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"""
create errno-specific classes for IO or os calls.
"""
import sys, os, errno
class Error(EnvironmentError):
def __repr__(self):
return "%s.%s %r: %s " %(self.__class__.__module__,
self.__class__.__name__,
self.__class__.__doc__,
" ".join(map(str, self.args)),
#repr(self.args)
)
def __str__(self):
s = "[%s]: %s" %(self.__class__.__doc__,
" ".join(map(str, self.args)),
)
return s
_winerrnomap = {
2: errno.ENOENT,
3: errno.ENOENT,
17: errno.EEXIST,
18: errno.EXDEV,
13: errno.EBUSY, # empty cd drive, but ENOMEDIUM seems unavailiable
22: errno.ENOTDIR,
20: errno.ENOTDIR,
267: errno.ENOTDIR,
5: errno.EACCES, # anything better?
}
class ErrorMaker(object):
""" lazily provides Exception classes for each possible POSIX errno
(as defined per the 'errno' module). All such instances
subclass EnvironmentError.
"""
Error = Error
_errno2class = {}
def __getattr__(self, name):
if name[0] == "_":
raise AttributeError(name)
eno = getattr(errno, name)
cls = self._geterrnoclass(eno)
setattr(self, name, cls)
return cls
def _geterrnoclass(self, eno):
try:
return self._errno2class[eno]
except KeyError:
clsname = errno.errorcode.get(eno, "UnknownErrno%d" %(eno,))
errorcls = type(Error)(clsname, (Error,),
{'__module__':'py.error',
'__doc__': os.strerror(eno)})
self._errno2class[eno] = errorcls
return errorcls
def checked_call(self, func, *args, **kwargs):
""" call a function and raise an errno-exception if applicable. """
__tracebackhide__ = True
try:
return func(*args, **kwargs)
except self.Error:
raise
except (OSError, EnvironmentError):
cls, value, tb = sys.exc_info()
if not hasattr(value, 'errno'):
raise
__tracebackhide__ = False
errno = value.errno
try:
if not isinstance(value, WindowsError):
raise NameError
except NameError:
# we are not on Windows, or we got a proper OSError
cls = self._geterrnoclass(errno)
else:
try:
cls = self._geterrnoclass(_winerrnomap[errno])
except KeyError:
raise value
raise cls("%s%r" % (func.__name__, args))
__tracebackhide__ = True
error = ErrorMaker()
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