# Can be raised for empty repositories

            return []

        return so.splitlines()

    def _get_all_revisions2(self):

        # alternate implementation using dulwich

        includes = [ascii_str(sha) for key, (sha, type_) in self._parsed_refs.iteritems()

                    if type_ != b'T']

        return [c.commit.id for c in self._repo.get_walker(include=includes)]

    def _get_revision(self, revision):

        """

        Given any revision identifier, returns a 40 char string with revision hash.

        """

        if self._empty:

            raise EmptyRepositoryError("There are no changesets yet")

        if revision in (None, '', 'tip', 'HEAD', 'head', -1):

            revision = -1

        if isinstance(revision, int):

            try:

                return self.revisions[revision]

            except IndexError:

                raise ChangesetDoesNotExistError(msg)

        if isinstance(revision, (str, unicode)):

            if revision.isdigit() and (len(revision) < 12 or len(revision) == revision.count('0')):

                try:

                    return self.revisions[int(revision)]

                except IndexError:

                    msg = "Revision %r does not exist for %s" % (revision, self)

                    raise ChangesetDoesNotExistError(msg)

            # get by branch/tag name

            _ref_revision = self._parsed_refs.get(revision)

            if _ref_revision:  # and _ref_revision[1] in [b'H', b'RH', b'T']:

                return ascii_str(_ref_revision[0])

            if revision in self.revisions:

                return revision

            # maybe it's a tag ? we don't have them in self.revisions

            if revision in self.tags.values():

                return revision

            if SHA_PATTERN.match(revision):

                raise ChangesetDoesNotExistError(msg)

        raise ChangesetDoesNotExistError("Given revision %r not recognized" % revision)

    def get_ref_revision(self, ref_type, ref_name):

        """

        Returns ``GitChangeset`` object representing repository's

        changeset at the given ``revision``.

        """

        return self._get_revision(ref_name)

    def _get_archives(self, archive_name='tip'):

        for i in [('zip', '.zip'), ('gz', '.tar.gz'), ('bz2', '.tar.bz2')]:

            yield {"type": i[0], "extension": i[1], "node": archive_name}

    def _get_url(self, url):

        """

        Returns normalized url. If schema is not given, would fall to

        filesystem (``file:///``) schema.

        """

        url = safe_str(url)

        if url != 'default' and '://' not in url:

            url = ':///'.join(('file', url))

        """

        Function will check for mercurial repository in given path and return

        a localrepo object. If there is no repository in that path it will

        raise an exception unless ``create`` parameter is set to True - in

        that case repository would be created and returned.

        If ``src_url`` is given, would try to clone repository from the

        location at given clone_point. Additionally it'll make update to

        working copy accordingly to ``update_after_clone`` flag

        """

        try:

            if src_url:

                url = safe_bytes(self._get_url(src_url))

                opts = {}

                if not update_after_clone:

                    opts.update({'noupdate': True})

                MercurialRepository._check_url(url, self.baseui)

                mercurial.commands.clone(self.baseui, url, self.path, **opts)

                # Don't try to create if we've already cloned repo

                create = False

            return mercurial.localrepo.instance(self.baseui, self.path, create=create)

        except (mercurial.error.Abort, mercurial.error.RepoError) as err:

            if create:

                msg = "Cannot create repository at %s. Original error was %s" \

            else:

                msg = "Not valid repository at %s. Original error was %s" \

            raise RepositoryError(msg)

    @LazyProperty

    def in_memory_changeset(self):

        return MercurialInMemoryChangeset(self)

    @LazyProperty

    def description(self):

        _desc = self._repo.ui.config(b'web', b'description', None, untrusted=True)

        return safe_unicode(_desc or b'unknown')

    @LazyProperty

    def contact(self):

        return safe_unicode(mercurial.hgweb.common.get_contact(self._repo.ui.config)

                            or b'Unknown')

    @LazyProperty

    def last_change(self):

        """

        Returns last change made on this repository as datetime object

        """

        return date_fromtimestamp(self._get_mtime(), makedate()[1])

    def _get_mtime(self):

            if os.path.exists(cl_path):

                return os.stat(cl_path).st_mtime

            else:

                return os.stat(st_path).st_mtime

    def _get_revision(self, revision):

        """

        Given any revision identifier, returns a 40 char string with revision hash.

        :param revision: str or int or None

        """

        if self._empty:

            raise EmptyRepositoryError("There are no changesets yet")

        if revision in [-1, None]:

            revision = b'tip'

        elif isinstance(revision, unicode):

            revision = safe_bytes(revision)

        try:

            if isinstance(revision, int):

                return ascii_str(self._repo[revision].hex())

            return ascii_str(mercurial.scmutil.revsymbol(self._repo, revision).hex())

        except (IndexError, ValueError, mercurial.error.RepoLookupError, TypeError):

            raise ChangesetDoesNotExistError(msg)

        except (LookupError, ):

            raise ChangesetDoesNotExistError(msg)

    def get_ref_revision(self, ref_type, ref_name):

        """

        Returns revision number for the given reference.

        """

        ref_name = safe_str(ref_name)

        if ref_type == 'rev' and not ref_name.strip('0'):

            return self.EMPTY_CHANGESET

        # lookup up the exact node id

        _revset_predicates = {

                'branch': 'branch',

                'book': 'bookmark',

                'tag': 'tag',

                'rev': 'id',

            }

        # avoid expensive branch(x) iteration over whole repo

        rev_spec = "%%s & %s(%%s)" % _revset_predicates[ref_type]

        try:

            revs = self._repo.revs(rev_spec, ref_name, ref_name)

        except LookupError:

            raise ChangesetDoesNotExistError(msg)

        except mercurial.error.RepoLookupError:

            raise ChangesetDoesNotExistError(msg)

        if revs:

            revision = revs.last()

        else:

            # TODO: just report 'not found'?

            revision = ref_name

        return self._get_revision(revision)

    def _get_archives(self, archive_name='tip'):

        allowed = self.baseui.configlist(b"web", b"allow_archive",

                                         untrusted=True)

        for name, ext in [(b'zip', '.zip'), (b'gz', '.tar.gz'), (b'bz2', '.tar.bz2')]:

            if name in allowed or self._repo.ui.configbool(b"web",

                                                           b"allow" + name,

                                                           untrusted=True):

                yield {"type": name, "extension": ext, "node": archive_name}

    def _get_url(self, url):

        """

        Returns normalized url. If schema is not given, would fall

        to filesystem

        (``file:///``) schema.

        """

    def get_changesets(self, start=None, end=None, start_date=None,

                       end_date=None, branch_name=None, reverse=False, max_revisions=None):

        """

        Returns iterator of ``MercurialChangeset`` objects from start to end

        (both are inclusive)

        :param start: None, str, int or mercurial lookup format

        :param end:  None, str, int or mercurial lookup format

        :param start_date:

        :param end_date:

        :param branch_name:

        :param reversed: return changesets in reversed order

        """

        start_raw_id = self._get_revision(start)

        start_pos = None if start is None else self.revisions.index(start_raw_id)

        end_raw_id = self._get_revision(end)

        end_pos = None if end is None else self.revisions.index(end_raw_id)

        if start_pos is not None and end_pos is not None and start_pos > end_pos:

            raise RepositoryError("Start revision '%s' cannot be "

                                  "after end revision '%s'" % (start, end))

        if branch_name and branch_name not in self.allbranches:

            raise BranchDoesNotExistError(msg)

        if end_pos is not None:

            end_pos += 1

        # filter branches

        filter_ = []

        if branch_name:

            filter_.append(b'branch("%s")' % safe_bytes(branch_name))

        if start_date:

            filter_.append(b'date(">%s")' % start_date)

        if end_date:

            filter_.append(b'date("<%s")' % end_date)

        if filter_ or max_revisions:

            if filter_:

                revspec = b' and '.join(filter_)

            else:

                revspec = b'all()'

            if max_revisions:

                revspec = b'limit(%s, %d)' % (revspec, max_revisions)

            revisions = mercurial.scmutil.revrange(self._repo, [revspec])

        else:

            revisions = self.revisions

        # this is very much a hack to turn this into a list; a better solution

        # would be to get rid of this function entirely and use revsets