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Python

# Table of Contents Extension for Python-Markdown
# ===============================================
# See https://Python-Markdown.github.io/extensions/toc
# for documentation.
# Original code Copyright 2008 [Jack Miller](https://codezen.org/)
# All changes Copyright 2008-2024 The Python Markdown Project
# License: [BSD](https://opensource.org/licenses/bsd-license.php)
"""
Add table of contents support to Python-Markdown.
See the [documentation](https://Python-Markdown.github.io/extensions/toc)
for details.
"""
from __future__ import annotations
from . import Extension
from ..treeprocessors import Treeprocessor
from ..util import parseBoolValue, AMP_SUBSTITUTE, deprecated, HTML_PLACEHOLDER_RE, AtomicString
from ..treeprocessors import UnescapeTreeprocessor
from ..serializers import RE_AMP
import re
import html
import unicodedata
from copy import deepcopy
import xml.etree.ElementTree as etree
from typing import TYPE_CHECKING, Any, Iterator, MutableSet
if TYPE_CHECKING: # pragma: no cover
from markdown import Markdown
def slugify(value: str, separator: str, unicode: bool = False) -> str:
""" Slugify a string, to make it URL friendly. """
if not unicode:
# Replace Extended Latin characters with ASCII, i.e. `žlutý` => `zluty`
value = unicodedata.normalize('NFKD', value)
value = value.encode('ascii', 'ignore').decode('ascii')
value = re.sub(r'[^\w\s-]', '', value).strip().lower()
return re.sub(r'[{}\s]+'.format(separator), separator, value)
def slugify_unicode(value: str, separator: str) -> str:
""" Slugify a string, to make it URL friendly while preserving Unicode characters. """
return slugify(value, separator, unicode=True)
IDCOUNT_RE = re.compile(r'^(.*)_([0-9]+)$')
def unique(id: str, ids: MutableSet[str]) -> str:
""" Ensure id is unique in set of ids. Append '_1', '_2'... if not """
while id in ids or not id:
m = IDCOUNT_RE.match(id)
if m:
id = '%s_%d' % (m.group(1), int(m.group(2))+1)
else:
id = '%s_%d' % (id, 1)
ids.add(id)
return id
@deprecated('Use `render_inner_html` and `striptags` instead.')
def get_name(el: etree.Element) -> str:
"""Get title name."""
text = []
for c in el.itertext():
if isinstance(c, AtomicString):
text.append(html.unescape(c))
else:
text.append(c)
return ''.join(text).strip()
@deprecated('Use `run_postprocessors`, `render_inner_html` and/or `striptags` instead.')
def stashedHTML2text(text: str, md: Markdown, strip_entities: bool = True) -> str:
""" Extract raw HTML from stash, reduce to plain text and swap with placeholder. """
def _html_sub(m: re.Match[str]) -> str:
""" Substitute raw html with plain text. """
try:
raw = md.htmlStash.rawHtmlBlocks[int(m.group(1))]
except (IndexError, TypeError): # pragma: no cover
return m.group(0)
# Strip out tags and/or entities - leaving text
res = re.sub(r'(<[^>]+>)', '', raw)
if strip_entities:
res = re.sub(r'(&[\#a-zA-Z0-9]+;)', '', res)
return res
return HTML_PLACEHOLDER_RE.sub(_html_sub, text)
def unescape(text: str) -> str:
""" Unescape Markdown backslash escaped text. """
c = UnescapeTreeprocessor()
return c.unescape(text)
def strip_tags(text: str) -> str:
""" Strip HTML tags and return plain text. Note: HTML entities are unaffected. """
# A comment could contain a tag, so strip comments first
while (start := text.find('<!--')) != -1 and (end := text.find('-->', start)) != -1:
text = f'{text[:start]}{text[end + 3:]}'
while (start := text.find('<')) != -1 and (end := text.find('>', start)) != -1:
text = f'{text[:start]}{text[end + 1:]}'
# Collapse whitespace
text = ' '.join(text.split())
return text
def escape_cdata(text: str) -> str:
""" Escape character data. """
if "&" in text:
# Only replace & when not part of an entity
text = RE_AMP.sub('&amp;', text)
if "<" in text:
text = text.replace("<", "&lt;")
if ">" in text:
text = text.replace(">", "&gt;")
return text
def run_postprocessors(text: str, md: Markdown) -> str:
""" Run postprocessors from Markdown instance on text. """
for pp in md.postprocessors:
text = pp.run(text)
return text.strip()
def render_inner_html(el: etree.Element, md: Markdown) -> str:
""" Fully render inner html of an `etree` element as a string. """
# The `UnescapeTreeprocessor` runs after `toc` extension so run here.
text = unescape(md.serializer(el))
# strip parent tag
start = text.index('>') + 1
end = text.rindex('<')
text = text[start:end].strip()
return run_postprocessors(text, md)
def remove_fnrefs(root: etree.Element) -> etree.Element:
""" Remove footnote references from a copy of the element, if any are present. """
# Remove footnote references, which look like this: `<sup id="fnref:1">...</sup>`.
# If there are no `sup` elements, then nothing to do.
if next(root.iter('sup'), None) is None:
return root
root = deepcopy(root)
# Find parent elements that contain `sup` elements.
for parent in root.findall('.//sup/..'):
carry_text = ""
for child in reversed(parent): # Reversed for the ability to mutate during iteration.
# Remove matching footnote references but carry any `tail` text to preceding elements.
if child.tag == 'sup' and child.get('id', '').startswith('fnref'):
carry_text = f'{child.tail or ""}{carry_text}'
parent.remove(child)
elif carry_text:
child.tail = f'{child.tail or ""}{carry_text}'
carry_text = ""
if carry_text:
parent.text = f'{parent.text or ""}{carry_text}'
return root
def nest_toc_tokens(toc_list):
"""Given an unsorted list with errors and skips, return a nested one.
[{'level': 1}, {'level': 2}]
=>
[{'level': 1, 'children': [{'level': 2, 'children': []}]}]
A wrong list is also converted:
[{'level': 2}, {'level': 1}]
=>
[{'level': 2, 'children': []}, {'level': 1, 'children': []}]
"""
ordered_list = []
if len(toc_list):
# Initialize everything by processing the first entry
last = toc_list.pop(0)
last['children'] = []
levels = [last['level']]
ordered_list.append(last)
parents = []
# Walk the rest nesting the entries properly
while toc_list:
t = toc_list.pop(0)
current_level = t['level']
t['children'] = []
# Reduce depth if current level < last item's level
if current_level < levels[-1]:
# Pop last level since we know we are less than it
levels.pop()
# Pop parents and levels we are less than or equal to
to_pop = 0
for p in reversed(parents):
if current_level <= p['level']:
to_pop += 1
else: # pragma: no cover
break
if to_pop:
levels = levels[:-to_pop]
parents = parents[:-to_pop]
# Note current level as last
levels.append(current_level)
# Level is the same, so append to
# the current parent (if available)
if current_level == levels[-1]:
(parents[-1]['children'] if parents
else ordered_list).append(t)
# Current level is > last item's level,
# So make last item a parent and append current as child
else:
last['children'].append(t)
parents.append(last)
levels.append(current_level)
last = t
return ordered_list
class TocTreeprocessor(Treeprocessor):
""" Step through document and build TOC. """
def __init__(self, md: Markdown, config: dict[str, Any]):
super().__init__(md)
self.marker: str = config["marker"]
self.title: str = config["title"]
self.base_level = int(config["baselevel"]) - 1
self.slugify = config["slugify"]
self.sep = config["separator"]
self.toc_class = config["toc_class"]
self.title_class: str = config["title_class"]
self.use_anchors: bool = parseBoolValue(config["anchorlink"])
self.anchorlink_class: str = config["anchorlink_class"]
self.use_permalinks = parseBoolValue(config["permalink"], False)
if self.use_permalinks is None:
self.use_permalinks = config["permalink"]
self.permalink_class: str = config["permalink_class"]
self.permalink_title: str = config["permalink_title"]
self.permalink_leading: bool | None = parseBoolValue(config["permalink_leading"], False)
self.header_rgx = re.compile("[Hh][123456]")
if isinstance(config["toc_depth"], str) and '-' in config["toc_depth"]:
self.toc_top, self.toc_bottom = [int(x) for x in config["toc_depth"].split('-')]
else:
self.toc_top = 1
self.toc_bottom = int(config["toc_depth"])
def iterparent(self, node: etree.Element) -> Iterator[tuple[etree.Element, etree.Element]]:
""" Iterator wrapper to get allowed parent and child all at once. """
# We do not allow the marker inside a header as that
# would causes an endless loop of placing a new TOC
# inside previously generated TOC.
for child in node:
if not self.header_rgx.match(child.tag) and child.tag not in ['pre', 'code']:
yield node, child
yield from self.iterparent(child)
def replace_marker(self, root: etree.Element, elem: etree.Element) -> None:
""" Replace marker with elem. """
for (p, c) in self.iterparent(root):
text = ''.join(c.itertext()).strip()
if not text:
continue
# To keep the output from screwing up the
# validation by putting a `<div>` inside of a `<p>`
# we actually replace the `<p>` in its entirety.
# The `<p>` element may contain more than a single text content
# (`nl2br` can introduce a `<br>`). In this situation, `c.text` returns
# the very first content, ignore children contents or tail content.
# `len(c) == 0` is here to ensure there is only text in the `<p>`.
if c.text and c.text.strip() == self.marker and len(c) == 0:
for i in range(len(p)):
if p[i] == c:
p[i] = elem
break
def set_level(self, elem: etree.Element) -> None:
""" Adjust header level according to base level. """
level = int(elem.tag[-1]) + self.base_level
if level > 6:
level = 6
elem.tag = 'h%d' % level
def add_anchor(self, c: etree.Element, elem_id: str) -> None:
anchor = etree.Element("a")
anchor.text = c.text
anchor.attrib["href"] = "#" + elem_id
anchor.attrib["class"] = self.anchorlink_class
c.text = ""
for elem in c:
anchor.append(elem)
while len(c):
c.remove(c[0])
c.append(anchor)
def add_permalink(self, c: etree.Element, elem_id: str) -> None:
permalink = etree.Element("a")
permalink.text = ("%spara;" % AMP_SUBSTITUTE
if self.use_permalinks is True
else self.use_permalinks)
permalink.attrib["href"] = "#" + elem_id
permalink.attrib["class"] = self.permalink_class
if self.permalink_title:
permalink.attrib["title"] = self.permalink_title
if self.permalink_leading:
permalink.tail = c.text
c.text = ""
c.insert(0, permalink)
else:
c.append(permalink)
def build_toc_div(self, toc_list: list) -> etree.Element:
""" Return a string div given a toc list. """
div = etree.Element("div")
div.attrib["class"] = self.toc_class
# Add title to the div
if self.title:
header = etree.SubElement(div, "span")
if self.title_class:
header.attrib["class"] = self.title_class
header.text = self.title
def build_etree_ul(toc_list: list, parent: etree.Element) -> etree.Element:
ul = etree.SubElement(parent, "ul")
for item in toc_list:
# List item link, to be inserted into the toc div
li = etree.SubElement(ul, "li")
link = etree.SubElement(li, "a")
link.text = item.get('name', '')
link.attrib["href"] = '#' + item.get('id', '')
if item['children']:
build_etree_ul(item['children'], li)
return ul
build_etree_ul(toc_list, div)
if 'prettify' in self.md.treeprocessors:
self.md.treeprocessors['prettify'].run(div)
return div
def run(self, doc: etree.Element) -> None:
# Get a list of id attributes
used_ids = set()
for el in doc.iter():
if "id" in el.attrib:
used_ids.add(el.attrib["id"])
toc_tokens = []
for el in doc.iter():
if isinstance(el.tag, str) and self.header_rgx.match(el.tag):
self.set_level(el)
innerhtml = render_inner_html(remove_fnrefs(el), self.md)
name = strip_tags(innerhtml)
# Do not override pre-existing ids
if "id" not in el.attrib:
el.attrib["id"] = unique(self.slugify(html.unescape(name), self.sep), used_ids)
data_toc_label = ''
if 'data-toc-label' in el.attrib:
data_toc_label = run_postprocessors(unescape(el.attrib['data-toc-label']), self.md)
# Overwrite name with sanitized value of `data-toc-label`.
name = escape_cdata(strip_tags(data_toc_label))
# Remove the data-toc-label attribute as it is no longer needed
del el.attrib['data-toc-label']
if int(el.tag[-1]) >= self.toc_top and int(el.tag[-1]) <= self.toc_bottom:
toc_tokens.append({
'level': int(el.tag[-1]),
'id': el.attrib["id"],
'name': name,
'html': innerhtml,
'data-toc-label': data_toc_label
})
if self.use_anchors:
self.add_anchor(el, el.attrib["id"])
if self.use_permalinks not in [False, None]:
self.add_permalink(el, el.attrib["id"])
toc_tokens = nest_toc_tokens(toc_tokens)
div = self.build_toc_div(toc_tokens)
if self.marker:
self.replace_marker(doc, div)
# serialize and attach to markdown instance.
toc = self.md.serializer(div)
for pp in self.md.postprocessors:
toc = pp.run(toc)
self.md.toc_tokens = toc_tokens
self.md.toc = toc
class TocExtension(Extension):
TreeProcessorClass = TocTreeprocessor
def __init__(self, **kwargs):
self.config = {
'marker': [
'[TOC]',
'Text to find and replace with Table of Contents. Set to an empty string to disable. '
'Default: `[TOC]`.'
],
'title': [
'', 'Title to insert into TOC `<div>`. Default: an empty string.'
],
'title_class': [
'toctitle', 'CSS class used for the title. Default: `toctitle`.'
],
'toc_class': [
'toc', 'CSS class(es) used for the link. Default: `toclink`.'
],
'anchorlink': [
False, 'True if header should be a self link. Default: `False`.'
],
'anchorlink_class': [
'toclink', 'CSS class(es) used for the link. Defaults: `toclink`.'
],
'permalink': [
0, 'True or link text if a Sphinx-style permalink should be added. Default: `False`.'
],
'permalink_class': [
'headerlink', 'CSS class(es) used for the link. Default: `headerlink`.'
],
'permalink_title': [
'Permanent link', 'Title attribute of the permalink. Default: `Permanent link`.'
],
'permalink_leading': [
False,
'True if permalinks should be placed at start of the header, rather than end. Default: False.'
],
'baselevel': ['1', 'Base level for headers. Default: `1`.'],
'slugify': [
slugify, 'Function to generate anchors based on header text. Default: `slugify`.'
],
'separator': ['-', 'Word separator. Default: `-`.'],
'toc_depth': [
6,
'Define the range of section levels to include in the Table of Contents. A single integer '
'(b) defines the bottom section level (<h1>..<hb>) only. A string consisting of two digits '
'separated by a hyphen in between (`2-5`) defines the top (t) and the bottom (b) (<ht>..<hb>). '
'Default: `6` (bottom).'
],
}
""" Default configuration options. """
super().__init__(**kwargs)
def extendMarkdown(self, md):
""" Add TOC tree processor to Markdown. """
md.registerExtension(self)
self.md = md
self.reset()
tocext = self.TreeProcessorClass(md, self.getConfigs())
md.treeprocessors.register(tocext, 'toc', 5)
def reset(self) -> None:
self.md.toc = ''
self.md.toc_tokens = []
def makeExtension(**kwargs): # pragma: no cover
return TocExtension(**kwargs)