Lao Tzu
163 lines
4.3 KiB
Python
163 lines
4.3 KiB
Python
#
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# Copyright (C) 2018-2020 Dimitar Toshkov Zhekov <dimitar.zhekov@gmail.com>
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#
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# This program is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the Free
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# Software Foundation; either version 2 of the License, or (at your option)
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# any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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# for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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#
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import sys
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import os
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import re
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# -- Params --
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class Params:
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def __init__(self):
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self.excstk = False
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# -- Options --
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class Options:
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def __init__(self, need_args, help_text, version_text):
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for name in need_args:
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if not re.fullmatch('(-[^-]|--[^=]+)', name):
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raise Exception('invalid option name "%s"' % name)
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self.need_args = need_args
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self.help_text = help_text
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self.version_text = version_text
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def posixly_correct(self): # pylint: disable=no-self-use
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return 'POSIXLY_CORRECT' in os.environ
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def needs_arg(self, name):
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return name in self.need_args
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def fallback(self, name, params):
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if name == '--excstk':
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params.excstk = True
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elif name == '--help' and self.help_text is not None:
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sys.stdout.write(self.help_text)
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sys.exit(0)
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elif name == '--version' and self.version_text is not None:
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sys.stdout.write(self.version_text)
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sys.exit(0)
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else:
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suffix = ' (taking an argument?)' if self.needs_arg(name) else ''
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suffix += ', try --help' if self.help_text is not None else ''
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raise Exception('unknown option "%s"%s' % (name, suffix))
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def reader(self, args, skip_zero=True):
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return Options.Reader(self, args, skip_zero)
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class Reader:
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def __init__(self, options, args, skip_zero):
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self.options = options
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self.args = args
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self.skip_zero = skip_zero
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def __iter__(self):
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return Options.Reader.Iterator(self)
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class Iterator:
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def __init__(self, reader):
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self.options = reader.options
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self.args = reader.args
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self.optind = int(reader.skip_zero)
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self.chrind = 1
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self.endopt = False
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def __next__(self):
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if self.chrind == 0:
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self.optind += 1
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self.chrind = 1
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if self.optind == len(self.args):
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raise StopIteration
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arg = self.args[self.optind]
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if self.endopt or arg == '-' or not arg.startswith('-'):
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self.endopt = self.options.posixly_correct()
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name = None
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value = arg
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elif arg == '--':
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self.chrind = 0
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self.endopt = True
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return next(self)
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elif not arg.startswith('--'):
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name = '-' + arg[self.chrind]
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self.chrind += 1
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if self.chrind < len(arg):
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if not self.options.needs_arg(name):
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return (name, None)
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value = arg[self.chrind:]
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else:
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value = None
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elif '=' in arg and arg.index('=') >= 3:
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name = arg.split('=', 1)[0]
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if not self.options.needs_arg(name):
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raise Exception('option "%s" does not take an argument' % name)
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value = arg[len(name) + 1:]
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else:
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name = arg
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value = None
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if value is None and int(self.options.needs_arg(name)) > 0:
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self.optind += 1
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if self.optind == len(self.args):
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raise Exception('option "%s" requires an argument' % name)
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value = self.args[self.optind]
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self.chrind = 0
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return (name, value)
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# -- Main --
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def start(program_name, options, params, main_program):
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parsed = Params() if params is None else params
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try:
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if sys.hexversion < 0x3050000:
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raise Exception('python 3.5.0 or later required')
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if params is None:
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return main_program(options.reader(sys.argv), lambda name: options.fallback(name, parsed))
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nonopt = []
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for [name, value] in options.reader(sys.argv):
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if name is None:
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nonopt.append(value)
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else:
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options.parse(name, value, parsed)
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return main_program(nonopt, parsed)
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except Exception as ex:
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if parsed.excstk:
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raise # loses the message information, but preserves the start() caller stack info
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message = getattr(ex, 'message', str(ex))
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sys.stderr.write('%s: %s\n' % (sys.argv[0] if sys.argv[0] else program_name, message))
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sys.exit(1)
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