Recent attempts at actual locking

main.py

@@ -18,10 +18,9 @@ from colorama import Fore, Back, Style, init as colorama_init
 import contentapi
 import myutils
 
-VERSION="0.1.0" # Arbitrary but whatever
+VERSION="0.1.1" # Arbitrary but whatever
 CONFIGFILE="config.toml"
 MAXTITLE=25
-MAXMESSAGEWIDTH=80 # May instead check the console window
 MSGPREFIX=Back.GREEN + " " + Back.RESET + " "
 
 # The entire config object with all defaults
@@ -34,6 +33,8 @@ config = {
     "expire_seconds" : 31536000, # 365 days in seconds, expiration for token
     "appear_in_global" : False,
     "print_status_after_insert" : True,
+    "output_buffer_timeout" : 0.05, # 50 milliseconds
+    "fixed_width" : 78, # Need room for the pre-message decoration
     "tokenfile" : ".qcstoken"
 }
 
@@ -71,7 +72,7 @@ def main():
     # Might as well reuse the websocket object for my websocket context data (oops, is that bad?)
     ws.context = context
     ws.user_info = context.user_me()
-    ws.pause_output = False # Whether all output from the websocket should be paused (including status updates)
+    ws.output_lock = threading.Lock()
     ws.output_buffer = [] # Individual print statements buffered from output. 
     ws.main_config = config
     ws.current_room = 0
@@ -109,10 +110,8 @@ def ws_onopen(ws):
         # The infinite input loop! Or something!
         while True:
 
-            ws.pause_output = False     # Allow arbitrary output again. Do this BEFORE other stuff for race conditions
-
-            # We can be certain that at this point, there is no user input (because this loop is all there is)
-            # As such, just dump the buffer
+            # Dump the buffer, if there is any, since we're outside of user input
+            with ws.output_lock:
                 for output in ws.output_buffer:
                     printr(output)
             
@@ -123,6 +122,8 @@ def ws_onopen(ws):
 
             printstatus = False         # Assume we are not printing the status every time (it's kinda annoying)
 
+            # Listen for a key. The implementation of 'readkey()' on this version of python and windows makes the CPU spike
+            # to 100%, so we switch to getch() if we detect windows.
             if platform.system().startswith("Windows"):
                 import msvcrt
                 logging.debug("on windows, using msvcrt.getch")
@@ -130,8 +131,9 @@ def ws_onopen(ws):
             else:
                 key = readchar.readkey()
 
-            ws.pause_output = True      # Disable output for the duration of input handling
-
+            # We get exclusive access to output while we're handling user input. This allows us to "pause/buffer" the 
+            # output that might come from websocket events
+            with ws.output_lock:
                 if key == "h":
                     print(" -- Help menu / Controls --")
                     for key, value in commands.items():
@@ -211,7 +213,7 @@ def ws_onmessage(ws, message):
                     user = contentapi.get_user_or_default(objects["user"], message["createUserId"])
                     ws_print(ws, MSGPREFIX + Fore.CYAN + Style.BRIGHT + user["username"] + " " + Style.DIM + "#%d" % user["id"] + 
                              Fore.MAGENTA + "  " + message["createDate"] + " [%d]" % message["id"])
-                    for t in textwrap.wrap(message["text"], width = MAXMESSAGEWIDTH):
+                    for t in textwrap.wrap(message["text"], width = ws.main_config["fixed_width"]):
                         ws_print(ws, MSGPREFIX + t)
 
     # Track ignored data
@@ -223,10 +225,14 @@ def ws_onmessage(ws, message):
 # Printing websocket event output is tricky because we don't want to interrupt user input (we don't have
 # curses). As such, we must buffer our output IF we are asked to pause
 def ws_print(ws, output):
-    if ws.pause_output:
-        ws.output_buffer.append(output)
-    else:
+    # We can't block output for too long, so we need to only try to acquire the lock for a very short time
+    if ws.output_lock.acquire(timeout=ws.main_config["output_buffer_timeout"]):
+        try:
             printr(output)
+        finally:
+            ws.output_lock.release()
+    else:
+        ws.output_buffer.append(output)
 
 
 # Loads the config from file into the global config var. If the file