helpers: introduce render_w_mentions

Eventually this function should support and auto detect multiple formats and is
thus not named for a specific format. But for now it is plain text only.

This kind of markup can quite easily and safely support additional magic
markup. It is much harder to do that on top of a richer markup format; it
must essentially be done in a single pass, with both all the various regexps
and the rst formatting done in a single pass.

kallithea/lib/helpers.py

@@ -55,7 +55,7 b' from kallithea.lib.annotate import annot'
 from kallithea.lib.utils import repo_name_slug, get_custom_lexer
 from kallithea.lib.utils2 import str2bool, safe_unicode, safe_str, \
     get_changeset_safe, datetime_to_time, time_to_datetime, AttributeDict, \
-    safe_int
+    safe_int, MENTIONS_REGEX
 from kallithea.lib.markup_renderer import MarkupRenderer, url_re
 from kallithea.lib.vcs.exceptions import ChangesetDoesNotExistError
 from kallithea.lib.vcs.backends.base import BaseChangeset, EmptyChangeset
@@ -1397,6 +1397,26 b' def rst_w_mentions(source):'
     return literal('<div class="rst-block">%s</div>' %
                    MarkupRenderer.rst_with_mentions(source))
 
+
+def mentions_replace(match_obj):
+    return '<b>@%s</b>' % match_obj.group(1)
+
+
+def render_w_mentions(source):
+    """
+    Render plain text with @mention highlighting.
+    """
+    s = source.rstrip()
+    s = safe_unicode(s)
+    s = '\n'.join(s.splitlines())
+    s = html_escape(s)
+    # this sequence of html-ifications seems to be safe and non-conflicting
+    # if the issues regexp is sane
+    s = _urlify_text(s)
+    s = MENTIONS_REGEX.sub(mentions_replace, s)
+    return literal('<code style="white-space:pre-wrap">%s</code>' % s)
+
+
 def short_ref(ref_type, ref_name):
     if ref_type == 'rev':
         return short_id(ref_name)