Use extra thread for transcription to not block UI

stt_voice_messages/stt_voice_messages.py

@@ -20,7 +20,7 @@ from functools import partial
 from pathlib import Path
 
 import whisper
-from gi.repository import Gtk
+from gi.repository import Gio, GObject, Gtk
 from stt_voice_messages.config_dialog import STTVoiceMessagesConfigDialog
 
 from gajim.plugins import GajimPlugin
@@ -69,12 +69,12 @@ class STTBox(Gtk.Box):
                  audio_file: Path,
                  ) -> None:
 
-        print('FOO')
         Gtk.Box.__init__(self, orientation=Gtk.Orientation.VERTICAL, spacing=12)
 
         self._config = config
         self._preview_audio = preview_audio_widget
         self._audio_file = audio_file
+        self._text = ''
 
         self._transcribe_button = Gtk.Button(label=_('Transcribe'))
 
@@ -89,20 +89,69 @@ class STTBox(Gtk.Box):
 
         self.show_all()
 
-
     def _on_transcribe_clicked(self, _button: Gtk.Button):
-        text = self._trascribe_by_whisper()
+        transcription_task = BackgroundTask(
-        if text.strip() != '':
+            self._trascribe_by_whisper,
-            self._transcription_label.set_text(text.strip())
+            self._show_result
+        )
+        transcription_task.start()
+
+    def _show_result(self):
+        if self._text.strip() != '':
+            self._transcription_label.set_text(self._text.strip())
         else:
             self._transcription_label.set_text(_('_Have not heard any word!_'))
 
     def _trascribe_by_whisper(self) -> str:
         model = whisper.load_model(self._config['model_size'])
         result = model.transcribe(self._audio_file)
-        text = result["text"]
+        self._text = result["text"]
         return text
 
 
+'''
+https://discourse.gnome.org/t/gtk-threading-problem-with-glib-idle-add/13597/5
+https://github.com/gdm-settings/gdm-settings/blob/f245d3000200fa6be2a35c7f6ac45b131dadb5d6/src/utils.py#L116..L162
+'''
+class BackgroundTask (GObject.Object):
+    __gtype_name__ = 'BackgroundTask'
 
+    def __init__ (self, function, finish_callback, **kwargs):
+        super().__init__(**kwargs)
 
+        self.function = function
+        self.finish_callback = finish_callback
+        self._current = None
+
+    def start(self):
+        if self._current:
+            AlreadyRunningError('Task is already running')
+
+        finish_callback = lambda self, task, nothing: self.finish_callback()
+
+        task = Gio.Task.new(self, None, finish_callback, None)
+        task.run_in_thread(self._thread_cb)
+
+        self._current = task
+
+    @staticmethod
+    def _thread_cb (task, self, task_data, cancellable):
+        try:
+            retval = self.function()
+            task.return_value(retval)
+        except Exception as e:
+            task.return_value(e)
+
+    def finish (self):
+        task = self._current
+        self._current = None
+
+        if not Gio.Task.is_valid(task, self):
+            raise InvalidGioTaskError()
+
+        value = task.propagate_value().value
+
+        if isinstance(value, Exception):
+            raise value
+
+        return value