"""Configuration file parser.

A setup file consists of sections, lead by a "[section]" header,

and followed by "name: value" entries, with continuations and such in

the style of RFC 822.

The option values can contain format strings which refer to other values in

the same section, or values in a special [DEFAULT] section.

For example:

    something: %(dir)s/whatever

would resolve the "%(dir)s" to the value of dir.  All reference

expansions are done late, on demand.

Intrinsic defaults can be specified by passing them into the

ConfigParser constructor as a dictionary.

class:

ConfigParser -- responsible for parsing a list of

                configuration files, and managing the parsed database.

    methods:

    __init__(defaults=None)

        create the parser and specify a dictionary of intrinsic defaults.  The

        keys must be strings, the values must be appropriate for %()s string

        interpolation.  Note that `__name__' is always an intrinsic default;

        its value is the section's name.

    sections()

        return all the configuration section names, sans DEFAULT

    has_section(section)

        return whether the given section exists

    has_option(section, option)

        return whether the given option exists in the given section

    options(section)

        return list of configuration options for the named section

    read(filenames)

        read and parse the list of named configuration files, given by

        name.  A single filename is also allowed.  Non-existing files

        are ignored.  Return list of successfully read files.

    readfp(fp, filename=None)

        read and parse one configuration file, given as a file object.

        The filename defaults to fp.name; it is only used in error

        messages (if fp has no `name' attribute, the string `<???>' is used).

    get(section, option, raw=False, vars=None)

        return a string value for the named option.  All % interpolations are

        expanded in the return values, based on the defaults passed into the

        constructor and the DEFAULT section.  Additional substitutions may be

        provided using the `vars' argument, which must be a dictionary whose

        contents override any pre-existing defaults.

    getint(section, options)

        like get(), but convert value to an integer

    getfloat(section, options)

        like get(), but convert value to a float

    getboolean(section, options)

        like get(), but convert value to a boolean (currently case

        insensitively defined as 0, false, no, off for False, and 1, true,

        yes, on for True).  Returns False or True.

    items(section, raw=False, vars=None)

        return a list of tuples with (name, value) for each option

        in the section.

    remove_section(section)

        remove the given file section and all its options

    remove_option(section, option)

        remove the given option from the given section

    set(section, option, value)

        set the given option

    write(fp)

        write the configuration state in .ini format

"""

import re

__all__ = ["NoSectionError", "DuplicateSectionError", "NoOptionError",

           "InterpolationError", "InterpolationDepthError",

           "InterpolationSyntaxError", "ParsingError",

           "MissingSectionHeaderError",

           "ConfigParser", "SafeConfigParser", "RawConfigParser",

           "DEFAULTSECT", "MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10

# exception classes

class Error(Exception):

    """Base class for ConfigParser exceptions."""

    def __init__(self, msg=''):

        self.message = msg

        Exception.__init__(self, msg)

    def __repr__(self):

        return self.message

    __str__ = __repr__

class NoSectionError(Error):

    """Raised when no section matches a requested option."""

    def __init__(self, section):

        Error.__init__(self, 'No section: %r' % (section,))

        self.section = section

class DuplicateSectionError(Error):

    """Raised when a section is multiply-created."""

    def __init__(self, section):

        Error.__init__(self, "Section %r already exists" % section)

        self.section = section

class NoOptionError(Error):

    """A requested option was not found."""

    def __init__(self, option, section):

        Error.__init__(self, "No option %r in section: %r" %

                       (option, section))

        self.option = option

        self.section = section

class InterpolationError(Error):

    """Base class for interpolation-related exceptions."""

    def __init__(self, option, section, msg):

        Error.__init__(self, msg)

        self.option = option

        self.section = section

class InterpolationMissingOptionError(InterpolationError):

    """A string substitution required a setting which was not available."""

    def __init__(self, option, section, rawval, reference):

        msg = ("Bad value substitution:\n"

               "\tsection: [%s]\n"

               "\toption : %s\n"

               "\tkey    : %s\n"

               "\trawval : %s\n"

               % (section, option, reference, rawval))

        InterpolationError.__init__(self, option, section, msg)

        self.reference = reference

class InterpolationSyntaxError(InterpolationError):

    """Raised when the source text into which substitutions are made

    does not conform to the required syntax."""

class InterpolationDepthError(InterpolationError):

    """Raised when substitutions are nested too deeply."""

    def __init__(self, option, section, rawval):

        msg = ("Value interpolation too deeply recursive:\n"

               "\tsection: [%s]\n"

               "\toption : %s\n"

               "\trawval : %s\n"

               % (section, option, rawval))

        InterpolationError.__init__(self, option, section, msg)

class ParsingError(Error):

    """Raised when a configuration file does not follow legal syntax."""

    def __init__(self, filename):

        Error.__init__(self, 'File contains parsing errors: %s' % filename)

        self.filename = filename

        self.errors = []

    def append(self, lineno, line):

        self.errors.append((lineno, line))

        self.message += '\n\t[line %2d]: %s' % (lineno, line)

class MissingSectionHeaderError(ParsingError):

    """Raised when a key-value pair is found before any section header."""

    def __init__(self, filename, lineno, line):

        Error.__init__(

            self,

            'File contains no section headers.\nfile: %s, line: %d\n%r' %

            (filename, lineno, line))

        self.filename = filename

        self.lineno = lineno

        self.line = line

class RawConfigParser:

    def __init__(self, defaults=None):

        self._sections = {}

        self._defaults = {}

        if defaults:

            for key, value in defaults.items():

                self._defaults[self.optionxform(key)] = value

    def defaults(self):

        return self._defaults

    def sections(self):

        """Return a list of section names, excluding [DEFAULT]"""

        # self._sections will never have [DEFAULT] in it

        return self._sections.keys()

    def add_section(self, section):

        """Create a new section in the configuration.

        Raise DuplicateSectionError if a section by the specified name

        already exists.

        """

        if section in self._sections:

            raise DuplicateSectionError(section)

        self._sections[section] = {}

    def has_section(self, section):

        """Indicate whether the named section is present in the configuration.

        The DEFAULT section is not acknowledged.

        """

        return section in self._sections

    def options(self, section):

        """Return a list of option names for the given section name."""

        try:

            opts = self._sections[section].copy()

        except KeyError:

            raise NoSectionError(section)

        opts.update(self._defaults)

        if '__name__' in opts:

            del opts['__name__']

        return opts.keys()

    def read(self, filenames):

        """Read and parse a filename or a list of filenames.

        Files that cannot be opened are silently ignored; this is

        designed so that you can specify a list of potential

        configuration file locations (e.g. current directory, user's

        home directory, systemwide directory), and all existing

        configuration files in the list will be read.  A single

        filename may also be given.

        Return list of successfully read files.

        """

        if isinstance(filenames, basestring):

            filenames = [filenames]

        read_ok = []

        for filename in filenames:

            try:

                fp = open(filename)

            except IOError:

                continue

            self._read(fp, filename)

            fp.close()

            read_ok.append(filename)

        return read_ok

    def readfp(self, fp, filename=None):

        """Like read() but the argument must be a file-like object.

        The `fp' argument must have a `readline' method.  Optional

        second argument is the `filename', which if not given, is

        taken from fp.name.  If fp has no `name' attribute, `<???>' is

        used.

        """

        if filename is None:

            try:

                filename = fp.name

            except AttributeError:

                filename = '<???>'

        self._read(fp, filename)

    def get(self, section, option):

        opt = self.optionxform(option)

        if section not in self._sections:

            if section != DEFAULTSECT:

                raise NoSectionError(section)

            if opt in self._defaults:

                return self._defaults[opt]

            else:

                raise NoOptionError(option, section)

        elif opt in self._sections[section]:

            return self._sections[section][opt]

        elif opt in self._defaults:

            return self._defaults[opt]

        else:

            raise NoOptionError(option, section)

    def items(self, section):

        try:

            d2 = self._sections[section]

        except KeyError:

            if section != DEFAULTSECT:

                raise NoSectionError(section)

            d2 = {}

        d = self._defaults.copy()

        d.update(d2)

        if "__name__" in d:

            del d["__name__"]

        return d.items()

    def _get(self, section, conv, option):

        return conv(self.get(section, option))

    def getint(self, section, option):

        return self._get(section, int, option)

    def getfloat(self, section, option):

        return self._get(section, float, option)

    _boolean_states = {'1': True, 'yes': True, 'true': True, 'on': True,

                       '0': False, 'no': False, 'false': False, 'off': False}

    def getboolean(self, section, option):

        v = self.get(section, option)

        if v.lower() not in self._boolean_states:

            raise ValueError, 'Not a boolean: %s' % v

        return self._boolean_states[v.lower()]

    def optionxform(self, optionstr):

        return optionstr.lower()

    def has_option(self, section, option):

        """Check for the existence of a given option in a given section."""

        if not section or section == DEFAULTSECT:

            option = self.optionxform(option)

            return option in self._defaults

        elif section not in self._sections:

            return False

        else:

            option = self.optionxform(option)

            return (option in self._sections[section]

                    or option in self._defaults)

    def set(self, section, option, value):

        """Set an option."""

        if not section or section == DEFAULTSECT:

            sectdict = self._defaults

        else:

            try:

                sectdict = self._sections[section]

            except KeyError:

                raise NoSectionError(section)

        sectdict[self.optionxform(option)] = value

    def write(self, fp):

        """Write an .ini-format representation of the configuration state."""

        if self._defaults:

            fp.write("[%s]\n" % DEFAULTSECT)

            for (key, value) in self._defaults.items():

                fp.write("%s = %s\n" % (key, str(value).replace('\n', '\n\t')))

            fp.write("\n")

        for section in self._sections:

            fp.write("[%s]\n" % section)

            for (key, value) in self._sections[section].items():

                if key != "__name__":

                    fp.write("%s = %s\n" %

                             (key, str(value).replace('\n', '\n\t')))

            fp.write("\n")

    def remove_option(self, section, option):

        """Remove an option."""

        if not section or section == DEFAULTSECT:

            sectdict = self._defaults

        else:

            try:

                sectdict = self._sections[section]

            except KeyError:

                raise NoSectionError(section)

        option = self.optionxform(option)

        existed = option in sectdict

        if existed:

            del sectdict[option]

        return existed

    def remove_section(self, section):

        """Remove a file section."""

        existed = section in self._sections

        if existed:

            del self._sections[section]

        return existed

    #

    # Regular expressions for parsing section headers and options.

    #

    SECTCRE = re.compile(

        r'\['                                 # [

        r'(?P<header>[^]]+)'                  # very permissive!

        r'\]'                                 # ]

        )

    OPTCRE = re.compile(

        r'(?P<option>[^:=\s][^:=]*)'          # very permissive!

        r'\s*(?P<vi>[:=])\s*'                 # any number of space/tab,

                                              # followed by separator

                                              # (either : or =), followed

                                              # by any # space/tab

        r'(?P<value>.*)$'                     # everything up to eol

        )

    def _read(self, fp, fpname):

        """Parse a sectioned setup file.

        The sections in setup file contains a title line at the top,

        indicated by a name in square brackets (`[]'), plus key/value

        options lines, indicated by `name: value' format lines.

        Continuations are represented by an embedded newline then

        leading whitespace.  Blank lines, lines beginning with a '#',

        and just about everything else are ignored.

        """

        cursect = None                            # None, or a dictionary

        optname = None

        lineno = 0

        e = None                                  # None, or an exception

        while True:

            line = fp.readline()

            if not line:

                break

            lineno = lineno + 1

            # comment or blank line?

            if line.strip() == '' or line[0] in '#;':

                continue

            if line.split(None, 1)[0].lower() == 'rem' and line[0] in "rR":

                # no leading whitespace

                continue

            # continuation line?

            if line[0].isspace() and cursect is not None and optname:

                value = line.strip()

                if value:

                    cursect[optname] = "%s\n%s" % (cursect[optname], value)

            # a section header or option header?

            else:

                # is it a section header?

                mo = self.SECTCRE.match(line)

                if mo:

                    sectname = mo.group('header')

                    if sectname in self._sections:

                        cursect = self._sections[sectname]

                    elif sectname == DEFAULTSECT:

                        cursect = self._defaults

                    else:

                        cursect = {'__name__': sectname}

                        self._sections[sectname] = cursect

                    # So sections can't start with a continuation line

                    optname = None

                # no section header in the file?

                elif cursect is None:

                    raise MissingSectionHeaderError(fpname, lineno, line)

                # an option line?

                else:

                    mo = self.OPTCRE.match(line)

                    if mo:

                        optname, vi, optval = mo.group('option', 'vi', 'value')

                        if vi in ('=', ':') and ';' in optval:

                            # ';' is a comment delimiter only if it follows

                            # a spacing character

                            pos = optval.find(';')

                            if pos != -1 and optval[pos-1].isspace():

                                optval = optval[:pos]

                        optval = optval.strip()

                        # allow empty values

                        if optval == '""':

                            optval = ''

                        optname = self.optionxform(optname.rstrip())

                        cursect[optname] = optval

                    else:

                        # a non-fatal parsing error occurred.  set up the

                        # exception but keep going. the exception will be

                        # raised at the end of the file and will contain a

                        # list of all bogus lines

                        if not e:

                            e = ParsingError(fpname)

                        e.append(lineno, repr(line))

        # if any parsing errors occurred, raise an exception

        if e:

            raise e

class ConfigParser(RawConfigParser):

    def get(self, section, option, raw=False, vars=None):

        """Get an option value for a given section.

        All % interpolations are expanded in the return values, based on the

        defaults passed into the constructor, unless the optional argument

        `raw' is true.  Additional substitutions may be provided using the

        `vars' argument, which must be a dictionary whose contents overrides

        any pre-existing defaults.

        The section DEFAULT is special.

        """

        d = self._defaults.copy()

        try:

            d.update(self._sections[section])

        except KeyError:

            if section != DEFAULTSECT:

                raise NoSectionError(section)

        # Update with the entry specific variables

        if vars:

            for key, value in vars.items():

                d[self.optionxform(key)] = value

        option = self.optionxform(option)

        try:

            value = d[option]

        except KeyError:

            raise NoOptionError(option, section)

        if raw:

            return value

        else:

            return self._interpolate(section, option, value, d)

    def items(self, section, raw=False, vars=None):

        """Return a list of tuples with (name, value) for each option

        in the section.