# 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 __future__ import absolute_import

import errno

import hashlib

import os

import stat

from .i18n import _

from . import (

    error,

    node,

    policy,

    pycompat,

    util,

    vfs as vfsmod,

)

parsers = policy.importmod(r'parsers')

# 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(".hg/", ".hg.hg/")

            .replace(".i/", ".i.hg/")

            .replace(".d/", ".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 ".hg/" not in path:

        return path

    return (path

            .replace(".d.hg/", ".d/")

            .replace(".i.hg/", ".i/")

            .replace(".hg.hg/", ".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 = '_'

    xchr = pycompat.bytechr

    asciistr = list(map(xchr, range(127)))

    capitals = list(range(ord("A"), ord("Z") + 1))

    cmap = dict((x, x) for x in asciistr)

    for x in _reserved():

        cmap[xchr(x)] = "~%02x" % x

    for x in capitals + [ord(e)]:

        cmap[xchr(x)] = e + xchr(x).lower()

    dmap = {}

    for k, v in cmap.iteritems():

        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: ''.join([cmap[s[c:c + 1]]

                               for c in pycompat.xrange(len(s))]),

            lambda s: ''.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 = dict([(xchr(x), xchr(x)) for x in pycompat.xrange(127)])

    for x in _reserved():

        cmap[xchr(x)] = "~%02x" % x

    for x in range(ord("A"), ord("Z") + 1):

        cmap[xchr(x)] = xchr(x).lower()

    def lowerencode(s):

        return "".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 = ('aux', 'con', 'prn', 'nul') # length 3

_winres4 = ('com', '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 '. ':

            n = "~%02x" % ord(n[0:1]) + n[1:]

            path[i] = n

        else:

            l = n.find('.')

            if l == -1:

                l = len(n)

            if ((l == 3 and n[:3] in _winres3) or

                (l == 4 and n[3:4] <= '9' and n[3:4] >= '1'

                        and n[:3] in _winres4)):

                # encode third letter ('aux' -> 'au~78')

                ec = "~%02x" % ord(n[2:3])

                n = n[0:2] + ec + n[3:]

                path[i] = n

        if n[-1] in '. ':

            # encode last period or space ('foo...' -> 'foo..~2e')

            path[i] = n[:-1] + "~%02x" % ord(n[-1:])

    return path

_maxstorepathlen = 120

_dirprefixlen = 8

_maxshortdirslen = 8 * (_dirprefixlen + 1) - 4

def _hashencode(path, dotencode):

    digest = node.hex(hashlib.sha1(path).digest())

    le = lowerencode(path[5:]).split('/') # 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 '. ':

            # Windows can't access dirs ending in period or space

            d = d[:-1] + '_'

        if sdirslen == 0:

            t = len(d)

        else:

            t = sdirslen + 1 + len(d)

            if t > _maxshortdirslen:

                break

        sdirs.append(d)

        sdirslen = t

    dirs = '/'.join(sdirs)

    if len(dirs) > 0:

        dirs += '/'

    res = 'dh/' + dirs + digest + ext

    spaceleft = _maxstorepathlen - len(res)

    if spaceleft > 0:

        filler = basename[:spaceleft]

        res = '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('/')

    res = '/'.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('/')

    res = '/'.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 = ('narrowspec data meta 00manifest.d 00manifest.i'

         ' 00changelog.d 00changelog.i phaseroots obsstore')

def isrevlog(f, kind, st):

    return kind == stat.S_IFREG and f[-2:] in ('.i', '.d')

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 + '/' + encodedir(f)

    def _walk(self, relpath, recurse, filefilter=isrevlog):

        '''yields (unencoded, encoded, size)'''

        path = self.path

        if relpath:

            path += '/' + 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 + '/' + f

                    if filefilter(f, kind, st):

                        n = util.pconvert(fp[striplen:])

                        l.append((decodedir(n), n, st.st_size))

                    elif kind == stat.S_IFDIR and recurse:

                        visit.append(fp)

        l.sort()

        return l

    def datafiles(self, matcher=None):

        return self._walk('data', True) + self._walk('meta', True)

    def topfiles(self):

        # yield manifest before changelog

        return reversed(self._walk('', False))

    def walk(self, matcher=None):

        '''yields (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 ['requires'] + _data.split()

    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 = "/".join(("data", path))

        # file?

        if self.vfs.exists(path + ".i"):

            return True

        # dir?

        if not path.endswith("/"):

            path = path + "/"

        return self.vfs.exists(path)

class encodedstore(basicstore):

    def __init__(self, path, vfstype):

        vfs = vfstype(path + '/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 a, b, size in super(encodedstore, self).datafiles():

            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, vfs):

        self.vfs = vfs

        self.entries = None

        self._dirty = False

    def _load(self):

        '''fill the entries from the fncache file'''

        self._dirty = False

        try:

            fp = self.vfs('fncache', mode='rb')

        except IOError:

            # skip nonexistent file

            self.entries = set()

            return

        self.entries = set(decodedir(fp.read()).splitlines())

        if '' in self.entries:

            fp.seek(0)

            for n, line in enumerate(util.iterfile(fp)):

                if not line.rstrip('\n'):

                    t = _('invalid entry in fncache, line %d') % (n + 1)

                    raise error.Abort(t)

        fp.close()

    def write(self, tr):

        if self._dirty:

            assert self.entries is not None

            tr.addbackup('fncache')

            fp = self.vfs('fncache', mode='wb', atomictemp=True)

            if self.entries:

                fp.write(encodedir('\n'.join(self.entries) + '\n'))

            fp.close()

            self._dirty = False