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bzrlib/cmdline.py
 
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# Copyright (C) 2010 Canonical Ltd
 
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#
 
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# This program is free software; you can redistribute it and/or modify
 
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# it under the terms of the GNU General Public License as published by
 
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# the Free Software Foundation; either version 2 of the License, or
 
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# (at your option) any later version.
 
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#
 
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# This program is distributed in the hope that it will be useful,
 
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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# GNU General Public License for more details.
 
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#
 
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# You should have received a copy of the GNU General Public License
 
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# along with this program; if not, write to the Free Software
 
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 
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"""Unicode-compatible command-line splitter for all platforms."""
 
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import re
 
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_whitespace_match = re.compile(u'\s', re.UNICODE).match
 
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class _PushbackSequence(object):
 
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    def __init__(self, orig):
 
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        self._iter = iter(orig)
 
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        self._pushback_buffer = []
 
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    def next(self):
 
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        if len(self._pushback_buffer) > 0:
 
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            return self._pushback_buffer.pop()
 
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        else:
 
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            return self._iter.next()
 
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    def pushback(self, char):
 
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        self._pushback_buffer.append(char)
 
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    def __iter__(self):
 
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        return self
 
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class _Whitespace(object):
 
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    def process(self, next_char, context):
 
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        if _whitespace_match(next_char):
 
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            if len(context.token) > 0:
 
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                return None
 
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            else:
 
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                return self
 
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        elif next_char in context.allowed_quote_chars:
 
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            context.quoted = True
 
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            return _Quotes(next_char, self)
 
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        elif next_char == u'\\':
 
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            return _Backslash(self)
 
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        else:
 
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            context.token.append(next_char)
 
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            return _Word()
 
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class _Quotes(object):
 
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    def __init__(self, quote_char, exit_state):
 
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        self.quote_char = quote_char
 
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        self.exit_state = exit_state
 
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    def process(self, next_char, context):
 
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        if next_char == u'\\':
 
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            return _Backslash(self)
 
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        elif next_char == self.quote_char:
 
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            return self.exit_state
 
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        else:
 
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            context.token.append(next_char)
 
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            return self
 
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class _Backslash(object):
 
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    # See http://msdn.microsoft.com/en-us/library/bb776391(VS.85).aspx
 
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    def __init__(self, exit_state):
 
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        self.exit_state = exit_state
 
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        self.count = 1
 
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    def process(self, next_char, context):
 
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        if next_char == u'\\':
 
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            self.count += 1
 
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            return self
 
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        elif next_char in context.allowed_quote_chars:
 
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            # 2N backslashes followed by a quote are N backslashes
 
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            context.token.append(u'\\' * (self.count/2))
 
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            # 2N+1 backslashes follwed by a quote are N backslashes followed by
 
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            # the quote which should not be processed as the start or end of
 
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            # the quoted arg
 
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            if self.count % 2 == 1:
 
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                # odd number of \ escapes the quote
 
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                context.token.append(next_char)
 
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            else:
 
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                # let exit_state handle next_char
 
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                context.seq.pushback(next_char)
 
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            self.count = 0
 
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            return self.exit_state
 
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        else:
 
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            # N backslashes not followed by a quote are just N backslashes
 
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            if self.count > 0:
 
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                context.token.append(u'\\' * self.count)
 
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                self.count = 0
 
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            # let exit_state handle next_char
 
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            context.seq.pushback(next_char)
 
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            return self.exit_state
 
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    def finish(self, context):
 
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        if self.count > 0:
 
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            context.token.append(u'\\' * self.count)
 
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class _Word(object):
 
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    def process(self, next_char, context):
 
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        if _whitespace_match(next_char):
 
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            return None
 
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        elif next_char in context.allowed_quote_chars:
 
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            return _Quotes(next_char, self)
 
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        elif next_char == u'\\':
 
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            return _Backslash(self)
 
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        else:
 
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            context.token.append(next_char)
 
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            return self
 
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class Splitter(object):
 
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    def __init__(self, command_line, single_quotes_allowed):
 
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        self.seq = _PushbackSequence(command_line)
 
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        self.allowed_quote_chars = u'"'
 
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        if single_quotes_allowed:
 
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            self.allowed_quote_chars += u"'"
 
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    def __iter__(self):
 
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        return self
 
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    def next(self):
 
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        quoted, token = self._get_token()
 
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        if token is None:
 
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            raise StopIteration
 
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        return quoted, token
 
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    def _get_token(self):
 
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        self.quoted = False
 
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        self.token = []
 
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        state = _Whitespace()
 
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        for next_char in self.seq:
 
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            state = state.process(next_char, self)
 
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            if state is None:
 
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                break
 
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        if not state is None and not getattr(state, 'finish', None) is None:
 
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            state.finish(self)
 
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        result = u''.join(self.token)
 
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        if not self.quoted and result == '':
 
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            result = None
 
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        return self.quoted, result
 
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def split(unsplit, single_quotes_allowed=True):
 
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    splitter = Splitter(unsplit, single_quotes_allowed=single_quotes_allowed)
 
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    return [arg for quoted, arg in splitter]