~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2010-2011 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Unicode-compatible command-line splitter for all platforms.

The user-visible behaviour of this module is described in

configuring_bazaar.txt.

"""

from __future__ import absolute_import

import re

_whitespace_match = re.compile(u'\s', re.UNICODE).match

class _PushbackSequence(object):

    def __init__(self, orig):

        self._iter = iter(orig)

        self._pushback_buffer = []

    def next(self):

        if len(self._pushback_buffer) > 0:

            return self._pushback_buffer.pop()

        else:

            return self._iter.next()

    def pushback(self, char):

        self._pushback_buffer.append(char)

    def __iter__(self):

        return self

class _Whitespace(object):

    def process(self, next_char, context):

        if _whitespace_match(next_char):

            if len(context.token) > 0:

                return None

            else:

                return self

        elif next_char in context.allowed_quote_chars:

            context.quoted = True

            return _Quotes(next_char, self)

        elif next_char == u'\\':

            return _Backslash(self)

        else:

            context.token.append(next_char)

            return _Word()

class _Quotes(object):

    def __init__(self, quote_char, exit_state):

        self.quote_char = quote_char

        self.exit_state = exit_state

    def process(self, next_char, context):

        if next_char == u'\\':

            return _Backslash(self)

        elif next_char == self.quote_char:

            return self.exit_state

        else:

            context.token.append(next_char)

            return self

class _Backslash(object):

    # See http://msdn.microsoft.com/en-us/library/bb776391(VS.85).aspx

    def __init__(self, exit_state):

        self.exit_state = exit_state

        self.count = 1

    def process(self, next_char, context):

        if next_char == u'\\':

            self.count += 1

            return self

        elif next_char in context.allowed_quote_chars:

            # 2N backslashes followed by a quote are N backslashes

            context.token.append(u'\\' * (self.count/2))

            # 2N+1 backslashes follwed by a quote are N backslashes followed by

            # the quote which should not be processed as the start or end of

            # the quoted arg

            if self.count % 2 == 1:

                # odd number of \ escapes the quote

                context.token.append(next_char)

            else:

                # let exit_state handle next_char

                context.seq.pushback(next_char)

            self.count = 0

            return self.exit_state

        else:

            # N backslashes not followed by a quote are just N backslashes

            if self.count > 0:

                context.token.append(u'\\' * self.count)

                self.count = 0

            # let exit_state handle next_char

            context.seq.pushback(next_char)

            return self.exit_state

    def finish(self, context):

        if self.count > 0:

            context.token.append(u'\\' * self.count)

class _Word(object):

    def process(self, next_char, context):

        if _whitespace_match(next_char):

            return None

        elif next_char in context.allowed_quote_chars:

            return _Quotes(next_char, self)

        elif next_char == u'\\':

            return _Backslash(self)

        else:

            context.token.append(next_char)

            return self

class Splitter(object):

    def __init__(self, command_line, single_quotes_allowed):

        self.seq = _PushbackSequence(command_line)

        self.allowed_quote_chars = u'"'

        if single_quotes_allowed:

            self.allowed_quote_chars += u"'"

    def __iter__(self):

        return self

    def next(self):

        quoted, token = self._get_token()

        if token is None:

            raise StopIteration

        return quoted, token

    def _get_token(self):

        self.quoted = False

        self.token = []

        state = _Whitespace()

        for next_char in self.seq:

            state = state.process(next_char, self)

            if state is None:

                break

        if not state is None and not getattr(state, 'finish', None) is None:

            state.finish(self)

        result = u''.join(self.token)

        if not self.quoted and result == '':

            result = None

        return self.quoted, result

def split(unsplit, single_quotes_allowed=True):

    splitter = Splitter(unsplit, single_quotes_allowed=single_quotes_allowed)

    return [arg for quoted, arg in splitter]