Keep GUI responsive during search. Allow aborting the search.

openlp/plugins/songs/forms/duplicatesongremovalform.py

@@ -65,6 +65,8 @@ class DuplicateSongRemovalForm(OpenLPWizard):
         self.duplicate_song_list = []
         self.review_current_count = 0
         self.review_total_count = 0
+        # Used to interrupt ongoing searches when cancel is clicked.
+        self.break_search = False
         OpenLPWizard.__init__(self, self.main_window, plugin, u'duplicateSongRemovalWizard',
             u':/wizards/wizard_duplicateremoval.bmp', False)
         self.setMinimumWidth(730)
@@ -154,6 +156,7 @@ class DuplicateSongRemovalForm(OpenLPWizard):
         self.button(QtGui.QWizard.BackButton).hide()
         if page_id == self.searching_page_id:
             self.application.set_busy_cursor()
+            try:
                 self.button(QtGui.QWizard.NextButton).hide()
                 # Search duplicate songs.
                 max_songs = self.plugin.manager.get_object_count(Song)
@@ -175,11 +178,16 @@ class DuplicateSongRemovalForm(OpenLPWizard):
                                 self.found_duplicates_edit.appendPlainText(songs[outer_song_counter].title + "  =  " +
                                     songs[inner_song_counter].title)
                         self.duplicate_search_progress_bar.setValue(self.duplicate_search_progress_bar.value() + 1)
+                        # The call to process_events() will keep the GUI responsive.
+                        self.application.process_events()
+                        if self.break_search:
+                            return
                 self.review_total_count = len(self.duplicate_song_list)
                 if self.review_total_count == 0:
                     self.notify_no_duplicates()
                 else:
                     self.button(QtGui.QWizard.NextButton).show()
+            finally:
                 self.application.set_normal_cursor()
         elif page_id == self.review_page_id:
             self.process_current_duplicate_entry()
@@ -238,6 +246,7 @@ class DuplicateSongRemovalForm(OpenLPWizard):
         Once the wizard is finished, refresh the song list,
         since we potentially removed songs from it.
         """
+        self.break_search = True
         self.plugin.media_item.on_search_text_button_clicked()
 
     def setDefaults(self):
@@ -337,3 +346,13 @@ class DuplicateSongRemovalForm(OpenLPWizard):
         return self._main_window
 
     main_window = property(_get_main_window)
+
+    def _get_application(self):
+        """
+        Adds the openlp to the class dynamically
+        """
+        if not hasattr(self, u'_application'):
+            self._application = Registry().get(u'application')
+        return self._application
+
+    application = property(_get_application)