1# -*- coding: utf-8 -*- 

2 

3# -- stdlib -- 

4import sys 

5 

6# -- third party -- 

7# -- own -- 

8 

9 

10# -- code -- 

11class ViralContext(object): 

12 VIRAL_SEARCH = ['self'] 

13 CONTINUE = object() 

14 

15 _viral_mro_cache = None 

16 

17 def __new__(cls, *a, **k): 

18 self = object.__new__(cls) 

19 cache = cls._viral_mro_cache if '_viral_mro_cache' in cls.__dict__ else None 

20 if not cache: 

21 cache = [c for c in cls.mro() if ViralContext in c.__bases__] 

22 cls._viral_mro_cache = cache 

23 

24 for c in cache: 

25 that = c.viral_search(start=2) if cls.VIRAL_SEARCH else None 

26 c.viral_import(self, that.viral_export() if that else None) 

27 

28 return self 

29 

30 @classmethod 

31 def viral_search(cls, start=1): 

32 f = sys._getframe(start) 

33 while f: 

34 for name in cls.VIRAL_SEARCH: 

35 that = f.f_locals.get(name) 

36 if that is not None and isinstance(that, cls): 

37 return that 

38 

39 f = f.f_back 

40 

41 return None 

42 

43 def viral_import(self, env): 

44 raise Exception('Override this!') 

45 

46 def viral_export(self): 

47 raise Exception('Override this!')