/psychopy/contrib/configobj/__init__.py

# configobj.py
# -*- coding: utf-8 -*-
# pylint: disable=bad-continuation

"""A config file reader/writer that supports nested sections in config files."""

# Copyright (C) 2005-2014:
# (name) : (email)
# Michael Foord: fuzzyman AT voidspace DOT org DOT uk
# Nicola Larosa: nico AT tekNico DOT net
# Rob Dennis: rdennis AT gmail DOT com
# Eli Courtwright: eli AT courtwright DOT org

# This software is licensed under the terms of the BSD license.
# http://opensource.org/licenses/BSD-3-Clause

# ConfigObj 5 - main repository for documentation and issue tracking:
# https://github.com/DiffSK/configobj

import os
import re
import sys
import copy

from codecs import BOM_UTF8, BOM_UTF16, BOM_UTF16_BE, BOM_UTF16_LE

try:
    # Python 3
    from collections.abc import Mapping
except ImportError:
    # Python 2.7
    from collections import Mapping

import six

# imported lazily to avoid startup performance hit if it isn't used
compiler = None

# A dictionary mapping BOM to
# the encoding to decode with, and what to set the
# encoding attribute to.
BOMS = {
    BOM_UTF8: ('utf_8', None),
    BOM_UTF16_BE: ('utf16_be', 'utf_16'),
    BOM_UTF16_LE: ('utf16_le', 'utf_16'),
    BOM_UTF16: ('utf_16', 'utf_16'),
    }
# All legal variants of the BOM codecs.
# TODO: the list of aliases is not meant to be exhaustive, is there a
#   better way ?
BOM_LIST = {
    'utf_16': 'utf_16',
    'u16': 'utf_16',
    'utf16': 'utf_16',
    'utf-16': 'utf_16',
    'utf16_be': 'utf16_be',
    'utf_16_be': 'utf16_be',
    'utf-16be': 'utf16_be',
    'utf16_le': 'utf16_le',
    'utf_16_le': 'utf16_le',
    'utf-16le': 'utf16_le',
    'utf_8': 'utf_8',
    'u8': 'utf_8',
    'utf': 'utf_8',
    'utf8': 'utf_8',
    'utf-8': 'utf_8',
    }

# Map of encodings to the BOM to write.
BOM_SET = {
    'utf_8': BOM_UTF8,
    'utf_16': BOM_UTF16,
    'utf16_be': BOM_UTF16_BE,
    'utf16_le': BOM_UTF16_LE,
    None: BOM_UTF8
    }


def match_utf8(encoding):
    return BOM_LIST.get(encoding.lower()) == 'utf_8'


# Quote strings used for writing values
squot = "'%s'"
dquot = '"%s"'
noquot = "%s"
wspace_plus = ' \r\n\v\t\'"'
tsquot = '"""%s"""'
tdquot = "'''%s'''"

# Sentinel for use in getattr calls to replace hasattr
MISSING = object()

__all__ = (
    'DEFAULT_INDENT_TYPE',
    'DEFAULT_INTERPOLATION',
    'ConfigObjError',
    'NestingError',
    'ParseError',
    'DuplicateError',
    'ConfigspecError',
    'ConfigObj',
    'SimpleVal',
    'InterpolationError',
    'InterpolationLoopError',
    'MissingInterpolationOption',
    'RepeatSectionError',
    'ReloadError',
    'UnreprError',
    'UnknownType',
    'flatten_errors',
    'get_extra_values'
)

DEFAULT_INTERPOLATION = 'configparser'
DEFAULT_INDENT_TYPE = '    '
MAX_INTERPOL_DEPTH = 10

OPTION_DEFAULTS = {
    'interpolation': True,
    'raise_errors': False,
    'list_values': True,
    'create_empty': False,
    'file_error': False,
    'configspec': None,
    'stringify': True,
    # option may be set to one of ('', ' ', '\t')
    'indent_type': None,
    'encoding': None,
    'default_encoding': None,
    'unrepr': False,
    'write_empty_values': False,
}

# this could be replaced if six is used for compatibility, or there are no
# more assertions about items being a string


def getObj(s):
    global compiler
    if compiler is None:
        import compiler
    s = "a=" + s
    p = compiler.parse(s)
    return p.getChildren()[1].getChildren()[0].getChildren()[1]


class UnknownType(Exception):
    pass


def unrepr(s):
    if not s:
        return s

    # this is supposed to be safe
    import ast
    return ast.literal_eval(s)


class ConfigObjError(SyntaxError):
    """
    This is the base class for all errors that ConfigObj raises.
    It is a subclass of SyntaxError.
    """
    def __init__(self, message='', line_number=None, line=''):
        self.line = line
        self.line_number = line_number
        SyntaxError.__init__(self, message)


class NestingError(ConfigObjError):
    """
    This error indicates a level of nesting that doesn't match.
    """


class ParseError(ConfigObjError):
    """
    This error indicates that a line is badly written.
    It is neither a valid ``key = value`` line,
    nor a valid section marker line.
    """


class ReloadError(IOError):
    """
    A 'reload' operation failed.
    This exception is a subclass of ``IOError``.
    """
    def __init__(self):
        IOError.__init__(self, 'reload failed, filename is not set.')


class DuplicateError(ConfigObjError):
    """
    The keyword or section specified already exists.
    """


class ConfigspecError(ConfigObjError):
    """
    An error occured whilst parsing a configspec.
    """


class InterpolationError(ConfigObjError):
    """Base class for the two interpolation errors."""


class InterpolationLoopError(InterpolationError):
    """Maximum interpolation depth exceeded in string interpolation."""

    def __init__(self, option):
        InterpolationError.__init__(
            self,
            'interpolation loop detected in value "%s".' % option)


class RepeatSectionError(ConfigObjError):
    """
    This error indicates additional sections in a section with a
    ``__many__`` (repeated) section.
    """


class MissingInterpolationOption(InterpolationError):
    """A value specified for interpolation was missing."""
    def __init__(self, option):
        msg = 'missing option "%s" in interpolation.' % option
        InterpolationError.__init__(self, msg)


class UnreprError(ConfigObjError):
    """An error parsing in unrepr mode."""



class InterpolationEngine(object):
    """
    A helper class to help perform string interpolation.

    This class is an abstract base class; its descendants perform
    the actual work.
    """

    # compiled regexp to use in self.interpolate()
    _KEYCRE = re.compile(r"%\(([^)]*)\)s")
    _cookie = '%'

    def __init__(self, section):
        # the Section instance that "owns" this engine
        self.section = section


    def interpolate(self, key, value):
        # short-cut
        if not self._cookie in value:
            return value

        def recursive_interpolate(key, value, section, backtrail):
            """The function that does the actual work.

            ``value``: the string we're trying to interpolate.
            ``section``: the section in which that string was found
            ``backtrail``: a dict to keep track of where we've been,
            to detect and prevent infinite recursion loops

            This is similar to a depth-first-search algorithm.
            """
            # Have we been here already?
            if (key, section.name) in backtrail:
                # Yes - infinite loop detected
                raise InterpolationLoopError(key)
            # Place a marker on our backtrail so we won't come back here again
            backtrail[(key, section.name)] = 1

            # Now start the actual work
            match = self._KEYCRE.search(value)
            while match:
                # The actual parsing of the match is implementation-dependent,
                # so delegate to our helper function
                k, v, s = self._parse_match(match)
                if k is None:
                    # That's the signal that no further interpolation is needed
                    replacement = v
                else:
                    # Further interpolation may be needed to obtain final value
                    replacement = recursive_interpolate(k, v, s, backtrail)
                # Replace the matched string with its final value
                start, end = match.span()
                value = ''.join((value[:start], replacement, value[end:]))
                new_search_start = start + len(replacement)
                # Pick up the next interpolation key, if any, for next time
                # through the while loop
                match = self._KEYCRE.search(value, new_search_start)

            # Now safe to come back here again; remove marker from backtrail
            del backtrail[(key, section.name)]

            return value

        # Back in interpolate(), all we have to do is kick off the recursive
        # function with appropriate starting values
        value = recursive_interpolate(key, value, self.section, {})
        return value


    def _fetch(self, key):
        """Helper function to fetch values from owning section.

        Returns a 2-tuple: the value, and the section where it was found.
        """
        # switch off interpolation before we try and fetch anything !
        save_interp = self.section.main.interpolation
        self.section.main.interpolation = False

        # Start at section that "owns" this InterpolationEngine
        current_section = self.section
        while True:
            # try the current section first
            val = current_section.get(key)
            if val is not None and not isinstance(val, Section):
                break
            # try "DEFAULT" next
            val = current_section.get('DEFAULT', {}).get(key)
            if val is not None and not isinstance(val, Section):
                break
            # move up to parent and try again
            # top-level's parent is itself
            if current_section.parent is current_section:
                # reached top level, time to give up
                break
            current_section = current_section.parent

        # restore interpolation to previous value before returning
        self.section.main.interpolation = save_interp
        if val is None:
            raise MissingInterpolationOption(key)
        return val, current_section


    def _parse_match(self, match):
        """Implementation-dependent helper function.

        Will be passed a match object corresponding to the interpolation
        key we just found (e.g., "%(foo)s" or "$foo"). Should look up that
        key in the appropriate config file section (using the ``_fetch()``
        helper function) and return a 3-tuple: (key, value, section)

        ``key`` is the name of the key we're looking for
        ``value`` is the value found for that key
        ``section`` is a reference to the section where it was found

        ``key`` and ``section`` should be None if no further
        interpolation should be performed on the resulting value
        (e.g., if we interpolated "$$" and returned "$").
        """
        raise NotImplementedError()



class ConfigParserInterpolation(InterpolationEngine):
    """Behaves like ConfigParser."""
    _cookie = '%'
    _KEYCRE = re.compile(r"%\(([^)]*)\)s")

    def _parse_match(self, match):
        key = match.group(1)
        value, section = self._fetch(key)
        return key, value, section



class TemplateInterpolation(InterpolationEngine):
    """Behaves like string.Template."""
    _cookie = '$'
    _delimiter = '$'
    _KEYCRE = re.compile(r"""
        \$(?:
          (?P<escaped>\$)              |   # Two $ signs
          (?P<named>[_a-z][_a-z0-9]*)  |   # $name format
          {(?P<braced>[^}]*)}              # ${name} format
        )
        """, re.IGNORECASE | re.VERBOSE)

    def _parse_match(self, match):
        # Valid name (in or out of braces): fetch value from section
        key = match.group('named') or match.group('braced')
        if key is not None:
            value, section = self._fetch(key)
            return key, value, section
        # Escaped delimiter (e.g., $$): return single delimiter
        if match.group('escaped') is not None:
            # Return None for key and section to indicate it's time to stop
            return None, self._delimiter, None
        # Anything else: ignore completely, just return it unchanged
        return None, match.group(), None


interpolation_engines = {
    'configparser': ConfigParserInterpolation,
    'template': TemplateInterpolation,
}


def __newobj__(cls, *args):
    # Hack for pickle
    return cls.__new__(cls, *args)

class Section(dict):
    """
    A dictionary-like object that represents a section in a config file.

    It does string interpolation if the 'interpolation' attribute
    of the 'main' object is set to True.

    Interpolation is tried first from this object, then from the 'DEFAULT'
    section of this object, next from the parent and its 'DEFAULT' section,
    and so on until the main object is reached.

    A Section will behave like an ordered dictionary - following the
    order of the ``scalars`` and ``sections`` attributes.
    You can use this to change the order of members.

    Iteration follows the order: scalars, then sections.
    """


    def __setstate__(self, state):
        dict.update(self, state[0])
        self.__dict__.update(state[1])

    def __reduce__(self):
        state = (dict(self), self.__dict__)
        return (__newobj__, (self.__class__,), state)


    def __init__(self, parent, depth, main, indict=None, name=None):
        """
        * parent is the section above
        * depth is the depth level of this section
        * main is the main ConfigObj
        * indict is a dictionary to initialise the section with
        """
        if indict is None:
            indict = {}
        dict.__init__(self)
        # used for nesting level *and* interpolation
        self.parent = parent
        # used for the interpolation attribute
        self.main = main
        # level of nesting depth of this Section
        self.depth = depth
        # purely for information
        self.name = name
        #
        self._initialise()
        # we do this explicitly so that __setitem__ is used properly
        # (rather than just passing to ``dict.__init__``)
        for entry, value in indict.items():
            self[entry] = value


    def _initialise(self):
        # the sequence of scalar values in this Section
        self.scalars = []
        # the sequence of sections in this Section
        self.sections = []
        # for comments :-)
        self.comments = {}
        self.inline_comments = {}
        # the configspec
        self.configspec = None
        # for defaults
        self.defaults = []
        self.default_values = {}
        self.extra_values = []
        self._created = False


    def _interpolate(self, key, value):
        try:
            # do we already have an interpolation engine?
            engine = self._interpolation_engine
        except AttributeError:
            # not yet: first time running _interpolate(), so pick the engine
            name = self.main.interpolation
            if name == True:  # note that "if name:" would be incorrect here
                # backwards-compatibility: interpolation=True means use default
                name = DEFAULT_INTERPOLATION
            name = name.lower()  # so that "Template", "template", etc. all work
            class_ = interpolation_engines.get(name, None)
            if class_ is None:
                # invalid value for self.main.interpolation
                self.main.interpolation = False
                return value
            else:
                # save reference to engine so we don't have to do this again
                engine = self._interpolation_engine = class_(self)
        # let the engine do the actual work
        return engine.interpolate(key, value)


    def __getitem__(self, key):
        """Fetch the item and do string interpolation."""
        val = dict.__getitem__(self, key)
        if self.main.interpolation:
            if isinstance(val, six.string_types):
                return self._interpolate(key, val)
            if isinstance(val, list):
                def _check(entry):
                    if isinstance(entry, six.string_types):
                        return self._interpolate(key, entry)
                    return entry
                new = [_check(entry) for entry in val]
                if new != val:
                    return new
        return val


    def __setitem__(self, key, value, unrepr=False):
        """
        Correctly set a value.

        Making dictionary values Section instances.
        (We have to special case 'Section' instances - which are also dicts)

        Keys must be strings.
        Values need only be strings (or lists of strings) if
        ``main.stringify`` is set.

        ``unrepr`` must be set when setting a value to a dictionary, without
        creating a new sub-section.
        """
        if not isinstance(key, six.string_types):
            raise ValueError('The key "%s" is not a string.' % key)

        # add the comment
        if key not in self.comments:
            self.comments[key] = []
            self.inline_comments[key] = ''
        # remove the entry from defaults
        if key in self.defaults:
            self.defaults.remove(key)
        #
        if isinstance(value, Section):
            if key not in self:
                self.sections.append(key)
            dict.__setitem__(self, key, value)
        elif isinstance(value, Mapping) and not unrepr:
            # First create the new depth level,
            # then create the section
            if key not in self:
                self.sections.append(key)
            new_depth = self.depth + 1
            dict.__setitem__(
                self,
                key,
                Section(
                    self,
                    new_depth,
                    self.main,
                    indict=value,
                    name=key))
        else:
            if key not in self:
                self.scalars.append(key)
            if not self.main.stringify:
                if isinstance(value, six.string_types):
                    pass
                elif isinstance(value, (list, tuple)):
                    for entry in value:
                        if not isinstance(entry, six.string_types):
                            raise TypeError('Value is not a string "%s".' % entry)
                else:
                    raise TypeError('Value is not a string "%s".' % value)
            dict.__setitem__(self, key, value)


    def __delitem__(self, key):
        """Remove items from the sequence when deleting."""
        dict. __delitem__(self, key)
        if key in self.scalars:
            self.scalars.remove(key)
        else:
            self.sections.remove(key)
        del self.comments[key]
        del self.inline_comments[key]


    def get(self, key, default=None):
        """A version of ``get`` that doesn't bypass string interpolation."""
        try:
            return self[key]
        except KeyError:
            return default


    def update(self, indict):
        """
        A version of update that uses our ``__setitem__``.
        """
        for entry in indict:
            self[entry] = indict[entry]


    def pop(self, key, default=MISSING):
        """
        'D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
        If key is not found, d is returned if given, otherwise KeyError is raised'
        """
        try:
            val = self[key]
        except KeyError:
            if default is MISSING:
                raise
            val = default
        else:
            del self[key]
        return val


    def popitem(self):
        """Pops the first (key,val)"""
        sequence = (self.scalars + self.sections)
        if not sequence:
            raise KeyError(": 'popitem(): dictionary is empty'")
        key = sequence[0]
        val =  self[key]
        del self[key]
        return key, val


    def clear(self):
        """
        A version of clear that also affects scalars/sections
        Also clears comments and configspec.

        Leaves other attributes alone :
            depth/main/parent are not affected
        """
        dict.clear(self)
        self.scalars = []
        self.sections = []
        self.comments = {}
        self.inline_comments = {}
        self.configspec = None
        self.defaults = []
        self.extra_values = []


    def setdefault(self, key, default=None):
        """A version of setdefault that sets sequence if appropriate."""
        try:
            return self[key]
        except KeyError:
            self[key] = default
            return self[key]


    def items(self):
        """D.items() -> list of D's (key, value) pairs, as 2-tuples"""
        return [(key, self[key]) for key in self.keys()]


    def keys(self):
        """D.keys() -> list of D's keys"""
        return self.scalars + self.sections


    def values(self):
        """D.values() -> list of D's values"""
        return [self[key] for key in self.keys()]


    def iteritems(self):
        """D.iteritems() -> an iterator over the (key, value) items of D"""
        return iter(self.items())


    def iterkeys(self):
        """D.iterkeys() -> an iterator over the keys of D"""
        return iter(self.keys())

    __iter__ = iterkeys


    def itervalues(self):
        """D.itervalues() -> an iterator over the values of D"""
        return iter(self.values())


    def __repr__(self):
        """x.__repr__() <==> repr(x)"""
        def _getval(key):
            try:
                return self[key]
            except MissingInterpolationOption:
                return dict.__getitem__(self, key)
        return '{%s}' % ', '.join([('{}: {}'.format(repr(key), repr(_getval(key))))
            for key in (self.scalars + self.sections)])

    __str__ = __repr__
    __str__.__doc__ = "x.__str__() <==> str(x)"


    # Extra methods - not in a normal dictionary

    def dict(self):
        """
        Return a deepcopy of self as a dictionary.

        All members that are ``Section`` instances are recursively turned to
        ordinary dictionaries - by calling their ``dict`` method.

        >>> n = a.dict()
        >>> n == a
        1
        >>> n is a
        0
        """
        newdict = {}
        for entry in self:
            this_entry = self[entry]
            if isinstance(this_entry, Section):
                this_entry = this_entry.dict()
            elif isinstance(this_entry, list):
                # create a copy rather than a reference
                this_entry = list(this_entry)
            elif isinstance(this_entry, tuple):
                # create a copy rather than a reference
                this_entry = tuple(this_entry)
            newdict[entry] = this_entry
        return newdict


    def merge(self, indict, decoupled=False):
        """
        A recursive update - useful for merging config files.

        Note: if ``decoupled`` is ``True``, then the target object (self)
        gets its own copy of any mutable objects in the source dictionary
        (both sections and values), paid for by more work for ``merge()``
        and more memory usage.

        >>> a = '''[section1]
        ...     option1 = True
        ...     [[subsection]]
        ...     more_options = False
        ...     # end of file'''.splitlines()
        >>> b = '''# File is user.ini
        ...     [section1]
        ...     option1 = False
        ...     # end of file'''.splitlines()
        >>> c1 = ConfigObj(b)
        >>> c2 = ConfigObj(a)
        >>> c2.merge(c1)
        >>> c2
        ConfigObj({'section1': {'option1': 'False', 'subsection': {'more_options': 'False'}}})
        """
        for key, val in indict.items():
            if decoupled:
                val = copy.deepcopy(val)
            if (key in self and isinstance(self[key], Mapping) and
                                isinstance(val, Mapping)):
                self[key].merge(val, decoupled=decoupled)
            else:
                self[key] = val


    def rename(self, oldkey, newkey):
        """
        Change a keyname to another, without changing position in sequence.

        Implemented so that transformations can be made on keys,
        as well as on values. (used by encode and decode)

        Also renames comments.
        """
        if oldkey in self.scalars:
            the_list = self.scalars
        elif oldkey in self.sections:
            the_list = self.sections
        else:
            raise KeyError('Key "%s" not found.' % oldkey)
        pos = the_list.index(oldkey)
        #
        val = self[oldkey]
        dict.__delitem__(self, oldkey)
        dict.__setitem__(self, newkey, val)
        the_list.remove(oldkey)
        the_list.insert(pos, newkey)
        comm = self.comments[oldkey]
        inline_comment = self.inline_comments[oldkey]
        del self.comments[oldkey]
        del self.inline_comments[oldkey]
        self.comments[newkey] = comm
        self.inline_comments[newkey] = inline_comment


    def walk(self, function, raise_errors=True,
            call_on_sections=False, **keywargs):
        """
        Walk every member and call a function on the keyword and value.

        Return a dictionary of the return values

        If the function raises an exception, raise the errror
        unless ``raise_errors=False``, in which case set the return value to
        ``False``.

        Any unrecognised keyword arguments you pass to walk, will be pased on
        to the function you pass in.

        Note: if ``call_on_sections`` is ``True`` then - on encountering a
        subsection, *first* the function is called for the *whole* subsection,
        and then recurses into it's members. This means your function must be
        able to handle strings, dictionaries and lists. This allows you
        to change the key of subsections as well as for ordinary members. The
        return value when called on the whole subsection has to be discarded.

        See  the encode and decode methods for examples, including functions.

        .. admonition:: caution

            You can use ``walk`` to transform the names of members of a section
            but you mustn't add or delete members.

        >>> config = '''[XXXXsection]
        ... XXXXkey = XXXXvalue'''.splitlines()
        >>> cfg = ConfigObj(config)
        >>> cfg
        ConfigObj({'XXXXsection': {'XXXXkey': 'XXXXvalue'}})
        >>> def transform(section, key):
        ...     val = section[key]
        ...     newkey = key.replace('XXXX', 'CLIENT1')
        ...     section.rename(key, newkey)
        ...     if isinstance(val, (tuple, list, dict)):
        ...         pass
        ...     else:
        ...         val = val.replace('XXXX', 'CLIENT1')
        ...         section[newkey] = val
        >>> cfg.walk(transform, call_on_sections=True)
        {'CLIENT1section': {'CLIENT1key': None}}
        >>> cfg
        ConfigObj({'CLIENT1section': {'CLIENT1key': 'CLIENT1value'}})
        """
        out = {}
        # scalars first
        for i in range(len(self.scalars)):
            entry = self.scalars[i]
            try:
                val = function(self, entry, **keywargs)
                # bound again in case name has changed
                entry = self.scalars[i]
                out[entry] = val
            except Exception:
                if raise_errors:
                    raise
                else:
                    entry = self.scalars[i]
                    out[entry] = False
        # then sections
        for i in range(len(self.sections)):
            entry = self.sections[i]
            if call_on_sections:
                try:
                    function(self, entry, **keywargs)
                except Exception:
                    if raise_errors:
                        raise
                    else:
                        entry = self.sections[i]
                        out[entry] = False
                # bound again in case name has changed
                entry = self.sections[i]
            # previous result is discarded
            out[entry] = self[entry].walk(
                function,
                raise_errors=raise_errors,
                call_on_sections=call_on_sections,
                **keywargs)
        return out


    def as_bool(self, key):
        """
        Accepts a key as input. The corresponding value must be a string or
        the objects (``True`` or 1) or (``False`` or 0). We allow 0 and 1 to
        retain compatibility with Python 2.2.

        If the string is one of  ``True``, ``On``, ``Yes``, or ``1`` it returns
        ``True``.

        If the string is one of  ``False``, ``Off``, ``No``, or ``0`` it returns
        ``False``.

        ``as_bool`` is not case sensitive.

        Any other input will raise a ``ValueError``.

        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_bool('a')
        Traceback (most recent call last):
        ValueError: Value "fish" is neither True nor False
        >>> a['b'] = 'True'
        >>> a.as_bool('b')
        1
        >>> a['b'] = 'off'
        >>> a.as_bool('b')
        0
        """
        val = self[key]
        if val == True:
            return True
        elif val == False:
            return False
        else:
            try:
                if not isinstance(val, six.string_types):
                    # TODO: Why do we raise a KeyError here?
                    raise KeyError()
                else:
                    return self.main._bools[val.lower()]
            except KeyError:
                raise ValueError('Value "%s" is neither True nor False' % val)


    def as_int(self, key):
        """
        A convenience method which coerces the specified value to an integer.

        If the value is an invalid literal for ``int``, a ``ValueError`` will
        be raised.

        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_int('a')
        Traceback (most recent call last):
        ValueError: invalid literal for int() with base 10: 'fish'
        >>> a['b'] = '1'
        >>> a.as_int('b')
        1
        >>> a['b'] = '3.2'
        >>> a.as_int('b')
        Traceback (most recent call last):
        ValueError: invalid literal for int() with base 10: '3.2'
        """
        return int(self[key])


    def as_float(self, key):
        """
        A convenience method which coerces the specified value to a float.

        If the value is an invalid literal for ``float``, a ``ValueError`` will
        be raised.

        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_float('a')  #doctest: +IGNORE_EXCEPTION_DETAIL
        Traceback (most recent call last):
        ValueError: invalid literal for float(): fish
        >>> a['b'] = '1'
        >>> a.as_float('b')
        1.0
        >>> a['b'] = '3.2'
        >>> a.as_float('b')  #doctest: +ELLIPSIS
        3.2...
        """
        return float(self[key])


    def as_list(self, key):
        """
        A convenience method which fetches the specified value, guaranteeing
        that it is a list.

        >>> a = ConfigObj()
        >>> a['a'] = 1
        >>> a.as_list('a')
        [1]
        >>> a['a'] = (1,)
        >>> a.as_list('a')
        [1]
        >>> a['a'] = [1]
        >>> a.as_list('a')
        [1]
        """
        result = self[key]
        if isinstance(result, (tuple, list)):
            return list(result)
        return [result]


    def restore_default(self, key):
        """
        Restore (and return) default value for the specified key.

        This method will only work for a ConfigObj that was created
        with a configspec and has been validated.

        If there is no default value for this key, ``KeyError`` is raised.
        """
        default = self.default_values[key]
        dict.__setitem__(self, key, default)
        if key not in self.defaults:
            self.defaults.append(key)
        return default


    def restore_defaults(self):
        """
        Recursively restore default values to all members
        that have them.

        This method will only work for a ConfigObj that was created
        with a configspec and has been validated.

        It doesn't delete or modify entries without default values.
        """
        for key in self.default_values:
            self.restore_default(key)

        for section in self.sections:
            self[section].restore_defaults()


def _get_triple_quote(value):
    """Helper for triple-quoting round-trips."""
    if ('"""' in value) and ("'''" in value):
        raise ConfigObjError('Value cannot be safely quoted: {!r}'.format(value))

    return tsquot if "'''" in value else tdquot


class ConfigObj(Section):
    """An object to read, create, and write config files."""

    MAX_PARSE_ERROR_DETAILS = 5

    # Override/append to this class variable for alternative comment markers
    # TODO: also support inline comments (needs dynamic compiling of the regex below)
    COMMENT_MARKERS = ['#']

    _keyword = re.compile(r'''^ # line start
        (\s*)                   # indentation
        (                       # keyword
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'"=].*?)       # no quotes
        )
        \s*=\s*                 # divider
        (.*)                    # value (including list values and comments)
        $   # line end
        ''',
        re.VERBOSE)

    _sectionmarker = re.compile(r'''^
        (\s*)                     # 1: indentation
        ((?:\[\s*)+)              # 2: section marker open
        (                         # 3: section name open
            (?:"\s*\S.*?\s*")|    # at least one non-space with double quotes
            (?:'\s*\S.*?\s*')|    # at least one non-space with single quotes
            (?:[^'"\s].*?)        # at least one non-space unquoted
        )                         # section name close
        ((?:\s*\])+)              # 4: section marker close
        (\s*(?:\#.*)?)?           # 5: optional comment
        $''',
        re.VERBOSE)

    # this regexp pulls list values out as a single string
    # or single values and comments
    # FIXME: this regex adds a '' to the end of comma terminated lists
    #   workaround in ``_handle_value``
    _valueexp = re.compile(r'''^
        (?:
            (?:
                (
                    (?:
                        (?:
                            (?:".*?")|              # double quotes
                            (?:'.*?')|              # single quotes
                            (?:[^'",\#][^,\#]*?)    # unquoted
                        )
                        \s*,\s*                     # comma
                    )*      # match all list items ending in a comma (if any)
                )
                (
                    (?:".*?")|                      # double quotes
                    (?:'.*?')|                      # single quotes
                    (?:[^'",\#\s][^,]*?)|           # unquoted
                    (?:(?<!,))                      # Empty value
                )?          # last item in a list - or string value
            )|
            (,)             # alternatively a single comma - empty list
        )
        (\s*(?:\#.*)?)?     # optional comment
        $''',
        re.VERBOSE)

    # use findall to get the members of a list value
    _listvalueexp = re.compile(r'''
        (
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'",\#]?.*?)    # unquoted
        )
        \s*,\s*                 # comma
        ''',
        re.VERBOSE)

    # this regexp is used for the value
    # when lists are switched off
    _nolistvalue = re.compile(r'''^
        (
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'"\#].*?)|     # unquoted
            (?:)                # Empty value
        )
        (\s*(?:\#.*)?)?         # optional comment
        $''',
        re.VERBOSE)

    # regexes for finding triple quoted values on one line
    _triple_trailer = r"(\s*(?:#.*)?)?$"
    _single_line_single = re.compile(r"^'''(.*?)'''" + _triple_trailer)
    _single_line_double = re.compile(r'^"""(.*?)"""' + _triple_trailer)
    _multi_line_single = re.compile(r"^(.*?)'''" + _triple_trailer)
    _multi_line_double = re.compile(r'^(.*?)"""' + _triple_trailer)

    _triple_quote = {
        "'''": (_single_line_single, _multi_line_single),
        '"""': (_single_line_double, _multi_line_double),
    }

    # Used by the ``istrue`` Section method
    _bools = {
        'yes': True, 'no': False,
        'on': True, 'off': False,
        '1': True, '0': False,
        'true': True, 'false': False,
        }


    def __init__(self, infile=None, options=None, configspec=None, encoding=None,
                 interpolation=True, raise_errors=False, list_values=True,
                 create_empty=False, file_error=False, stringify=True,
                 indent_type=None, default_encoding=None, unrepr=False,
                 write_empty_values=False, _inspec=False):
        """
        Parse a config file or create a config file object.

        ``ConfigObj(infile=None, configspec=None, encoding=None,
                    interpolation=True, raise_errors=False, list_values=True,
                    create_empty=False, file_error=False, stringify=True,
                    indent_type=None, default_encoding=None, unrepr=False,
                    write_empty_values=False, _inspec=False)``
        """
        self._inspec = _inspec
        # init the superclass
        Section.__init__(self, self, 0, self)

        infile = infile or []

        _options = {'configspec': configspec,
                    'encoding': encoding, 'interpolation': interpolation,
                    'raise_errors': raise_errors, 'list_values': list_values,
                    'create_empty': create_empty, 'file_error': file_error,
                    'stringify': stringify, 'indent_type': indent_type,
                    'default_encoding': default_encoding, 'unrepr': unrepr,
                    'write_empty_values': write_empty_values}

        if options is None:
            options = _options
        else:
            import warnings
            warnings.warn('Passing in an options dictionary to ConfigObj() is '
                          'deprecated. Use **options instead.',
                          DeprecationWarning)

            # TODO: check the values too.
            for entry in options:
                if entry not in OPTION_DEFAULTS:
                    raise TypeError('Unrecognised option "%s".' % entry)
            for entry, value in list(OPTION_DEFAULTS.items()):
                if entry not in options:
                    options[entry] = value
                keyword_value = _options[entry]
                if value != keyword_value:
                    options[entry] = keyword_value

        # XXXX this ignores an explicit list_values = True in combination
        # with _inspec. The user should *never* do that anyway, but still...
        if _inspec:
            options['list_values'] = False

        self._initialise(options)
        configspec = options['configspec']
        self._original_configspec = configspec
        self._load(infile, configspec)

    def _load(self, infile, configspec):
        try:
            infile = infile.__fspath__()
        except AttributeError:
            pass

        if isinstance(infile, six.string_types):
            self.filename = infile
            if os.path.isfile(infile):
                with open(infile, 'rb') as h:
                    content = h.readlines() or []
            elif self.file_error:
                # raise an error if the file doesn't exist
                raise IOError('Config file not found: "%s".' % self.filename)
            else:
                # file doesn't already exist
                if self.create_empty:
                    # this is a good test that the filename specified
                    # isn't impossible - like on a non-existent device
                    with open(infile, 'w') as h:
                        h.write('')
                content = []

        elif isinstance(infile, (list, tuple)):
            content = list(infile)

        elif isinstance(infile, dict):
            # initialise self
            # the Section class handles creating subsections
            if isinstance(infile, ConfigObj):
                # get a copy of our ConfigObj
                def set_section(in_section, this_section):
                    for entry in in_section.scalars:
                        this_section[entry] = in_section[entry]
                    for section in in_section.sections:
                        this_section[section] = {}
                        set_section(in_section[section], this_section[section])
                set_section(infile, self)

            else:
                for entry in infile:
                    self[entry] = infile[entry]
            del self._errors

            if configspec is not None:
                self._handle_configspec(configspec)
            else:
                self.configspec = None
            return

        elif getattr(infile, 'read', MISSING) is not MISSING:
            # This supports file like objects
            content = infile.read() or []
            # needs splitting into lines - but needs doing *after* decoding
            # in case it's not an 8 bit encoding
        else:
            raise TypeError('infile must be a path-like object, file like object, or list of lines.')

        if content:
            # don't do it for the empty ConfigObj
            content = self._handle_bom(content)
            # infile is now *always* a list
            #
            # Set the newlines attribute (first line ending it finds)
            # and strip trailing '\n' or '\r' from lines
            for line in content:
                if (not line) or (line[-1] not in ('\r', '\n')):
                    continue
                for end in ('\r\n', '\n', '\r'):
                    if line.endswith(end):
                        self.newlines = end
                        break
                break

        assert all(isinstance(line, six.string_types) for line in content), repr(content)
        content = [line.rstrip('\r\n') for line in content]

        self._parse(content)
        # if we had any errors, now is the time to raise them
        if self._errors:
            if len(self._errors) > 1:
                msg = ["Parsing failed with {} errors.".format(len(self._errors))]
                for error in self._errors[:self.MAX_PARSE_ERROR_DETAILS]:
                    msg.append(str(error))
                if len(self._errors) > self.MAX_PARSE_ERROR_DETAILS:
                    msg.append("{} more error(s)!"
                               .format(len(self._errors) - self.MAX_PARSE_ERROR_DETAILS))
                error = ConfigObjError('\n    '.join(msg))
            else:
                error = self._errors[0]
            # set the errors attribute; it's a list of tuples:
            # (error_type, message, line_number)
            error.errors = self._errors
            # set the config attribute
            error.config = self
            raise error
        # delete private attributes
        del self._errors

        if configspec is None:
            self.configspec = None
        else:
            self._handle_configspec(configspec)


    def _initialise(self, options=None):
        if options is None:
            options = OPTION_DEFAULTS

        # initialise a few variables
        self.filename = None
        self._errors = []
        self.raise_errors = options['raise_errors']
        self.interpolation = options['interpolation']
        self.list_values = options['list_values']
        self.create_empty = options['create_empty']
        self.file_error = options['file_error']
        self.stringify = options['stringify']
        self.indent_type = options['indent_type']
        self.encoding = options['encoding']
        self.default_encoding = options['default_encoding']
        self.BOM = False
        self.newlines = None
        self.write_empty_values = options['write_empty_values']
        self.unrepr = options['unrepr']

        self.initial_comment = []
        self.final_comment = []
        self.configspec = None

        if self._inspec:
            self.list_values = False

        # Clear section attributes as well
        Section._initialise(self)


    def __repr__(self):
        def _getval(key):
            try:
                return self[key]
            except MissingInterpolationOption:
                return dict.__getitem__(self, key)
        return ('{}({{{}}})'.format(self.__class__.__name__,
                ', '.join([('{}: {}'.format(repr(key), repr(_getval(key))))
                for key in (self.scalars + self.sections)])))


    def _handle_bom(self, infile):
        """
        Handle any BOM, and decode if necessary.

        If an encoding is specified, that *must* be used - but the BOM should
        still be removed (and the BOM attribute set).

        (If the encoding is wrongly specified, then a BOM for an alternative
        encoding won't be discovered or removed.)

        If an encoding is not specified, UTF8 or UTF16 BOM will be detected and
        removed. The BOM attribute will be set. UTF16 will be decoded to
        unicode.

        NOTE: This method must not be called with an empty ``infile``.

        Specifying the *wrong* encoding is likely to cause a
        ``UnicodeDecodeError``.

        ``infile`` must always be returned as a list of lines, but may be
        passed in as a single string.
        """

        if ((self.encoding is not None) and
            (self.encoding.lower() not in BOM_LIST)):
            # No need to check for a BOM
            # the encoding specified doesn't have one
            # just decode
            return self._decode(infile, self.encoding)

        if isinstance(infile, (list, tuple)):
            line = infile[0]
        else:
            line = infile

        if isinstance(line, six.text_type):
            # it's already decoded and there's no need to do anything
            # else, just use the _decode utility method to handle
            # listifying appropriately
            return self._decode(infile, self.encoding)

        if self.encoding is not None:
            # encoding explicitly supplied
            # And it could have an associated BOM
            # TODO: if encoding is just UTF16 - we ought to check for both
            # TODO: big endian and little endian versions.
            enc = BOM_LIST[self.encoding.lower()]
            if enc == 'utf_16':
                # For UTF16 we try big endian and little endian
                for BOM, (encoding, final_encoding) in list(BOMS.items()):
                    if not final_encoding:
                        # skip UTF8
                        continue
                    if infile.startswith(BOM):
                        ### BOM discovered
                        ##self.BOM = True
                        # Don't need to remove BOM
                        return self._decode(infile, encoding)

                # If we get this far, will *probably* raise a DecodeError
                # As it doesn't appear to start with a BOM
                return self._decode(infile, self.encoding)

            # Must be UTF8
            BOM = BOM_SET[enc]
            if not line.startswith(BOM):
                return self._decode(infile, self.encoding)

            newline = line[len(BOM):]

            # BOM removed
            if isinstance(infile, (list, tuple)):
                infile[0] = newline
            else:
                infile = newline
            self.BOM = True
            return self._decode(infile, self.encoding)

        # No encoding specified - so we need to check for UTF8/UTF16
        for BOM, (encoding, final_encoding) in list(BOMS.items()):
            if not isinstance(line, six.binary_type) or not line.startswith(BOM):
                # didn't specify a BOM, or it's not a bytestring
                continue
            else:
                # BOM discovered
                self.encoding = final_encoding
                if not final_encoding:
                    self.BOM = True
                    # UTF8
                    # remove BOM
                    newline = line[len(BOM):]
                    if isinstance(infile, (list, tuple)):
                        infile[0] = newline
                    else:
                        infile = newline
                    # UTF-8
                    if isinstance(infile, six.text_type):
                        return infile.splitlines(True)
                    elif isinstance(infile, six.binary_type):
                        return infile.decode('utf-8').splitlines(True)
                    else:
                        return self._decode(infile, 'utf-8')
                # UTF16 - have to decode
                return self._decode(infile, encoding)


        if six.PY2 and isinstance(line, str):
            # don't actually do any decoding, since we're on python 2 and
            # returning a bytestring is fine
            return self._decode(infile, None)
        # No BOM discovered and no encoding specified, default to UTF-8
        if isinstance(infile, six.binary_type):
            return infile.decode('utf-8').splitlines(True)
        else:
            return self._decode(infile, 'utf-8')


    def _decode(self, infile, encoding):
        """
        Decode infile to unicode. Using the specified encoding.

        if is a string, it also needs converting to a list.
        """
        if isinstance(infile, six.binary_type):
            # NOTE: Could raise a ``UnicodeDecodeError``
            if encoding:
                return infile.decode(encoding).splitlines(True)
            else:
                return infile.splitlines(True)
        if isinstance(infile, six.string_types):
            return infile.splitlines(True)

        if encoding:
            for i, line in enumerate(infile):
                if isinstance(line,