Mercurial > hg
view mercurial/diffhelper.py @ 39017:ef3d3a2f9aa5
changegroup: refactor delta parent code
We had recently abstracted the delta parent functions to
facilitate extracting code from cgpacker. Now that we're in
a better place, it is time to revisit the design.
Changegroup version 1 requires that the previous node be used as the
delta parent. Later versions allow any available node to be used
as the base.
In the case where an arbitrary parent can be used, the choice of
a delta parent is best left in the hands of the storage backend.
So it makes sense for the delta parent selection to be hidden
away in the storage layer. This means deferring the choice of the
delta parent selection function to as close to delta generation
time as possible.
This commit moves the delta selection logic to essentially just
before delta generation. However, because changegroup version 1
limits what we can do, we have retained the ability to force a
delta against the previous revision.
As part of this, I realized that the ellipsis parent function was
unused! That's because ellipsis mode always sends full revisions
and not deltas.
Differential Revision: https://phab.mercurial-scm.org/D4214
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 08 Aug 2018 20:17:48 -0700 |
parents | e7aa113b14f7 |
children | 57875cf423c9 |
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# diffhelper.py - helper routines for patch # # 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. from __future__ import absolute_import from .i18n import _ from . import ( error, pycompat, ) def addlines(fp, hunk, lena, lenb, a, b): """Read lines from fp into the hunk The hunk is parsed into two arrays, a and b. a gets the old state of the text, b gets the new state. The control char from the hunk is saved when inserting into a, but not b (for performance while deleting files.) """ while True: todoa = lena - len(a) todob = lenb - len(b) num = max(todoa, todob) if num == 0: break for i in pycompat.xrange(num): s = fp.readline() if not s: raise error.ParseError(_('incomplete hunk')) if s == "\\ No newline at end of file\n": fixnewline(hunk, a, b) continue if s == '\n' or s == '\r\n': # Some patches may be missing the control char # on empty lines. Supply a leading space. s = ' ' + s hunk.append(s) if s.startswith('+'): b.append(s[1:]) elif s.startswith('-'): a.append(s) else: b.append(s[1:]) a.append(s) def fixnewline(hunk, a, b): """Fix up the last lines of a and b when the patch has no newline at EOF""" l = hunk[-1] # tolerate CRLF in last line if l.endswith('\r\n'): hline = l[:-2] else: hline = l[:-1] if hline.startswith((' ', '+')): b[-1] = hline[1:] if hline.startswith((' ', '-')): a[-1] = hline hunk[-1] = hline def testhunk(a, b, bstart): """Compare the lines in a with the lines in b a is assumed to have a control char at the start of each line, this char is ignored in the compare. """ alen = len(a) blen = len(b) if alen > blen - bstart or bstart < 0: return False for i in pycompat.xrange(alen): if a[i][1:] != b[i + bstart]: return False return True