# -*- coding: utf-8 -*-

"""

    rhodecode.controllers.feed

    ~~~~~~~~~~~~~~~~~~~~~~~~~~

    Feed controller for rhodecode

    :created_on: Apr 23, 2010

    :author: marcink

    :copyright: (C) 2010-2012 Marcin Kuzminski <marcin@python-works.com>

    :license: GPLv3, see COPYING for more details.

"""

# 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/>.

import logging

from pylons import url, response, tmpl_context as c

from pylons.i18n.translation import _

from beaker.cache import cache_region, region_invalidate

from webhelpers.feedgenerator import Atom1Feed, Rss201rev2Feed

from rhodecode.lib import helpers as h

from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator

from rhodecode.lib.base import BaseRepoController

from rhodecode.lib.diffs import DiffProcessor, LimitedDiffContainer

from rhodecode.model.db import CacheInvalidation

from rhodecode.lib.utils2 import safe_int, str2bool

log = logging.getLogger(__name__)

class FeedController(BaseRepoController):

    @LoginRequired(api_access=True)

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

                                   'repository.admin')

    def __before__(self):

        super(FeedController, self).__before__()

        #common values for feeds

        self.description = _('Changes on %s repository')

        self.title = self.title = _('%s %s feed') % (c.rhodecode_name, '%s')

        self.language = 'en-us'

        self.ttl = "5"

        import rhodecode

        CONF = rhodecode.CONFIG

        self.include_diff = str2bool(CONF.get('rss_include_diff', False))

        self.feed_nr = safe_int(CONF.get('rss_items_per_page', 20))

        # we need to protect from parsing huge diffs here other way

        # we can kill the server

        self.feed_diff_limit = safe_int(CONF.get('rss_cut_off_limit'), 32 * 1024)

    def _get_title(self, cs):

        return "%s" % (

            h.shorter(cs.message, 160)

        )

    def __changes(self, cs):

        changes = []

        diff_processor = DiffProcessor(cs.diff(),

                                       diff_limit=self.feed_diff_limit)

        _parsed = diff_processor.prepare(inline_diff=False)

        limited_diff = False

        if isinstance(_parsed, LimitedDiffContainer):

            limited_diff = True

        for st in _parsed:

            st.update({'added': st['stats'][0],

                       'removed': st['stats'][1]})

            changes.append('\n %(operation)s %(filename)s '

                           '(%(added)s lines added, %(removed)s lines removed)'

                            % st)

        if limited_diff:

            changes = changes + ['\n ' +

                                 _('Changeset was too big and was cut off...')]

        return diff_processor, changes

    def __get_desc(self, cs):

        desc_msg = []

        desc_msg.append('%s %s %s<br/>' % (h.person(cs.author),

                                           _('commited on'),

                                           h.fmt_date(cs.date)))

        #branches, tags, bookmarks

        if cs.branch:

            desc_msg.append('branch: %s<br/>' % cs.branch)

        if h.is_hg(c.rhodecode_repo):

            for book in cs.bookmarks:

                desc_msg.append('bookmark: %s<br/>' % book)

        for tag in cs.tags:

            desc_msg.append('tag: %s<br/>' % tag)

        diff_processor, changes = self.__changes(cs)

        # rev link

        _url = url('changeset_home', repo_name=cs.repository.name,

                   revision=cs.raw_id, qualified=True)

        desc_msg.append('changesest: <a href="%s">%s</a>' % (_url, cs.raw_id[:8]))

        desc_msg.append('<pre>')

        desc_msg.append(cs.message)

        desc_msg.append('\n')

        desc_msg.extend(changes)

        if self.include_diff:

            desc_msg.append('\n\n')

            desc_msg.append(diff_processor.as_raw())

        desc_msg.append('</pre>')

        return desc_msg

    def atom(self, repo_name):

        """Produce an atom-1.0 feed via feedgenerator module"""

        @cache_region('long_term')

        def _get_feed_from_cache(key):

            feed = Atom1Feed(

                 title=self.title % repo_name,

                 link=url('summary_home', repo_name=repo_name,

                          qualified=True),

                 description=self.description % repo_name,

                 language=self.language,

                 ttl=self.ttl

            )

            for cs in reversed(list(c.rhodecode_repo[-self.feed_nr:])):

                feed.add_item(title=self._get_title(cs),

                              link=url('changeset_home', repo_name=repo_name,

                                       revision=cs.raw_id, qualified=True),

                              author_name=cs.author,

                              description=''.join(self.__get_desc(cs)),

                              pubdate=cs.date,

                              )

            response.content_type = feed.mime_type

            return feed.writeString('utf-8')

        key = repo_name + '_ATOM'

        inv = CacheInvalidation.invalidate(key)

        if inv is not None:

            region_invalidate(_get_feed_from_cache, None, key)

            CacheInvalidation.set_valid(inv.cache_key)

        return _get_feed_from_cache(key)

    def rss(self, repo_name):

        """Produce an rss2 feed via feedgenerator module"""

        @cache_region('long_term')

        def _get_feed_from_cache(key):

            feed = Rss201rev2Feed(

                title=self.title % repo_name,

                link=url('summary_home', repo_name=repo_name,

                         qualified=True),

                description=self.description % repo_name,

                language=self.language,

                ttl=self.ttl

            )

            for cs in reversed(list(c.rhodecode_repo[-self.feed_nr:])):

                feed.add_item(title=self._get_title(cs),

                              link=url('changeset_home', repo_name=repo_name,

                                       revision=cs.raw_id, qualified=True),

                              author_name=cs.author,

                              description=''.join(self.__get_desc(cs)),

                              pubdate=cs.date,

                             )

            response.content_type = feed.mime_type

            return feed.writeString('utf-8')

        key = repo_name + '_RSS'

        inv = CacheInvalidation.invalidate(key)

        if inv is not None:

            region_invalidate(_get_feed_from_cache, None, key)

            CacheInvalidation.set_valid(inv.cache_key)

        return _get_feed_from_cache(key)

# -*- coding: utf-8 -*-

"""

    rhodecode.lib.diffs

    ~~~~~~~~~~~~~~~~~~~

    Set of diffing helpers, previously part of vcs

    :created_on: Dec 4, 2011

    :author: marcink

    :copyright: (C) 2010-2012 Marcin Kuzminski <marcin@python-works.com>

    :original copyright: 2007-2008 by Armin Ronacher

    :license: GPLv3, see COPYING for more details.

"""

# 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/>.

import re

import difflib

import logging

import traceback

from itertools import tee, imap

from mercurial import patch

from mercurial.mdiff import diffopts

from mercurial.bundlerepo import bundlerepository

from pylons.i18n.translation import _

from rhodecode.lib.compat import BytesIO

from rhodecode.lib.vcs.utils.hgcompat import localrepo

from rhodecode.lib.vcs.exceptions import VCSError

from rhodecode.lib.vcs.nodes import FileNode, SubModuleNode

from rhodecode.lib.vcs.backends.base import EmptyChangeset

from rhodecode.lib.helpers import escape

from rhodecode.lib.utils import make_ui

from rhodecode.lib.utils2 import safe_unicode

log = logging.getLogger(__name__)

def wrap_to_table(str_):

    return '''<table class="code-difftable">

                <tr class="line no-comment">

                <td class="lineno new"></td>

                <td class="code no-comment"><pre>%s</pre></td>

                </tr>

              </table>''' % str_

def wrapped_diff(filenode_old, filenode_new, cut_off_limit=None,

                ignore_whitespace=True, line_context=3,

                enable_comments=False):

    """

    returns a wrapped diff into a table, checks for cut_off_limit and presents

    proper message

    """

    if filenode_old is None:

        filenode_old = FileNode(filenode_new.path, '', EmptyChangeset())

    if filenode_old.is_binary or filenode_new.is_binary:

        diff = wrap_to_table(_('binary file'))

        stats = (0, 0)

        size = 0

    elif cut_off_limit != -1 and (cut_off_limit is None or

    (filenode_old.size < cut_off_limit and filenode_new.size < cut_off_limit)):

        f_gitdiff = get_gitdiff(filenode_old, filenode_new,

                                ignore_whitespace=ignore_whitespace,

                                context=line_context)

        diff_processor = DiffProcessor(f_gitdiff, format='gitdiff')

        diff = diff_processor.as_html(enable_comments=enable_comments)

        stats = diff_processor.stat()

        size = len(diff or '')

    else:

        diff = wrap_to_table(_('Changeset was too big and was cut off, use '

                               'diff menu to display this diff'))

        stats = (0, 0)

        size = 0

    if not diff:

        submodules = filter(lambda o: isinstance(o, SubModuleNode),

                            [filenode_new, filenode_old])

        if submodules:

            diff = wrap_to_table(escape('Submodule %r' % submodules[0]))

        else:

            diff = wrap_to_table(_('No changes detected'))

    cs1 = filenode_old.changeset.raw_id

    cs2 = filenode_new.changeset.raw_id

    return size, cs1, cs2, diff, stats

def get_gitdiff(filenode_old, filenode_new, ignore_whitespace=True, context=3):

    """

    Returns git style diff between given ``filenode_old`` and ``filenode_new``.

    :param ignore_whitespace: ignore whitespaces in diff

    """

    # make sure we pass in default context

    context = context or 3

    submodules = filter(lambda o: isinstance(o, SubModuleNode),

                        [filenode_new, filenode_old])

    if submodules:

        return ''

    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 = repo.get_diff(old_raw_id, new_raw_id, filenode_new.path,

                                ignore_whitespace, context)

    return vcs_gitdiff

NEW_FILENODE = 1

DEL_FILENODE = 2

MOD_FILENODE = 3

RENAMED_FILENODE = 4

CHMOD_FILENODE = 5

class DiffLimitExceeded(Exception):

    pass

class LimitedDiffContainer(object):

    def __init__(self, diff_limit, cur_diff_size, diff):

        self.diff = diff

        self.diff_limit = diff_limit

        self.cur_diff_size = cur_diff_size

    def __iter__(self):

        for l in self.diff:

            yield l

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.

    """

    _chunk_re = re.compile(r'^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@(.*)')

    _newline_marker = re.compile(r'^\\ No newline at end of file')

    _git_header_re = re.compile(r"""

        #^diff[ ]--git

            [ ]a/(?P<a_path>.+?)[ ]b/(?P<b_path>.+?)\n

        (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%\n

           ^rename[ ]from[ ](?P<rename_from>\S+)\n

           ^rename[ ]to[ ](?P<rename_to>\S+)(?:\n|$))?

        (?:^old[ ]mode[ ](?P<old_mode>\d+)\n

           ^new[ ]mode[ ](?P<new_mode>\d+)(?:\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|$))?

        (?:^---[ ](a/(?P<a_file>.+)|/dev/null)(?:\n|$))?

        (?:^\+\+\+[ ](b/(?P<b_file>.+)|/dev/null)(?:\n|$))?

    """, re.VERBOSE | re.MULTILINE)

    _hg_header_re = re.compile(r"""

        #^diff[ ]--git

            [ ]a/(?P<a_path>.+?)[ ]b/(?P<b_path>.+?)\n

        (?:^similarity[ ]index[ ](?P<similarity_index>\d+)%(?:\n|$))?

        (?:^rename[ ]from[ ](?P<rename_from>\S+)\n

           ^rename[ ]to[ ](?P<rename_to>\S+)(?:\n|$))?

        (?:^old[ ]mode[ ](?P<old_mode>\d+)\n

           ^new[ ]mode[ ](?P<new_mode>\d+)(?:\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|$))?

        (?:^---[ ](a/(?P<a_file>.+)|/dev/null)(?:\n|$))?

        (?:^\+\+\+[ ](b/(?P<b_file>.+)|/dev/null)(?:\n|$))?

    """, re.VERBOSE | re.MULTILINE)

    def __init__(self, diff, vcs='hg', format='gitdiff', diff_limit=None):

        """

        :param diff:   a text in diff format

        :param vcs: type of version controll hg or git

        :param format: format of diff passed, `udiff` or `gitdiff`

        :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, basestring):

            raise Exception('Diff must be a basestring got %s instead' % type(diff))

        self._diff = diff

        self._format = format

        self.adds = 0

        self.removes = 0

        # calculate diff size

        self.diff_size = len(diff)

        self.diff_limit = diff_limit

        self.cur_diff_size = 0

        self.parsed = False

        self.parsed_diff = []

        self.vcs = vcs

        if format == 'gitdiff':

            self.differ = self._highlight_line_difflib

            self._parser = self._parse_gitdiff

        else:

            self.differ = self._highlight_line_udiff

            self._parser = self._parse_udiff

    def _copy_iterator(self):

        """

        make a fresh copy of generator, we should not iterate thru

        an original as it's needed for repeating operations on

        this instance of DiffProcessor

        """

        self.__udiff, iterator_copy = tee(self.__udiff)

        return iterator_copy

    def _escaper(self, string):

        """

        Escaper for diff escapes special chars and checks the diff limit

        :param string:

        :type string:

        """

        self.cur_diff_size += len(string)

        # escaper get's iterated on each .next() call and it checks if each

        # parsed line doesn't exceed the diff limit

        if self.diff_limit is not None and self.cur_diff_size > self.diff_limit:

            raise DiffLimitExceeded('Diff Limit Exceeded')

        return safe_unicode(string).replace('&', '&')\

                .replace('<', '&lt;')\

                .replace('>', '>')

    def _line_counter(self, l):

        """

        Checks each line and bumps total adds/removes for this diff

        :param l:

        """

        if l.startswith('+') and not l.startswith('+++'):

            self.adds += 1

        elif l.startswith('-') and not l.startswith('---'):

            self.removes += 1

        return safe_unicode(l)

    def _highlight_line_difflib(self, line, next_):

        """

        Highlight inline changes in both lines.

        """

        if line['action'] == 'del':

            old, new = line, next_

        else:

            old, new = next_, line

        oldwords = re.split(r'(\W)', old['line'])

        newwords = re.split(r'(\W)', 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)

    def _highlight_line_udiff(self, line, next_):

        """

        Highlight inline changes in both lines.

        """

        start = 0

        limit = min(len(line['line']), len(next_['line']))

        while start < limit and line['line'][start] == next_['line'][start]:

            start += 1

        end = -1

        limit -= start

        while -end <= limit and line['line'][end] == next_['line'][end]:

            end -= 1

        end += 1

        if start or end:

            def do(l):

                last = end + len(l['line'])

                if l['action'] == 'add':

                    tag = 'ins'

                else:

                    tag = 'del'

                l['line'] = '%s<%s>%s</%s>%s' % (

                    l['line'][:start],

                    tag,

                    l['line'][start:last],

                    tag,

                    l['line'][last:]

                )

            do(line)

            do(next_)

    def _get_header(self, diff_chunk):

        """

        parses the diff header, and returns parts, and leftover diff

        parts consists of 14 elements::

            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

        :param diff_chunk:

        :type diff_chunk:

        """

        if self.vcs == 'git':

            match = self._git_header_re.match(diff_chunk)

            diff = diff_chunk[match.end():]

            return match.groupdict(), imap(self._escaper, diff.splitlines(1))

        elif self.vcs == 'hg':

            match = self._hg_header_re.match(diff_chunk)

            diff = diff_chunk[match.end():]

            return match.groupdict(), imap(self._escaper, diff.splitlines(1))

        else:

            raise Exception('VCS type %s is not supported' % self.vcs)

    def _clean_line(self, line, command):

        if command in ['+', '-', ' ']:

            #only modify the line if it's actually a diff thing

            line = line[1:]

        return line

    def _parse_gitdiff(self, inline_diff=True):

        _files = []

        diff_container = lambda arg: arg

        ##split the diff in chunks of separate --git a/file b/file chunks

        for raw_diff in ('\n' + self._diff).split('\ndiff --git')[1:]:

            binary = False

            binary_msg = 'unknown binary'

            head, diff = self._get_header(raw_diff)

            if not head['a_file'] and head['b_file']:

                op = 'A'

            elif head['a_file'] and head['b_file']:

                op = 'M'

            elif head['a_file'] and not head['b_file']:

                op = 'D'

            else:

                #probably we're dealing with a binary file 1

                binary = True

                if head['deleted_file_mode']:

                    op = 'D'

                    stats = ['b', DEL_FILENODE]

                    binary_msg = 'deleted binary file'

                elif head['new_file_mode']:

                    op = 'A'

                    stats = ['b', NEW_FILENODE]

                    binary_msg = 'new binary file %s' % head['new_file_mode']

                else:

                    if head['new_mode'] and head['old_mode']:

                        stats = ['b', CHMOD_FILENODE]

                        op = 'M'

                        binary_msg = ('modified binary file chmod %s => %s'

                                      % (head['old_mode'], head['new_mode']))

                    elif (head['rename_from'] and head['rename_to']

                          and head['rename_from'] != head['rename_to']):

                        stats = ['b', RENAMED_FILENODE]

                        op = 'M'

                        binary_msg = ('file renamed from %s to %s'

                                      % (head['rename_from'], head['rename_to']))

                    else:

                        stats = ['b', MOD_FILENODE]

                        op = 'M'

                        binary_msg = 'modified binary file'

            if not binary:

                try:

                    chunks, stats = self._parse_lines(diff)

                except DiffLimitExceeded:

                    diff_container = lambda _diff: LimitedDiffContainer(

                                                self.diff_limit,

                                                self.cur_diff_size,

                                                _diff)

                    break

            else:

                chunks = []

                chunks.append([{

                    'old_lineno': '',

                    'new_lineno': '',

                    'action':     'binary',

                    'line':       binary_msg,

                }])

            _files.append({

                'filename':         head['b_path'],

                'old_revision':     head['a_blob_id'],

                'new_revision':     head['b_blob_id'],

                'chunks':           chunks,

                'operation':        op,

                'stats':            stats,

            })

        sorter = lambda info: {'A': 0, 'M': 1, 'D': 2}.get(info['operation'])

        if inline_diff is False:

            return diff_container(sorted(_files, key=sorter))

        # highlight inline changes

        for diff_data in _files:

            for chunk in diff_data['chunks']:

                lineiter = iter(chunk)

                try:

                    while 1:

                        line = lineiter.next()

                        if line['action'] not in ['unmod', 'context']:

                            nextline = lineiter.next()

                            if nextline['action'] in ['unmod', 'context'] or \

                               nextline['action'] == line['action']:

                                continue

                            self.differ(line, nextline)

                except StopIteration:

                    pass

        return diff_container(sorted(_files, key=sorter))

    def _parse_udiff(self, inline_diff=True):

        raise NotImplementedError()

    def _parse_lines(self, diff):

        """

        Parse the diff an return data for the template.

        """

        lineiter = iter(diff)

        stats = [0, 0]

        try:

            chunks = []

            line = lineiter.next()

            while line:

                lines = []

                chunks.append(lines)

                match = self._chunk_re.match(line)

                if not match:

                    break

                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 = lineiter.next()

                while old_line < old_end or new_line < new_end:

                    command = ' '

                    if line:

                        command = line[0]

                    affects_old = affects_new = False

                    # ignore those if we don't expect them

                    if command in '#@':

                        continue

                    elif command == '+':

                        affects_new = True

                        action = 'add'

                        stats[0] += 1

                    elif command == '-':

                        affects_old = True

                        action = 'del'

                        stats[1] += 1

                    else:

                        affects_old = affects_new = True

                        action = 'unmod'

                    if not self._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':         self._clean_line(line, command)

                        })

                    line = lineiter.next()

                    if self._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':         self._clean_line(line, command)

                        })

        except StopIteration:

            pass

        return chunks, stats

    def _safe_id(self, idstring):

        """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', "_", '%s' % idstring)

        # Remove everything that is not a hyphen or a member of \w

        idstring = re.sub(r'(?!-)\W', "", idstring).lower()

        return idstring

    def prepare(self, inline_diff=True):

        """

        Prepare the passed udiff for HTML rendering. It'l return a list

        of dicts with diff information

        """

        parsed = self._parser(inline_diff=inline_diff)

        self.parsed = True

        self.parsed_diff = parsed

        return parsed

    def as_raw(self, diff_lines=None):

        """

        Returns raw string diff

        """

        return self._diff

        #return u''.join(imap(self._line_counter, self._diff.splitlines(1)))

    def as_html(self, table_class='code-difftable', line_class='line',

                new_lineno_class='lineno old', old_lineno_class='lineno new',

                code_class='code', enable_comments=False, parsed_lines=None):

        """

        Return given diff as html table with customized css classes

        """

        def _link_to_if(condition, label, url):

            """

            Generates a link if condition is meet or just the label if not.

            """

            if condition:

                return '''<a href="%(url)s">%(label)s</a>''' % {

                    'url': url,

                    'label': label

                }

            else:

                return label

        if not self.parsed:

            self.prepare()

        diff_lines = self.parsed_diff

        if parsed_lines:

            diff_lines = parsed_lines

        _html_empty = True

        _html = []

        _html.append('''<table class="%(table_class)s">\n''' % {

            'table_class': table_class

        })

        for diff in diff_lines:

            for line in diff['chunks']:

                _html_empty = False

                for change in line:

                    _html.append('''<tr class="%(lc)s %(action)s">\n''' % {

                        'lc': line_class,

                        'action': change['action']

                    })

                    anchor_old_id = ''

                    anchor_new_id = ''

                    anchor_old = "%(filename)s_o%(oldline_no)s" % {

                        'filename': self._safe_id(diff['filename']),

                        'oldline_no': change['old_lineno']

                    }

                    anchor_new = "%(filename)s_n%(oldline_no)s" % {

                        'filename': self._safe_id(diff['filename']),

                        'oldline_no': change['new_lineno']

                    }

                    cond_old = (change['old_lineno'] != '...' and

                                change['old_lineno'])

                    cond_new = (change['new_lineno'] != '...' and

                                change['new_lineno'])

                    if cond_old:

                        anchor_old_id = 'id="%s"' % anchor_old

                    if cond_new:

                        anchor_new_id = 'id="%s"' % anchor_new

                    ###########################################################

                    # OLD LINE NUMBER

                    ###########################################################

                    _html.append('''\t<td %(a_id)s class="%(olc)s">''' % {

                        'a_id': anchor_old_id,

                        'olc': old_lineno_class

                    })

                    _html.append('''%(link)s''' % {

                        'link': _link_to_if(True, change['old_lineno'],

                                            '#%s' % anchor_old)

                    })

                    _html.append('''</td>\n''')

                    ###########################################################

                    # NEW LINE NUMBER

                    ###########################################################

                    _html.append('''\t<td %(a_id)s class="%(nlc)s">''' % {

                        'a_id': anchor_new_id,

                        'nlc': new_lineno_class

                    })

                    _html.append('''%(link)s''' % {

                        'link': _link_to_if(True, change['new_lineno'],

                                            '#%s' % anchor_new)

                    })

                    _html.append('''</td>\n''')

                    ###########################################################

                    # CODE

                    ###########################################################

                    comments = '' if enable_comments else 'no-comment'

                    _html.append('''\t<td class="%(cc)s %(inc)s">''' % {

                        'cc': code_class,

                        'inc': comments

                    })

                    _html.append('''\n\t\t<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 stat(self):

        """

        Returns tuple of added, and removed lines for this instance

        """