revlogv2: introduce a very basic docket file
This is the first stone toward using a docket file in revlogv2. Right now the
docket is very basic and only store the version number (which is -also- stored
into the index file…) and the other files have fixed name. This new
implementation break transactionally… but they are no test checking
transactionally for revlogv2… So I take this as an opportunity to start small.
They are no usage of revlogv2 outside of tests anyway.
The docket keeps the `.i` naming used by previous version index to preserve a
unique entry point. We could decide to use a different name and look it up
first, or to fully rework this in a future "store" version. However that does
not seems necessary right now.
We will re-introduces transactionality (and associated testing…) in a later
changesets.
A long list of TODOs have been added to the relevant comment.
Differential Revision: https://phab.mercurial-scm.org/D10624
# store.py - repository store handling for Mercurial
#
# Copyright 2008 Olivia Mackall <olivia@selenic.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 errno
import functools
import os
import re
import stat
from .i18n import _
from .pycompat import getattr
from .node import hex
from . import (
changelog,
error,
manifest,
policy,
pycompat,
util,
vfs as vfsmod,
)
from .utils import hashutil
parsers = policy.importmod('parsers')
# how much bytes should be read from fncache in one read
# It is done to prevent loading large fncache files into memory
fncache_chunksize = 10 ** 6
def _matchtrackedpath(path, matcher):
"""parses a fncache entry and returns whether the entry is tracking a path
matched by matcher or not.
If matcher is None, returns True"""
if matcher is None:
return True
path = decodedir(path)
if path.startswith(b'data/'):
return matcher(path[len(b'data/') : -len(b'.i')])
elif path.startswith(b'meta/'):
return matcher.visitdir(path[len(b'meta/') : -len(b'/00manifest.i')])
raise error.ProgrammingError(b"cannot decode path %s" % path)
# This avoids a collision between a file named foo and a dir named
# foo.i or foo.d
def _encodedir(path):
"""
>>> _encodedir(b'data/foo.i')
'data/foo.i'
>>> _encodedir(b'data/foo.i/bla.i')
'data/foo.i.hg/bla.i'
>>> _encodedir(b'data/foo.i.hg/bla.i')
'data/foo.i.hg.hg/bla.i'
>>> _encodedir(b'data/foo.i\\ndata/foo.i/bla.i\\ndata/foo.i.hg/bla.i\\n')
'data/foo.i\\ndata/foo.i.hg/bla.i\\ndata/foo.i.hg.hg/bla.i\\n'
"""
return (
path.replace(b".hg/", b".hg.hg/")
.replace(b".i/", b".i.hg/")
.replace(b".d/", b".d.hg/")
)
encodedir = getattr(parsers, 'encodedir', _encodedir)
def decodedir(path):
"""
>>> decodedir(b'data/foo.i')
'data/foo.i'
>>> decodedir(b'data/foo.i.hg/bla.i')
'data/foo.i/bla.i'
>>> decodedir(b'data/foo.i.hg.hg/bla.i')
'data/foo.i.hg/bla.i'
"""
if b".hg/" not in path:
return path
return (
path.replace(b".d.hg/", b".d/")
.replace(b".i.hg/", b".i/")
.replace(b".hg.hg/", b".hg/")
)
def _reserved():
"""characters that are problematic for filesystems
* ascii escapes (0..31)
* ascii hi (126..255)
* windows specials
these characters will be escaped by encodefunctions
"""
winreserved = [ord(x) for x in u'\\:*?"<>|']
for x in range(32):
yield x
for x in range(126, 256):
yield x
for x in winreserved:
yield x
def _buildencodefun():
"""
>>> enc, dec = _buildencodefun()
>>> enc(b'nothing/special.txt')
'nothing/special.txt'
>>> dec(b'nothing/special.txt')
'nothing/special.txt'
>>> enc(b'HELLO')
'_h_e_l_l_o'
>>> dec(b'_h_e_l_l_o')
'HELLO'
>>> enc(b'hello:world?')
'hello~3aworld~3f'
>>> dec(b'hello~3aworld~3f')
'hello:world?'
>>> enc(b'the\\x07quick\\xADshot')
'the~07quick~adshot'
>>> dec(b'the~07quick~adshot')
'the\\x07quick\\xadshot'
"""
e = b'_'
xchr = pycompat.bytechr
asciistr = list(map(xchr, range(127)))
capitals = list(range(ord(b"A"), ord(b"Z") + 1))
cmap = {x: x for x in asciistr}
for x in _reserved():
cmap[xchr(x)] = b"~%02x" % x
for x in capitals + [ord(e)]:
cmap[xchr(x)] = e + xchr(x).lower()
dmap = {}
for k, v in pycompat.iteritems(cmap):
dmap[v] = k
def decode(s):
i = 0
while i < len(s):
for l in pycompat.xrange(1, 4):
try:
yield dmap[s[i : i + l]]
i += l
break
except KeyError:
pass
else:
raise KeyError
return (
lambda s: b''.join(
[cmap[s[c : c + 1]] for c in pycompat.xrange(len(s))]
),
lambda s: b''.join(list(decode(s))),
)
_encodefname, _decodefname = _buildencodefun()
def encodefilename(s):
"""
>>> encodefilename(b'foo.i/bar.d/bla.hg/hi:world?/HELLO')
'foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o'
"""
return _encodefname(encodedir(s))
def decodefilename(s):
"""
>>> decodefilename(b'foo.i.hg/bar.d.hg/bla.hg.hg/hi~3aworld~3f/_h_e_l_l_o')
'foo.i/bar.d/bla.hg/hi:world?/HELLO'
"""
return decodedir(_decodefname(s))
def _buildlowerencodefun():
"""
>>> f = _buildlowerencodefun()
>>> f(b'nothing/special.txt')
'nothing/special.txt'
>>> f(b'HELLO')
'hello'
>>> f(b'hello:world?')
'hello~3aworld~3f'
>>> f(b'the\\x07quick\\xADshot')
'the~07quick~adshot'
"""
xchr = pycompat.bytechr
cmap = {xchr(x): xchr(x) for x in pycompat.xrange(127)}
for x in _reserved():
cmap[xchr(x)] = b"~%02x" % x
for x in range(ord(b"A"), ord(b"Z") + 1):
cmap[xchr(x)] = xchr(x).lower()
def lowerencode(s):
return b"".join([cmap[c] for c in pycompat.iterbytestr(s)])
return lowerencode
lowerencode = getattr(parsers, 'lowerencode', None) or _buildlowerencodefun()
# Windows reserved names: con, prn, aux, nul, com1..com9, lpt1..lpt9
_winres3 = (b'aux', b'con', b'prn', b'nul') # length 3
_winres4 = (b'com', b'lpt') # length 4 (with trailing 1..9)
def _auxencode(path, dotencode):
"""
Encodes filenames containing names reserved by Windows or which end in
period or space. Does not touch other single reserved characters c.
Specifically, c in '\\:*?"<>|' or ord(c) <= 31 are *not* encoded here.
Additionally encodes space or period at the beginning, if dotencode is
True. Parameter path is assumed to be all lowercase.
A segment only needs encoding if a reserved name appears as a
basename (e.g. "aux", "aux.foo"). A directory or file named "foo.aux"
doesn't need encoding.
>>> s = b'.foo/aux.txt/txt.aux/con/prn/nul/foo.'
>>> _auxencode(s.split(b'/'), True)
['~2efoo', 'au~78.txt', 'txt.aux', 'co~6e', 'pr~6e', 'nu~6c', 'foo~2e']
>>> s = b'.com1com2/lpt9.lpt4.lpt1/conprn/com0/lpt0/foo.'
>>> _auxencode(s.split(b'/'), False)
['.com1com2', 'lp~749.lpt4.lpt1', 'conprn', 'com0', 'lpt0', 'foo~2e']
>>> _auxencode([b'foo. '], True)
['foo.~20']
>>> _auxencode([b' .foo'], True)
['~20.foo']
"""
for i, n in enumerate(path):
if not n:
continue
if dotencode and n[0] in b'. ':
n = b"~%02x" % ord(n[0:1]) + n[1:]
path[i] = n
else:
l = n.find(b'.')
if l == -1:
l = len(n)
if (l == 3 and n[:3] in _winres3) or (
l == 4
and n[3:4] <= b'9'
and n[3:4] >= b'1'
and n[:3] in _winres4
):
# encode third letter ('aux' -> 'au~78')
ec = b"~%02x" % ord(n[2:3])
n = n[0:2] + ec + n[3:]
path[i] = n
if n[-1] in b'. ':
# encode last period or space ('foo...' -> 'foo..~2e')
path[i] = n[:-1] + b"~%02x" % ord(n[-1:])
return path
_maxstorepathlen = 120
_dirprefixlen = 8
_maxshortdirslen = 8 * (_dirprefixlen + 1) - 4
def _hashencode(path, dotencode):
digest = hex(hashutil.sha1(path).digest())
le = lowerencode(path[5:]).split(b'/') # skips prefix 'data/' or 'meta/'
parts = _auxencode(le, dotencode)
basename = parts[-1]
_root, ext = os.path.splitext(basename)
sdirs = []
sdirslen = 0
for p in parts[:-1]:
d = p[:_dirprefixlen]
if d[-1] in b'. ':
# Windows can't access dirs ending in period or space
d = d[:-1] + b'_'
if sdirslen == 0:
t = len(d)
else:
t = sdirslen + 1 + len(d)
if t > _maxshortdirslen:
break
sdirs.append(d)
sdirslen = t
dirs = b'/'.join(sdirs)
if len(dirs) > 0:
dirs += b'/'
res = b'dh/' + dirs + digest + ext
spaceleft = _maxstorepathlen - len(res)
if spaceleft > 0:
filler = basename[:spaceleft]
res = b'dh/' + dirs + filler + digest + ext
return res
def _hybridencode(path, dotencode):
"""encodes path with a length limit
Encodes all paths that begin with 'data/', according to the following.
Default encoding (reversible):
Encodes all uppercase letters 'X' as '_x'. All reserved or illegal
characters are encoded as '~xx', where xx is the two digit hex code
of the character (see encodefilename).
Relevant path components consisting of Windows reserved filenames are
masked by encoding the third character ('aux' -> 'au~78', see _auxencode).
Hashed encoding (not reversible):
If the default-encoded path is longer than _maxstorepathlen, a
non-reversible hybrid hashing of the path is done instead.
This encoding uses up to _dirprefixlen characters of all directory
levels of the lowerencoded path, but not more levels than can fit into
_maxshortdirslen.
Then follows the filler followed by the sha digest of the full path.
The filler is the beginning of the basename of the lowerencoded path
(the basename is everything after the last path separator). The filler
is as long as possible, filling in characters from the basename until
the encoded path has _maxstorepathlen characters (or all chars of the
basename have been taken).
The extension (e.g. '.i' or '.d') is preserved.
The string 'data/' at the beginning is replaced with 'dh/', if the hashed
encoding was used.
"""
path = encodedir(path)
ef = _encodefname(path).split(b'/')
res = b'/'.join(_auxencode(ef, dotencode))
if len(res) > _maxstorepathlen:
res = _hashencode(path, dotencode)
return res
def _pathencode(path):
de = encodedir(path)
if len(path) > _maxstorepathlen:
return _hashencode(de, True)
ef = _encodefname(de).split(b'/')
res = b'/'.join(_auxencode(ef, True))
if len(res) > _maxstorepathlen:
return _hashencode(de, True)
return res
_pathencode = getattr(parsers, 'pathencode', _pathencode)
def _plainhybridencode(f):
return _hybridencode(f, False)
def _calcmode(vfs):
try:
# files in .hg/ will be created using this mode
mode = vfs.stat().st_mode
# avoid some useless chmods
if (0o777 & ~util.umask) == (0o777 & mode):
mode = None
except OSError:
mode = None
return mode
_data = [
b'bookmarks',
b'narrowspec',
b'data',
b'meta',
b'00manifest.d',
b'00manifest.i',
b'00changelog.d',
b'00changelog.i',
b'phaseroots',
b'obsstore',
b'requires',
]
REVLOG_FILES_MAIN_EXT = (b'.i', b'i.tmpcensored')
REVLOG_FILES_OTHER_EXT = (b'.idx', b'.d', b'.n', b'.nd', b'd.tmpcensored')
# files that are "volatile" and might change between listing and streaming
#
# note: the ".nd" file are nodemap data and won't "change" but they might be
# deleted.
REVLOG_FILES_VOLATILE_EXT = (b'.n', b'.nd')
# some exception to the above matching
EXCLUDED = re.compile(b'.*undo\.[^/]+\.(nd?|i)$')
def is_revlog(f, kind, st):
if kind != stat.S_IFREG:
return None
return revlog_type(f)
def revlog_type(f):
if f.endswith(REVLOG_FILES_MAIN_EXT) and EXCLUDED.match(f) is None:
return FILEFLAGS_REVLOG_MAIN
elif f.endswith(REVLOG_FILES_OTHER_EXT) and EXCLUDED.match(f) is None:
t = FILETYPE_FILELOG_OTHER
if f.endswith(REVLOG_FILES_VOLATILE_EXT):
t |= FILEFLAGS_VOLATILE
return t
# the file is part of changelog data
FILEFLAGS_CHANGELOG = 1 << 13
# the file is part of manifest data
FILEFLAGS_MANIFESTLOG = 1 << 12
# the file is part of filelog data
FILEFLAGS_FILELOG = 1 << 11
# file that are not directly part of a revlog
FILEFLAGS_OTHER = 1 << 10
# the main entry point for a revlog
FILEFLAGS_REVLOG_MAIN = 1 << 1
# a secondary file for a revlog
FILEFLAGS_REVLOG_OTHER = 1 << 0
# files that are "volatile" and might change between listing and streaming
FILEFLAGS_VOLATILE = 1 << 20
FILETYPE_CHANGELOG_MAIN = FILEFLAGS_CHANGELOG | FILEFLAGS_REVLOG_MAIN
FILETYPE_CHANGELOG_OTHER = FILEFLAGS_CHANGELOG | FILEFLAGS_REVLOG_OTHER
FILETYPE_MANIFESTLOG_MAIN = FILEFLAGS_MANIFESTLOG | FILEFLAGS_REVLOG_MAIN
FILETYPE_MANIFESTLOG_OTHER = FILEFLAGS_MANIFESTLOG | FILEFLAGS_REVLOG_OTHER
FILETYPE_FILELOG_MAIN = FILEFLAGS_FILELOG | FILEFLAGS_REVLOG_MAIN
FILETYPE_FILELOG_OTHER = FILEFLAGS_FILELOG | FILEFLAGS_REVLOG_OTHER
FILETYPE_OTHER = FILEFLAGS_OTHER
class basicstore(object):
'''base class for local repository stores'''
def __init__(self, path, vfstype):
vfs = vfstype(path)
self.path = vfs.base
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
self.vfs = vfsmod.filtervfs(vfs, encodedir)
self.opener = self.vfs
def join(self, f):
return self.path + b'/' + encodedir(f)
def _walk(self, relpath, recurse):
'''yields (unencoded, encoded, size)'''
path = self.path
if relpath:
path += b'/' + relpath
striplen = len(self.path) + 1
l = []
if self.rawvfs.isdir(path):
visit = [path]
readdir = self.rawvfs.readdir
while visit:
p = visit.pop()
for f, kind, st in readdir(p, stat=True):
fp = p + b'/' + f
rl_type = is_revlog(f, kind, st)
if rl_type is not None:
n = util.pconvert(fp[striplen:])
l.append((rl_type, decodedir(n), n, st.st_size))
elif kind == stat.S_IFDIR and recurse:
visit.append(fp)
l.sort()
return l
def changelog(self, trypending, concurrencychecker=None):
return changelog.changelog(
self.vfs,
trypending=trypending,
concurrencychecker=concurrencychecker,
)
def manifestlog(self, repo, storenarrowmatch):
rootstore = manifest.manifestrevlog(repo.nodeconstants, self.vfs)
return manifest.manifestlog(self.vfs, repo, rootstore, storenarrowmatch)
def datafiles(self, matcher=None):
files = self._walk(b'data', True) + self._walk(b'meta', True)
for (t, u, e, s) in files:
yield (FILEFLAGS_FILELOG | t, u, e, s)
def topfiles(self):
# yield manifest before changelog
files = reversed(self._walk(b'', False))
for (t, u, e, s) in files:
if u.startswith(b'00changelog'):
yield (FILEFLAGS_CHANGELOG | t, u, e, s)
elif u.startswith(b'00manifest'):
yield (FILEFLAGS_MANIFESTLOG | t, u, e, s)
else:
yield (FILETYPE_OTHER | t, u, e, s)
def walk(self, matcher=None):
"""return file related to data storage (ie: revlogs)
yields (file_type, unencoded, encoded, size)
if a matcher is passed, storage files of only those tracked paths
are passed with matches the matcher
"""
# yield data files first
for x in self.datafiles(matcher):
yield x
for x in self.topfiles():
yield x
def copylist(self):
return _data
def write(self, tr):
pass
def invalidatecaches(self):
pass
def markremoved(self, fn):
pass
def __contains__(self, path):
'''Checks if the store contains path'''
path = b"/".join((b"data", path))
# file?
if self.vfs.exists(path + b".i"):
return True
# dir?
if not path.endswith(b"/"):
path = path + b"/"
return self.vfs.exists(path)
class encodedstore(basicstore):
def __init__(self, path, vfstype):
vfs = vfstype(path + b'/store')
self.path = vfs.base
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
self.vfs = vfsmod.filtervfs(vfs, encodefilename)
self.opener = self.vfs
def datafiles(self, matcher=None):
for t, a, b, size in super(encodedstore, self).datafiles():
try:
a = decodefilename(a)
except KeyError:
a = None
if a is not None and not _matchtrackedpath(a, matcher):
continue
yield t, a, b, size
def join(self, f):
return self.path + b'/' + encodefilename(f)
def copylist(self):
return [b'requires', b'00changelog.i'] + [b'store/' + f for f in _data]
class fncache(object):
# the filename used to be partially encoded
# hence the encodedir/decodedir dance
def __init__(self, vfs):
self.vfs = vfs
self.entries = None
self._dirty = False
# set of new additions to fncache
self.addls = set()
def ensureloaded(self, warn=None):
"""read the fncache file if not already read.
If the file on disk is corrupted, raise. If warn is provided,
warn and keep going instead."""
if self.entries is None:
self._load(warn)
def _load(self, warn=None):
'''fill the entries from the fncache file'''
self._dirty = False
try:
fp = self.vfs(b'fncache', mode=b'rb')
except IOError:
# skip nonexistent file
self.entries = set()
return
self.entries = set()
chunk = b''
for c in iter(functools.partial(fp.read, fncache_chunksize), b''):
chunk += c
try:
p = chunk.rindex(b'\n')
self.entries.update(decodedir(chunk[: p + 1]).splitlines())
chunk = chunk[p + 1 :]
except ValueError:
# substring '\n' not found, maybe the entry is bigger than the
# chunksize, so let's keep iterating
pass
if chunk:
msg = _(b"fncache does not ends with a newline")
if warn:
warn(msg + b'\n')
else:
raise error.Abort(
msg,
hint=_(
b"use 'hg debugrebuildfncache' to "
b"rebuild the fncache"
),
)
self._checkentries(fp, warn)
fp.close()
def _checkentries(self, fp, warn):
"""make sure there is no empty string in entries"""
if b'' in self.entries:
fp.seek(0)
for n, line in enumerate(util.iterfile(fp)):
if not line.rstrip(b'\n'):
t = _(b'invalid entry in fncache, line %d') % (n + 1)
if warn:
warn(t + b'\n')
else:
raise error.Abort(t)
def write(self, tr):
if self._dirty:
assert self.entries is not None
self.entries = self.entries | self.addls
self.addls = set()
tr.addbackup(b'fncache')
fp = self.vfs(b'fncache', mode=b'wb', atomictemp=True)
if self.entries:
fp.write(encodedir(b'\n'.join(self.entries) + b'\n'))
fp.close()
self._dirty = False
if self.addls:
# if we have just new entries, let's append them to the fncache
tr.addbackup(b'fncache')
fp = self.vfs(b'fncache', mode=b'ab', atomictemp=True)
if self.addls:
fp.write(encodedir(b'\n'.join(self.addls) + b'\n'))
fp.close()
self.entries = None
self.addls = set()
def add(self, fn):
if self.entries is None:
self._load()
if fn not in self.entries:
self.addls.add(fn)
def remove(self, fn):
if self.entries is None:
self._load()
if fn in self.addls:
self.addls.remove(fn)
return
try:
self.entries.remove(fn)
self._dirty = True
except KeyError:
pass
def __contains__(self, fn):
if fn in self.addls:
return True
if self.entries is None:
self._load()
return fn in self.entries
def __iter__(self):
if self.entries is None:
self._load()
return iter(self.entries | self.addls)
class _fncachevfs(vfsmod.proxyvfs):
def __init__(self, vfs, fnc, encode):
vfsmod.proxyvfs.__init__(self, vfs)
self.fncache = fnc
self.encode = encode
def __call__(self, path, mode=b'r', *args, **kw):
encoded = self.encode(path)
if mode not in (b'r', b'rb') and (
path.startswith(b'data/') or path.startswith(b'meta/')
):
# do not trigger a fncache load when adding a file that already is
# known to exist.
notload = self.fncache.entries is None and self.vfs.exists(encoded)
if notload and b'r+' in mode and not self.vfs.stat(encoded).st_size:
# when appending to an existing file, if the file has size zero,
# it should be considered as missing. Such zero-size files are
# the result of truncation when a transaction is aborted.
notload = False
if not notload:
self.fncache.add(path)
return self.vfs(encoded, mode, *args, **kw)
def join(self, path):
if path:
return self.vfs.join(self.encode(path))
else:
return self.vfs.join(path)
class fncachestore(basicstore):
def __init__(self, path, vfstype, dotencode):
if dotencode:
encode = _pathencode
else:
encode = _plainhybridencode
self.encode = encode
vfs = vfstype(path + b'/store')
self.path = vfs.base
self.pathsep = self.path + b'/'
self.createmode = _calcmode(vfs)
vfs.createmode = self.createmode
self.rawvfs = vfs
fnc = fncache(vfs)
self.fncache = fnc
self.vfs = _fncachevfs(vfs, fnc, encode)
self.opener = self.vfs
def join(self, f):
return self.pathsep + self.encode(f)
def getsize(self, path):
return self.rawvfs.stat(path).st_size
def datafiles(self, matcher=None):
for f in sorted(self.fncache):
if not _matchtrackedpath(f, matcher):
continue
ef = self.encode(f)
try:
t = revlog_type(f)
t |= FILEFLAGS_FILELOG
yield t, f, ef, self.getsize(ef)
except OSError as err:
if err.errno != errno.ENOENT:
raise
def copylist(self):
d = (
b'bookmarks',
b'narrowspec',
b'data',
b'meta',
b'dh',
b'fncache',
b'phaseroots',
b'obsstore',
b'00manifest.d',
b'00manifest.i',
b'00changelog.d',
b'00changelog.i',
b'requires',
)
return [b'requires', b'00changelog.i'] + [b'store/' + f for f in d]
def write(self, tr):
self.fncache.write(tr)
def invalidatecaches(self):
self.fncache.entries = None
self.fncache.addls = set()
def markremoved(self, fn):
self.fncache.remove(fn)
def _exists(self, f):
ef = self.encode(f)
try:
self.getsize(ef)
return True
except OSError as err:
if err.errno != errno.ENOENT:
raise
# nonexistent entry
return False
def __contains__(self, path):
'''Checks if the store contains path'''
path = b"/".join((b"data", path))
# check for files (exact match)
e = path + b'.i'
if e in self.fncache and self._exists(e):
return True
# now check for directories (prefix match)
if not path.endswith(b'/'):
path += b'/'
for e in self.fncache:
if e.startswith(path) and self._exists(e):
return True
return False