thread is None, assuming shutdown and returning')
             return
 
-        while True:
+        while not monitor.event_queue.empty():
             entry = monitor.get_entry()
             if not entry:
                 # This is expected due to some monitor.py code that appends `None`

monitor.py

@@ -1,6 +1,7 @@
 """Monitor for new Journal files and contents of latest."""
 
 import json
+import queue
 import re
 import threading
 from calendar import timegm
@@ -78,7 +79,8 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
         self.observer: Optional['Observer'] = None
         self.observed = None  # a watchdog ObservedWatch, or None if polling
         self.thread: Optional[threading.Thread] = None
-        self.event_queue: List = []  # For communicating journal entries back to main thread
+        # For communicating journal entries back to main thread
+        self.event_queue: queue.Queue = queue.Queue(maxsize=0)
 
         # On startup we might be:
         # 1) Looking at an old journal file because the game isn't running or the user has exited to the main menu.
@@ -342,11 +344,11 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
                     entry['StationType'] = self.stationtype
                     entry['MarketID'] = self.station_marketid
 
-                self.event_queue.append(json.dumps(entry, separators=(', ', ':')))
+                self.event_queue.put(json.dumps(entry, separators=(', ', ':')))
 
             else:
                 # Generate null event to update the display (with possibly out-of-date info)
-                self.event_queue.append(None)
+                self.event_queue.put(None)
                 self.live = False
 
         # Watchdog thread -- there is a way to get this by using self.observer.emitters and checking for an attribute:
@@ -396,12 +398,13 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
                         return  # Terminate
 
                     if b'"event":"Location"' in line:
-                        logger.trace('Found "Location" event, appending to event_queue')
+                        logger.trace('Found "Location" event, adding to event_queue')
 
-                    self.event_queue.append(line)
+                    self.event_queue.put(line)
 
-                if self.event_queue:
+                if not self.event_queue.empty():
                     if not config.shutting_down:
+                        # logger.trace('Sending <<JournalEvent>>')
                         self.root.event_generate('<<JournalEvent>>', when="tail")
 
                 log_pos = loghandle.tell()
@@ -420,11 +423,12 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
                 if not self.game_running():
                     logger.info('Detected exit from game, synthesising ShutDown event')
                     timestamp = strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())
-                    self.event_queue.append(
+                    self.event_queue.put(
                         f'{{ "timestamp":"{timestamp}", "event":"ShutDown" }}'
                     )
 
                     if not config.shutting_down:
+                        # logger.trace('Sending <<JournalEvent>>')
                         self.root.event_generate('<<JournalEvent>>', when="tail")
 
                     self.game_was_running = False
@@ -482,6 +486,7 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
                     'Raw':          defaultdict(int),
                     'Manufactured': defaultdict(int),
                     'Encoded':      defaultdict(int),
+                    'Component':    defaultdict(int),
                     'Engineers':    {},
                     'Rank':         {},
                     'Reputation':   {},
@@ -975,54 +980,55 @@ class EDLogs(FileSystemEventHandler):  # type: ignore # See below
             logger.debug('Called whilst self.thread is None, returning')
             return None
 
-        if not self.event_queue:
+        # logger.trace('Begin')
-            logger.trace('Called with no event_queue')
+        if self.event_queue.empty() and self.game_running():
+            logger.error('event_queue is empty whilst game_running, this should not happen, returning')
             return None
 
-        else:
+        # logger.trace('event_queue NOT empty')
-            entry = self.parse_entry(self.event_queue.pop(0))
+        entry = self.parse_entry(self.event_queue.get_nowait())
+
+        if entry['event'] == 'Location':
+            logger.trace('"Location" event')
+
+        if not self.live and entry['event'] not in (None, 'Fileheader'):
+            # Game not running locally, but Journal has been updated
+            self.live = True
+            if self.station:
+                entry = OrderedDict([
+                    ('timestamp', strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())),
+                    ('event', 'StartUp'),
+                    ('Docked', True),
+                    ('MarketID', self.station_marketid),
+                    ('StationName', self.station),
+                    ('StationType', self.stationtype),
+                    ('StarSystem', self.system),
+                    ('StarPos', self.coordinates),
+                    ('SystemAddress', self.systemaddress),
+                ])
+
+            else:
+                entry = OrderedDict([
+                    ('timestamp', strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())),
+                    ('event', 'StartUp'),
+                    ('Docked', False),
+                    ('StarSystem', self.system),
+                    ('StarPos', self.coordinates),
+                    ('SystemAddress', self.systemaddress),
+                ])
 
             if entry['event'] == 'Location':
-                logger.trace('"Location" event')
+                logger.trace('Appending "Location" event to event_queue')
 
-            if not self.live and entry['event'] not in (None, 'Fileheader'):
+            self.event_queue.put(json.dumps(entry, separators=(', ', ':')))
-                # Game not running locally, but Journal has been updated
-                self.live = True
-                if self.station:
-                    entry = OrderedDict([
-                        ('timestamp', strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())),
-                        ('event', 'StartUp'),
-                        ('Docked', True),
-                        ('MarketID', self.station_marketid),
-                        ('StationName', self.station),
-                        ('StationType', self.stationtype),
-                        ('StarSystem', self.system),
-                        ('StarPos', self.coordinates),
-                        ('SystemAddress', self.systemaddress),
-                    ])
 
-                else:
+        elif self.live and entry['event'] == 'Music' and entry.get('MusicTrack') == 'MainMenu':
-                    entry = OrderedDict([
+            ts = strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())
-                        ('timestamp', strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())),
+            self.event_queue.put(
-                        ('event', 'StartUp'),
+                f'{{ "timestamp":"{ts}", "event":"ShutDown" }}'
-                        ('Docked', False),
+            )
-                        ('StarSystem', self.system),
-                        ('StarPos', self.coordinates),
-                        ('SystemAddress', self.systemaddress),
-                    ])
 
-                if entry['event'] == 'Location':
+        return entry
-                    logger.trace('Appending "Location" event to event_queue')
-
-                self.event_queue.append(json.dumps(entry, separators=(', ', ':')))
-
-            elif self.live and entry['event'] == 'Music' and entry.get('MusicTrack') == 'MainMenu':
-                ts = strftime('%Y-%m-%dT%H:%M:%SZ', gmtime())
-                self.event_queue.append(
-                    f'{{ "timestamp":"{ts}", "event":"ShutDown" }}'
-                )
-
-            return entry
 
     def game_running(self) -> bool:  # noqa: CCR001
         """