c.fulldiff = request.GET.get('fulldiff')

        # partial uses compare_cs.html template directly

        partial = request.environ.get('HTTP_X_PARTIAL_XHR')

        # as_form puts hidden input field with changeset revisions

        c.as_form = partial and request.GET.get('as_form')

        # swap url for compare_diff page - never partial and never as_form

        c.swap_url = h.url('compare_url',

            repo_name=other_repo,

            org_ref_type=other_ref[0], org_ref=other_ref[1],

            other_repo=org_repo,

            other_ref_type=org_ref[0], other_ref=org_ref[1],

            merge=merge or '')

        org_repo = Repository.get_by_repo_name(org_repo)

        other_repo = Repository.get_by_repo_name(other_repo)

        if org_repo is None:

            log.error('Could not find org repo %s' % org_repo)

            raise HTTPNotFound

        if other_repo is None:

            log.error('Could not find other repo %s' % other_repo)

            raise HTTPNotFound

        if org_repo != other_repo and h.is_git(org_repo):

            log.error('compare of two remote repos not available for GIT REPOS')

            raise HTTPNotFound

        if org_repo.scm_instance.alias != other_repo.scm_instance.alias:

            log.error('compare of two different kind of remote repos not available')

            raise HTTPNotFound

        self.__get_cs_or_redirect(rev=org_ref, repo=org_repo, partial=partial)

        self.__get_cs_or_redirect(rev=other_ref, repo=other_repo, partial=partial)

        c.org_repo = org_repo

        c.other_repo = other_repo

        c.org_ref = org_ref[1]

        c.other_ref = other_ref[1]

        c.org_ref_type = org_ref[0]

        c.other_ref_type = other_ref[0]

        c.cs_ranges, c.ancestor = self._get_changesets(org_repo.scm_instance.alias,

                                                       org_repo.scm_instance, org_ref,

                                                       other_repo.scm_instance, other_ref,

                                                       merge)

        c.statuses = c.rhodecode_db_repo.statuses([x.raw_id for x in

                                                   c.cs_ranges])

        if partial:

            return render('compare/compare_cs.html')

        if c.ancestor:

            assert merge

            # case we want a simple diff without incoming changesets,

            # previewing what will be merged.

            # Make the diff on the other repo (which is known to have other_ref)

            log.debug('Using ancestor %s as org_ref instead of %s'

                      % (c.ancestor, org_ref))

            org_ref = ('rev', c.ancestor)

            org_repo = other_repo

        diff_limit = self.cut_off_limit if not c.fulldiff else None

        log.debug('running diff between %s and %s in %s'

                  % (org_ref, other_ref, org_repo.scm_instance.path))

        txtdiff = org_repo.scm_instance.get_diff(rev1=safe_str(org_ref[1]), rev2=safe_str(other_ref[1]))

        diff_processor = diffs.DiffProcessor(txtdiff or '', format='gitdiff',

                                             diff_limit=diff_limit)

        _parsed = diff_processor.prepare()

        c.limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

            c.limited_diff = True

        c.files = []

        c.changes = {}

        c.lines_added = 0

        c.lines_deleted = 0

        for f in _parsed:

            st = f['stats']

            if not st['binary']:

                c.lines_added += st['added']

                c.lines_deleted += st['deleted']

            fid = h.FID('', f['filename'])

            c.files.append([fid, f['operation'], f['filename'], f['stats']])

            htmldiff = diff_processor.as_html(enable_comments=False, parsed_lines=[f])

            c.changes[fid] = [f['operation'], f['filename'], htmldiff]

        return render('compare/compare_diff.html')