ref: dff1e3813fb0deb18ca790b7c28f6a1405720ff6
dir: /sys/lib/python/mercurial/store.py/
# store.py - repository store handling for Mercurial # # Copyright 2008 Matt Mackall <[email protected]> # # 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)