changegroup: compute seen files as changesets are added (issue4750)
Before this patch, addchangegroup() would walk the changelog and compute
the set of seen files between applying changesets and applying
manifests. When cloning large repositories such as mozilla-central,
this consumed a non-trivial amount of time. On my MBP, this walk takes
~10s. On a dainty EC2 instance, this was measured to take ~125s! On the
latter machine, this delay was enough for the Mercurial server to
disconnect the client, thinking it had timed out, thus causing a clone
to abort.
This patch enables the changelog to compute the set of changed files as
new revisions are added. By doing so, we:
* avoid a potentially heavy computation between changelog and manifest
processing by spreading the computation across all changelog additions
* avoid extra reads from the changelog by operating on the data as it is
added
The downside of this is that the add revision callback does result in
extra I/O. Before, we would perform a flush (and subsequent read to
construct the full revision) when new delta chains were created. For
changelogs, this is typically every 2-4 revisions. Using the callback
guarantees there will be a flush after every added revision *and* an
open + read of the changelog to obtain the full revision in order to
read the added files. So, this increases the frequency of these
operations by the average chain length. In the future, the revlog
should be smart enough to know how to read revisions that haven't been
flushed yet, thus eliminating this extra I/O.
On my MBP, the total CPU times for an `hg unbundle` with a local
mozilla-central gzip bundle containing 251,934 changesets and 211,065
files did not have a statistically significant change with this patch,
holding steady around 360s. So, the increased revlog flushing did not
have an effect.
With this patch, there is no longer a visible pause between applying
changeset and manifest data. Before, it sure felt like Mercurial was
lethargic making this transition. Now, the transition is nearly
instantaneous, giving the impression that Mercurial is faster. Of course,
eliminating this pause means that the potential for network disconnect due
to channel inactivity during the changelog walk is eliminated as well.
And that is the impetus behind this change.
# win32mbcs.py -- MBCS filename support for Mercurial
#
# Copyright (c) 2008 Shun-ichi Goto <shunichi.goto@gmail.com>
#
# Version: 0.3
# Author: Shun-ichi Goto <shunichi.goto@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
'''allow the use of MBCS paths with problematic encodings
Some MBCS encodings are not good for some path operations (i.e.
splitting path, case conversion, etc.) with its encoded bytes. We call
such a encoding (i.e. shift_jis and big5) as "problematic encoding".
This extension can be used to fix the issue with those encodings by
wrapping some functions to convert to Unicode string before path
operation.
This extension is useful for:
- Japanese Windows users using shift_jis encoding.
- Chinese Windows users using big5 encoding.
- All users who use a repository with one of problematic encodings on
case-insensitive file system.
This extension is not needed for:
- Any user who use only ASCII chars in path.
- Any user who do not use any of problematic encodings.
Note that there are some limitations on using this extension:
- You should use single encoding in one repository.
- If the repository path ends with 0x5c, .hg/hgrc cannot be read.
- win32mbcs is not compatible with fixutf8 extension.
By default, win32mbcs uses encoding.encoding decided by Mercurial.
You can specify the encoding by config option::
[win32mbcs]
encoding = sjis
It is useful for the users who want to commit with UTF-8 log message.
'''
import os, sys
from mercurial.i18n import _
from mercurial import util, encoding
# Note for extension authors: ONLY specify testedwith = 'internal' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'internal'
_encoding = None # see extsetup
def decode(arg):
if isinstance(arg, str):
uarg = arg.decode(_encoding)
if arg == uarg.encode(_encoding):
return uarg
raise UnicodeError("Not local encoding")
elif isinstance(arg, tuple):
return tuple(map(decode, arg))
elif isinstance(arg, list):
return map(decode, arg)
elif isinstance(arg, dict):
for k, v in arg.items():
arg[k] = decode(v)
return arg
def encode(arg):
if isinstance(arg, unicode):
return arg.encode(_encoding)
elif isinstance(arg, tuple):
return tuple(map(encode, arg))
elif isinstance(arg, list):
return map(encode, arg)
elif isinstance(arg, dict):
for k, v in arg.items():
arg[k] = encode(v)
return arg
def appendsep(s):
# ensure the path ends with os.sep, appending it if necessary.
try:
us = decode(s)
except UnicodeError:
us = s
if us and us[-1] not in ':/\\':
s += os.sep
return s
def basewrapper(func, argtype, enc, dec, args, kwds):
# check check already converted, then call original
for arg in args:
if isinstance(arg, argtype):
return func(*args, **kwds)
try:
# convert string arguments, call func, then convert back the
# return value.
return enc(func(*dec(args), **dec(kwds)))
except UnicodeError:
raise util.Abort(_("[win32mbcs] filename conversion failed with"
" %s encoding\n") % (_encoding))
def wrapper(func, args, kwds):
return basewrapper(func, unicode, encode, decode, args, kwds)
def reversewrapper(func, args, kwds):
return basewrapper(func, str, decode, encode, args, kwds)
def wrapperforlistdir(func, args, kwds):
# Ensure 'path' argument ends with os.sep to avoids
# misinterpreting last 0x5c of MBCS 2nd byte as path separator.
if args:
args = list(args)
args[0] = appendsep(args[0])
if 'path' in kwds:
kwds['path'] = appendsep(kwds['path'])
return func(*args, **kwds)
def wrapname(name, wrapper):
module, name = name.rsplit('.', 1)
module = sys.modules[module]
func = getattr(module, name)
def f(*args, **kwds):
return wrapper(func, args, kwds)
try:
f.__name__ = func.__name__ # fails with Python 2.3
except Exception:
pass
setattr(module, name, f)
# List of functions to be wrapped.
# NOTE: os.path.dirname() and os.path.basename() are safe because
# they use result of os.path.split()
funcs = '''os.path.join os.path.split os.path.splitext
os.path.normpath os.makedirs
mercurial.util.endswithsep mercurial.util.splitpath mercurial.util.checkcase
mercurial.util.fspath mercurial.util.pconvert mercurial.util.normpath
mercurial.util.checkwinfilename mercurial.util.checkosfilename
mercurial.util.split'''
# These functions are required to be called with local encoded string
# because they expects argument is local encoded string and cause
# problem with unicode string.
rfuncs = '''mercurial.encoding.upper mercurial.encoding.lower'''
# List of Windows specific functions to be wrapped.
winfuncs = '''os.path.splitunc'''
# codec and alias names of sjis and big5 to be faked.
problematic_encodings = '''big5 big5-tw csbig5 big5hkscs big5-hkscs
hkscs cp932 932 ms932 mskanji ms-kanji shift_jis csshiftjis shiftjis
sjis s_jis shift_jis_2004 shiftjis2004 sjis_2004 sjis2004
shift_jisx0213 shiftjisx0213 sjisx0213 s_jisx0213 950 cp950 ms950 '''
def extsetup(ui):
# TODO: decide use of config section for this extension
if ((not os.path.supports_unicode_filenames) and
(sys.platform != 'cygwin')):
ui.warn(_("[win32mbcs] cannot activate on this platform.\n"))
return
# determine encoding for filename
global _encoding
_encoding = ui.config('win32mbcs', 'encoding', encoding.encoding)
# fake is only for relevant environment.
if _encoding.lower() in problematic_encodings.split():
for f in funcs.split():
wrapname(f, wrapper)
if os.name == 'nt':
for f in winfuncs.split():
wrapname(f, wrapper)
wrapname("mercurial.osutil.listdir", wrapperforlistdir)
# wrap functions to be called with local byte string arguments
for f in rfuncs.split():
wrapname(f, reversewrapper)
# Check sys.args manually instead of using ui.debug() because
# command line options is not yet applied when
# extensions.loadall() is called.
if '--debug' in sys.argv:
ui.write("[win32mbcs] activated with encoding: %s\n"
% _encoding)