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Implemented reprocess for weave

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bzrlib/textmerge.py
 
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# Copyright (C) 2005, 2006 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
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#
 
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# Author: Martin Pool <mbp@canonical.com> 
 
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#         Aaron Bentley <aaron.bentley@utoronto.ca>
 
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from difflib import SequenceMatcher
 
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class TextMerge(object):
 
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    """Base class for text-mergers
 
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    Subclasses must implement _merge_struct.
 
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    """
 
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    def __init__(self, a_marker='<<<<<<< \n', b_marker='>>>>>>> \n',
 
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                 split_marker='=======\n'):
 
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        self.a_marker = a_marker
 
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        self.b_marker = b_marker
 
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        self.split_marker = split_marker
 
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    def struct_to_lines(self, struct_iter):
 
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        """Convert merge result tuples to lines"""
 
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        for lines in struct_iter:
 
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            if len(lines) == 1:
 
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                for line in lines[0]:
 
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                    yield line
 
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            else:
 
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                yield self.a_marker
 
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                for line in lines[0]: 
 
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                    yield line
 
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                yield self.split_marker
 
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                for line in lines[1]: 
 
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                    yield line
 
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                yield self.b_marker
 
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    def iter_useful(self, struct_iter):
 
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        """Iterate through input tuples, skipping empty ones."""
 
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        for group in struct_iter:
 
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            if len(group[0]) > 0:
 
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                yield group
 
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            elif len(group) > 1 and len(group[1]) > 0:
 
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                yield group
 
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    def merge_lines(self, reprocess=False):
 
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        return self.struct_to_lines(self.merge_struct(reprocess))
 
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    def merge_struct(self, reprocess=False):
 
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        struct_iter = self.iter_useful(self._merge_struct())
 
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        if reprocess is True:
 
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            return self.reprocess_struct(struct_iter)
 
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        else:
 
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            return struct_iter
 
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    @staticmethod
 
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    def reprocess_struct(struct_iter):
 
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        for group in struct_iter:
 
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            if len(group) == 1:
 
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                yield group
 
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            else:
 
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                for newgroup in Merge2(group[0], group[1]).merge_struct():
 
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                    yield newgroup
 
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class Merge2(TextMerge):
 
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    """
 
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    Two-way merge.
 
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    In a two way merge, common regions are shown as unconflicting, and uncommon
 
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    regions produce conflicts.
 
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    """
 
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    def __init__(self, lines_a, lines_b, a_marker='<<<<<<< \n', 
 
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                 b_marker='>>>>>>> \n', split_marker='=======\n'):
 
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        TextMerge.__init__(self, a_marker, b_marker, split_marker)
 
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        self.lines_a = lines_a
 
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        self.lines_b = lines_b
 
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    def _merge_struct(self):
 
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        sm = SequenceMatcher(None, self.lines_a, self.lines_b)
 
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        pos_a = 0
 
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        pos_b = 0
 
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        for ai, bi, l in sm.get_matching_blocks():
 
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            # non-matching lines
 
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            yield(self.lines_a[pos_a:ai], self.lines_b[pos_b:bi])
 
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            # matching lines
 
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            yield(self.lines_a[ai:ai+l],)
 
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            pos_a = ai + l 
 
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            pos_b = bi + l
 
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        # final non-matching lines
 
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        yield(self.lines_a[pos_a:-1], self.lines_b[pos_b:-1])