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