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import os, re, sys try: SetType = set except NameError: import sets SetType = sets.Set set = sets.Set def parse_versions(vstring): import operator operators = { None: operator.eq, '=': operator.eq, '>=': operator.ge, '<=': operator.le, '<<': operator.lt } vinfo = {} exact_versions = set([]) version_range = set(supported_versions(version_only=True)) relop_seen = False for field in vstring.split(','): field = field.strip() if field == 'all': vinfo['all'] = 'all' continue if field in ('current', 'current_ext'): vinfo['current'] = field continue vinfo.setdefault('versions', set()) ve = re.compile('(>=|<=|<<|=)? *(\d\.\d)$') m = ve.match(field) try: op, v = m.group(1), m.group(2) if op in (None, '='): exact_versions.add(v) else: relop_seen = True filtop = operators[op] version_range = [av for av in version_range if filtop(av ,v)] except Exception: raise ValueError, 'error parsing Python-Version attribute' if 'versions' in vinfo: vinfo['versions'] = exact_versions if relop_seen: vinfo['versions'] = exact_versions.union(version_range) return vinfo _supported_versions = None def supported_versions(version_only=False): global _supported_versions if not _supported_versions: if os.path.exists('/usr/share/python/debian_defaults'): from ConfigParser import SafeConfigParser config = SafeConfigParser() config.readfp(file('/usr/share/python/debian_defaults')) value = config.get('DEFAULT', 'supported-versions') _supported_versions = [s.strip() for s in value.split(',')] else: cmd = ['/usr/bin/apt-cache', '--no-all-versions', 'show', 'python-all'] try: import subprocess p = subprocess.Popen(cmd, bufsize=1, shell=False, stdout=subprocess.PIPE) fd = p.stdout except ImportError: fd = os.popen(' '.join(cmd)) depends = None for line in fd: if line.startswith('Depends:'): depends = line.split(':', 1)[1].strip().split(',') fd.close() depends = [re.sub(r'\s*(\S+)[ (]?.*', r'\1', s) for s in depends] _supported_versions = depends if version_only: return [v[6:] for v in _supported_versions] else: return _supported_versions _default_version = None def default_version(version_only=False): global _default_version if not _default_version: _default_version = link = os.readlink('/usr/bin/python') if version_only: return _default_version[6:] else: return _default_version def requested_versions(vstring, version_only=False): versions = None vinfo = parse_versions(vstring) supported = supported_versions(version_only=True) if len(vinfo) == 1: if 'all' in vinfo: versions = supported elif 'current' in vinfo: versions = [default_version(version_only=True)] else: versions = vinfo['versions'].intersection(supported) elif 'all' in vinfo and 'current' in vinfo: raise ValueError, "both `current' and `all' in version string" elif 'all' in vinfo: versions = versions = vinfo['versions'].intersection(supported) elif 'current' in vinfo: current = default_version(version_only=True) if not current in vinfo['versions']: raise ValueError, "`current' version not in supported versions" versions = [current] else: raise ValueError, 'error in version string' if not versions: raise ValueError, 'empty set of versions' if version_only: return versions else: return ['python%s' % v for v in versions] def installed_versions(version_only=False): import glob supported = supported_versions() versions = [os.path.basename(s) for s in glob.glob('/usr/bin/python[0-9].[0-9]') if os.path.basename(s) in supported] versions.sort() if version_only: return [v[6:] for v in versions] else: return versions def extract_pyversion_attribute(fn, pkg): """read the debian/control file, extract the XS-Python-Version field; check that XB-Python-Version exists for the package.""" version = None sversion = None section = None for line in file(fn): line = line.strip() if line == '': section = None elif line.startswith('Source:'): section = 'Source' elif line.startswith('Package: ' + pkg): section = self.name elif line.startswith('XS-Python-Version:'): if section != 'Source': raise ValueError, \ 'attribute XS-Python-Version not in Source section' sversion = line.split(':', 1)[1].strip() elif line.startswith('XB-Python-Version:'): if section == pkg: version = line.split(':', 1)[1].strip() if pkg == 'Source': if sversion == None: raise ValueError, 'missing XS-Python-Version in control file' return sversion if version == None: raise ValueError, \ 'missing XB-Python-Version for package `%s' % pkg return version def main(): from optparse import OptionParser usage = '[-v] [-h] [-d|--default] [-s|--supported] [-i|--installed] [-r|--requested <version string>|<control file>]' parser = OptionParser(usage=usage) parser.add_option('-d', '--default', help='print the default python version', action='store_true', dest='default') parser.add_option('-s', '--supported', help='print the supported python versions', action='store_true', dest='supported') parser.add_option('-r', '--requested', help='print the python versions requested by a build; the argument is either the name of a control file or the value of the XS-Python-Version attribute', action='store', dest='versions') parser.add_option('-i', '--installed', help='print the installed supported python versions', action='store_true', dest='installed') parser.add_option('-v', '--version', help='print just the version number(s)', default=False, action='store_true', dest='version_only') opts, args = parser.parse_args() program = os.path.basename(sys.argv[0]) if opts.default: print default_version(opts.version_only) elif opts.supported: print ' '.join(supported_versions(opts.version_only)) elif opts.installed: print ' '.join(installed_versions(opts.version_only)) elif opts.versions: try: if os.path.isfile(opts.versions): vs = extract_pyversion_attribute(opts.versions, 'Source') else: vs = opts.versions print ' '.join(requested_versions(vs, opts.version_only)) except ValueError, msg: print "%s: %s" % (program, msg) sys.exit(1) else: print "usage: %s %s" % (program, usage) sys.exit(1) if __name__ == '__main__': main() 
