destroy_buffer interface is enough, remove before_destroy_buffer.

app/camera/buffer.py

@@ -52,6 +52,7 @@ class AppBuffer(Buffer):
 
     def destroy_buffer(self):
         self.buffer_widget.stop_camera()
+        
         super().destroy_buffer()
 
 class CameraWidget(QWidget):

app/file-browser/buffer.py

@@ -40,6 +40,8 @@ class AppBuffer(Buffer):
     def destroy_buffer(self):
         os.kill(self.buffer_widget.background_process.pid, signal.SIGKILL)
 
+        super().destroy_buffer()
+
 class Image(qrcode.image.base.BaseImage):
     def __init__(self, border, width, box_size):
         self.border = border

app/file-sender/buffer.py

@@ -138,8 +138,10 @@ class FileTransferWidget(QWidget):
         httpd = BaseHTTPServer.HTTPServer(('', self.port), SimpleHTTPRequestHandler)
         httpd.serve_forever()
 
-    def before_destroy_buffer(self):
+    def destroy_buffer(self):
         global local_file_path
 
         self.message_to_emacs.emit("Stop file sender server: http://{0}:{1}/{2}".format(self.local_ip, self.port, local_file_path))
         self.sender_thread.stop()
+
+        super().destroy_buffer()

app/pdf-viewer/buffer.py

@@ -49,11 +49,13 @@ class AppBuffer(Buffer):
                             "toggle_read_mode", "toggle_inverted_mode", "toggle_mark_link"]:
             self.build_widget_method(method_name)
 
-    def before_destroy_buffer(self):
+    def destroy_buffer(self):
         if self.delete_temp_file:
             if os.path.exists(self.url):
                 os.remove(self.url)
 
+        super().destroy_buffer()
+
     def get_table_file(self):
         return self.buffer_widget.table_file_path
 

app/video-player/buffer.py

@@ -61,9 +61,11 @@ class AppBuffer(Buffer):
             self.buffer_widget.media_player.play()
             self.buffer_widget.video_need_replay = True
 
-    def before_destroy_buffer(self):
+    def destroy_buffer(self):
         self.buffer_widget.media_player.pause()
 
+        super().destroy_buffer()
+
 class VideoPlayerWidget(QWidget):
 
     def __init__(self, parent=None):

core/buffer.py

@@ -166,12 +166,7 @@ class Buffer(QGraphicsScene):
 
         self.buffer_widget.buffer = self
 
-    def before_destroy_buffer(self):
-        pass
-
     def destroy_buffer(self):
-        self.before_destroy_buffer()
-
         if self.buffer_widget is not None:
             self.buffer_widget.deleteLater()