diffs: fix broken comment in wrap_to_table

kallithea/lib/diffs.py

@@ -1,713 +1,713 b''
 # -*- coding: utf-8 -*-
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 kallithea.lib.diffs
 ~~~~~~~~~~~~~~~~~~~
 
 Set of diffing helpers, previously part of vcs
 
 
 This file was forked by the Kallithea project in July 2014.
 Original author and date, and relevant copyright and licensing information is below:
 :created_on: Dec 4, 2011
 :author: marcink
 :copyright: (c) 2013 RhodeCode GmbH, and others.
 :license: GPLv3, see LICENSE.md for more details.
 """
 import difflib
 import logging
 import re
 
 from tg.i18n import ugettext as _
 
 from kallithea.lib import webutils
 from kallithea.lib.utils2 import safe_str
 from kallithea.lib.vcs.backends.base import EmptyChangeset
 from kallithea.lib.vcs.exceptions import VCSError
 from kallithea.lib.vcs.nodes import FileNode, SubModuleNode
 
 
 log = logging.getLogger(__name__)
 
 
 def _safe_id(idstring):
     r"""Make a string safe for including in an id attribute.
 
     The HTML spec says that id attributes 'must begin with
     a letter ([A-Za-z]) and may be followed by any number
     of letters, digits ([0-9]), hyphens ("-"), underscores
     ("_"), colons (":"), and periods (".")'. These regexps
     are slightly over-zealous, in that they remove colons
     and periods unnecessarily.
 
     Whitespace is transformed into underscores, and then
     anything which is not a hyphen or a character that
     matches \w (alphanumerics and underscore) is removed.
 
     """
     # Transform all whitespace to underscore
     idstring = re.sub(r'\s', "_", idstring)
     # Remove everything that is not a hyphen or a member of \w
     idstring = re.sub(r'(?!-)\W', "", idstring).lower()
     return idstring
 
 
 def as_html(table_class='code-difftable', line_class='line',
             old_lineno_class='lineno old', new_lineno_class='lineno new',
             no_lineno_class='lineno',
             code_class='code', parsed_lines=None):
     """
     Return given diff as html table with customized css classes
     """
     _html_empty = True
     _html = []
     _html.append('''<table class="%(table_class)s">\n''' % {
         'table_class': table_class
     })
 
     for file_info in parsed_lines:
         count_no_lineno = 0  # counter to allow comments on lines without new/old line numbers
         for chunk in file_info['chunks']:
             _html_empty = False
             for change in chunk:
                 _html.append('''<tr class="%(lc)s %(action)s">\n''' % {
                     'lc': line_class,
                     'action': change['action']
                 })
                 if change['old_lineno'] or change['new_lineno']:
                     ###########################################################
                     # OLD LINE NUMBER
                     ###########################################################
                     anchor_old = "%(filename)s_o%(oldline_no)s" % {
                         'filename': _safe_id(file_info['filename']),
                         'oldline_no': change['old_lineno']
                     }
                     anchor_old_id = ''
                     if change['old_lineno']:
                         anchor_old_id = 'id="%s"' % anchor_old
                     _html.append('''\t<td %(a_id)s class="%(olc)s">''' % {
                         'a_id': anchor_old_id,
                         'olc': old_lineno_class,
                     })
                     _html.append('''<a href="%(url)s" data-pseudo-content="%(label)s"></a>''' % {
                         'label': change['old_lineno'],
                         'url': '#%s' % anchor_old,
                     })
                     _html.append('''</td>\n''')
                     ###########################################################
                     # NEW LINE NUMBER
                     ###########################################################
                     anchor_new = "%(filename)s_n%(newline_no)s" % {
                         'filename': _safe_id(file_info['filename']),
                         'newline_no': change['new_lineno']
                     }
                     anchor_new_id = ''
                     if change['new_lineno']:
                         anchor_new_id = 'id="%s"' % anchor_new
                     _html.append('''\t<td %(a_id)s class="%(nlc)s">''' % {
                         'a_id': anchor_new_id,
                         'nlc': new_lineno_class
                     })
                     _html.append('''<a href="%(url)s" data-pseudo-content="%(label)s"></a>''' % {
                         'label': change['new_lineno'],
                         'url': '#%s' % anchor_new,
                     })
                     _html.append('''</td>\n''')
                 else:
                     ###########################################################
                     # NO LINE NUMBER
                     ###########################################################
                     anchor = "%(filename)s_%(count_no_lineno)s" % {
                         'filename': _safe_id(file_info['filename']),
                         'count_no_lineno': count_no_lineno,
                     }
                     count_no_lineno += 1
                     _html.append('''\t<td id="%(anchor)s" class="%(olc)s" colspan="2">''' % {
                         'anchor': anchor,
                         'olc': no_lineno_class,
                     })
                     _html.append('''</td>\n''')
                 ###########################################################
                 # CODE
                 ###########################################################
                 _html.append('''\t<td class="%(cc)s">''' % {
                     'cc': code_class,
                 })
                 _html.append('''\n\t\t<div class="add-bubble"><div>&nbsp;</div></div><pre>%(code)s</pre>\n''' % {
                     'code': change['line']
                 })
 
                 _html.append('''\t</td>''')
                 _html.append('''\n</tr>\n''')
     _html.append('''</table>''')
     if _html_empty:
         return None
     return ''.join(_html)
 
 
 def wrap_to_table(html):
     """Given a string with html, return it wrapped in a table, similar to what
-    DiffProcessor returns."""
+    as_html returns."""
     return '''\
               <table class="code-difftable">
                 <tr class="line">
                 <td class="lineno new"></td>
                 <td class="code"><pre>%s</pre></td>
                 </tr>
               </table>''' % html
 
 
 def wrapped_diff(filenode_old, filenode_new, diff_limit=None,
                 ignore_whitespace=True, line_context=3):
     """
     Returns a file diff wrapped into a table.
     Checks for diff_limit and presents a message if the diff is too big.
     """
     if filenode_old is None:
         filenode_old = FileNode(filenode_new.path, '', EmptyChangeset())
 
     op = None
     a_path = filenode_old.path # default, might be overriden by actual rename in diff
     if filenode_old.is_binary or filenode_new.is_binary:
         html_diff = wrap_to_table(_('Binary file'))
         stats = (0, 0)
 
     elif diff_limit != -1 and (
             diff_limit is None or
             (filenode_old.size < diff_limit and filenode_new.size < diff_limit)):
 
         raw_diff = get_gitdiff(filenode_old, filenode_new,
                                 ignore_whitespace=ignore_whitespace,
                                 context=line_context)
         diff_processor = DiffProcessor(raw_diff)
         if diff_processor.parsed: # there should be exactly one element, for the specified file
             f = diff_processor.parsed[0]
             op = f['operation']
             a_path = f['old_filename']
 
         html_diff = as_html(parsed_lines=diff_processor.parsed)
         stats = diff_processor.stat()
 
     else:
         html_diff = wrap_to_table(_('Changeset was too big and was cut off, use '
                                'diff menu to display this diff'))
         stats = (0, 0)
 
     if not html_diff:
         submodules = [o for o in [filenode_new, filenode_old] if isinstance(o, SubModuleNode)]
         if submodules:
             html_diff = wrap_to_table(webutils.escape('Submodule %r' % submodules[0]))
         else:
             html_diff = wrap_to_table(_('No changes detected'))
 
     cs1 = filenode_old.changeset.raw_id
     cs2 = filenode_new.changeset.raw_id
 
     return cs1, cs2, a_path, html_diff, stats, op
 
 
 def get_gitdiff(filenode_old, filenode_new, ignore_whitespace=True, context=3):
     """
     Returns git style diff between given ``filenode_old`` and ``filenode_new``.
     """
     # make sure we pass in default context
     context = context or 3
     submodules = [o for o in [filenode_new, filenode_old] if isinstance(o, SubModuleNode)]
     if submodules:
         return b''
 
     for filenode in (filenode_old, filenode_new):
         if not isinstance(filenode, FileNode):
             raise VCSError("Given object should be FileNode object, not %s"
                 % filenode.__class__)
 
     repo = filenode_new.changeset.repository
     old_raw_id = getattr(filenode_old.changeset, 'raw_id', repo.EMPTY_CHANGESET)
     new_raw_id = getattr(filenode_new.changeset, 'raw_id', repo.EMPTY_CHANGESET)
 
     vcs_gitdiff = get_diff(repo, old_raw_id, new_raw_id, filenode_new.path,
                            ignore_whitespace, context)
     return vcs_gitdiff
 
 
 def get_diff(scm_instance, rev1, rev2, path=None, ignore_whitespace=False, context=3):
     """
     A thin wrapper around vcs lib get_diff.
     """
     try:
         return scm_instance.get_diff(rev1, rev2, path=path,
                                      ignore_whitespace=ignore_whitespace, context=context)
     except MemoryError:
         webutils.flash('MemoryError: Diff is too big', category='error')
         return b''
 
 
 NEW_FILENODE = 1
 DEL_FILENODE = 2
 MOD_FILENODE = 3
 RENAMED_FILENODE = 4
 COPIED_FILENODE = 5
 CHMOD_FILENODE = 6
 BIN_FILENODE = 7
 
 
 class DiffProcessor(object):
     """
     Give it a unified or git diff and it returns a list of the files that were
     mentioned in the diff together with a dict of meta information that
     can be used to render it in a HTML template.
     """
     _diff_git_re = re.compile(b'^diff --git', re.MULTILINE)
 
     def __init__(self, diff, vcs='hg', diff_limit=None, inline_diff=True):
         """
         :param diff:   a text in diff format
         :param vcs: type of version control hg or git
         :param diff_limit: define the size of diff that is considered "big"
             based on that parameter cut off will be triggered, set to None
             to show full diff
         """
         if not isinstance(diff, bytes):
             raise Exception('Diff must be bytes - got %s' % type(diff))
 
         self._diff = memoryview(diff)
         self.adds = 0
         self.removes = 0
         self.diff_limit = diff_limit
         self.limited_diff = False
         self.vcs = vcs
         self.parsed = self._parse_gitdiff(inline_diff=inline_diff)
 
     def _parse_gitdiff(self, inline_diff):
         """Parse self._diff and return a list of dicts with meta info and chunks for each file.
         Might set limited_diff.
         Optionally, do an extra pass and to extra markup of one-liner changes.
         """
         _files = [] # list of dicts with meta info and chunks
 
         starts = [m.start() for m in self._diff_git_re.finditer(self._diff)]
         starts.append(len(self._diff))
 
         for start, end in zip(starts, starts[1:]):
             if self.diff_limit and end > self.diff_limit:
                 self.limited_diff = True
                 continue
 
             head, diff_lines = _get_header(self.vcs, self._diff[start:end])
 
             op = None
             stats = {
                 'added': 0,
                 'deleted': 0,
                 'binary': False,
                 'ops': {},
             }
 
             if head['deleted_file_mode']:
                 op = 'removed'
                 stats['binary'] = True
                 stats['ops'][DEL_FILENODE] = 'deleted file'
 
             elif head['new_file_mode']:
                 op = 'added'
                 stats['binary'] = True
                 stats['ops'][NEW_FILENODE] = 'new file %s' % head['new_file_mode']
             else:  # modify operation, can be cp, rename, chmod
                 # CHMOD
                 if head['new_mode'] and head['old_mode']:
                     op = 'modified'
                     stats['binary'] = True
                     stats['ops'][CHMOD_FILENODE] = ('modified file chmod %s => %s'
                                         % (head['old_mode'], head['new_mode']))
                 # RENAME
                 if (head['rename_from'] and head['rename_to']
                       and head['rename_from'] != head['rename_to']):
                     op = 'renamed'
                     stats['binary'] = True
                     stats['ops'][RENAMED_FILENODE] = ('file renamed from %s to %s'
                                     % (head['rename_from'], head['rename_to']))
                 # COPY
                 if head.get('copy_from') and head.get('copy_to'):
                     op = 'modified'
                     stats['binary'] = True
                     stats['ops'][COPIED_FILENODE] = ('file copied from %s to %s'
                                         % (head['copy_from'], head['copy_to']))
                 # FALL BACK: detect missed old style add or remove
                 if op is None:
                     if not head['a_file'] and head['b_file']:
                         op = 'added'
                         stats['binary'] = True
                         stats['ops'][NEW_FILENODE] = 'new file'
 
                     elif head['a_file'] and not head['b_file']:
                         op = 'removed'
                         stats['binary'] = True
                         stats['ops'][DEL_FILENODE] = 'deleted file'
 
                 # it's not ADD not DELETE
                 if op is None:
                     op = 'modified'
                     stats['binary'] = True
                     stats['ops'][MOD_FILENODE] = 'modified file'
 
             # a real non-binary diff
             if head['a_file'] or head['b_file']:
                 chunks, added, deleted = _parse_lines(diff_lines)
                 stats['binary'] = False
                 stats['added'] = added
                 stats['deleted'] = deleted
                 # explicit mark that it's a modified file
                 if op == 'modified':
                     stats['ops'][MOD_FILENODE] = 'modified file'
             else:  # Git binary patch (or empty diff)
                 # Git binary patch
                 if head['bin_patch']:
                     stats['ops'][BIN_FILENODE] = 'binary diff not shown'
                 chunks = []
 
             if op == 'removed' and chunks:
                 # a way of seeing deleted content could perhaps be nice - but
                 # not with the current UI
                 chunks = []
 
             chunks.insert(0, [{
                 'old_lineno': '',
                 'new_lineno': '',
                 'action':     'context',
                 'line':       msg,
                 } for _op, msg in stats['ops'].items()
                   if _op not in [MOD_FILENODE]])
 
             _files.append({
                 'old_filename':     head['a_path'],
                 'filename':         head['b_path'],
                 'old_revision':     head['a_blob_id'],
                 'new_revision':     head['b_blob_id'],
                 'chunks':           chunks,
                 'operation':        op,
                 'stats':            stats,
             })
 
         if not inline_diff:
             return _files
 
         # highlight inline changes when one del is followed by one add
         for diff_data in _files:
             for chunk in diff_data['chunks']:
                 lineiter = iter(chunk)
                 try:
                     peekline = next(lineiter)
                     while True:
                         # find a first del line
                         while peekline['action'] != 'del':
                             peekline = next(lineiter)
                         delline = peekline
                         peekline = next(lineiter)
                         # if not followed by add, eat all following del lines
                         if peekline['action'] != 'add':
                             while peekline['action'] == 'del':
                                 peekline = next(lineiter)
                             continue
                         # found an add - make sure it is the only one
                         addline = peekline
                         try:
                             peekline = next(lineiter)
                         except StopIteration:
                             # add was last line - ok
                             _highlight_inline_diff(delline, addline)
                             raise
                         if peekline['action'] != 'add':
                             # there was only one add line - ok
                             _highlight_inline_diff(delline, addline)
                 except StopIteration:
                     pass
 
         return _files
 
     def stat(self):
         """
         Returns tuple of added, and removed lines for this instance
         """
         return self.adds, self.removes
 
 
 _escape_re = re.compile(r'(&)|(<)|(>)|(\t)($)?|(\r)|( $)')
 
 
 def _escaper(diff_line):
     r"""
     Do HTML escaping/markup of a single diff line (including first +/- column)
 
     >>> _escaper('foobar')
     'foobar'
     >>> _escaper('@foo & bar')
     '@foo &amp; bar'
     >>> _escaper('+foo < bar')
     '+foo &lt; bar'
     >>> _escaper('-foo > bar')
     '-foo &gt; bar'
     >>> _escaper(' <foo>')
     ' &lt;foo&gt;'
     >>> _escaper(' foo\tbar')
     ' foo<u>\t</u>bar'
     >>> _escaper(' foo\rbar\r')
     ' foo<u class="cr"></u>bar<u class="cr"></u>'
     >>> _escaper(' foo\t')
     ' foo<u>\t</u><i></i>'
     >>> _escaper(' foo ')
     ' foo <i></i>'
     >>> _escaper(' foo  ')
     ' foo  <i></i>'
     >>> _escaper(' ')
     ' '
     >>> _escaper('  ')
     '  <i></i>'
     >>> _escaper(' \t')
     ' <u>\t</u><i></i>'
     >>> _escaper(' \t  ')
     ' <u>\t</u>  <i></i>'
     >>> _escaper('   \t')
     '   <u>\t</u><i></i>'
     >>> _escaper(' \t\t  ')
     ' <u>\t</u><u>\t</u>  <i></i>'
     >>> _escaper('   \t\t')
     '   <u>\t</u><u>\t</u><i></i>'
     >>> _escaper(' foo&bar<baz>  ')
     ' foo&amp;bar&lt;baz&gt;  <i></i>'
     """
 
     def substitute(m):
         groups = m.groups()
         if groups[0]:
             return '&amp;'
         if groups[1]:
             return '&lt;'
         if groups[2]:
             return '&gt;'
         if groups[3]:
             if groups[4] is not None:  # end of line
                 return '<u>\t</u><i></i>'
             return '<u>\t</u>'
         if groups[5]:
             return '<u class="cr"></u>'
         if groups[6]:
             if m.start() == 0:
                 return ' '  # first column space shouldn't make empty lines show up as trailing space
             return ' <i></i>'
         assert False
 
     return _escape_re.sub(substitute, diff_line)
 
 
 _git_header_re = re.compile(br"""
     ^diff[ ]--git[ ]a/(?P<a_path>.+?)[ ]b/(?P<b_path>.+?)\n
     (?:^old[ ]mode[ ](?P<old_mode>\d+)\n
        ^new[ ]mode[ ](?P<new_mode>\d+)(?:\n|$))?
     (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%\n
        ^rename[ ]from[ ](?P<rename_from>.+)\n
        ^rename[ ]to[ ](?P<rename_to>.+)(?:\n|$))?
     (?:^new[ ]file[ ]mode[ ](?P<new_file_mode>.+)(?:\n|$))?
     (?:^deleted[ ]file[ ]mode[ ](?P<deleted_file_mode>.+)(?:\n|$))?
     (?:^index[ ](?P<a_blob_id>[0-9A-Fa-f]+)
         \.\.(?P<b_blob_id>[0-9A-Fa-f]+)[ ]?(?P<b_mode>.+)?(?:\n|$))?
     (?:^(?P<bin_patch>GIT[ ]binary[ ]patch)(?:\n|$))?
     (?:^---[ ](a/(?P<a_file>.+?)|/dev/null)\t?(?:\n|$))?
     (?:^\+\+\+[ ](b/(?P<b_file>.+?)|/dev/null)\t?(?:\n|$))?
 """, re.VERBOSE | re.MULTILINE)
 
 
 _hg_header_re = re.compile(br"""
     ^diff[ ]--git[ ]a/(?P<a_path>.+?)[ ]b/(?P<b_path>.+?)\n
     (?:^old[ ]mode[ ](?P<old_mode>\d+)\n
        ^new[ ]mode[ ](?P<new_mode>\d+)(?:\n|$))?
     (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%(?:\n|$))?
     (?:^rename[ ]from[ ](?P<rename_from>.+)\n
        ^rename[ ]to[ ](?P<rename_to>.+)(?:\n|$))?
     (?:^copy[ ]from[ ](?P<copy_from>.+)\n
        ^copy[ ]to[ ](?P<copy_to>.+)(?:\n|$))?
     (?:^new[ ]file[ ]mode[ ](?P<new_file_mode>.+)(?:\n|$))?
     (?:^deleted[ ]file[ ]mode[ ](?P<deleted_file_mode>.+)(?:\n|$))?
     (?:^index[ ](?P<a_blob_id>[0-9A-Fa-f]+)
         \.\.(?P<b_blob_id>[0-9A-Fa-f]+)[ ]?(?P<b_mode>.+)?(?:\n|$))?
     (?:^(?P<bin_patch>GIT[ ]binary[ ]patch)(?:\n|$))?
     (?:^---[ ](a/(?P<a_file>.+?)|/dev/null)\t?(?:\n|$))?
     (?:^\+\+\+[ ](b/(?P<b_file>.+?)|/dev/null)\t?(?:\n|$))?
 """, re.VERBOSE | re.MULTILINE)
 
 
 _header_next_check = re.compile(br'''(?!@)(?!literal )(?!delta )''')
 
 
 def _get_header(vcs, diff_chunk):
     """
     Parses a Git diff for a single file (header and chunks) and returns a tuple with:
 
     1. A dict with meta info:
 
         a_path, b_path, similarity_index, rename_from, rename_to,
         old_mode, new_mode, new_file_mode, deleted_file_mode,
         a_blob_id, b_blob_id, b_mode, a_file, b_file
 
     2. An iterator yielding lines with simple HTML markup.
     """
     match = None
     if vcs == 'git':
         match = _git_header_re.match(diff_chunk)
     elif vcs == 'hg':
         match = _hg_header_re.match(diff_chunk)
     if match is None:
         raise Exception('diff not recognized as valid %s diff' % vcs)
     meta_info = {k: None if v is None else safe_str(v) for k, v in match.groupdict().items()}
     rest = diff_chunk[match.end():]
     if rest:
         if _header_next_check.match(rest):
             raise Exception('cannot parse %s diff header: %r followed by %r' % (vcs, safe_str(bytes(diff_chunk[:match.end()])), safe_str(bytes(rest[:1000]))))
         if rest[-1:] != b'\n':
             # The diff will generally already have trailing \n (and be a memoryview). It might also be huge so we don't want to allocate it twice. But in this very rare case, we don't care.
             rest = bytes(rest) + b'\n'
     diff_lines = (_escaper(safe_str(m.group(1))) for m in re.finditer(br'(.*)\n', rest))
     return meta_info, diff_lines
 
 
 _chunk_re = re.compile(r'^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@(.*)')
 _newline_marker = re.compile(r'^\\ No newline at end of file')
 
 
 def _parse_lines(diff_lines):
     """
     Given an iterator of diff body lines, parse them and return a dict per
     line and added/removed totals.
     """
     added = deleted = 0
     old_line = old_end = new_line = new_end = None
 
     chunks = []
     try:
         line = next(diff_lines)
 
         while True:
             lines = []
             chunks.append(lines)
 
             match = _chunk_re.match(line)
 
             if not match:
                 raise Exception('error parsing diff @@ line %r' % line)
 
             gr = match.groups()
             (old_line, old_end,
              new_line, new_end) = [int(x or 1) for x in gr[:-1]]
             old_line -= 1
             new_line -= 1
 
             context = len(gr) == 5
             old_end += old_line
             new_end += new_line
 
             if context:
                 # skip context only if it's first line
                 if int(gr[0]) > 1:
                     lines.append({
                         'old_lineno': '',
                         'new_lineno': '',
                         'action':     'context',
                         'line':       line,
                     })
 
             line = next(diff_lines)
 
             while old_line < old_end or new_line < new_end:
                 if not line:
                     raise Exception('error parsing diff - empty line at -%s+%s' % (old_line, new_line))
 
                 affects_old = affects_new = False
 
                 command = line[0]
                 if command == '+':
                     affects_new = True
                     action = 'add'
                     added += 1
                 elif command == '-':
                     affects_old = True
                     action = 'del'
                     deleted += 1
                 elif command == ' ':
                     affects_old = affects_new = True
                     action = 'unmod'
                 else:
                     raise Exception('error parsing diff - unknown command in line %r at -%s+%s' % (line, old_line, new_line))
 
                 if not _newline_marker.match(line):
                     old_line += affects_old
                     new_line += affects_new
                     lines.append({
                         'old_lineno':   affects_old and old_line or '',
                         'new_lineno':   affects_new and new_line or '',
                         'action':       action,
                         'line':         line[1:],
                     })
 
                 line = next(diff_lines)
 
                 if _newline_marker.match(line):
                     # we need to append to lines, since this is not
                     # counted in the line specs of diff
                     lines.append({
                         'old_lineno':   '',
                         'new_lineno':   '',
                         'action':       'context',
                         'line':         line,
                     })
                     line = next(diff_lines)
             if old_line > old_end:
                 raise Exception('error parsing diff - more than %s "-" lines at -%s+%s' % (old_end, old_line, new_line))
             if new_line > new_end:
                 raise Exception('error parsing diff - more than %s "+" lines at -%s+%s' % (new_end, old_line, new_line))
     except StopIteration:
         pass
     if old_line != old_end or new_line != new_end:
         raise Exception('diff processing broken when old %s<>%s or new %s<>%s line %r' % (old_line, old_end, new_line, new_end, line))
 
     return chunks, added, deleted
 
 # Used for inline highlighter word split, must match the substitutions in _escaper
 _token_re = re.compile(r'()(&amp;|&lt;|&gt;|<u>\t</u>|<u class="cr"></u>| <i></i>|\W+?)')
 
 
 def _highlight_inline_diff(old, new):
     """
     Highlight simple add/remove in two lines given as info dicts. They are
     modified in place and given markup with <del>/<ins>.
     """
     assert old['action'] == 'del'
     assert new['action'] == 'add'
 
     oldwords = _token_re.split(old['line'])
     newwords = _token_re.split(new['line'])
     sequence = difflib.SequenceMatcher(None, oldwords, newwords)
 
     oldfragments, newfragments = [], []
     for tag, i1, i2, j1, j2 in sequence.get_opcodes():
         oldfrag = ''.join(oldwords[i1:i2])
         newfrag = ''.join(newwords[j1:j2])
         if tag != 'equal':
             if oldfrag:
                 oldfrag = '<del>%s</del>' % oldfrag
             if newfrag:
                 newfrag = '<ins>%s</ins>' % newfrag
         oldfragments.append(oldfrag)
         newfragments.append(newfrag)
 
     old['line'] = "".join(oldfragments)
     new['line'] = "".join(newfragments)