blob: 7d42c13be7befa34e090970906bb378da381f89d [file] [log] [blame]
# Copyright 2015 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Implements Gitiles' notification, aside and promotion blocks.
This extention makes the Markdown parser recognize the Gitiles' extended
blocks notation. The syntax is explained at:
https://gerrit.googlesource.com/gitiles/+/master/Documentation/markdown.md#Notification_aside_promotion-blocks
"""
from markdown.blockprocessors import BlockProcessor
from markdown.extensions import Extension
import re
import xml.etree.ElementTree as etree
class _GitilesExtBlockProcessor(BlockProcessor):
"""Process Gitiles' notification, aside and promotion blocks."""
RE_START = re.compile(r'^\*\*\* (note|aside|promo) *\n')
RE_END = re.compile(r'\n\*\*\* *\n?$')
def __init__(self, *args, **kwargs):
self._last_parent = None
BlockProcessor.__init__(self, *args, **kwargs)
def test(self, parent, block):
return self.RE_START.search(block) or self.RE_END.search(block)
def run(self, parent, blocks):
raw_block = blocks.pop(0)
match_start = self.RE_START.search(raw_block)
if match_start:
# Opening a new block.
rest = raw_block[match_start.end():]
if self._last_parent:
# Inconsistent state (nested starting markers). Ignore the marker
# and keep going.
blocks.insert(0, rest)
return
div = etree.SubElement(parent, 'div')
# Setting the class name is sufficient, because doc.css already has
# styles for these classes.
div.set('class', match_start.group(1))
self._last_parent = parent
blocks.insert(0, rest)
self.parser.parseBlocks(div, blocks)
return
match_end = self.RE_END.search(raw_block)
if match_end:
# Ending an existing block.
# Process the text preceding the ending marker in the current context
# (i.e. within the div block).
rest = raw_block[:match_end.start()]
self.parser.parseBlocks(parent, [rest])
if not self._last_parent:
# Inconsistent state (the ending marker is found but there is no
# matching starting marker).
# Let's continue as if we did not see the ending marker.
return
last_parent = self._last_parent
self._last_parent = None
self.parser.parseBlocks(last_parent, blocks)
return
class _GitilesExtBlockExtension(Extension):
"""Add Gitiles' extended blocks to Markdown, with a priority higher than the
highest builtin."""
def extendMarkdown(self, md):
md.parser.blockprocessors.register(_GitilesExtBlockProcessor(md.parser),
'gitilesextblocks', 101)
def makeExtension(*args, **kwargs):
return _GitilesExtBlockExtension(*args, **kwargs)