view mercurial/archival.py @ 51492:2e8a88e5809f

branchcache: stop writing more branchcache file on disk than needed

Before this change, we were unconditionally writing a branchmap file for the
filter level passed to `update_disk`. This is actually counter productive if no
update were needed for this filter level. In many case, the branch cache for a
filter level is identical to its parent "subset" and it is better to simply
keep the subset update and reuse it every time instead of having to do identical
work for similar subset.

So we change the `update_disk` method to only write a file when that filter
level differ from its parent. This removes many cases where identical files were
written, requiring multiple boring update in the test suite.

The only notable changes is the change to `test-strip-branch-cache.t`, this
case was checking a scenario that no longer reproduce the bug as writing less
branchmap file result in less stalled cache on disk.

Strictly speaking, we could create a more convoluted scenario that create a
similar issue. However the next changeset would also cover that scenario so we
directly updated that test case to a "no longer buggy" state.

# archival.py - revision archival 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.


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,
)

from .utils import stringutil

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 exts.items():
        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:
    """write archive to tar file or stream.  can write uncompressed,
    or compress with gzip or bzip2."""

    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 = gzip.GzipFile(
                    name,
                    pycompat.sysstr(mode + b'b'),
                    zlib.Z_BEST_COMPRESSION,
                    fileobj,
                    mtime=mtime,
                )
                self.fileobj = gzfileobj
                return (
                    # taropen() wants Literal['a', 'r', 'w', 'x'] for the mode,
                    # but Literal[] is only available in 3.8+ without the
                    # typing_extensions backport.
                    # pytype: disable=wrong-arg-types
                    tarfile.TarFile.taropen(  # pytype: disable=attribute-error
                        name, pycompat.sysstr(mode), gzfileobj
                    )
                    # pytype: enable=wrong-arg-types
                )
            else:
                try:
                    return tarfile.open(
                        name, pycompat.sysstr(mode + kind), fileobj
                    )
                except tarfile.CompressionError as e:
                    raise error.Abort(stringutil.forcebytestr(e))

        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:
    """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:
    '''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'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