view MoinMoin/error.py @ 1079:029754c52b11

Changed file format of meta file (\r\n line endings). Enhanced docstrings.
author Alexander Schremmer <alex AT alexanderweb DOT de>
date Fri, 28 Jul 2006 16:01:19 +0200
parents 141083b64fb1
children 2e1aff91a0a5
line wrap: on
line source
# -*- coding: iso-8859-1 -*-
""" MoinMoin errors

Supply Error class and sub classes used to raise various errors

@copyright: 2004, 2005 by Nir Soffer <nirs@freeshell.org>
@license: GNU GPL, see COPYING for details.
"""
import sys
from MoinMoin import config


class Error(Exception):
    """ Base class for moin moin errors

    Use this class when you raise errors or create sub classes that
    may be used to display non ASCII error message.
    
    Standard errors work safely only with strings using ascii or
    unicode. This class can be used safely with both strings using
    config.charset and unicode.

    You can init this class with either unicode or string using
    config.charset encoding. On output, the class will convert the string
    to unicode or the unicode to string, using config.charset.
            
    When you want to render an error, use unicode() or str() as needed.
    
    TODO: translate strings?
    """

    def __init__(self, message):
        """ Initialize an error, decode if needed

        @param message: unicode, str or object that support __unicode__
            and __str__. __str__ should use config.charset.
        """
        self.message = message

    def __unicode__(self):
        """ Return unicode error message """
        if isinstance(self.message, str):
            return unicode(self.message, config.charset)
        else:
            return unicode(self.message)

    def __str__(self):
        """ Return encoded message """
        if isinstance(self.message, unicode):
            return self.message.encode(config.charset)
        else:
            return str(self.message)

    def __getitem__(self, item):
        """ Make it possible to access attributes like a dict """
        return getattr(self, item)


class CompositeError(Error):
    ''' Base class for exceptions containing an exception

    Do not use this class but its more specific sub classes.

    Useful for hiding low level error inside high level user error,
    while keeping the inner error information for debugging.

    Example::

        class InternalError(CompositeError):
            """ Raise for internal errors """
        
        try:
            # code that might fail...
        except HairyLowLevelError:
            raise InternalError("Sorry, internal error occurred")
            
    When showing a traceback, both InternalError traceback and
    HairyLowLevelError traceback are available.
    '''

    def __init__(self, message):
        """ Save system exception info before this exception is raised """
        Error.__init__(self, message)
        self.innerException = sys.exc_info()

    def exceptions(self):
        """ Return a list of all inner exceptions """
        all = [self.innerException]
        while 1:
            lastException = all[-1][1]
            try:
                all.append(lastException.innerException)
            except AttributeError:
                break
        return all

class FatalError(CompositeError):
    """ Base class for fatal error we can't handle

    Do not use this class but its more specific sub classes.
    """

class ConfigurationError(FatalError):
    """ Raise when fatal misconfiguration is found """

class InternalError(FatalError):
    """ Raise when internal fatal error is found """