copies: document how 'copies' dict instances are reused
We avoid copying these instances as much as we can, so it's not
obvious what's safe to do with them. This patch tries to explain what
is safe and what is not.
Differential Revision: https://phab.mercurial-scm.org/D6578
# 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