Potential fix for nvda2cthulhu plugin crash bug.

src/cthulhu/plugins/nvda2cthulhu/plugin.py

@@ -29,6 +29,9 @@ from collections import OrderedDict
 import subprocess
 import threading
 import urllib.parse
+from typing import Any, Callable
+
+from gi.repository import GLib
 
 try:
     import msgpack
@@ -202,17 +205,27 @@ class Nvda2Cthulhu(Plugin):
         return True
 
     def handle_message(self, message):
+        try:
             request = self._parse_request(message)
+        except Exception as exc:
+            logger.warning(f"NVDA to Cthulhu: failed to parse message: {exc}")
+            debug.printException(debug.LEVEL_WARNING)
+            return
+
         if not request:
             return
 
+        try:
             requestType, payload = request
             if requestType == "SpeakText":
                 self._handle_speak(payload)
             elif requestType == "BrailleText":
-            self._handle_braille(payload)
+                self._schedule_on_main_thread(self._handle_braille, payload)
             elif requestType == "CancelSpeech":
-            speech.stop()
+                self._schedule_on_main_thread(self._handle_cancel_speech)
+        except Exception as exc:
+            logger.warning(f"NVDA to Cthulhu: failed to handle message: {exc}")
+            debug.printException(debug.LEVEL_WARNING)
 
     def _server_main(self):
         if not self._dependencies_available():
@@ -234,7 +247,7 @@ class Nvda2Cthulhu(Plugin):
             self.ioLoop.start()
         except Exception as exc:
             logger.error(f"NVDA to Cthulhu failed to start server: {exc}")
-            self._present_message("NVDA to Cthulhu server failed to start")
+            self._schedule_on_main_thread(self._present_message, "NVDA to Cthulhu server failed to start")
         finally:
             self.httpServer = None
             if self.ioLoop:
@@ -261,7 +274,7 @@ class Nvda2Cthulhu(Plugin):
         if not self._dependencies_available():
             return None
         if isinstance(message, str):
-            return "SpeakText", message
+            return self._parse_payload(message)
 
         if not isinstance(message, (bytes, bytearray)):
             return None
@@ -318,7 +331,13 @@ class Nvda2Cthulhu(Plugin):
             translated = self._translate_text(text)
             logger.info(f"NVDA to Cthulhu: translated to: {translated[:50]}")
             text = translated
-        speech.speak(text, interrupt=self.interruptEnabled)
+        self._schedule_on_main_thread(self._speak_text, text, self.interruptEnabled)
+
+    def _speak_text(self, text: str, interrupt: bool) -> None:
+        speech.speak(text, interrupt=interrupt)
+
+    def _handle_cancel_speech(self) -> None:
+        speech.stop()
 
     def _handle_braille(self, text):
         if not text or not text.strip():
@@ -350,6 +369,23 @@ class Nvda2Cthulhu(Plugin):
         except Exception:
             logger.info(message)
 
+    def _schedule_on_main_thread(self, callback: Callable[..., Any], *args: Any) -> bool:
+        try:
+            GLib.idle_add(self._run_on_main_thread, callback, args)
+            return True
+        except Exception as exc:
+            logger.warning(f"NVDA to Cthulhu: failed to queue main-loop callback: {exc}")
+            debug.printException(debug.LEVEL_WARNING)
+            return False
+
+    def _run_on_main_thread(self, callback: Callable[..., Any], args: tuple[Any, ...]) -> bool:
+        try:
+            callback(*args)
+        except Exception as exc:
+            logger.warning(f"NVDA to Cthulhu: main-loop callback failed: {exc}")
+            debug.printException(debug.LEVEL_WARNING)
+        return False
+
     def _dependencies_available(self):
         return msgpack is not None and tornado is not None