zulip/zerver/lib/bugdown/codehilite.py

228 lines
8.3 KiB
Python

"""
CodeHilite Extension for Python-Markdown
========================================
Adds code/syntax highlighting to standard Python-Markdown code blocks.
Copyright 2006-2008 [Waylan Limberg](http://achinghead.com/).
Project website: <http://packages.python.org/Markdown/extensions/code_hilite.html>
Contact: markdown@freewisdom.org
License: BSD (see ../LICENSE.md for details)
Dependencies:
* [Python 2.3+](http://python.org/)
* [Markdown 2.0+](http://packages.python.org/Markdown/)
* [Pygments](http://pygments.org/)
"""
from typing import Any, Dict, List
import markdown
try:
from pygments import highlight
from pygments.lexers import get_lexer_by_name, guess_lexer, TextLexer
from pygments.formatters import HtmlFormatter
pygments = True
except ImportError:
pygments = False
# ------------------ The Main CodeHilite Class ----------------------
class CodeHilite(object):
"""
Determine language of source code, and pass it into the pygments hilighter.
Basic Usage:
>>> code = CodeHilite(src = 'some text')
>>> html = code.hilite()
* src: Source string or any object with a .readline attribute.
* force_linenos: (Boolean) Force line numbering 'on' (True) or 'off' (False).
If not specified, number lines iff a shebang line is present.
* guess_lang: (Boolean) Turn language auto-detection 'on' or 'off' (on by default).
* css_class: Set class name of wrapper div ('codehilite' by default).
Low Level Usage:
>>> code = CodeHilite()
>>> code.src = 'some text' # String or anything with a .readline attr.
>>> code.linenos = True # True or False; Turns line numbering on or of.
>>> html = code.hilite()
"""
def __init__(self, src=None, force_linenos=None, guess_lang=True,
css_class="codehilite", lang=None, style='default',
noclasses=False, tab_length=4):
self.src = src
self.lang = lang
self.linenos = force_linenos
self.guess_lang = guess_lang
self.css_class = css_class
self.style = style
self.noclasses = noclasses
self.tab_length = tab_length
def hilite(self):
"""
Pass code to the [Pygments](http://pygments.pocoo.org/) highliter with
optional line numbers. The output should then be styled with css to
your liking. No styles are applied by default - only styling hooks
(i.e.: <span class="k">).
returns : A string of html.
"""
self.src = self.src.strip('\n')
if self.lang is None:
self._getLang()
if pygments:
try:
lexer = get_lexer_by_name(self.lang)
except ValueError:
try:
if self.guess_lang:
lexer = guess_lexer(self.src)
else:
lexer = TextLexer()
except ValueError:
lexer = TextLexer()
formatter = HtmlFormatter(linenos=bool(self.linenos),
cssclass=self.css_class,
style=self.style,
noclasses=self.noclasses)
return highlight(self.src, lexer, formatter)
else:
# just escape and build markup usable by JS highlighting libs
txt = self.src.replace('&', '&amp;')
txt = txt.replace('<', '&lt;')
txt = txt.replace('>', '&gt;')
txt = txt.replace('"', '&quot;')
classes = []
if self.lang:
classes.append('language-%s' % (self.lang,))
if self.linenos:
classes.append('linenums')
class_str = ''
if classes:
class_str = ' class="%s"' % ' '.join(classes)
return '<pre class="%s"><code%s>%s</code></pre>\n'% \
(self.css_class, class_str, txt)
def _getLang(self):
"""
Determines language of a code block from shebang line and whether said
line should be removed or left in place. If the sheband line contains a
path (even a single /) then it is assumed to be a real shebang line and
left alone. However, if no path is given (e.i.: #!python or :::python)
then it is assumed to be a mock shebang for language identifitation of a
code fragment and removed from the code block prior to processing for
code highlighting. When a mock shebang (e.i: #!python) is found, line
numbering is turned on. When colons are found in place of a shebang
(e.i.: :::python), line numbering is left in the current state - off
by default.
"""
import re
# split text into lines
lines = self.src.split("\n")
# pull first line to examine
fl = lines.pop(0)
c = re.compile(r'''
(?:(?:^::+)|(?P<shebang>^[#]!)) # Shebang or 2 or more colons.
(?P<path>(?:/\w+)*[/ ])? # Zero or 1 path
(?P<lang>[\w+-]*) # The language
''', re.VERBOSE)
# search first line for shebang
m = c.search(fl)
if m:
# we have a match
try:
self.lang = m.group('lang').lower()
except IndexError:
self.lang = None
if m.group('path'):
# path exists - restore first line
lines.insert(0, fl)
if m.group('shebang') and self.linenos is None:
# shebang exists - use line numbers
self.linenos = True
else:
# No match
lines.insert(0, fl)
self.src = "\n".join(lines).strip("\n")
# ------------------ The Markdown Extension -------------------------------
class HiliteTreeprocessor(markdown.treeprocessors.Treeprocessor):
""" Hilight source code in code blocks. """
def run(self, root):
""" Find code blocks and store in htmlStash. """
blocks = root.getiterator('pre')
for block in blocks:
children = block.getchildren()
if len(children) == 1 and children[0].tag == 'code':
code = CodeHilite(children[0].text,
force_linenos=self.config['force_linenos'],
guess_lang=self.config['guess_lang'],
css_class=self.config['css_class'],
style=self.config['pygments_style'],
noclasses=self.config['noclasses'],
tab_length=self.markdown.tab_length)
placeholder = self.markdown.htmlStash.store(code.hilite(),
safe=True)
# Clear codeblock in etree instance
block.clear()
# Change to p element which will later
# be removed when inserting raw html
block.tag = 'p'
block.text = placeholder
class CodeHiliteExtension(markdown.Extension):
""" Add source code hilighting to markdown codeblocks. """
def __init__(self, configs):
# define default configs
self.config = {
'force_linenos' : [None, "Force line numbers - Default: detect based on shebang"],
'guess_lang' : [True, "Automatic language detection - Default: True"],
'css_class' : ["codehilite",
"Set class name for wrapper <div> - Default: codehilite"],
'pygments_style' : ['default', 'Pygments HTML Formatter Style (Colorscheme) - Default: default'],
'noclasses': [False, 'Use inline styles instead of CSS classes - Default false']
} # type: Dict[str, List[Any]]
# Override defaults with user settings
for key, value in configs:
# convert strings to booleans
if value == 'True': value = True
if value == 'False': value = False
self.setConfig(key, value)
def extendMarkdown(self, md, md_globals):
""" Add HilitePostprocessor to Markdown instance. """
hiliter = HiliteTreeprocessor(md)
hiliter.config = self.getConfigs()
md.treeprocessors.add("hilite", hiliter, "<inline")
md.registerExtension(self)
def makeExtension(configs=None):
return CodeHiliteExtension(configs=configs or [])