"""Configuration file parser.

Modified by hyriand, 2003-2004.

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 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;
		it's 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.

	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=0, 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 0, and 1, true,
		yes, on for 1).  Returns 0 or 1.

	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
import types

__all__ = ["NoSectionError","DuplicateSectionError","NoOptionError",
		"InterpolationError","InterpolationDepthError","ParsingError",
		"MissingSectionHeaderError","ConfigParser",
		"DEFAULTSECT", "MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10

from utils import SortedDict

# exception classes
class Error(Exception):
	def __init__(self, msg=''):
		self._msg = msg
		Exception.__init__(self, msg)
	def __repr__(self):
		return self._msg
	__str__ = __repr__

class NoSectionError(Error):
	def __init__(self, section):
		Error.__init__(self, 'No section: %s' % section)
		self.section = section

class DuplicateSectionError(Error):
	def __init__(self, section):
		Error.__init__(self, "Section %s already exists" % section)
		self.section = section

class NoOptionError(Error):
	def __init__(self, option, section):
		Error.__init__(self, "No option `%s' in section: %s" %
					(option, section))
		self.option = option
		self.section = section

class InterpolationError(Error):
	def __init__(self, reference, option, section, rawval):
		Error.__init__(self,
			"Bad value substitution:\n"
			"\tsection: [%s]\n"
			"\toption : %s\n"
			"\tkey    : %s\n"
			"\trawval : %s\n"
			% (section, option, reference, rawval))
		self.reference = reference
		self.option = option
		self.section = section

class InterpolationDepthError(Error):
	def __init__(self, option, section, rawval):
		Error.__init__(self,
			"Value interpolation too deeply recursive:\n"
			"\tsection: [%s]\n"
			"\toption : %s\n"
			"\trawval : %s\n"
			% (section, option, rawval))
		self.option = option
		self.section = section

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

class MissingSectionHeaderError(ParsingError):
	def __init__(self, filename, lineno, line):
		Error.__init__(
			self,
			'File contains no section headers.\nfile: %s, line: %d\n%s' %
			(filename, lineno, line))
		self.filename = filename
		self.lineno = lineno
		self.line = line



class ConfigParser:
	def __init__(self, defaults=None):
		self.__sections = SortedDict()
		if defaults is None:
			self.__defaults = SortedDict()
		else:
			self.__defaults = SortedDict()
			for key, value in defaults.items():
				self.__defaults[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.
		"""
		if isinstance(filenames, types.StringTypes):
			filenames = [filenames]
		for filename in filenames:
			try:
				fp = open(filename)
			except IOError:
				continue
			self.__read(fp, filename)
			fp.close()

	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, raw=0, 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 is not None:
			d.update(vars)
		option = self.optionxform(option)
		try:
			value = d[option]
		except KeyError:
			raise NoOptionError(option, section)

		if raw:
			return value
		return self._interpolate(section, option, value, d)

	def _interpolate(self, section, option, rawval, vars):
		# do the string interpolation
		value = rawval
		depth = MAX_INTERPOLATION_DEPTH
		while depth:                    # Loop through this until it's done
			depth -= 1
			if value.find("%(") != -1:
				try:
					value = value % vars
				except KeyError, key:
					raise InterpolationError(key, option, section, rawval)
			else:
				break
		if value.find("%(") != -1:
			raise InterpolationDepthError(option, section, rawval)
		return value

	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, data) in self.__sections.iteritems():
			fp.write("[%s]\n" % section)
			keys = data.keys()
			keys.sort()
			for key in keys:
				value = self.__sections[section][key]
				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.
		Continuation are represented by an embedded newline then
		leading whitespace.  Blank lines, lines beginning with a '#',
		and just about everything else is ignored.
		"""
		cursect = None                            # None, or a dictionary
		optname = None
		lineno = 0
		e = None                                  # None, or an exception
		while 1:
			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')
						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, `line`)
		# if any parsing errors occurred, raise an exception
		if e:
			raise e
