mercurial/pure/diffhelpers.py
author Martin Geisler <mg@aragost.com>
Mon, 23 Jul 2012 15:55:26 -0600
branchstable
changeset 17236 9fb8312dbdbd
parent 12387 4f8067c94729
child 27336 80214358ac88
permissions -rw-r--r--
encoding: add fast-path for ASCII uppercase. This copies the performance hack from encoding.lower (c481761033bd). The case-folding logic that kicks in on case-insensitive filesystems hits encoding.upper hard: with a repository with 75k files, the timings went from hg perfstatus ! wall 3.156000 comb 3.156250 user 1.625000 sys 1.531250 (best of 3) to hg perfstatus ! wall 2.390000 comb 2.390625 user 1.078125 sys 1.312500 (best of 5) This is a 24% decrease. For comparison, Mercurial 2.0 gives: hg perfstatus ! wall 2.172000 comb 2.171875 user 0.984375 sys 1.187500 (best of 5) so we're only 10% slower than before we added the extra case-folding logic. The same decrease is seen when executing 'hg status' as normal, where we go from: hg status --time time: real 4.322 secs (user 2.219+0.000 sys 2.094+0.000) to hg status --time time: real 3.307 secs (user 1.750+0.000 sys 1.547+0.000)

# diffhelpers.py - pure Python implementation of diffhelpers.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.

def addlines(fp, hunk, lena, lenb, a, b):
    while True:
        todoa = lena - len(a)
        todob = lenb - len(b)
        num = max(todoa, todob)
        if num == 0:
            break
        for i in xrange(num):
            s = fp.readline()
            c = s[0]
            if s == "\\ No newline at end of file\n":
                fix_newline(hunk, a, b)
                continue
            if c == "\n":
                # Some patches may be missing the control char
                # on empty lines. Supply a leading space.
                s = " \n"
            hunk.append(s)
            if c == "+":
                b.append(s[1:])
            elif c == "-":
                a.append(s)
            else:
                b.append(s[1:])
                a.append(s)
    return 0

def fix_newline(hunk, a, b):
    l = hunk[-1]
    # tolerate CRLF in last line
    if l.endswith('\r\n'):
        hline = l[:-2]
    else:
        hline = l[:-1]
    c = hline[0]

    if c in " +":
        b[-1] = hline[1:]
    if c in " -":
        a[-1] = hline
    hunk[-1] = hline
    return 0


def testhunk(a, b, bstart):
    alen = len(a)
    blen = len(b)
    if alen > blen - bstart:
        return -1
    for i in xrange(alen):
        if a[i][1:] != b[i + bstart]:
            return -1
    return 0