# -*- coding: utf-8 -*-
from functools import wraps
import ctypes
def mac_strerror(errno):
"""Returns an error string for a classic MacOS error return code"""
# TODO: Find a replacement which isn't deprecated in Python 3000:
try:
import MacOS
return MacOS.GetErrorString(errno)
except ImportError:
return "Unknown error %d: MacOS.GetErrorString is not available by this Python"
def carbon_errcheck(rc, func, args):
if rc < 0:
# TODO: Do we need to create a function which can safely check __name__
# and handle non-existence? It should be set for anything using ctypes
# and this shouldn't be useful otherwise
# TODO: Create a custom exception which preserves the original rc value?
raise RuntimeError("%s(%s) returned %d: %s" % (func.__name__, map(repr, args), rc, mac_strerror(rc)))
return rc
def carbon_call(f, *args):
"""
Wrapper for Carbon calls inspired by subprocess.check_call(): a negative
rc will generate a RuntimeError with a [hopefully] informative message.
"""
rc = f(*args)
return carbon_errcheck(rc, f, args)
def load_carbon_framework(f_path):
"""
Load a Carbon framework using ctypes.CDLL and add an errcheck wrapper to
replace traditional errno-style error checks with exception handling.
Example:
>>> PyMacAdmin.load_carbon_framework('/System/Library/Frameworks/Security.framework/Versions/Current/Security')
<CDLL '/System/Library/Frameworks/Security.framework/Versions/Current/Security', handle 318320 at 2515f0>
"""
framework = ctypes.cdll.LoadLibrary(f_path)
# TODO: Do we ever need to wrap framework.__getattr__ too?
old_getitem = framework.__getitem__
@wraps(old_getitem)
def new_getitem(k):
v = old_getitem(k)
if hasattr(v, "errcheck") and not v.errcheck:
v.errcheck = carbon_errcheck
return v
framework.__getitem__ = new_getitem
return framework
