[utils] Add classproperty() decorator from yt-dlp

youtube_dl/utils.py

@@ -6510,3 +6510,33 @@ def join_nonempty(*values, **kwargs):
     if from_dict is not None:
         values = (traverse_obj(from_dict, variadic(v)) for v in values)
     return delim.join(map(compat_str, filter(None, values)))
+
+
+# from yt-dlp
+class classproperty(object):
+    """property access for class methods with optional caching"""
+    def __new__(cls, *args, **kwargs):
+        if 'func' in kwargs:
+            func = kwargs.pop('func')
+        elif len(args) > 0:
+            func = args[0]
+            args = args[1:]
+        else:
+            func = None
+        if not func:
+            return functools.partial(cls, *args, **kwargs)
+        return super(classproperty, cls).__new__(cls)
+
+    def __init__(self, func, **kwargs):
+        # kw-only arg
+        cache = kwargs.get('cache', False)
+        functools.update_wrapper(self, func)
+        self.func = func
+        self._cache = {} if cache else None
+
+    def __get__(self, n, cls):
+        if self._cache is None:
+            return self.func(cls)
+        elif cls not in self._cache:
+            self._cache[cls] = self.func(cls)
+        return self._cache[cls]