| """Command line parsing machinery. |
| |
| The FancyGetopt class is a Wrapper around the getopt module that |
| provides the following additional features: |
| * short and long options are tied together |
| * options have help strings, so fancy_getopt could potentially |
| create a complete usage summary |
| * options set attributes of a passed-in object. |
| |
| It is used under the hood by the command classes. Do not use directly. |
| """ |
| |
| import getopt |
| import re |
| import sys |
| import textwrap |
| |
| from packaging.errors import PackagingGetoptError, PackagingArgError |
| |
| # Much like command_re in packaging.core, this is close to but not quite |
| # the same as a Python NAME -- except, in the spirit of most GNU |
| # utilities, we use '-' in place of '_'. (The spirit of LISP lives on!) |
| # The similarities to NAME are again not a coincidence... |
| longopt_pat = r'[a-zA-Z](?:[a-zA-Z0-9-]*)' |
| longopt_re = re.compile(r'^%s$' % longopt_pat) |
| |
| # For recognizing "negative alias" options, eg. "quiet=!verbose" |
| neg_alias_re = re.compile("^(%s)=!(%s)$" % (longopt_pat, longopt_pat)) |
| |
| |
| class FancyGetopt: |
| """Wrapper around the standard 'getopt()' module that provides some |
| handy extra functionality: |
| * short and long options are tied together |
| * options have help strings, and help text can be assembled |
| from them |
| * options set attributes of a passed-in object |
| * boolean options can have "negative aliases" -- eg. if |
| --quiet is the "negative alias" of --verbose, then "--quiet" |
| on the command line sets 'verbose' to false |
| """ |
| |
| def __init__(self, option_table=None): |
| |
| # The option table is (currently) a list of tuples. The |
| # tuples may have 3 or four values: |
| # (long_option, short_option, help_string [, repeatable]) |
| # if an option takes an argument, its long_option should have '=' |
| # appended; short_option should just be a single character, no ':' |
| # in any case. If a long_option doesn't have a corresponding |
| # short_option, short_option should be None. All option tuples |
| # must have long options. |
| self.option_table = option_table |
| |
| # 'option_index' maps long option names to entries in the option |
| # table (ie. those 3-tuples). |
| self.option_index = {} |
| if self.option_table: |
| self._build_index() |
| |
| # 'alias' records (duh) alias options; {'foo': 'bar'} means |
| # --foo is an alias for --bar |
| self.alias = {} |
| |
| # 'negative_alias' keeps track of options that are the boolean |
| # opposite of some other option |
| self.negative_alias = {} |
| |
| # These keep track of the information in the option table. We |
| # don't actually populate these structures until we're ready to |
| # parse the command line, since the 'option_table' passed in here |
| # isn't necessarily the final word. |
| self.short_opts = [] |
| self.long_opts = [] |
| self.short2long = {} |
| self.attr_name = {} |
| self.takes_arg = {} |
| |
| # And 'option_order' is filled up in 'getopt()'; it records the |
| # original order of options (and their values) on the command line, |
| # but expands short options, converts aliases, etc. |
| self.option_order = [] |
| |
| def _build_index(self): |
| self.option_index.clear() |
| for option in self.option_table: |
| self.option_index[option[0]] = option |
| |
| def set_option_table(self, option_table): |
| self.option_table = option_table |
| self._build_index() |
| |
| def add_option(self, long_option, short_option=None, help_string=None): |
| if long_option in self.option_index: |
| raise PackagingGetoptError( |
| "option conflict: already an option '%s'" % long_option) |
| else: |
| option = (long_option, short_option, help_string) |
| self.option_table.append(option) |
| self.option_index[long_option] = option |
| |
| def has_option(self, long_option): |
| """Return true if the option table for this parser has an |
| option with long name 'long_option'.""" |
| return long_option in self.option_index |
| |
| def _check_alias_dict(self, aliases, what): |
| assert isinstance(aliases, dict) |
| for alias, opt in aliases.items(): |
| if alias not in self.option_index: |
| raise PackagingGetoptError( |
| ("invalid %s '%s': " |
| "option '%s' not defined") % (what, alias, alias)) |
| if opt not in self.option_index: |
| raise PackagingGetoptError( |
| ("invalid %s '%s': " |
| "aliased option '%s' not defined") % (what, alias, opt)) |
| |
| def set_aliases(self, alias): |
| """Set the aliases for this option parser.""" |
| self._check_alias_dict(alias, "alias") |
| self.alias = alias |
| |
| def set_negative_aliases(self, negative_alias): |
| """Set the negative aliases for this option parser. |
| 'negative_alias' should be a dictionary mapping option names to |
| option names, both the key and value must already be defined |
| in the option table.""" |
| self._check_alias_dict(negative_alias, "negative alias") |
| self.negative_alias = negative_alias |
| |
| def _grok_option_table(self): |
| """Populate the various data structures that keep tabs on the |
| option table. Called by 'getopt()' before it can do anything |
| worthwhile. |
| """ |
| self.long_opts = [] |
| self.short_opts = [] |
| self.short2long.clear() |
| self.repeat = {} |
| |
| for option in self.option_table: |
| if len(option) == 3: |
| longopt, short, help = option |
| repeat = 0 |
| elif len(option) == 4: |
| longopt, short, help, repeat = option |
| else: |
| # the option table is part of the code, so simply |
| # assert that it is correct |
| raise ValueError("invalid option tuple: %r" % option) |
| |
| # Type- and value-check the option names |
| if not isinstance(longopt, str) or len(longopt) < 2: |
| raise PackagingGetoptError( |
| ("invalid long option '%s': " |
| "must be a string of length >= 2") % longopt) |
| |
| if (not ((short is None) or |
| (isinstance(short, str) and len(short) == 1))): |
| raise PackagingGetoptError( |
| ("invalid short option '%s': " |
| "must be a single character or None") % short) |
| |
| self.repeat[longopt] = repeat |
| self.long_opts.append(longopt) |
| |
| if longopt[-1] == '=': # option takes an argument? |
| if short: |
| short = short + ':' |
| longopt = longopt[0:-1] |
| self.takes_arg[longopt] = 1 |
| else: |
| |
| # Is option is a "negative alias" for some other option (eg. |
| # "quiet" == "!verbose")? |
| alias_to = self.negative_alias.get(longopt) |
| if alias_to is not None: |
| if self.takes_arg[alias_to]: |
| raise PackagingGetoptError( |
| ("invalid negative alias '%s': " |
| "aliased option '%s' takes a value") % \ |
| (longopt, alias_to)) |
| |
| self.long_opts[-1] = longopt # XXX redundant?! |
| self.takes_arg[longopt] = 0 |
| |
| else: |
| self.takes_arg[longopt] = 0 |
| |
| # If this is an alias option, make sure its "takes arg" flag is |
| # the same as the option it's aliased to. |
| alias_to = self.alias.get(longopt) |
| if alias_to is not None: |
| if self.takes_arg[longopt] != self.takes_arg[alias_to]: |
| raise PackagingGetoptError( |
| ("invalid alias '%s': inconsistent with " |
| "aliased option '%s' (one of them takes a value, " |
| "the other doesn't") % (longopt, alias_to)) |
| |
| # Now enforce some bondage on the long option name, so we can |
| # later translate it to an attribute name on some object. Have |
| # to do this a bit late to make sure we've removed any trailing |
| # '='. |
| if not longopt_re.match(longopt): |
| raise PackagingGetoptError( |
| ("invalid long option name '%s' " + |
| "(must be letters, numbers, hyphens only") % longopt) |
| |
| self.attr_name[longopt] = longopt.replace('-', '_') |
| if short: |
| self.short_opts.append(short) |
| self.short2long[short[0]] = longopt |
| |
| def getopt(self, args=None, object=None): |
| """Parse command-line options in args. Store as attributes on object. |
| |
| If 'args' is None or not supplied, uses 'sys.argv[1:]'. If |
| 'object' is None or not supplied, creates a new OptionDummy |
| object, stores option values there, and returns a tuple (args, |
| object). If 'object' is supplied, it is modified in place and |
| 'getopt()' just returns 'args'; in both cases, the returned |
| 'args' is a modified copy of the passed-in 'args' list, which |
| is left untouched. |
| """ |
| if args is None: |
| args = sys.argv[1:] |
| if object is None: |
| object = OptionDummy() |
| created_object = 1 |
| else: |
| created_object = 0 |
| |
| self._grok_option_table() |
| |
| short_opts = ' '.join(self.short_opts) |
| |
| try: |
| opts, args = getopt.getopt(args, short_opts, self.long_opts) |
| except getopt.error as msg: |
| raise PackagingArgError(msg) |
| |
| for opt, val in opts: |
| if len(opt) == 2 and opt[0] == '-': # it's a short option |
| opt = self.short2long[opt[1]] |
| else: |
| assert len(opt) > 2 and opt[:2] == '--' |
| opt = opt[2:] |
| |
| alias = self.alias.get(opt) |
| if alias: |
| opt = alias |
| |
| if not self.takes_arg[opt]: # boolean option? |
| assert val == '', "boolean option can't have value" |
| alias = self.negative_alias.get(opt) |
| if alias: |
| opt = alias |
| val = 0 |
| else: |
| val = 1 |
| |
| attr = self.attr_name[opt] |
| # The only repeating option at the moment is 'verbose'. |
| # It has a negative option -q quiet, which should set verbose = 0. |
| if val and self.repeat.get(attr) is not None: |
| val = getattr(object, attr, 0) + 1 |
| setattr(object, attr, val) |
| self.option_order.append((opt, val)) |
| |
| # for opts |
| if created_object: |
| return args, object |
| else: |
| return args |
| |
| def get_option_order(self): |
| """Returns the list of (option, value) tuples processed by the |
| previous run of 'getopt()'. Raises RuntimeError if |
| 'getopt()' hasn't been called yet. |
| """ |
| if self.option_order is None: |
| raise RuntimeError("'getopt()' hasn't been called yet") |
| else: |
| return self.option_order |
| |
| return self.option_order |
| |
| def generate_help(self, header=None): |
| """Generate help text (a list of strings, one per suggested line of |
| output) from the option table for this FancyGetopt object. |
| """ |
| # Blithely assume the option table is good: probably wouldn't call |
| # 'generate_help()' unless you've already called 'getopt()'. |
| |
| # First pass: determine maximum length of long option names |
| max_opt = 0 |
| for option in self.option_table: |
| longopt = option[0] |
| short = option[1] |
| l = len(longopt) |
| if longopt[-1] == '=': |
| l = l - 1 |
| if short is not None: |
| l = l + 5 # " (-x)" where short == 'x' |
| if l > max_opt: |
| max_opt = l |
| |
| opt_width = max_opt + 2 + 2 + 2 # room for indent + dashes + gutter |
| |
| # Typical help block looks like this: |
| # --foo controls foonabulation |
| # Help block for longest option looks like this: |
| # --flimflam set the flim-flam level |
| # and with wrapped text: |
| # --flimflam set the flim-flam level (must be between |
| # 0 and 100, except on Tuesdays) |
| # Options with short names will have the short name shown (but |
| # it doesn't contribute to max_opt): |
| # --foo (-f) controls foonabulation |
| # If adding the short option would make the left column too wide, |
| # we push the explanation off to the next line |
| # --flimflam (-l) |
| # set the flim-flam level |
| # Important parameters: |
| # - 2 spaces before option block start lines |
| # - 2 dashes for each long option name |
| # - min. 2 spaces between option and explanation (gutter) |
| # - 5 characters (incl. space) for short option name |
| |
| # Now generate lines of help text. (If 80 columns were good enough |
| # for Jesus, then 78 columns are good enough for me!) |
| line_width = 78 |
| text_width = line_width - opt_width |
| big_indent = ' ' * opt_width |
| if header: |
| lines = [header] |
| else: |
| lines = ['Option summary:'] |
| |
| for option in self.option_table: |
| longopt, short, help = option[:3] |
| text = textwrap.wrap(help, text_width) |
| |
| # Case 1: no short option at all (makes life easy) |
| if short is None: |
| if text: |
| lines.append(" --%-*s %s" % (max_opt, longopt, text[0])) |
| else: |
| lines.append(" --%-*s " % (max_opt, longopt)) |
| |
| # Case 2: we have a short option, so we have to include it |
| # just after the long option |
| else: |
| opt_names = "%s (-%s)" % (longopt, short) |
| if text: |
| lines.append(" --%-*s %s" % |
| (max_opt, opt_names, text[0])) |
| else: |
| lines.append(" --%-*s" % opt_names) |
| |
| for l in text[1:]: |
| lines.append(big_indent + l) |
| |
| return lines |
| |
| def print_help(self, header=None, file=None): |
| if file is None: |
| file = sys.stdout |
| for line in self.generate_help(header): |
| file.write(line + "\n") |
| |
| |
| def fancy_getopt(options, negative_opt, object, args): |
| parser = FancyGetopt(options) |
| parser.set_negative_aliases(negative_opt) |
| return parser.getopt(args, object) |
| |
| |
| class OptionDummy: |
| """Dummy class just used as a place to hold command-line option |
| values as instance attributes.""" |
| |
| def __init__(self, options=[]): |
| """Create a new OptionDummy instance. The attributes listed in |
| 'options' will be initialized to None.""" |
| for opt in options: |
| setattr(self, opt, None) |