From 191975bd149dceac3efe51268acae484bf7c788f Mon Sep 17 00:00:00 2001
From: DYefremov <dmitry.v.yefremov@gmail.com>
Date: Fri, 10 Feb 2023 11:59:14 +0300
Subject: [PATCH] extension as singleton

---
 app/ui/extensions/__init__.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/app/ui/extensions/__init__.py b/app/ui/extensions/__init__.py
index d9609036..54058f6a 100644
--- a/app/ui/extensions/__init__.py
+++ b/app/ui/extensions/__init__.py
@@ -26,7 +26,16 @@
 #
 
 
-class BaseExtension:
+class Singleton(type):
+    _INSTANCE = None
+
+    def __call__(cls, *args, **kwargs):
+        if not cls._INSTANCE:
+            cls._INSTANCE = type.__call__(cls, *args, **kwargs)
+        return cls._INSTANCE
+
+
+class BaseExtension(metaclass=Singleton):
     """ Base extension (plugin) class. """
     # The label that will be displayed in the "Tools" menu.
     LABEL = "Base extension"