1# $Id: frontend.py 8676 2021-04-08 16:36:09Z milde $
2# Author: David Goodger <goodger@python.org>
3# Copyright: This module has been placed in the public domain.
4
5"""
6Command-line and common processing for Docutils front-end tools.
7
8Exports the following classes:
9
10* `OptionParser`: Standard Docutils command-line processing.
11* `Option`: Customized version of `optparse.Option`; validation support.
12* `Values`: Runtime settings; objects are simple structs
13  (``object.attribute``).  Supports cumulative list settings (attributes).
14* `ConfigParser`: Standard Docutils config file processing.
15
16Also exports the following functions:
17
18* Option callbacks: `store_multiple`, `read_config_file`.
19* Setting validators: `validate_encoding`,
20  `validate_encoding_error_handler`,
21  `validate_encoding_and_error_handler`,
22  `validate_boolean`, `validate_ternary`, `validate_threshold`,
23  `validate_colon_separated_list`,
24  `validate_comma_separated_list`,
25  `validate_dependency_file`.
26* `make_paths_absolute`.
27* SettingSpec manipulation: `filter_settings_spec`.
28"""
29
30__docformat__ = 'reStructuredText'
31
32import os
33import os.path
34import sys
35import warnings
36import codecs
37import optparse
38from optparse import SUPPRESS_HELP
39if sys.version_info >= (3, 0):
40    from configparser import RawConfigParser
41    from os import getcwd
42else:
43    from ConfigParser import RawConfigParser
44    from os import getcwdu as getcwd
45
46import docutils
47import docutils.utils
48import docutils.nodes
49from docutils.utils.error_reporting import (locale_encoding, SafeString,
50                                            ErrorOutput, ErrorString)
51
52if sys.version_info >= (3, 0):
53    unicode = str  # noqa
54
55
56def store_multiple(option, opt, value, parser, *args, **kwargs):
57    """
58    Store multiple values in `parser.values`.  (Option callback.)
59
60    Store `None` for each attribute named in `args`, and store the value for
61    each key (attribute name) in `kwargs`.
62    """
63    for attribute in args:
64        setattr(parser.values, attribute, None)
65    for key, value in kwargs.items():
66        setattr(parser.values, key, value)
67
68def read_config_file(option, opt, value, parser):
69    """
70    Read a configuration file during option processing.  (Option callback.)
71    """
72    try:
73        new_settings = parser.get_config_file_settings(value)
74    except ValueError as error:
75        parser.error(error)
76    parser.values.update(new_settings, parser)
77
78def validate_encoding(setting, value, option_parser,
79                      config_parser=None, config_section=None):
80    try:
81        codecs.lookup(value)
82    except LookupError:
83        raise LookupError('setting "%s": unknown encoding: "%s"'
84                          % (setting, value))
85    return value
86
87def validate_encoding_error_handler(setting, value, option_parser,
88                                    config_parser=None, config_section=None):
89    try:
90        codecs.lookup_error(value)
91    except LookupError:
92        raise LookupError(
93            'unknown encoding error handler: "%s" (choices: '
94            '"strict", "ignore", "replace", "backslashreplace", '
95            '"xmlcharrefreplace", and possibly others; see documentation for '
96            'the Python ``codecs`` module)' % value)
97    return value
98
99def validate_encoding_and_error_handler(
100    setting, value, option_parser, config_parser=None, config_section=None):
101    """
102    Side-effect: if an error handler is included in the value, it is inserted
103    into the appropriate place as if it was a separate setting/option.
104    """
105    if ':' in value:
106        encoding, handler = value.split(':')
107        validate_encoding_error_handler(
108            setting + '_error_handler', handler, option_parser,
109            config_parser, config_section)
110        if config_parser:
111            config_parser.set(config_section, setting + '_error_handler',
112                              handler)
113        else:
114            setattr(option_parser.values, setting + '_error_handler', handler)
115    else:
116        encoding = value
117    validate_encoding(setting, encoding, option_parser,
118                      config_parser, config_section)
119    return encoding
120
121def validate_boolean(setting, value, option_parser,
122                     config_parser=None, config_section=None):
123    """Check/normalize boolean settings:
124         True:  '1', 'on', 'yes', 'true'
125         False: '0', 'off', 'no','false', ''
126    """
127    if isinstance(value, bool):
128        return value
129    try:
130        return option_parser.booleans[value.strip().lower()]
131    except KeyError:
132        raise LookupError('unknown boolean value: "%s"' % value)
133
134def validate_ternary(setting, value, option_parser,
135                     config_parser=None, config_section=None):
136    """Check/normalize three-value settings:
137         True:  '1', 'on', 'yes', 'true'
138         False: '0', 'off', 'no','false', ''
139         any other value: returned as-is.
140    """
141    if isinstance(value, bool) or value is None:
142        return value
143    try:
144        return option_parser.booleans[value.strip().lower()]
145    except KeyError:
146        return value
147
148def validate_nonnegative_int(setting, value, option_parser,
149                             config_parser=None, config_section=None):
150    value = int(value)
151    if value < 0:
152        raise ValueError('negative value; must be positive or zero')
153    return value
154
155def validate_threshold(setting, value, option_parser,
156                       config_parser=None, config_section=None):
157    try:
158        return int(value)
159    except ValueError:
160        try:
161            return option_parser.thresholds[value.lower()]
162        except (KeyError, AttributeError):
163            raise LookupError('unknown threshold: %r.' % value)
164
165def validate_colon_separated_string_list(
166    setting, value, option_parser, config_parser=None, config_section=None):
167    if not isinstance(value, list):
168        value = value.split(':')
169    else:
170        last = value.pop()
171        value.extend(last.split(':'))
172    return value
173
174def validate_comma_separated_list(setting, value, option_parser,
175                                    config_parser=None, config_section=None):
176    """Check/normalize list arguments (split at "," and strip whitespace).
177    """
178    # `value` may be ``unicode``, ``str``, or a ``list`` (when  given as
179    # command line option and "action" is "append").
180    if not isinstance(value, list):
181        value = [value]
182    # this function is called for every option added to `value`
183    # -> split the last item and append the result:
184    last = value.pop()
185    items = [i.strip(u' \t\n') for i in last.split(u',') if i.strip(u' \t\n')]
186    value.extend(items)
187    return value
188
189def validate_url_trailing_slash(
190    setting, value, option_parser, config_parser=None, config_section=None):
191    if not value:
192        return './'
193    elif value.endswith('/'):
194        return value
195    else:
196        return value + '/'
197
198def validate_dependency_file(setting, value, option_parser,
199                             config_parser=None, config_section=None):
200    try:
201        return docutils.utils.DependencyList(value)
202    except IOError:
203        return docutils.utils.DependencyList(None)
204
205def validate_strip_class(setting, value, option_parser,
206                         config_parser=None, config_section=None):
207    # value is a comma separated string list:
208    value = validate_comma_separated_list(setting, value, option_parser,
209                                          config_parser, config_section)
210    # validate list elements:
211    for cls in value:
212        normalized = docutils.nodes.make_id(cls)
213        if cls != normalized:
214            raise ValueError('Invalid class value %r (perhaps %r?)'
215                             % (cls, normalized))
216    return value
217
218def validate_smartquotes_locales(setting, value, option_parser,
219                         config_parser=None, config_section=None):
220    """Check/normalize a comma separated list of smart quote definitions.
221
222    Return a list of (language-tag, quotes) string tuples."""
223
224    # value is a comma separated string list:
225    value = validate_comma_separated_list(setting, value, option_parser,
226                                          config_parser, config_section)
227    # validate list elements
228    lc_quotes = []
229    for item in value:
230        try:
231            lang, quotes = item.split(':', 1)
232        except AttributeError:
233            # this function is called for every option added to `value`
234            # -> ignore if already a tuple:
235            lc_quotes.append(item)
236            continue
237        except ValueError:
238            raise ValueError(u'Invalid value "%s".'
239                             ' Format is "<language>:<quotes>".'
240                             % item.encode('ascii', 'backslashreplace'))
241        # parse colon separated string list:
242        quotes = quotes.strip()
243        multichar_quotes = quotes.split(':')
244        if len(multichar_quotes) == 4:
245            quotes = multichar_quotes
246        elif len(quotes) != 4:
247            raise ValueError('Invalid value "%s". Please specify 4 quotes\n'
248                '    (primary open/close; secondary open/close).'
249                             % item.encode('ascii', 'backslashreplace'))
250        lc_quotes.append((lang, quotes))
251    return lc_quotes
252
253def make_paths_absolute(pathdict, keys, base_path=None):
254    """
255    Interpret filesystem path settings relative to the `base_path` given.
256
257    Paths are values in `pathdict` whose keys are in `keys`.  Get `keys` from
258    `OptionParser.relative_path_settings`.
259    """
260    if base_path is None:
261        base_path = getcwd() # type(base_path) == unicode
262        # to allow combining non-ASCII cwd with unicode values in `pathdict`
263    for key in keys:
264        if key in pathdict:
265            value = pathdict[key]
266            if isinstance(value, list):
267                value = [make_one_path_absolute(base_path, path)
268                         for path in value]
269            elif value:
270                value = make_one_path_absolute(base_path, value)
271            pathdict[key] = value
272
273def make_one_path_absolute(base_path, path):
274    return os.path.abspath(os.path.join(base_path, path))
275
276def filter_settings_spec(settings_spec, *exclude, **replace):
277    """Return a copy of `settings_spec` excluding/replacing some settings.
278
279    `settings_spec` is a tuple of configuration settings with a structure
280    described for docutils.SettingsSpec.settings_spec.
281
282    Optional positional arguments are names of to-be-excluded settings.
283    Keyword arguments are option specification replacements.
284    (See the html4strict writer for an example.)
285    """
286    settings = list(settings_spec)
287    # every third item is a sequence of option tuples
288    for i in range(2, len(settings), 3):
289        newopts = []
290        for opt_spec in settings[i]:
291            # opt_spec is ("<help>", [<option strings>], {<keyword args>})
292            opt_name = [opt_string[2:].replace('-', '_')
293                        for opt_string in opt_spec[1]
294                            if opt_string.startswith('--')
295                       ][0]
296            if opt_name in exclude:
297                continue
298            if opt_name in replace.keys():
299                newopts.append(replace[opt_name])
300            else:
301                newopts.append(opt_spec)
302        settings[i] = tuple(newopts)
303    return tuple(settings)
304
305
306class Values(optparse.Values):
307
308    """
309    Updates list attributes by extension rather than by replacement.
310    Works in conjunction with the `OptionParser.lists` instance attribute.
311    """
312
313    def __init__(self, *args, **kwargs):
314        optparse.Values.__init__(self, *args, **kwargs)
315        if (not hasattr(self, 'record_dependencies')
316            or self.record_dependencies is None):
317            # Set up dependency list, in case it is needed.
318            self.record_dependencies = docutils.utils.DependencyList()
319
320    def update(self, other_dict, option_parser):
321        if isinstance(other_dict, Values):
322            other_dict = other_dict.__dict__
323        other_dict = other_dict.copy()
324        for setting in option_parser.lists.keys():
325            if (hasattr(self, setting) and setting in other_dict):
326                value = getattr(self, setting)
327                if value:
328                    value += other_dict[setting]
329                    del other_dict[setting]
330        self._update_loose(other_dict)
331
332    def copy(self):
333        """Return a shallow copy of `self`."""
334        return self.__class__(defaults=self.__dict__)
335
336    def setdefault(self, name, default):
337        """V.setdefault(n[,d]) -> getattr(V,n,d), also set D.n=d if n not in D or None.
338        """
339        if getattr(self, name, None) is None:
340            setattr(self, name, default)
341        return getattr(self, name)
342
343
344class Option(optparse.Option):
345
346    ATTRS = optparse.Option.ATTRS + ['validator', 'overrides']
347
348    def process(self, opt, value, values, parser):
349        """
350        Call the validator function on applicable settings and
351        evaluate the 'overrides' option.
352        Extends `optparse.Option.process`.
353        """
354        result = optparse.Option.process(self, opt, value, values, parser)
355        setting = self.dest
356        if setting:
357            if self.validator:
358                value = getattr(values, setting)
359                try:
360                    new_value = self.validator(setting, value, parser)
361                except Exception as error:
362                    raise optparse.OptionValueError(
363                        'Error in option "%s":\n    %s'
364                        % (opt, ErrorString(error)))
365                setattr(values, setting, new_value)
366            if self.overrides:
367                setattr(values, self.overrides, None)
368        return result
369
370
371class OptionParser(optparse.OptionParser, docutils.SettingsSpec):
372
373    """
374    Parser for command-line and library use.  The `settings_spec`
375    specification here and in other Docutils components are merged to build
376    the set of command-line options and runtime settings for this process.
377
378    Common settings (defined below) and component-specific settings must not
379    conflict.  Short options are reserved for common settings, and components
380    are restrict to using long options.
381    """
382
383    standard_config_files = [
384        '/etc/docutils.conf',           # system-wide
385        './docutils.conf',              # project-specific
386        '~/.docutils']                  # user-specific
387    """Docutils configuration files, using ConfigParser syntax.  Filenames
388    will be tilde-expanded later.  Later files override earlier ones."""
389
390    threshold_choices = 'info 1 warning 2 error 3 severe 4 none 5'.split()
391    """Possible inputs for for --report and --halt threshold values."""
392
393    thresholds = {'info': 1, 'warning': 2, 'error': 3, 'severe': 4, 'none': 5}
394    """Lookup table for --report and --halt threshold values."""
395
396    booleans={'1': True, 'on': True, 'yes': True, 'true': True,
397              '0': False, 'off': False, 'no': False, 'false': False, '': False}
398    """Lookup table for boolean configuration file settings."""
399
400    default_error_encoding = getattr(sys.stderr, 'encoding',
401                                     None) or locale_encoding or 'ascii'
402
403    default_error_encoding_error_handler = 'backslashreplace'
404
405    settings_spec = (
406        'General Docutils Options',
407        None,
408        (('Specify the document title as metadata.',
409          ['--title'], {}),
410         ('Include a "Generated by Docutils" credit and link.',
411          ['--generator', '-g'], {'action': 'store_true',
412                                  'validator': validate_boolean}),
413         ('Do not include a generator credit.',
414          ['--no-generator'], {'action': 'store_false', 'dest': 'generator'}),
415         ('Include the date at the end of the document (UTC).',
416          ['--date', '-d'], {'action': 'store_const', 'const': '%Y-%m-%d',
417                             'dest': 'datestamp'}),
418         ('Include the time & date (UTC).',
419          ['--time', '-t'], {'action': 'store_const',
420                             'const': '%Y-%m-%d %H:%M UTC',
421                             'dest': 'datestamp'}),
422         ('Do not include a datestamp of any kind.',
423          ['--no-datestamp'], {'action': 'store_const', 'const': None,
424                               'dest': 'datestamp'}),
425         ('Include a "View document source" link.',
426          ['--source-link', '-s'], {'action': 'store_true',
427                                    'validator': validate_boolean}),
428         ('Use <URL> for a source link; implies --source-link.',
429          ['--source-url'], {'metavar': '<URL>'}),
430         ('Do not include a "View document source" link.',
431          ['--no-source-link'],
432          {'action': 'callback', 'callback': store_multiple,
433           'callback_args': ('source_link', 'source_url')}),
434         ('Link from section headers to TOC entries.  (default)',
435          ['--toc-entry-backlinks'],
436          {'dest': 'toc_backlinks', 'action': 'store_const', 'const': 'entry',
437           'default': 'entry'}),
438         ('Link from section headers to the top of the TOC.',
439          ['--toc-top-backlinks'],
440          {'dest': 'toc_backlinks', 'action': 'store_const', 'const': 'top'}),
441         ('Disable backlinks to the table of contents.',
442          ['--no-toc-backlinks'],
443          {'dest': 'toc_backlinks', 'action': 'store_false'}),
444         ('Link from footnotes/citations to references. (default)',
445          ['--footnote-backlinks'],
446          {'action': 'store_true', 'default': 1,
447           'validator': validate_boolean}),
448         ('Disable backlinks from footnotes and citations.',
449          ['--no-footnote-backlinks'],
450          {'dest': 'footnote_backlinks', 'action': 'store_false'}),
451         ('Enable section numbering by Docutils.  (default)',
452          ['--section-numbering'],
453          {'action': 'store_true', 'dest': 'sectnum_xform',
454           'default': 1, 'validator': validate_boolean}),
455         ('Disable section numbering by Docutils.',
456          ['--no-section-numbering'],
457          {'action': 'store_false', 'dest': 'sectnum_xform'}),
458         ('Remove comment elements from the document tree.',
459          ['--strip-comments'],
460          {'action': 'store_true', 'validator': validate_boolean}),
461         ('Leave comment elements in the document tree. (default)',
462          ['--leave-comments'],
463          {'action': 'store_false', 'dest': 'strip_comments'}),
464         ('Remove all elements with classes="<class>" from the document tree. '
465          'Warning: potentially dangerous; use with caution. '
466          '(Multiple-use option.)',
467          ['--strip-elements-with-class'],
468          {'action': 'append', 'dest': 'strip_elements_with_classes',
469           'metavar': '<class>', 'validator': validate_strip_class}),
470         ('Remove all classes="<class>" attributes from elements in the '
471          'document tree. Warning: potentially dangerous; use with caution. '
472          '(Multiple-use option.)',
473          ['--strip-class'],
474          {'action': 'append', 'dest': 'strip_classes',
475           'metavar': '<class>', 'validator': validate_strip_class}),
476         ('Report system messages at or higher than <level>: "info" or "1", '
477          '"warning"/"2" (default), "error"/"3", "severe"/"4", "none"/"5"',
478          ['--report', '-r'], {'choices': threshold_choices, 'default': 2,
479                               'dest': 'report_level', 'metavar': '<level>',
480                               'validator': validate_threshold}),
481         ('Report all system messages.  (Same as "--report=1".)',
482          ['--verbose', '-v'], {'action': 'store_const', 'const': 1,
483                                'dest': 'report_level'}),
484         ('Report no system messages.  (Same as "--report=5".)',
485          ['--quiet', '-q'], {'action': 'store_const', 'const': 5,
486                              'dest': 'report_level'}),
487         ('Halt execution at system messages at or above <level>.  '
488          'Levels as in --report.  Default: 4 (severe).',
489          ['--halt'], {'choices': threshold_choices, 'dest': 'halt_level',
490                       'default': 4, 'metavar': '<level>',
491                       'validator': validate_threshold}),
492         ('Halt at the slightest problem.  Same as "--halt=info".',
493          ['--strict'], {'action': 'store_const', 'const': 1,
494                         'dest': 'halt_level'}),
495         ('Enable a non-zero exit status for non-halting system messages at '
496          'or above <level>.  Default: 5 (disabled).',
497          ['--exit-status'], {'choices': threshold_choices,
498                              'dest': 'exit_status_level',
499                              'default': 5, 'metavar': '<level>',
500                              'validator': validate_threshold}),
501         ('Enable debug-level system messages and diagnostics.',
502          ['--debug'], {'action': 'store_true', 'validator': validate_boolean}),
503         ('Disable debug output.  (default)',
504          ['--no-debug'], {'action': 'store_false', 'dest': 'debug'}),
505         ('Send the output of system messages to <file>.',
506          ['--warnings'], {'dest': 'warning_stream', 'metavar': '<file>'}),
507         ('Enable Python tracebacks when Docutils is halted.',
508          ['--traceback'], {'action': 'store_true', 'default': None,
509                            'validator': validate_boolean}),
510         ('Disable Python tracebacks.  (default)',
511          ['--no-traceback'], {'dest': 'traceback', 'action': 'store_false'}),
512         ('Specify the encoding and optionally the '
513          'error handler of input text.  Default: <locale-dependent>:strict.',
514          ['--input-encoding', '-i'],
515          {'metavar': '<name[:handler]>',
516           'validator': validate_encoding_and_error_handler}),
517         ('Specify the error handler for undecodable characters.  '
518          'Choices: "strict" (default), "ignore", and "replace".',
519          ['--input-encoding-error-handler'],
520          {'default': 'strict', 'validator': validate_encoding_error_handler}),
521         ('Specify the text encoding and optionally the error handler for '
522          'output.  Default: UTF-8:strict.',
523          ['--output-encoding', '-o'],
524          {'metavar': '<name[:handler]>', 'default': 'utf-8',
525           'validator': validate_encoding_and_error_handler}),
526         ('Specify error handler for unencodable output characters; '
527          '"strict" (default), "ignore", "replace", '
528          '"xmlcharrefreplace", "backslashreplace".',
529          ['--output-encoding-error-handler'],
530          {'default': 'strict', 'validator': validate_encoding_error_handler}),
531         ('Specify text encoding and error handler for error output.  '
532          'Default: %s:%s.'
533          % (default_error_encoding, default_error_encoding_error_handler),
534          ['--error-encoding', '-e'],
535          {'metavar': '<name[:handler]>', 'default': default_error_encoding,
536           'validator': validate_encoding_and_error_handler}),
537         ('Specify the error handler for unencodable characters in '
538          'error output.  Default: %s.'
539          % default_error_encoding_error_handler,
540          ['--error-encoding-error-handler'],
541          {'default': default_error_encoding_error_handler,
542           'validator': validate_encoding_error_handler}),
543         ('Specify the language (as BCP 47 language tag).  Default: en.',
544          ['--language', '-l'], {'dest': 'language_code', 'default': 'en',
545                                 'metavar': '<name>'}),
546         ('Write output file dependencies to <file>.',
547          ['--record-dependencies'],
548          {'metavar': '<file>', 'validator': validate_dependency_file,
549           'default': None}),           # default set in Values class
550         ('Read configuration settings from <file>, if it exists.',
551          ['--config'], {'metavar': '<file>', 'type': 'string',
552                         'action': 'callback', 'callback': read_config_file}),
553         ("Show this program's version number and exit.",
554          ['--version', '-V'], {'action': 'version'}),
555         ('Show this help message and exit.',
556          ['--help', '-h'], {'action': 'help'}),
557         # Typically not useful for non-programmatical use:
558         (SUPPRESS_HELP, ['--id-prefix'], {'default': ''}),
559         (SUPPRESS_HELP, ['--auto-id-prefix'], {'default': 'id'}),
560         # Hidden options, for development use only:
561         (SUPPRESS_HELP, ['--dump-settings'], {'action': 'store_true'}),
562         (SUPPRESS_HELP, ['--dump-internals'], {'action': 'store_true'}),
563         (SUPPRESS_HELP, ['--dump-transforms'], {'action': 'store_true'}),
564         (SUPPRESS_HELP, ['--dump-pseudo-xml'], {'action': 'store_true'}),
565         (SUPPRESS_HELP, ['--expose-internal-attribute'],
566          {'action': 'append', 'dest': 'expose_internals',
567           'validator': validate_colon_separated_string_list}),
568         (SUPPRESS_HELP, ['--strict-visitor'], {'action': 'store_true'}),
569         ))
570    """Runtime settings and command-line options common to all Docutils front
571    ends.  Setting specs specific to individual Docutils components are also
572    used (see `populate_from_components()`)."""
573
574    settings_defaults = {'_disable_config': None,
575                         '_source': None,
576                         '_destination': None,
577                         '_config_files': None}
578    """Defaults for settings that don't have command-line option equivalents."""
579
580    relative_path_settings = ('warning_stream',)
581
582    config_section = 'general'
583
584    version_template = ('%%prog (Docutils %s%s, Python %s, on %s)'
585                        % (docutils.__version__,
586                           docutils.__version_details__ and
587                           ' [%s]'%docutils.__version_details__ or '',
588                           sys.version.split()[0], sys.platform))
589    """Default version message."""
590
591    def __init__(self, components=(), defaults=None, read_config_files=None,
592                 *args, **kwargs):
593        """
594        `components` is a list of Docutils components each containing a
595        ``.settings_spec`` attribute.  `defaults` is a mapping of setting
596        default overrides.
597        """
598
599        self.lists = {}
600        """Set of list-type settings."""
601
602        self.config_files = []
603        """List of paths of applied configuration files."""
604
605        optparse.OptionParser.__init__(
606            self, option_class=Option, add_help_option=None,
607            formatter=optparse.TitledHelpFormatter(width=78),
608            *args, **kwargs)
609        if not self.version:
610            self.version = self.version_template
611        # Make an instance copy (it will be modified):
612        self.relative_path_settings = list(self.relative_path_settings)
613        self.components = (self,) + tuple(components)
614        self.populate_from_components(self.components)
615        self.set_defaults_from_dict(defaults or {})
616        if read_config_files and not self.defaults['_disable_config']:
617            try:
618                config_settings = self.get_standard_config_settings()
619            except ValueError as error:
620                self.error(SafeString(error))
621            self.set_defaults_from_dict(config_settings.__dict__)
622
623    def populate_from_components(self, components):
624        """
625        For each component, first populate from the `SettingsSpec.settings_spec`
626        structure, then from the `SettingsSpec.settings_defaults` dictionary.
627        After all components have been processed, check for and populate from
628        each component's `SettingsSpec.settings_default_overrides` dictionary.
629        """
630        for component in components:
631            if component is None:
632                continue
633            settings_spec = component.settings_spec
634            self.relative_path_settings.extend(
635                component.relative_path_settings)
636            for i in range(0, len(settings_spec), 3):
637                title, description, option_spec = settings_spec[i:i+3]
638                if title:
639                    group = optparse.OptionGroup(self, title, description)
640                    self.add_option_group(group)
641                else:
642                    group = self        # single options
643                for (help_text, option_strings, kwargs) in option_spec:
644                    option = group.add_option(help=help_text, *option_strings,
645                                              **kwargs)
646                    if kwargs.get('action') == 'append':
647                        self.lists[option.dest] = True
648                if component.settings_defaults:
649                    self.defaults.update(component.settings_defaults)
650        for component in components:
651            if component and component.settings_default_overrides:
652                self.defaults.update(component.settings_default_overrides)
653
654    def get_standard_config_files(self):
655        """Return list of config files, from environment or standard."""
656        try:
657            config_files = os.environ['DOCUTILSCONFIG'].split(os.pathsep)
658        except KeyError:
659            config_files = self.standard_config_files
660
661        # If 'HOME' is not set, expandvars() requires the 'pwd' module which is
662        # not available under certain environments, for example, within
663        # mod_python.  The publisher ends up in here, and we need to publish
664        # from within mod_python.  Therefore we need to avoid expanding when we
665        # are in those environments.
666        expand = os.path.expanduser
667        if 'HOME' not in os.environ:
668            try:
669                import pwd
670            except ImportError:
671                expand = lambda x: x
672        return [expand(f) for f in config_files if f.strip()]
673
674    def get_standard_config_settings(self):
675        settings = Values()
676        for filename in self.get_standard_config_files():
677            settings.update(self.get_config_file_settings(filename), self)
678        return settings
679
680    def get_config_file_settings(self, config_file):
681        """Returns a dictionary containing appropriate config file settings."""
682        parser = ConfigParser()
683        parser.read(config_file, self)
684        self.config_files.extend(parser._files)
685        base_path = os.path.dirname(config_file)
686        applied = {}
687        settings = Values()
688        for component in self.components:
689            if not component:
690                continue
691            for section in (tuple(component.config_section_dependencies or ())
692                            + (component.config_section,)):
693                if section in applied:
694                    continue
695                applied[section] = 1
696                settings.update(parser.get_section(section), self)
697        make_paths_absolute(
698            settings.__dict__, self.relative_path_settings, base_path)
699        return settings.__dict__
700
701    def check_values(self, values, args):
702        """Store positional arguments as runtime settings."""
703        values._source, values._destination = self.check_args(args)
704        make_paths_absolute(values.__dict__, self.relative_path_settings)
705        values._config_files = self.config_files
706        return values
707
708    def check_args(self, args):
709        source = destination = None
710        if args:
711            source = args.pop(0)
712            if source == '-':           # means stdin
713                source = None
714        if args:
715            destination = args.pop(0)
716            if destination == '-':      # means stdout
717                destination = None
718        if args:
719            self.error('Maximum 2 arguments allowed.')
720        if source and source == destination:
721            self.error('Do not specify the same file for both source and '
722                       'destination.  It will clobber the source file.')
723        return source, destination
724
725    def set_defaults_from_dict(self, defaults):
726        self.defaults.update(defaults)
727
728    def get_default_values(self):
729        """Needed to get custom `Values` instances."""
730        defaults = Values(self.defaults)
731        defaults._config_files = self.config_files
732        return defaults
733
734    def get_option_by_dest(self, dest):
735        """
736        Get an option by its dest.
737
738        If you're supplying a dest which is shared by several options,
739        it is undefined which option of those is returned.
740
741        A KeyError is raised if there is no option with the supplied
742        dest.
743        """
744        for group in self.option_groups + [self]:
745            for option in group.option_list:
746                if option.dest == dest:
747                    return option
748        raise KeyError('No option with dest == %r.' % dest)
749
750
751class ConfigParser(RawConfigParser):
752
753    old_settings = {
754        'pep_stylesheet': ('pep_html writer', 'stylesheet'),
755        'pep_stylesheet_path': ('pep_html writer', 'stylesheet_path'),
756        'pep_template': ('pep_html writer', 'template')}
757    """{old setting: (new section, new setting)} mapping, used by
758    `handle_old_config`, to convert settings from the old [options] section."""
759
760    old_warning = """
761The "[option]" section is deprecated.  Support for old-format configuration
762files may be removed in a future Docutils release.  Please revise your
763configuration files.  See <http://docutils.sf.net/docs/user/config.html>,
764section "Old-Format Configuration Files".
765"""
766
767    not_utf8_error = """\
768Unable to read configuration file "%s": content not encoded as UTF-8.
769Skipping "%s" configuration file.
770"""
771
772    def __init__(self, *args, **kwargs):
773        RawConfigParser.__init__(self, *args, **kwargs)
774
775        self._files = []
776        """List of paths of configuration files read."""
777
778        self._stderr = ErrorOutput()
779        """Wrapper around sys.stderr catching en-/decoding errors"""
780
781    def read(self, filenames, option_parser):
782        if type(filenames) in (str, unicode):
783            filenames = [filenames]
784        for filename in filenames:
785            try:
786                # Config files are UTF-8-encoded:
787                fp = codecs.open(filename, 'r', 'utf-8')
788            except IOError:
789                continue
790            try:
791                if sys.version_info < (3, 0):
792                    RawConfigParser.readfp(self, fp, filename)
793                else:
794                    RawConfigParser.read_file(self, fp, filename)
795            except UnicodeDecodeError:
796                self._stderr.write(self.not_utf8_error % (filename, filename))
797                fp.close()
798                continue
799            fp.close()
800            self._files.append(filename)
801            if self.has_section('options'):
802                self.handle_old_config(filename)
803            self.validate_settings(filename, option_parser)
804
805    def handle_old_config(self, filename):
806        warnings.warn_explicit(self.old_warning, ConfigDeprecationWarning,
807                               filename, 0)
808        options = self.get_section('options')
809        if not self.has_section('general'):
810            self.add_section('general')
811        for key, value in options.items():
812            if key in self.old_settings:
813                section, setting = self.old_settings[key]
814                if not self.has_section(section):
815                    self.add_section(section)
816            else:
817                section = 'general'
818                setting = key
819            if not self.has_option(section, setting):
820                self.set(section, setting, value)
821        self.remove_section('options')
822
823    def validate_settings(self, filename, option_parser):
824        """
825        Call the validator function and implement overrides on all applicable
826        settings.
827        """
828        for section in self.sections():
829            for setting in self.options(section):
830                try:
831                    option = option_parser.get_option_by_dest(setting)
832                except KeyError:
833                    continue
834                if option.validator:
835                    value = self.get(section, setting)
836                    try:
837                        new_value = option.validator(
838                            setting, value, option_parser,
839                            config_parser=self, config_section=section)
840                    except Exception as error:
841                        raise ValueError(
842                            'Error in config file "%s", section "[%s]":\n'
843                            '    %s\n'
844                            '        %s = %s'
845                            % (filename, section, ErrorString(error),
846                               setting, value))
847                    self.set(section, setting, new_value)
848                if option.overrides:
849                    self.set(section, option.overrides, None)
850
851    def optionxform(self, optionstr):
852        """
853        Transform '-' to '_' so the cmdline form of option names can be used.
854        """
855        return optionstr.lower().replace('-', '_')
856
857    def get_section(self, section):
858        """
859        Return a given section as a dictionary (empty if the section
860        doesn't exist).
861        """
862        section_dict = {}
863        if self.has_section(section):
864            for option in self.options(section):
865                section_dict[option] = self.get(section, option)
866        return section_dict
867
868
869class ConfigDeprecationWarning(DeprecationWarning):
870    """Warning for deprecated configuration file features."""
871