Mercurial > hg
view mercurial/pure/bdiff.py @ 47072:4c041c71ec01
revlog: introduce an explicit tracking of what the revlog is about
Since the dawn of time, people have been forced to rely to lossy introspection
of the index filename to determine what the purpose and role of the revlog they
encounter is. This is hacky, error prone, inflexible, abstraction-leaky,
<insert-your-own-complaints-here>.
In f63299ee7e4d Raphaël introduced a new attribute to track this information:
`revlog_kind`. However it is initialized in an odd place and various instances
end up not having it set. In addition is only tracking some of the information
we end up having to introspect in various pieces of code.
So we add a new attribute that holds more data and is more strictly enforced.
This work is done in collaboration with Raphaël.
The `revlog_kind` one will be removed/adapted in the next changeset. We expect
to be able to clean up various existing piece of code and to simplify coming
work around the newer revlog format.
Differential Revision: https://phab.mercurial-scm.org/D10352
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Tue, 06 Apr 2021 05:20:24 +0200 |
parents | d4ba4d51f85f |
children | 6000f5b25c9b |
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# bdiff.py - Python implementation of bdiff.c # # Copyright 2009 Olivia Mackall <olivia@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. from __future__ import absolute_import import difflib import re import struct def splitnewlines(text): '''like str.splitlines, but only split on newlines.''' lines = [l + b'\n' for l in text.split(b'\n')] if lines: if lines[-1] == b'\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 if prev is not None: r.append(prev) return r def bdiff(a, b): a = bytes(a).splitlines(True) b = bytes(b).splitlines(True) if not a: s = b"".join(b) return s and (struct.pack(b">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 = b"".join(b[lb:bm]) if am > la or s: bin.append(struct.pack(b">lll", p[la], p[am], len(s)) + s) la = am + size lb = bm + size return b"".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(b'[ \t\r]+', b'', text) else: text = re.sub(b'[ \t\r]+', b' ', text) text = text.replace(b' \n', b'\n') return text