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@dsc
Created August 11, 2020 15:57
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A debugging tool for the lazy: pay a ridiculous performance penalty so you don't have to actually have to pay attention to what's calling what.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
""" A debugging tool for the lazy: pay a ridiculous performance penalty so
you don't have to actually have to pay attention to what's calling what.
"""
# import logging
# log = logging.getLogger('lessly')
import inspect, weakref
from contextlib import contextmanager
from proxy import AttributeProxy
class StackFrame(AttributeProxy):
""" Context manager for a frame on the stack. Provides convenience for
chaining frames and prevents leaks due to reference cycles.
"""
weakframe = None
frame = None
def __init__(self, frame=None):
super(StackFrame, self).__init__('frame')
self.weakframe = weakref.ref(frame or inspect.currentframe().f_back)
def cleanup(self, *args, **kw):
try:
del self.frame
finally:
self.frame = None
def previous(self):
"Moves up to the previous frame in the stack."
if self.frame:
f_back = StackFrame(self.frame.f_back)
if f_back:
try:
self.cleanup()
self.frame = f_back
return self
finally:
del f_back
else:
return None
else:
raise ReferenceError("Can only traverse the stack in a context block!")
def locals(self):
return self.frame.f_locals
def globals(self):
return self.frame.f_globals
def code(self):
return self.frame.f_code
### Context Manager Protocol ###
def __enter__(self):
self.frame = self.weakframe()
return self
__exit__ = cleanup
__del__ = cleanup
# from lessly.meta.managed import InnerClass
def find_calling_instance(Type):
frame = inspect.currentframe().f_back
try:
while frame:
for v in frame.f_locals.values():
if isinstance(v, Type):
return v
# elif issubclass(type(v), InnerClass):
# log.debug('InnerClass detected while looking for %s: <%s at 0x%x>...' % (Type, type(v).__name__, id(v)))
# for attr in dir(v):
# inner = getattr(v, attr, None)
# if isinstance(inner, Type):
# log.debug('--> success! %s' % inner)
# return inner
frame = frame.f_back
finally:
del frame
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