Mercurial > hg
view mercurial/pure/bdiff.py @ 26720:6c22a17faa18
destupdate: extract validation logic
One of the main goal of having consolidated destination function is to allow
extension to play with this logic. We extract sub logic to make is wrapping more
practical.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Thu, 15 Oct 2015 14:10:57 +0100 |
parents | eeac5e179243 |
children | c4e3ff497f89 |
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# bdiff.py - Python implementation of bdiff.c # # Copyright 2009 Matt Mackall <mpm@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import struct, difflib, re def splitnewlines(text): '''like str.splitlines, but only split on newlines.''' lines = [l + '\n' for l in text.split('\n')] if lines: if lines[-1] == '\n': lines.pop() else: lines[-1] = lines[-1][:-1] return lines def _normalizeblocks(a, b, blocks): prev = None r = [] for curr in blocks: if prev is None: prev = curr continue shift = 0 a1, b1, l1 = prev a1end = a1 + l1 b1end = b1 + l1 a2, b2, l2 = curr a2end = a2 + l2 b2end = b2 + l2 if a1end == a2: while (a1end + shift < a2end and a[a1end + shift] == b[b1end + shift]): shift += 1 elif b1end == b2: while (b1end + shift < b2end and a[a1end + shift] == b[b1end + shift]): shift += 1 r.append((a1, b1, l1 + shift)) prev = a2 + shift, b2 + shift, l2 - shift r.append(prev) return r def bdiff(a, b): a = str(a).splitlines(True) b = str(b).splitlines(True) if not a: s = "".join(b) return s and (struct.pack(">lll", 0, 0, len(s)) + s) bin = [] p = [0] for i in a: p.append(p[-1] + len(i)) d = difflib.SequenceMatcher(None, a, b).get_matching_blocks() d = _normalizeblocks(a, b, d) la = 0 lb = 0 for am, bm, size in d: s = "".join(b[lb:bm]) if am > la or s: bin.append(struct.pack(">lll", p[la], p[am], len(s)) + s) la = am + size lb = bm + size return "".join(bin) def blocks(a, b): an = splitnewlines(a) bn = splitnewlines(b) d = difflib.SequenceMatcher(None, an, bn).get_matching_blocks() d = _normalizeblocks(an, bn, d) return [(i, i + n, j, j + n) for (i, j, n) in d] def fixws(text, allws): if allws: text = re.sub('[ \t\r]+', '', text) else: text = re.sub('[ \t\r]+', ' ', text) text = text.replace(' \n', '\n') return text