#
# Last Change: 2026-03-18
#

import threading

class Singleton:
	"""
		A thread lock protected singleton,
		makes any inherting class into a singlton.

		The SINGLETON_LOCK object is shared between all inherited children,
		unless they initiate their own using the 'decouple_lock_from_parent_class' method.
	"""

	SINGLETON_INSTANCE = None
	SINGLETON_LOCK = threading.Lock()

	@classmethod
	def decouple_lock_from_parent_class( cls ):
		if cls.SINGLETON_LOCK is not super().SINGLETON_LOCK: return
		cls.SINGLETON_LOCK = threading.Lock()

	def __new__( cls, *args, **kwargs ):
		if cls.SINGLETON_INSTANCE: return cls.SINGLETON_INSTANCE

		with cls.SINGLETON_LOCK:
			if cls.SINGLETON_INSTANCE: return cls.SINGLETON_INSTANCE
			cls.SINGLETON_INSTANCE = super().__new__( cls, *args, **kwargs )

		return cls.SINGLETON_INSTANCE