zulip/zerver/lib/bugdown/fenced_code.py

284 lines
8.2 KiB
Python

#!/usr/bin/env python
"""
Fenced Code Extension for Python Markdown
=========================================
This extension adds Fenced Code Blocks to Python-Markdown.
>>> import markdown
>>> text = '''
... A paragraph before a fenced code block:
...
... ~~~
... Fenced code block
... ~~~
... '''
>>> html = markdown.markdown(text, extensions=['fenced_code'])
>>> print html
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Works with safe_mode also (we check this because we are using the HtmlStash):
>>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
<p>A paragraph before a fenced code block:</p>
<pre><code>Fenced code block
</code></pre>
Include tilde's in a code block and wrap with blank lines:
>>> text = '''
... ~~~~~~~~
...
... ~~~~
... ~~~~~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code>
~~~~
</code></pre>
Language tags:
>>> text = '''
... ~~~~{.python}
... # Some python code
... ~~~~'''
>>> print markdown.markdown(text, extensions=['fenced_code'])
<pre><code class="python"># Some python code
</code></pre>
Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
Contact: markdown@freewisdom.org
License: BSD (see ../docs/LICENSE for details)
Dependencies:
* [Python 2.4+](http://python.org)
* [Markdown 2.0+](http://packages.python.org/Markdown/)
* [Pygments (optional)](http://pygments.org)
"""
import re
import markdown
from zerver.lib.bugdown.codehilite import CodeHilite, CodeHiliteExtension
from six import text_type
from typing import Any, Dict, List, Sequence
# Global vars
FENCE_RE = re.compile(u"""
# ~~~ or ```
(?P<fence>
^(?:~{3,}|`{3,})
)
[ ]* # spaces
(
\\{?\\.?
(?P<lang>
[a-zA-Z0-9_+-]*
) # "py" or "javascript"
\\}?
) # language, like ".py" or "{javascript}"
[ ]* # spaces
$
""", re.VERBOSE)
CODE_WRAP = u'<pre><code%s>%s</code></pre>'
LANG_TAG = u' class="%s"'
class FencedCodeExtension(markdown.Extension):
def extendMarkdown(self, md, md_globals):
""" Add FencedBlockPreprocessor to the Markdown instance. """
md.registerExtension(self)
# Newer versions of Python-Markdown (starting at 2.3?) have
# a normalize_whitespace preprocessor that needs to go first.
position = ('>normalize_whitespace'
if 'normalize_whitespace' in md.preprocessors
else '_begin')
md.preprocessors.add('fenced_code_block',
FencedBlockPreprocessor(md),
position)
class FencedBlockPreprocessor(markdown.preprocessors.Preprocessor):
def __init__(self, md):
markdown.preprocessors.Preprocessor.__init__(self, md)
self.checked_for_codehilite = False
self.codehilite_conf = {} # type: Dict[str, List[Any]]
def run(self, lines):
""" Match and store Fenced Code Blocks in the HtmlStash. """
output = [] # type: List[str]
class Record(object):
pass
processor = self
handlers = []
def push(handler):
handlers.append(handler)
def pop():
handlers.pop()
def check_for_new_fence(output, line):
m = FENCE_RE.match(line)
if m:
fence = m.group('fence')
lang = m.group('lang')
handler = generic_handler(output, fence, lang)
push(handler)
else:
output.append(line)
class OuterHandler(object):
def __init__(self, output):
self.output = output
def handle_line(self, line):
check_for_new_fence(self.output, line)
def done(self):
pop()
def generic_handler(output, fence, lang):
if lang in ('quote', 'quoted'):
return QuoteHandler(output, fence)
else:
return CodeHandler(output, fence, lang)
class QuoteHandler(object):
def __init__(self, output, fence):
self.output = output
self.fence = fence
self.lines = [] # type: Sequence[str]
def handle_line(self, line):
if line.rstrip() == self.fence:
self.done()
else:
check_for_new_fence(self.lines, line)
def done(self):
text = '\n'.join(self.lines)
text = processor.format_quote(text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
pop()
class CodeHandler(object):
def __init__(self, output, fence, lang):
self.output = output
self.fence = fence
self.lang = lang
self.lines = [] # type: Sequence[str]
def handle_line(self, line):
if line.rstrip() == self.fence:
self.done()
else:
self.lines.append(line)
def done(self):
text = '\n'.join(self.lines)
text = processor.format_code(self.lang, text)
text = processor.placeholder(text)
processed_lines = text.split('\n')
self.output.append('')
self.output.extend(processed_lines)
self.output.append('')
pop()
handler = OuterHandler(output)
push(handler)
for line in lines:
handlers[-1].handle_line(line)
while handlers:
handlers[-1].done()
# This fiddly handling of new lines at the end of our output was done to make
# existing tests pass. Bugdown is just kind of funny when it comes to new lines,
# but we could probably remove this hack.
if len(output) > 2 and output[-2] != '':
output.append('')
return output
def format_code(self, lang, text):
# type: (text_type, text_type) -> text_type
if lang:
langclass = LANG_TAG % (lang,)
else:
langclass = ''
# Check for code hilite extension
if not self.checked_for_codehilite:
for ext in self.markdown.registeredExtensions:
if isinstance(ext, CodeHiliteExtension):
self.codehilite_conf = ext.config
break
self.checked_for_codehilite = True
# If config is not empty, then the codehighlite extension
# is enabled, so we call it to highlite the code
if self.codehilite_conf:
highliter = CodeHilite(text,
force_linenos=self.codehilite_conf['force_linenos'][0],
guess_lang=self.codehilite_conf['guess_lang'][0],
css_class=self.codehilite_conf['css_class'][0],
style=self.codehilite_conf['pygments_style'][0],
lang=(lang or None),
noclasses=self.codehilite_conf['noclasses'][0])
code = highliter.hilite()
else:
code = CODE_WRAP % (langclass, self._escape(text))
return code
def format_quote(self, text):
paragraphs = text.split("\n\n")
quoted_paragraphs = []
for paragraph in paragraphs:
lines = paragraph.split("\n")
quoted_paragraphs.append("\n".join("> " + line for line in lines if line != ''))
return "\n\n".join(quoted_paragraphs)
def placeholder(self, code):
return self.markdown.htmlStash.store(code, safe=True)
def _escape(self, txt):
""" basic html escaping """
txt = txt.replace('&', '&amp;')
txt = txt.replace('<', '&lt;')
txt = txt.replace('>', '&gt;')
txt = txt.replace('"', '&quot;')
return txt
def makeExtension(configs=None):
return FencedCodeExtension(configs=configs)
if __name__ == "__main__":
import doctest
doctest.testmod()