test_ok2/py/_io/saferepr.py

57 lines
1.9 KiB
Python

import py
import sys, os.path
builtin_repr = repr
reprlib = py.builtin._tryimport('repr', 'reprlib')
sysex = (KeyboardInterrupt, MemoryError, SystemExit)
class SafeRepr(reprlib.Repr):
""" subclass of repr.Repr that limits the resulting size of repr()
and includes information on exceptions raised during the call.
"""
def repr(self, x):
return self._callhelper(reprlib.Repr.repr, self, x)
def repr_instance(self, x, level):
return self._callhelper(builtin_repr, x)
def _callhelper(self, call, x, *args):
try:
# Try the vanilla repr and make sure that the result is a string
s = call(x, *args)
except sysex:
raise
except:
cls, e, tb = sys.exc_info()
exc_name = getattr(cls, '__name__', 'unknown')
try:
exc_info = str(e)
except sysex:
raise
except:
exc_info = 'unknown'
return '<[%s("%s") raised in repr()] %s object at 0x%x>' % (
exc_name, exc_info, x.__class__.__name__, id(x))
else:
if len(s) > self.maxsize:
i = max(0, (self.maxsize-3)//2)
j = max(0, self.maxsize-3-i)
s = s[:i] + '...' + s[len(s)-j:]
return s
def saferepr(obj, maxsize=240):
""" return a size-limited safe repr-string for the given object.
Failing __repr__ functions of user instances will be represented
with a short exception info and 'saferepr' generally takes
care to never raise exceptions itself. This function is a wrapper
around the Repr/reprlib functionality of the standard 2.6 lib.
"""
# review exception handling
srepr = SafeRepr()
srepr.maxstring = maxsize
srepr.maxsize = maxsize
srepr.maxother = 160
return srepr.repr(obj)