app: Cleanup w/o relying on return from exec_()

Author: ferdnyc

src/classes/app.py

@@ -35,10 +35,18 @@
 
 from PyQt5.QtCore import PYQT_VERSION_STR
 from PyQt5.QtCore import QT_VERSION_STR
-from PyQt5.QtCore import Qt
+from PyQt5.QtCore import Qt, pyqtSlot
 from PyQt5.QtGui import QPalette, QColor, QFontDatabase, QFont
 from PyQt5.QtWidgets import QApplication, QStyleFactory, QMessageBox
 
+try:
+    # This apparently has to be done before loading QtQuick
+    # (via QtWebEgine) AND before creating the QApplication instance
+    QApplication.setAttribute(Qt.AA_ShareOpenGLContexts)
+    from OpenGL import GL  # noqa
+except (ImportError, AttributeError):
+    pass
+
 try:
     # QtWebEngineWidgets must be loaded prior to creating a QApplication
     # But on systems with only WebKit, this will fail (and we ignore the failure)
@@ -76,17 +84,10 @@ def __init__(self, *args, mode=None):
             log.info(time.asctime().center(48))
             log.info('Starting new session'.center(48))
 
-            if mode != "unittest" and (
-                    not info.WEB_BACKEND
-                    or info.WEB_BACKEND in ["auto", "webengine"]):
-                try:
-                    from OpenGL import GL
-                    self.setAttribute(Qt.AA_ShareOpenGLContexts)
-                except (ImportError, AttributeError):
-                    pass
-
-            from classes import settings, project_data, updates, language, ui_util, logger_libopenshot
-            from . import openshot_rc  # noqa
+            from classes import (
+                settings, project_data, updates, language, ui_util,
+                logger_libopenshot
+                )
             import openshot
 
             # Re-route stdout and stderr to logger
@@ -255,6 +256,9 @@ def __init__(self, *args, mode=None):
         self.updates.reset()
         self.window.updateStatusChanged(False, False)
 
+        # Connect our exit signals
+        self.aboutToQuit.connect(self.cleanup)
+
         log.info('Process command-line arguments: %s' % args)
         if len(args[0]) == 2:
             path = args[0][1]
@@ -275,17 +279,17 @@ def _tr(self, message):
     # Start event loop
     def run(self):
         """ Start the primary Qt event loop for the interface """
+        return self.exec_()
 
-        res = self.exec_()
-
+    @pyqtSlot()
+    def cleanup(self):
+        """aboutToQuit signal handler for application exit"""
         try:
             from classes.logger import log
             self.settings.save()
         except Exception:
             log.error("Couldn't save user settings on exit.", exc_info=1)
 
-        # return exit result
-        return res
 
 
 # Log the session's end