sshuttle/options.py

202 lines
6.4 KiB
Python
Raw Normal View History

"""Command-line options parser.
With the help of an options spec string, easily parse command-line options.
"""
import sys, os, textwrap, getopt, re, struct
class OptDict:
def __init__(self):
self._opts = {}
def __setitem__(self, k, v):
if k.startswith('no-') or k.startswith('no_'):
k = k[3:]
v = not v
self._opts[k] = v
def __getitem__(self, k):
if k.startswith('no-') or k.startswith('no_'):
return not self._opts[k[3:]]
return self._opts[k]
def __getattr__(self, k):
return self[k]
def _default_onabort(msg):
sys.exit(97)
def _intify(v):
try:
vv = int(v or '')
if str(vv) == v:
return vv
except ValueError:
pass
return v
def _atoi(v):
try:
return int(v or 0)
except ValueError:
return 0
def _remove_negative_kv(k, v):
if k.startswith('no-') or k.startswith('no_'):
return k[3:], not v
return k,v
def _remove_negative_k(k):
return _remove_negative_kv(k, None)[0]
def _tty_width():
s = struct.pack("HHHH", 0, 0, 0, 0)
try:
import fcntl, termios
s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
except (IOError, ImportError):
return _atoi(os.environ.get('WIDTH')) or 70
(ysize,xsize,ypix,xpix) = struct.unpack('HHHH', s)
return xsize
class Options:
"""Option parser.
When constructed, two strings are mandatory. The first one is the command
name showed before error messages. The second one is a string called an
optspec that specifies the synopsis and option flags and their description.
For more information about optspecs, consult the bup-options(1) man page.
Two optional arguments specify an alternative parsing function and an
alternative behaviour on abort (after having output the usage string).
By default, the parser function is getopt.gnu_getopt, and the abort
behaviour is to exit the program.
"""
def __init__(self, exe, optspec, optfunc=getopt.gnu_getopt,
onabort=_default_onabort):
self.exe = exe
self.optspec = optspec
self._onabort = onabort
self.optfunc = optfunc
self._aliases = {}
self._shortopts = 'h?'
self._longopts = ['help']
self._hasparms = {}
self._defaults = {}
self._usagestr = self._gen_usage()
def _gen_usage(self):
out = []
lines = self.optspec.strip().split('\n')
lines.reverse()
first_syn = True
while lines:
l = lines.pop()
if l == '--': break
out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
first_syn = False
out.append('\n')
last_was_option = False
while lines:
l = lines.pop()
if l.startswith(' '):
out.append('%s%s\n' % (last_was_option and '\n' or '',
l.lstrip()))
last_was_option = False
elif l:
(flags, extra) = l.split(' ', 1)
extra = extra.strip()
if flags.endswith('='):
flags = flags[:-1]
has_parm = 1
else:
has_parm = 0
g = re.search(r'\[([^\]]*)\]$', extra)
if g:
defval = g.group(1)
else:
defval = None
flagl = flags.split(',')
flagl_nice = []
for f in flagl:
f,dvi = _remove_negative_kv(f, _intify(defval))
self._aliases[f] = _remove_negative_k(flagl[0])
self._hasparms[f] = has_parm
self._defaults[f] = dvi
if len(f) == 1:
self._shortopts += f + (has_parm and ':' or '')
flagl_nice.append('-' + f)
else:
f_nice = re.sub(r'\W', '_', f)
self._aliases[f_nice] = _remove_negative_k(flagl[0])
self._longopts.append(f + (has_parm and '=' or ''))
self._longopts.append('no-' + f)
flagl_nice.append('--' + f)
flags_nice = ', '.join(flagl_nice)
if has_parm:
flags_nice += ' ...'
prefix = ' %-20s ' % flags_nice
argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
initial_indent=prefix,
subsequent_indent=' '*28))
out.append(argtext + '\n')
last_was_option = True
else:
out.append('\n')
last_was_option = False
return ''.join(out).rstrip() + '\n'
def usage(self, msg=""):
"""Print usage string to stderr and abort."""
sys.stderr.write(self._usagestr)
e = self._onabort and self._onabort(msg) or None
if e:
raise e
def fatal(self, s):
"""Print an error message to stderr and abort with usage string."""
msg = 'error: %s\n' % s
sys.stderr.write(msg)
return self.usage(msg)
def parse(self, args):
"""Parse a list of arguments and return (options, flags, extra).
In the returned tuple, "options" is an OptDict with known options,
"flags" is a list of option flags that were used on the command-line,
and "extra" is a list of positional arguments.
"""
try:
(flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
except getopt.GetoptError, e:
self.fatal(e)
opt = OptDict()
for k,v in self._defaults.iteritems():
k = self._aliases[k]
opt[k] = v
for (k,v) in flags:
k = k.lstrip('-')
if k in ('h', '?', 'help'):
self.usage()
if k.startswith('no-'):
k = self._aliases[k[3:]]
v = 0
else:
k = self._aliases[k]
if not self._hasparms[k]:
assert(v == '')
v = (opt._opts.get(k) or 0) + 1
else:
v = _intify(v)
opt[k] = v
for (f1,f2) in self._aliases.iteritems():
opt[f1] = opt._opts.get(f2)
return (opt,flags,extra)