# Copyright (C) 2005-2010 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 from __future__ import absolute_import # mbp: "you know that thing where cvs gives you conflict markers?" # s: "i hate that." from bzrlib import ( errors, patiencediff, textfile, ) def intersect(ra, rb): """Given two ranges return the range where they intersect or None. >>> intersect((0, 10), (0, 6)) (0, 6) >>> intersect((0, 10), (5, 15)) (5, 10) >>> intersect((0, 10), (10, 15)) >>> intersect((0, 9), (10, 15)) >>> intersect((0, 9), (7, 15)) (7, 9) """ # preconditions: (ra[0] <= ra[1]) and (rb[0] <= rb[1]) sa = max(ra[0], rb[0]) sb = min(ra[1], rb[1]) if sa < sb: return sa, sb else: return None def compare_range(a, astart, aend, b, bstart, bend): """Compare a[astart:aend] == b[bstart:bend], without slicing. """ if (aend-astart) != (bend-bstart): return False for ia, ib in zip(xrange(astart, aend), xrange(bstart, bend)): if a[ia] != b[ib]: return False else: return True class Merge3(object): """3-way merge of texts. Given BASE, OTHER, THIS, tries to produce a combined text incorporating the changes from both BASE->OTHER and BASE->THIS. All three will typically be sequences of lines.""" def __init__(self, base, a, b, is_cherrypick=False, allow_objects=False): """Constructor. :param base: lines in BASE :param a: lines in A :param b: lines in B :param is_cherrypick: flag indicating if this merge is a cherrypick. When cherrypicking b => a, matches with b and base do not conflict. :param allow_objects: if True, do not require that base, a and b are plain Python strs. Also prevents BinaryFile from being raised. Lines can be any sequence of comparable and hashable Python objects. """ if not allow_objects: textfile.check_text_lines(base) textfile.check_text_lines(a) textfile.check_text_lines(b) self.base = base self.a = a self.b = b self.is_cherrypick = is_cherrypick def merge_lines(self, name_a=None, name_b=None, name_base=None, start_marker='<<<<<<<', mid_marker='=======', end_marker='>>>>>>>', base_marker=None, reprocess=False): """Return merge in cvs-like form. """ newline = '\n' if len(self.a) > 0: if self.a[0].endswith('\r\n'): newline = '\r\n' elif self.a[0].endswith('\r'): newline = '\r' if base_marker and reprocess: raise errors.CantReprocessAndShowBase() if name_a: start_marker = start_marker + ' ' + name_a if name_b: end_marker = end_marker + ' ' + name_b if name_base and base_marker: base_marker = base_marker + ' ' + name_base merge_regions = self.merge_regions() if reprocess is True: merge_regions = self.reprocess_merge_regions(merge_regions) for t in merge_regions: what = t[0] if what == 'unchanged': for i in range(t[1], t[2]): yield self.base[i] elif what == 'a' or what == 'same': for i in range(t[1], t[2]): yield self.a[i] elif what == 'b': for i in range(t[1], t[2]): yield self.b[i] elif what == 'conflict': yield start_marker + newline for i in range(t[3], t[4]): yield self.a[i] if base_marker is not None: yield base_marker + newline for i in range(t[1], t[2]): yield self.base[i] yield mid_marker + newline for i in range(t[5], t[6]): yield self.b[i] yield end_marker + newline else: raise ValueError(what) def merge_annotated(self): """Return merge with conflicts, showing origin of lines. Most useful for debugging merge. """ for t in self.merge_regions(): what = t[0] if what == 'unchanged': for i in range(t[1], t[2]): yield 'u | ' + self.base[i] elif what == 'a' or what == 'same': for i in range(t[1], t[2]): yield what[0] + ' | ' + self.a[i] elif what == 'b': for i in range(t[1], t[2]): yield 'b | ' + self.b[i] elif what == 'conflict': yield '<<<<\n' for i in range(t[3], t[4]): yield 'A | ' + self.a[i] yield '----\n' for i in range(t[5], t[6]): yield 'B | ' + self.b[i] yield '>>>>\n' else: raise ValueError(what) def merge_groups(self): """Yield sequence of line groups. Each one is a tuple: 'unchanged', lines Lines unchanged from base 'a', lines Lines taken from a 'same', lines Lines taken from a (and equal to b) 'b', lines Lines taken from b 'conflict', base_lines, a_lines, b_lines Lines from base were changed to either a or b and conflict. """ for t in self.merge_regions(): what = t[0] if what == 'unchanged': yield what, self.base[t[1]:t[2]] elif what == 'a' or what == 'same': yield what, self.a[t[1]:t[2]] elif what == 'b': yield what, self.b[t[1]:t[2]] elif what == 'conflict': yield (what, self.base[t[1]:t[2]], self.a[t[3]:t[4]], self.b[t[5]:t[6]]) else: raise ValueError(what) def merge_regions(self): """Return sequences of matching and conflicting regions. This returns tuples, where the first value says what kind we have: 'unchanged', start, end Take a region of base[start:end] 'same', astart, aend b and a are different from base but give the same result 'a', start, end Non-clashing insertion from a[start:end] Method is as follows: The two sequences align only on regions which match the base and both descendents. These are found by doing a two-way diff of each one against the base, and then finding the intersections between those regions. These "sync regions" are by definition unchanged in both and easily dealt with. The regions in between can be in any of three cases: conflicted, or changed on only one side. """ # section a[0:ia] has been disposed of, etc iz = ia = ib = 0 for zmatch, zend, amatch, aend, bmatch, bend in self.find_sync_regions(): matchlen = zend - zmatch # invariants: # matchlen >= 0 # matchlen == (aend - amatch) # matchlen == (bend - bmatch) len_a = amatch - ia len_b = bmatch - ib len_base = zmatch - iz # invariants: # assert len_a >= 0 # assert len_b >= 0 # assert len_base >= 0 #print 'unmatched a=%d, b=%d' % (len_a, len_b) if len_a or len_b: # try to avoid actually slicing the lists same = compare_range(self.a, ia, amatch, self.b, ib, bmatch) if same: yield 'same', ia, amatch else: equal_a = compare_range(self.a, ia, amatch, self.base, iz, zmatch) equal_b = compare_range(self.b, ib, bmatch, self.base, iz, zmatch) if equal_a and not equal_b: yield 'b', ib, bmatch elif equal_b and not equal_a: yield 'a', ia, amatch elif not equal_a and not equal_b: if self.is_cherrypick: for node in self._refine_cherrypick_conflict( iz, zmatch, ia, amatch, ib, bmatch): yield node else: yield 'conflict', iz, zmatch, ia, amatch, ib, bmatch else: raise AssertionError("can't handle a=b=base but unmatched") ia = amatch ib = bmatch iz = zmatch # if the same part of the base was deleted on both sides # that's OK, we can just skip it. if matchlen > 0: # invariants: # assert ia == amatch # assert ib == bmatch # assert iz == zmatch yield 'unchanged', zmatch, zend iz = zend ia = aend ib = bend def _refine_cherrypick_conflict(self, zstart, zend, astart, aend, bstart, bend): """When cherrypicking b => a, ignore matches with b and base.""" # Do not emit regions which match, only regions which do not match matches = patiencediff.PatienceSequenceMatcher(None, self.base[zstart:zend], self.b[bstart:bend]).get_matching_blocks() last_base_idx = 0 last_b_idx = 0 last_b_idx = 0 yielded_a = False for base_idx, b_idx, match_len in matches: conflict_z_len = base_idx - last_base_idx conflict_b_len = b_idx - last_b_idx if conflict_b_len == 0: # There are no lines in b which conflict, # so skip it pass else: if yielded_a: yield ('conflict', zstart + last_base_idx, zstart + base_idx, aend, aend, bstart + last_b_idx, bstart + b_idx) else: # The first conflict gets the a-range yielded_a = True yield ('conflict', zstart + last_base_idx, zstart + base_idx, astart, aend, bstart + last_b_idx, bstart + b_idx) last_base_idx = base_idx + match_len last_b_idx = b_idx + match_len if last_base_idx != zend - zstart or last_b_idx != bend - bstart: if yielded_a: yield ('conflict', zstart + last_base_idx, zstart + base_idx, aend, aend, bstart + last_b_idx, bstart + b_idx) else: # The first conflict gets the a-range yielded_a = True yield ('conflict', zstart + last_base_idx, zstart + base_idx, astart, aend, bstart + last_b_idx, bstart + b_idx) if not yielded_a: yield ('conflict', zstart, zend, astart, aend, bstart, bend) def reprocess_merge_regions(self, merge_regions): """Where there are conflict regions, remove the agreed lines. Lines where both A and B have made the same changes are eliminated. """ for region in merge_regions: if region[0] != "conflict": yield region continue type, iz, zmatch, ia, amatch, ib, bmatch = region a_region = self.a[ia:amatch] b_region = self.b[ib:bmatch] matches = patiencediff.PatienceSequenceMatcher( None, a_region, b_region).get_matching_blocks() next_a = ia next_b = ib for region_ia, region_ib, region_len in matches[:-1]: region_ia += ia region_ib += ib reg = self.mismatch_region(next_a, region_ia, next_b, region_ib) if reg is not None: yield reg yield 'same', region_ia, region_len+region_ia next_a = region_ia + region_len next_b = region_ib + region_len reg = self.mismatch_region(next_a, amatch, next_b, bmatch) if reg is not None: yield reg @staticmethod def mismatch_region(next_a, region_ia, next_b, region_ib): if next_a < region_ia or next_b < region_ib: return 'conflict', None, None, next_a, region_ia, next_b, region_ib def find_sync_regions(self): """Return a list of sync regions, where both descendents match the base. Generates a list of (base1, base2, a1, a2, b1, b2). There is always a zero-length sync region at the end of all the files. """ ia = ib = 0 amatches = patiencediff.PatienceSequenceMatcher( None, self.base, self.a).get_matching_blocks() bmatches = patiencediff.PatienceSequenceMatcher( None, self.base, self.b).get_matching_blocks() len_a = len(amatches) len_b = len(bmatches) sl = [] while ia < len_a and ib < len_b: abase, amatch, alen = amatches[ia] bbase, bmatch, blen = bmatches[ib] # there is an unconflicted block at i; how long does it # extend? until whichever one ends earlier. i = intersect((abase, abase+alen), (bbase, bbase+blen)) if i: intbase = i[0] intend = i[1] intlen = intend - intbase # found a match of base[i[0], i[1]]; this may be less than # the region that matches in either one # assert intlen <= alen # assert intlen <= blen # assert abase <= intbase # assert bbase <= intbase asub = amatch + (intbase - abase) bsub = bmatch + (intbase - bbase) aend = asub + intlen bend = bsub + intlen # assert self.base[intbase:intend] == self.a[asub:aend], \ # (self.base[intbase:intend], self.a[asub:aend]) # assert self.base[intbase:intend] == self.b[bsub:bend] sl.append((intbase, intend, asub, aend, bsub, bend)) # advance whichever one ends first in the base text if (abase + alen) < (bbase + blen): ia += 1 else: ib += 1 intbase = len(self.base) abase = len(self.a) bbase = len(self.b) sl.append((intbase, intbase, abase, abase, bbase, bbase)) return sl def find_unconflicted(self): """Return a list of ranges in base that are not conflicted.""" am = patiencediff.PatienceSequenceMatcher( None, self.base, self.a).get_matching_blocks() bm = patiencediff.PatienceSequenceMatcher( None, self.base, self.b).get_matching_blocks() unc = [] while am and bm: # there is an unconflicted block at i; how long does it # extend? until whichever one ends earlier. a1 = am[0][0] a2 = a1 + am[0][2] b1 = bm[0][0] b2 = b1 + bm[0][2] i = intersect((a1, a2), (b1, b2)) if i: unc.append(i) if a2 < b2: del am[0] else: del bm[0] return unc def main(argv): # as for diff3 and meld the syntax is "MINE BASE OTHER" a = file(argv[1], 'rt').readlines() base = file(argv[2], 'rt').readlines() b = file(argv[3], 'rt').readlines() m3 = Merge3(base, a, b) #for sr in m3.find_sync_regions(): # print sr # sys.stdout.writelines(m3.merge_lines(name_a=argv[1], name_b=argv[3])) sys.stdout.writelines(m3.merge_annotated()) if __name__ == '__main__': import sys sys.exit(main(sys.argv))