revision = None

        ext = None

        subrepos = request.GET.get('subrepos') == 'true'

        for a_type, ext_data in settings.ARCHIVE_SPECS.items():

            archive_spec = fname.split(ext_data[1])

            if len(archive_spec) == 2 and archive_spec[1] == '':

                fileformat = a_type or ext_data[1]

                revision = archive_spec[0]

                ext = ext_data[1]

        try:

            dbrepo = RepoModel().get_by_repo_name(repo_name)

            if dbrepo.enable_downloads is False:

                return _('downloads disabled')

            if c.rhodecode_repo.alias == 'hg':

                # patch and reset hooks section of UI config to not run any

                # hooks on fetching archives with subrepos

                for k, v in c.rhodecode_repo._repo.ui.configitems('hooks'):

                    c.rhodecode_repo._repo.ui.setconfig('hooks', k, None)

            cs = c.rhodecode_repo.get_changeset(revision)

            content_type = settings.ARCHIVE_SPECS[fileformat][0]

        except ChangesetDoesNotExistError:

            return _('Unknown revision %s') % revision

        except EmptyRepositoryError:

            return _('Empty repository')

        except (ImproperArchiveTypeError, KeyError):

            return _('Unknown archive type')

        fd, archive = tempfile.mkstemp()

        t = open(archive, 'wb')

        cs.fill_archive(stream=t, kind=fileformat, subrepos=subrepos)

        t.close()

        def get_chunked_archive(archive):

            stream = open(archive, 'rb')

            while True:

                data = stream.read(16 * 1024)

                if not data:

                    stream.close()

                    os.close(fd)

                    os.remove(archive)

                    break

                yield data

        response.content_disposition = str('attachment; filename=%s-%s%s' \

        response.content_type = str(content_type)

        return get_chunked_archive(archive)

    @LoginRequired()

    @HasRepoPermissionAnyDecorator('repository.read', 'repository.write',

                                   'repository.admin')

    def diff(self, repo_name, f_path):

        ignore_whitespace = request.GET.get('ignorews') == '1'

        line_context = request.GET.get('context', 3)

        diff1 = request.GET.get('diff1', '')

        diff2 = request.GET.get('diff2', '')

        c.action = request.GET.get('diff')

        c.no_changes = diff1 == diff2

        c.f_path = f_path

        c.big_diff = False

        c.anchor_url = anchor_url

        c.ignorews_url = _ignorews_url

        c.context_url = _context_url

        c.changes = OrderedDict()

        c.changes[diff2] = []

        #special case if we want a show rev only, it's impl here

        #to reduce JS and callbacks

        if request.GET.get('show_rev'):

            if str2bool(request.GET.get('annotate', 'False')):

                _url = url('files_annotate_home', repo_name=c.repo_name,

                           revision=diff1, f_path=c.f_path)

            else:

                _url = url('files_home', repo_name=c.repo_name,

                           revision=diff1, f_path=c.f_path)

            return redirect(_url)

        try:

            if diff1 not in ['', None, 'None', '0' * 12, '0' * 40]:

                c.changeset_1 = c.rhodecode_repo.get_changeset(diff1)

                try:

                    node1 = c.changeset_1.get_node(f_path)

                    if node1.is_dir():

                        raise NodeError('%s path is a %s not a file' % (node1, type(node1)))

                except NodeDoesNotExistError:

                    c.changeset_1 = EmptyChangeset(cs=diff1,

                                                   revision=c.changeset_1.revision,

                                                   repo=c.rhodecode_repo)

                    node1 = FileNode(f_path, '', changeset=c.changeset_1)

            else:

                c.changeset_1 = EmptyChangeset(repo=c.rhodecode_repo)

                node1 = FileNode(f_path, '', changeset=c.changeset_1)

                Session().add(inv_obj)

                if commit:

                    Session().commit()

            except Exception:

                log.error(traceback.format_exc())

                Session().rollback()

        return inv_obj

    @classmethod

    def invalidate(cls, key):

        """

        Returns Invalidation object if this given key should be invalidated

        None otherwise. `cache_active = False` means that this cache

        state is not valid and needs to be invalidated

        :param key:

        """

        repo_name = key

        repo_name = remove_suffix(repo_name, '_README')

        repo_name = remove_suffix(repo_name, '_RSS')

        repo_name = remove_suffix(repo_name, '_ATOM')

        # adds instance prefix

        key, _prefix, _org_key = cls._get_key(key)

        inv = cls._get_or_create_key(key, repo_name)

        if inv and inv.cache_active is False:

            return inv

    @classmethod

    def set_invalidate(cls, key=None, repo_name=None):

        """

        Mark this Cache key for invalidation, either by key or whole

        cache sets based on repo_name

        :param key:

        """

        invalidated_keys = []

        if key:

            key, _prefix, _org_key = cls._get_key(key)

            inv_objs = Session().query(cls).filter(cls.cache_key == key).all()

        elif repo_name:

            inv_objs = Session().query(cls).filter(cls.cache_args == repo_name).all()

        try:

            for inv_obj in inv_objs:

                inv_obj.cache_active = False

                log.debug('marking %s key for invalidation based on key=%s,repo_name=%s'

                invalidated_keys.append(inv_obj.cache_key)

                Session().add(inv_obj)

            Session().commit()

        except Exception:

            log.error(traceback.format_exc())

            Session().rollback()

        return invalidated_keys

    @classmethod

    def set_valid(cls, key):

        """

        Mark this cache key as active and currently cached

        :param key:

        """

        inv_obj = cls.get_by_key(key)

        inv_obj.cache_active = True

        Session().add(inv_obj)

        Session().commit()

    @classmethod

    def get_cache_map(cls):

        class cachemapdict(dict):

            def __init__(self, *args, **kwargs):

                fixkey = kwargs.get('fixkey')

                if fixkey:

                    del kwargs['fixkey']

                self.fixkey = fixkey

                super(cachemapdict, self).__init__(*args, **kwargs)

            def __getattr__(self, name):

                key = name

                if self.fixkey:

                    key, _prefix, _org_key = cls._get_key(key)

                if key in self.__dict__:

                    return self.__dict__[key]

                else:

                    return self[key]

            def __getitem__(self, key):

                if self.fixkey:

                    key, _prefix, _org_key = cls._get_key(key)

                try:

                    return super(cachemapdict, self).__getitem__(key)

                except KeyError:

                    return