ref: ef17043327d999101009f85aae72f77399db15ac
dir: /sys/src/cmd/hg/mercurial/store.py/
# 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, incorporated herein by reference.
from i18n import _
import osutil, 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):
if not path.startswith('data/'):
return path
return (path
.replace(".hg/", ".hg.hg/")
.replace(".i/", ".i.hg/")
.replace(".d/", ".d.hg/"))
def decodedir(path):
if not path.startswith('data/'):
return path
return (path
.replace(".d.hg/", ".d/")
.replace(".i.hg/", ".i/")
.replace(".hg.hg/", ".hg/"))
def _buildencodefun():
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():
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):
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])
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):
'''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, opener, pathjoiner):
self.pathjoiner = pathjoiner
self.path = path
self.createmode = _calcmode(path)
op = opener(self.path)
op.createmode = self.createmode
self.opener = lambda f, *args, **kw: op(encodedir(f), *args, **kw)
def join(self, f):
return self.pathjoiner(self.path, encodedir(f))
def _walk(self, relpath, recurse):
'''yields (unencoded, encoded, size)'''
path = self.pathjoiner(self.path, relpath)
striplen = len(self.path) + len(os.sep)
l = []
if os.path.isdir(path):
visit = [path]
while visit:
p = visit.pop()
for f, kind, st in osutil.listdir(p, stat=True):
fp = self.pathjoiner(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()
class encodedstore(basicstore):
def __init__(self, path, opener, pathjoiner):
self.pathjoiner = pathjoiner
self.path = self.pathjoiner(path, 'store')
self.createmode = _calcmode(self.path)
op = opener(self.path)
op.createmode = self.createmode
self.opener = lambda f, *args, **kw: op(encodefilename(f), *args, **kw)
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.pathjoiner(self.path, encodefilename(f))
def copylist(self):
return (['requires', '00changelog.i'] +
[self.pathjoiner('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
def _load(self):
'''fill the entries from the fncache file'''
self.entries = set()
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)
def add(self, fn):
if self.entries is None:
self._load()
self.opener('fncache', 'ab').write(encodedir(fn) + '\n')
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 fncachestore(basicstore):
def __init__(self, path, opener, pathjoiner):
self.pathjoiner = pathjoiner
self.path = self.pathjoiner(path, 'store')
self.createmode = _calcmode(self.path)
op = opener(self.path)
op.createmode = self.createmode
fnc = fncache(op)
self.fncache = fnc
def fncacheopener(path, mode='r', *args, **kw):
if (mode not in ('r', 'rb')
and path.startswith('data/')
and path not in fnc):
fnc.add(path)
return op(hybridencode(path), mode, *args, **kw)
self.opener = fncacheopener
def join(self, f):
return self.pathjoiner(self.path, hybridencode(f))
def datafiles(self):
rewrite = False
existing = []
pjoin = self.pathjoiner
spath = self.path
for f in self.fncache:
ef = hybridencode(f)
try:
st = os.stat(pjoin(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'
return (['requires', '00changelog.i'] +
[self.pathjoiner('store', f) for f in d.split()])
def store(requirements, path, opener, pathjoiner=None):
pathjoiner = pathjoiner or os.path.join
if 'store' in requirements:
if 'fncache' in requirements:
return fncachestore(path, opener, pathjoiner)
return encodedstore(path, opener, pathjoiner)
return basicstore(path, opener, pathjoiner)