revlog: support writing generaldelta revlogs
With generaldelta switched on, deltas are always computed against the first
parent when adding revisions. This is done regardless of what revision the
incoming bundle, if any, is deltaed against.
The exact delta building strategy is subject to change, but this will not
affect compatibility.
Generaldelta is switched off by default.
# store.py - repository store handling for Mercurial
#
# Copyright 2008 Matt Mackall <mpm@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 i18n import _
import osutil, scmutil, util
import os, stat
_sha = util.sha1
# This avoids a collision between a file named foo and a dir named
# foo.i or foo.d
def encodedir(path):
'''
>>> encodedir('data/foo.i')
'data/foo.i'
>>> encodedir('data/foo.i/bla.i')
'data/foo.i.hg/bla.i'
>>> encodedir('data/foo.i.hg/bla.i')
'data/foo.i.hg.hg/bla.i'
'''
if not path.startswith('data/'):
return path
return (path
.replace(".hg/", ".hg.hg/")
.replace(".i/", ".i.hg/")
.replace(".d/", ".d.hg/"))
def decodedir(path):
'''
>>> decodedir('data/foo.i')
'data/foo.i'
>>> decodedir('data/foo.i.hg/bla.i')
'data/foo.i/bla.i'
>>> decodedir('data/foo.i.hg.hg/bla.i')
'data/foo.i.hg/bla.i'
'''
if not path.startswith('data/') or ".hg/" not in path:
return path
return (path
.replace(".d.hg/", ".d/")
.replace(".i.hg/", ".i/")
.replace(".hg.hg/", ".hg/"))
def _buildencodefun():
'''
>>> enc, dec = _buildencodefun()
>>> enc('nothing/special.txt')
'nothing/special.txt'
>>> dec('nothing/special.txt')
'nothing/special.txt'
>>> enc('HELLO')
'_h_e_l_l_o'
>>> dec('_h_e_l_l_o')
'HELLO'
>>> enc('hello:world?')
'hello~3aworld~3f'
>>> dec('hello~3aworld~3f')
'hello:world?'
>>> enc('the\x07quick\xADshot')
'the~07quick~adshot'
>>> dec('the~07quick~adshot')
'the\\x07quick\\xadshot'
'''
e = '_'
win_reserved = [ord(x) for x in '\\:*?"<>|']
cmap = dict([(chr(x), chr(x)) for x in xrange(127)])
for x in (range(32) + range(126, 256) + win_reserved):
cmap[chr(x)] = "~%02x" % x
for x in range(ord("A"), ord("Z")+1) + [ord(e)]:
cmap[chr(x)] = e + chr(x).lower()
dmap = {}
for k, v in cmap.iteritems():
dmap[v] = k
def decode(s):
i = 0
while i < len(s):
for l in xrange(1, 4):
try:
yield dmap[s[i:i + l]]
i += l
break
except KeyError:
pass
else:
raise KeyError
return (lambda s: "".join([cmap[c] for c in encodedir(s)]),
lambda s: decodedir("".join(list(decode(s)))))
encodefilename, decodefilename = _buildencodefun()
def _build_lower_encodefun():
'''
>>> f = _build_lower_encodefun()
>>> f('nothing/special.txt')
'nothing/special.txt'
>>> f('HELLO')
'hello'
>>> f('hello:world?')
'hello~3aworld~3f'
>>> f('the\x07quick\xADshot')
'the~07quick~adshot'
'''
win_reserved = [ord(x) for x in '\\:*?"<>|']
cmap = dict([(chr(x), chr(x)) for x in xrange(127)])
for x in (range(32) + range(126, 256) + win_reserved):
cmap[chr(x)] = "~%02x" % x
for x in range(ord("A"), ord("Z")+1):
cmap[chr(x)] = chr(x).lower()
return lambda s: "".join([cmap[c] for c in s])
lowerencode = _build_lower_encodefun()
_windows_reserved_filenames = '''con prn aux nul
com1 com2 com3 com4 com5 com6 com7 com8 com9
lpt1 lpt2 lpt3 lpt4 lpt5 lpt6 lpt7 lpt8 lpt9'''.split()
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.
path is assumed to be all lowercase.
>>> _auxencode('.foo/aux.txt/txt.aux/con/prn/nul/foo.', True)
'~2efoo/au~78.txt/txt.aux/co~6e/pr~6e/nu~6c/foo~2e'
>>> _auxencode('.com1com2/lpt9.lpt4.lpt1/conprn/foo.', False)
'.com1com2/lp~749.lpt4.lpt1/conprn/foo~2e'
>>> _auxencode('foo. ', True)
'foo.~20'
>>> _auxencode(' .foo', True)
'~20.foo'
'''
res = []
for n in path.split('/'):
if n:
base = n.split('.')[0]
if base and (base in _windows_reserved_filenames):
# encode third letter ('aux' -> 'au~78')
ec = "~%02x" % ord(n[2])
n = n[0:2] + ec + n[3:]
if n[-1] in '. ':
# encode last period or space ('foo...' -> 'foo..~2e')
n = n[:-1] + "~%02x" % ord(n[-1])
if dotencode and n[0] in '. ':
n = "~%02x" % ord(n[0]) + n[1:]
res.append(n)
return '/'.join(res)
MAX_PATH_LEN_IN_HGSTORE = 120
DIR_PREFIX_LEN = 8
_MAX_SHORTENED_DIRS_LEN = 8 * (DIR_PREFIX_LEN + 1) - 4
def _hybridencode(path, auxencode):
'''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 MAX_PATH_LEN_IN_HGSTORE, a
non-reversible hybrid hashing of the path is done instead.
This encoding uses up to DIR_PREFIX_LEN characters of all directory
levels of the lowerencoded path, but not more levels than can fit into
_MAX_SHORTENED_DIRS_LEN.
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 MAX_PATH_LEN_IN_HGSTORE 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.
'''
if not path.startswith('data/'):
return path
# escape directories ending with .i and .d
path = encodedir(path)
ndpath = path[len('data/'):]
res = 'data/' + auxencode(encodefilename(ndpath))
if len(res) > MAX_PATH_LEN_IN_HGSTORE:
digest = _sha(path).hexdigest()
aep = auxencode(lowerencode(ndpath))
_root, ext = os.path.splitext(aep)
parts = aep.split('/')
basename = parts[-1]
sdirs = []
for p in parts[:-1]:
d = p[:DIR_PREFIX_LEN]
if d[-1] in '. ':
# Windows can't access dirs ending in period or space
d = d[:-1] + '_'
t = '/'.join(sdirs) + '/' + d
if len(t) > _MAX_SHORTENED_DIRS_LEN:
break
sdirs.append(d)
dirs = '/'.join(sdirs)
if len(dirs) > 0:
dirs += '/'
res = 'dh/' + dirs + digest + ext
space_left = MAX_PATH_LEN_IN_HGSTORE - len(res)
if space_left > 0:
filler = basename[:space_left]
res = 'dh/' + dirs + filler + digest + ext
return res
def _calcmode(path):
try:
# files in .hg/ will be created using this mode
mode = os.stat(path).st_mode
# avoid some useless chmods
if (0777 & ~util.umask) == (0777 & mode):
mode = None
except OSError:
mode = None
return mode
_data = 'data 00manifest.d 00manifest.i 00changelog.d 00changelog.i'
class basicstore(object):
'''base class for local repository stores'''
def __init__(self, path, openertype):
self.path = path
self.createmode = _calcmode(path)
op = openertype(self.path)
op.createmode = self.createmode
self.opener = scmutil.filteropener(op, encodedir)
def join(self, f):
return self.path + '/' + encodedir(f)
def _walk(self, relpath, recurse):
'''yields (unencoded, encoded, size)'''
path = self.path
if relpath:
path += '/' + relpath
striplen = len(self.path) + 1
l = []
if os.path.isdir(path):
visit = [path]
while visit:
p = visit.pop()
for f, kind, st in osutil.listdir(p, stat=True):
fp = p + '/' + f
if kind == stat.S_IFREG and f[-2:] in ('.d', '.i'):
n = util.pconvert(fp[striplen:])
l.append((decodedir(n), n, st.st_size))
elif kind == stat.S_IFDIR and recurse:
visit.append(fp)
return sorted(l)
def datafiles(self):
return self._walk('data', True)
def walk(self):
'''yields (unencoded, encoded, size)'''
# yield data files first
for x in self.datafiles():
yield x
# yield manifest before changelog
for x in reversed(self._walk('', False)):
yield x
def copylist(self):
return ['requires'] + _data.split()
def write(self):
pass
class encodedstore(basicstore):
def __init__(self, path, openertype):
self.path = path + '/store'
self.createmode = _calcmode(self.path)
op = openertype(self.path)
op.createmode = self.createmode
self.opener = scmutil.filteropener(op, encodefilename)
def datafiles(self):
for a, b, size in self._walk('data', True):
try:
a = decodefilename(a)
except KeyError:
a = None
yield a, b, size
def join(self, f):
return self.path + '/' + encodefilename(f)
def copylist(self):
return (['requires', '00changelog.i'] +
['store/' + f for f in _data.split()])
class fncache(object):
# the filename used to be partially encoded
# hence the encodedir/decodedir dance
def __init__(self, opener):
self.opener = opener
self.entries = None
self._dirty = False
def _load(self):
'''fill the entries from the fncache file'''
self.entries = set()
self._dirty = False
try:
fp = self.opener('fncache', mode='rb')
except IOError:
# skip nonexistent file
return
for n, line in enumerate(fp):
if (len(line) < 2) or (line[-1] != '\n'):
t = _('invalid entry in fncache, line %s') % (n + 1)
raise util.Abort(t)
self.entries.add(decodedir(line[:-1]))
fp.close()
def rewrite(self, files):
fp = self.opener('fncache', mode='wb')
for p in files:
fp.write(encodedir(p) + '\n')
fp.close()
self.entries = set(files)
self._dirty = False
def write(self):
if not self._dirty:
return
fp = self.opener('fncache', mode='wb', atomictemp=True)
for p in self.entries:
fp.write(encodedir(p) + '\n')
fp.rename()
self._dirty = False
def add(self, fn):
if self.entries is None:
self._load()
if fn not in self.entries:
self._dirty = True
self.entries.add(fn)
def __contains__(self, fn):
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)
class _fncacheopener(scmutil.abstractopener):
def __init__(self, op, fnc, encode):
self.opener = op
self.fncache = fnc
self.encode = encode
def __call__(self, path, mode='r', *args, **kw):
if mode not in ('r', 'rb') and path.startswith('data/'):
self.fncache.add(path)
return self.opener(self.encode(path), mode, *args, **kw)
class fncachestore(basicstore):
def __init__(self, path, openertype, encode):
self.encode = encode
self.path = path + '/store'
self.createmode = _calcmode(self.path)
op = openertype(self.path)
op.createmode = self.createmode
fnc = fncache(op)
self.fncache = fnc
self.opener = _fncacheopener(op, fnc, encode)
def join(self, f):
return self.path + '/' + self.encode(f)
def datafiles(self):
rewrite = False
existing = []
spath = self.path
for f in self.fncache:
ef = self.encode(f)
try:
st = os.stat(spath + '/' + ef)
yield f, ef, st.st_size
existing.append(f)
except OSError:
# nonexistent entry
rewrite = True
if rewrite:
# rewrite fncache to remove nonexistent entries
# (may be caused by rollback / strip)
self.fncache.rewrite(existing)
def copylist(self):
d = ('data dh fncache'
' 00manifest.d 00manifest.i 00changelog.d 00changelog.i')
return (['requires', '00changelog.i'] +
['store/' + f for f in d.split()])
def write(self):
self.fncache.write()
def store(requirements, path, openertype):
if 'store' in requirements:
if 'fncache' in requirements:
auxencode = lambda f: _auxencode(f, 'dotencode' in requirements)
encode = lambda f: _hybridencode(f, auxencode)
return fncachestore(path, openertype, encode)
return encodedstore(path, openertype)
return basicstore(path, openertype)