mercurial/strutil.py

bundle2: only emit compressed chunks if they have data

This is similar to 58467204cac0. Not all calls into the compressor
return compressed data, as the compressor may buffer compressed
output internally. It is cheaper to check for empty chunks than to
send empty chunks through the generator.

When generating a gzip-v2 bundle of the mozilla-unified repo, this
change results in 50,093 empty chunks not being sent through the
generator (out of 1,902,996 total input chunks).

# strutil.py - string utilities for Mercurial
#
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# 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

def findall(haystack, needle, start=0, end=None):
    if end is None:
        end = len(haystack)
    if end < 0:
        end += len(haystack)
    if start < 0:
        start += len(haystack)
    while start < end:
        c = haystack.find(needle, start, end)
        if c == -1:
            break
        yield c
        start = c + 1

def rfindall(haystack, needle, start=0, end=None):
    if end is None:
        end = len(haystack)
    if end < 0:
        end += len(haystack)
    if start < 0:
        start += len(haystack)
    while end >= 0:
        c = haystack.rfind(needle, start, end)
        if c == -1:
            break
        yield c
        end = c - 1