view hgext/lfs/pointer.py @ 43026:0b87eb2fba67

copies: prepare changelog for more copies storage mode

We want to store copies information in sidedata, the logic will be quite similar
to the one used for extra, but sightly different (not in extra, no hash impact).

We start with small refactoring to make our work easier and the coming changesets
cleaners.

Differential Revision: https://phab.mercurial-scm.org/D6936

# pointer.py - Git-LFS pointer serialization
#
# Copyright 2017 Facebook, Inc.
#
# 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 re

from mercurial.i18n import _

from mercurial import (
    error,
    pycompat,
)
from mercurial.utils import (
    stringutil,
)

class InvalidPointer(error.StorageError):
    pass

class gitlfspointer(dict):
    VERSION = 'https://git-lfs.github.com/spec/v1'

    def __init__(self, *args, **kwargs):
        self['version'] = self.VERSION
        super(gitlfspointer, self).__init__(*args)
        self.update(pycompat.byteskwargs(kwargs))

    @classmethod
    def deserialize(cls, text):
        try:
            return cls(l.split(' ', 1) for l in text.splitlines()).validate()
        except ValueError: # l.split returns 1 item instead of 2
            raise InvalidPointer(_('cannot parse git-lfs text: %s')
                                 % stringutil.pprint(text))

    def serialize(self):
        sortkeyfunc = lambda x: (x[0] != 'version', x)
        items = sorted(self.validate().iteritems(), key=sortkeyfunc)
        return ''.join('%s %s\n' % (k, v) for k, v in items)

    def oid(self):
        return self['oid'].split(':')[-1]

    def size(self):
        return int(self['size'])

    # regular expressions used by _validate
    # see https://github.com/git-lfs/git-lfs/blob/master/docs/spec.md
    _keyre = re.compile(br'\A[a-z0-9.-]+\Z')
    _valuere = re.compile(br'\A[^\n]*\Z')
    _requiredre = {
        'size': re.compile(br'\A[0-9]+\Z'),
        'oid': re.compile(br'\Asha256:[0-9a-f]{64}\Z'),
        'version': re.compile(br'\A%s\Z' % stringutil.reescape(VERSION)),
    }

    def validate(self):
        """raise InvalidPointer on error. return self if there is no error"""
        requiredcount = 0
        for k, v in self.iteritems():
            if k in self._requiredre:
                if not self._requiredre[k].match(v):
                    raise InvalidPointer(
                        _('unexpected lfs pointer value: %s=%s')
                        % (k, stringutil.pprint(v)))
                requiredcount += 1
            elif not self._keyre.match(k):
                raise InvalidPointer(_('unexpected lfs pointer key: %s') % k)
            if not self._valuere.match(v):
                raise InvalidPointer(_('unexpected lfs pointer value: %s=%s')
                                     % (k, stringutil.pprint(v)))
        if len(self._requiredre) != requiredcount:
            miss = sorted(set(self._requiredre.keys()).difference(self.keys()))
            raise InvalidPointer(_('missing lfs pointer keys: %s')
                                 % ', '.join(miss))
        return self

deserialize = gitlfspointer.deserialize