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