Mercurial > hg
view mercurial/archival.py @ 44950:f9734b2d59cc
py3: make stdout line-buffered if connected to a TTY
Status messages that are to be shown on the terminal should be written to the
file descriptor before anything further is done, to keep the user updated.
One common way to achieve this is to make stdout line-buffered if it is
connected to a TTY. This is done on Python 2 (except on Windows, where libc,
which the CPython 2 streams depend on, does not properly support this).
Python 3 rolls it own I/O streams. On Python 3, buffered binary streams can't be
set line-buffered. The previous code (added in 227ba1afcb65) incorrectly
assumed that on Python 3, pycompat.stdout (sys.stdout.buffer) is already
line-buffered. However the interpreter initializes it with a block-buffered
stream or an unbuffered stream (when the -u option or the PYTHONUNBUFFERED
environment variable is set), never with a line-buffered stream.
One example where the current behavior is unacceptable is when running
`hg pull https://www.mercurial-scm.org/repo/hg` on Python 3, where the line
"pulling from https://www.mercurial-scm.org/repo/hg" does not appear on the
terminal before the hg process blocks while waiting for the server.
Various approaches to fix this problem are possible, including:
1. Weaken the contract of procutil.stdout to not give any guarantees about
buffering behavior. In this case, users of procutil.stdout need to be
changed to do enough flushes. In particular,
1. either ui must insert enough flushes for ui.write() and friends, or
2. ui.write() and friends get split into flushing and fully buffered
methods, or
3. users of ui.write() and friends must flush explicitly.
2. Make stdout unbuffered.
3. Make stdout line-buffered. Since Python 3 does not natively support that for
binary streams, we must implement it ourselves.
(2.) is problematic because using unbuffered I/O changes the performance
characteristics significantly compared to line-buffered (which is used on
Python 2) and this would be a regression.
(1.2.) and (1.3) are a substantial amount of work. It’s unclear whether the
added complexity would be justified, given that raw performance doesn’t matter
that much when writing to a terminal much faster than the user could read it.
(1.1.) pushes complexity into the ui class instead of separating the concern of
how stdout is buffered. Other users of procutil.stdout would still need to take
care of the flushes.
This patch implements (3.). The general performance considerations are very
similar to (1.1.). The extra method invocation and method forwarding add a
little more overhead if the class is used. In exchange, it doesn’t add overhead
if not used.
For the benchmarks, I compared the previous implementation (incorrect on Python
3), (1.1.), (3.) and (2.). The command was chosen so that the streams were
configured as if they were writing to a TTY, but actually write to a pager,
which is also the default:
HGRCPATH=/dev/null python3 ./hg --cwd ~/vcs/mozilla-central --time --pager yes --config pager.pager='cat > /dev/null' status --all
previous:
time: real 7.880 secs (user 7.290+0.050 sys 0.580+0.170)
time: real 7.830 secs (user 7.220+0.070 sys 0.590+0.140)
time: real 7.800 secs (user 7.210+0.050 sys 0.570+0.170)
(1.1.) using Yuya Nishihara’s patch:
time: real 9.860 secs (user 8.670+0.350 sys 1.160+0.830)
time: real 9.540 secs (user 8.430+0.370 sys 1.100+0.770)
time: real 9.830 secs (user 8.630+0.370 sys 1.180+0.840)
(3.) using this patch:
time: real 9.580 secs (user 8.480+0.350 sys 1.090+0.770)
time: real 9.670 secs (user 8.480+0.330 sys 1.170+0.860)
time: real 9.640 secs (user 8.500+0.350 sys 1.130+0.810)
(2.) using a previous patch by me:
time: real 10.480 secs (user 8.850+0.720 sys 1.590+1.500)
time: real 10.490 secs (user 8.750+0.750 sys 1.710+1.470)
time: real 10.240 secs (user 8.600+0.700 sys 1.590+1.510)
As expected, there’s no difference on Python 2, as exactly the same code paths
are used:
previous:
time: real 6.950 secs (user 5.870+0.330 sys 1.070+0.770)
time: real 7.040 secs (user 6.040+0.360 sys 0.980+0.750)
time: real 7.070 secs (user 5.950+0.360 sys 1.100+0.760)
this patch:
time: real 7.010 secs (user 5.900+0.390 sys 1.070+0.730)
time: real 7.000 secs (user 5.850+0.350 sys 1.120+0.760)
time: real 7.000 secs (user 5.790+0.380 sys 1.170+0.710)
author | Manuel Jacob <me@manueljacob.de> |
---|---|
date | Wed, 10 Jun 2020 13:02:39 +0200 |
parents | f8427841c8fc |
children | 2c0043977b6d a56ba57c837d |
line wrap: on
line source
# archival.py - revision archival for mercurial # # Copyright 2006 Vadim Gelfer <vadim.gelfer@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. from __future__ import absolute_import import gzip import os import struct import tarfile import time import zipfile import zlib from .i18n import _ from .node import nullrev from .pycompat import open from . import ( error, formatter, match as matchmod, pycompat, scmutil, util, vfs as vfsmod, ) stringio = util.stringio # from unzip source code: _UNX_IFREG = 0x8000 _UNX_IFLNK = 0xA000 def tidyprefix(dest, kind, prefix): '''choose prefix to use for names in archive. make sure prefix is safe for consumers.''' if prefix: prefix = util.normpath(prefix) else: if not isinstance(dest, bytes): raise ValueError(b'dest must be string if no prefix') prefix = os.path.basename(dest) lower = prefix.lower() for sfx in exts.get(kind, []): if lower.endswith(sfx): prefix = prefix[: -len(sfx)] break lpfx = os.path.normpath(util.localpath(prefix)) prefix = util.pconvert(lpfx) if not prefix.endswith(b'/'): prefix += b'/' # Drop the leading '.' path component if present, so Windows can read the # zip files (issue4634) if prefix.startswith(b'./'): prefix = prefix[2:] if prefix.startswith(b'../') or os.path.isabs(lpfx) or b'/../' in prefix: raise error.Abort(_(b'archive prefix contains illegal components')) return prefix exts = { b'tar': [b'.tar'], b'tbz2': [b'.tbz2', b'.tar.bz2'], b'tgz': [b'.tgz', b'.tar.gz'], b'zip': [b'.zip'], b'txz': [b'.txz', b'.tar.xz'], } def guesskind(dest): for kind, extensions in pycompat.iteritems(exts): if any(dest.endswith(ext) for ext in extensions): return kind return None def _rootctx(repo): # repo[0] may be hidden for rev in repo: return repo[rev] return repo[nullrev] # {tags} on ctx includes local tags and 'tip', with no current way to limit # that to global tags. Therefore, use {latesttag} as a substitute when # the distance is 0, since that will be the list of global tags on ctx. _defaultmetatemplate = br''' repo: {root} node: {ifcontains(rev, revset("wdir()"), "{p1node}{dirty}", "{node}")} branch: {branch|utf8} {ifeq(latesttagdistance, 0, join(latesttag % "tag: {tag}", "\n"), separate("\n", join(latesttag % "latesttag: {tag}", "\n"), "latesttagdistance: {latesttagdistance}", "changessincelatesttag: {changessincelatesttag}"))} '''[ 1: ] # drop leading '\n' def buildmetadata(ctx): '''build content of .hg_archival.txt''' repo = ctx.repo() opts = { b'template': repo.ui.config( b'experimental', b'archivemetatemplate', _defaultmetatemplate ) } out = util.stringio() fm = formatter.formatter(repo.ui, out, b'archive', opts) fm.startitem() fm.context(ctx=ctx) fm.data(root=_rootctx(repo).hex()) if ctx.rev() is None: dirty = b'' if ctx.dirty(missing=True): dirty = b'+' fm.data(dirty=dirty) fm.end() return out.getvalue() class tarit(object): '''write archive to tar file or stream. can write uncompressed, or compress with gzip or bzip2.''' if pycompat.ispy3: GzipFileWithTime = gzip.GzipFile # camelcase-required else: class GzipFileWithTime(gzip.GzipFile): def __init__(self, *args, **kw): timestamp = None if 'mtime' in kw: timestamp = kw.pop('mtime') if timestamp is None: self.timestamp = time.time() else: self.timestamp = timestamp gzip.GzipFile.__init__(self, *args, **kw) def _write_gzip_header(self): self.fileobj.write(b'\037\213') # magic header self.fileobj.write(b'\010') # compression method fname = self.name if fname and fname.endswith(b'.gz'): fname = fname[:-3] flags = 0 if fname: flags = gzip.FNAME # pytype: disable=module-attr self.fileobj.write(pycompat.bytechr(flags)) gzip.write32u( # pytype: disable=module-attr self.fileobj, int(self.timestamp) ) self.fileobj.write(b'\002') self.fileobj.write(b'\377') if fname: self.fileobj.write(fname + b'\000') def __init__(self, dest, mtime, kind=b''): self.mtime = mtime self.fileobj = None def taropen(mode, name=b'', fileobj=None): if kind == b'gz': mode = mode[0:1] if not fileobj: fileobj = open(name, mode + b'b') gzfileobj = self.GzipFileWithTime( name, pycompat.sysstr(mode + b'b'), zlib.Z_BEST_COMPRESSION, fileobj, mtime=mtime, ) self.fileobj = gzfileobj return tarfile.TarFile.taropen( # pytype: disable=attribute-error name, pycompat.sysstr(mode), gzfileobj ) else: return tarfile.open(name, pycompat.sysstr(mode + kind), fileobj) if isinstance(dest, bytes): self.z = taropen(b'w:', name=dest) else: self.z = taropen(b'w|', fileobj=dest) def addfile(self, name, mode, islink, data): name = pycompat.fsdecode(name) i = tarfile.TarInfo(name) i.mtime = self.mtime i.size = len(data) if islink: i.type = tarfile.SYMTYPE i.mode = 0o777 i.linkname = pycompat.fsdecode(data) data = None i.size = 0 else: i.mode = mode data = stringio(data) self.z.addfile(i, data) def done(self): self.z.close() if self.fileobj: self.fileobj.close() class zipit(object): '''write archive to zip file or stream. can write uncompressed, or compressed with deflate.''' def __init__(self, dest, mtime, compress=True): if isinstance(dest, bytes): dest = pycompat.fsdecode(dest) self.z = zipfile.ZipFile( dest, 'w', compress and zipfile.ZIP_DEFLATED or zipfile.ZIP_STORED ) # Python's zipfile module emits deprecation warnings if we try # to store files with a date before 1980. epoch = 315532800 # calendar.timegm((1980, 1, 1, 0, 0, 0, 1, 1, 0)) if mtime < epoch: mtime = epoch self.mtime = mtime self.date_time = time.gmtime(mtime)[:6] def addfile(self, name, mode, islink, data): i = zipfile.ZipInfo(pycompat.fsdecode(name), self.date_time) i.compress_type = self.z.compression # pytype: disable=attribute-error # unzip will not honor unix file modes unless file creator is # set to unix (id 3). i.create_system = 3 ftype = _UNX_IFREG if islink: mode = 0o777 ftype = _UNX_IFLNK i.external_attr = (mode | ftype) << 16 # add "extended-timestamp" extra block, because zip archives # without this will be extracted with unexpected timestamp, # if TZ is not configured as GMT i.extra += struct.pack( b'<hhBl', 0x5455, # block type: "extended-timestamp" 1 + 4, # size of this block 1, # "modification time is present" int(self.mtime), ) # last modification (UTC) self.z.writestr(i, data) def done(self): self.z.close() class fileit(object): '''write archive as files in directory.''' def __init__(self, name, mtime): self.basedir = name self.opener = vfsmod.vfs(self.basedir) self.mtime = mtime def addfile(self, name, mode, islink, data): if islink: self.opener.symlink(data, name) return f = self.opener(name, b"w", atomictemp=False) f.write(data) f.close() destfile = os.path.join(self.basedir, name) os.chmod(destfile, mode) if self.mtime is not None: os.utime(destfile, (self.mtime, self.mtime)) def done(self): pass archivers = { b'files': fileit, b'tar': tarit, b'tbz2': lambda name, mtime: tarit(name, mtime, b'bz2'), b'tgz': lambda name, mtime: tarit(name, mtime, b'gz'), b'txz': lambda name, mtime: tarit(name, mtime, b'xz'), b'uzip': lambda name, mtime: zipit(name, mtime, False), b'zip': zipit, } def archive( repo, dest, node, kind, decode=True, match=None, prefix=b'', mtime=None, subrepos=False, ): '''create archive of repo as it was at node. dest can be name of directory, name of archive file, or file object to write archive to. kind is type of archive to create. decode tells whether to put files through decode filters from hgrc. match is a matcher to filter names of files to write to archive. prefix is name of path to put before every archive member. mtime is the modified time, in seconds, or None to use the changeset time. subrepos tells whether to include subrepos. ''' if kind == b'txz' and not pycompat.ispy3: raise error.Abort(_(b'xz compression is only available in Python 3')) if kind == b'files': if prefix: raise error.Abort(_(b'cannot give prefix when archiving to files')) else: prefix = tidyprefix(dest, kind, prefix) def write(name, mode, islink, getdata): data = getdata() if decode: data = repo.wwritedata(name, data) archiver.addfile(prefix + name, mode, islink, data) if kind not in archivers: raise error.Abort(_(b"unknown archive type '%s'") % kind) ctx = repo[node] archiver = archivers[kind](dest, mtime or ctx.date()[0]) if not match: match = scmutil.matchall(repo) if repo.ui.configbool(b"ui", b"archivemeta"): name = b'.hg_archival.txt' if match(name): write(name, 0o644, False, lambda: buildmetadata(ctx)) files = list(ctx.manifest().walk(match)) total = len(files) if total: files.sort() scmutil.prefetchfiles( repo, [ctx.rev()], scmutil.matchfiles(repo, files) ) progress = repo.ui.makeprogress( _(b'archiving'), unit=_(b'files'), total=total ) progress.update(0) for f in files: ff = ctx.flags(f) write(f, b'x' in ff and 0o755 or 0o644, b'l' in ff, ctx[f].data) progress.increment(item=f) progress.complete() if subrepos: for subpath in sorted(ctx.substate): sub = ctx.workingsub(subpath) submatch = matchmod.subdirmatcher(subpath, match) subprefix = prefix + subpath + b'/' total += sub.archive(archiver, subprefix, submatch, decode) if total == 0: raise error.Abort(_(b'no files match the archive pattern')) archiver.done() return total