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 not dbrepo.enable_downloads:

                return _('Downloads disabled')

            if c.db_repo_scm_instance.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.db_repo_scm_instance._repo.ui.configitems('hooks'):

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

            cs = c.db_repo_scm_instance.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')

        # archive cache

        from kallithea import CONFIG

        rev_name = cs.raw_id[:12]

        archive_name = '%s-%s%s' % (safe_str(repo_name.replace('/', '_')),

                                    safe_str(rev_name), ext)

        use_cached_archive = False  # defines if we use cached version of archive

        archive_cache_enabled = CONFIG.get('archive_cache_dir')

        if not subrepos and archive_cache_enabled:

            #check if we it's ok to write

            if not os.path.isdir(CONFIG['archive_cache_dir']):

                os.makedirs(CONFIG['archive_cache_dir'])

            cached_archive_path = os.path.join(CONFIG['archive_cache_dir'], archive_name)

            if os.path.isfile(cached_archive_path):

                log.debug('Found cached archive in %s' % cached_archive_path)

                fd, archive = None, cached_archive_path

                use_cached_archive = True

            else:

                log.debug('Archive %s is not yet cached' % (archive_name))

        if not use_cached_archive:

            # generate new archive

        def get_chunked_archive(archive):

            stream = open(archive, 'rb')

            while True:

                data = stream.read(16 * 1024)

                if not data:

                    stream.close()

                    if fd:  # fd means we used temporary file

                        os.close(fd)

                    if not archive_cache_enabled:

                        log.debug('Destroing temp archive %s' % archive)

                        os.remove(archive)

                    break

                yield data

        # store download action

        action_logger(user=c.authuser,

                      action='user_downloaded_archive:%s' % (archive_name),

                      repo=repo_name, ipaddr=self.ip_addr, commit=True)

        response.content_disposition = str('attachment; filename=%s' % (archive_name))

        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)

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

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