view mercurial/pure/diffhelpers.py @ 20835:0e8417131a29

util: add the code path to "cachefunc()" for the function taking no arguments

Before this patch, "util.cachefunc()" caches the value returned by the
specified function into dictionary "cache", even if the specified
function takes no arguments.

In such case, "cache" has at most one entry, and distinction between
entries in "cache" is meaningless.

This patch adds the code path to "cachefunc()" for the function taking
no arguments for efficiency: to store only one cached value, using
list "cache" is a little faster than using dictionary "cache".

# diffhelpers.py - pure Python implementation of diffhelpers.c
#
# Copyright 2009 Matt Mackall <[e-mail]> 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