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477 lines
17 KiB
Python
477 lines
17 KiB
Python
2 months ago
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# Python Markdown
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# A Python implementation of John Gruber's Markdown.
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# Documentation: https://python-markdown.github.io/
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# GitHub: https://github.com/Python-Markdown/markdown/
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# PyPI: https://pypi.org/project/Markdown/
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# Started by Manfred Stienstra (http://www.dwerg.net/).
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# Maintained for a few years by Yuri Takhteyev (http://www.freewisdom.org).
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# Currently maintained by Waylan Limberg (https://github.com/waylan),
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# Dmitry Shachnev (https://github.com/mitya57) and Isaac Muse (https://github.com/facelessuser).
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# Copyright 2007-2023 The Python Markdown Project (v. 1.7 and later)
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# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
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# Copyright 2004 Manfred Stienstra (the original version)
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# License: BSD (see LICENSE.md for details).
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"""
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Tree processors manipulate the tree created by block processors. They can even create an entirely
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new `ElementTree` object. This is an excellent place for creating summaries, adding collected
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references, or last minute adjustments.
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"""
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from __future__ import annotations
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import re
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import xml.etree.ElementTree as etree
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from typing import TYPE_CHECKING, Any
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from . import util
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from . import inlinepatterns
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if TYPE_CHECKING: # pragma: no cover
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from markdown import Markdown
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def build_treeprocessors(md: Markdown, **kwargs: Any) -> util.Registry[Treeprocessor]:
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""" Build the default `treeprocessors` for Markdown. """
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treeprocessors = util.Registry()
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treeprocessors.register(InlineProcessor(md), 'inline', 20)
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treeprocessors.register(PrettifyTreeprocessor(md), 'prettify', 10)
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treeprocessors.register(UnescapeTreeprocessor(md), 'unescape', 0)
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return treeprocessors
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def isString(s: object) -> bool:
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""" Return `True` if object is a string but not an [`AtomicString`][markdown.util.AtomicString]. """
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if not isinstance(s, util.AtomicString):
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return isinstance(s, str)
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return False
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class Treeprocessor(util.Processor):
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"""
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`Treeprocessor`s are run on the `ElementTree` object before serialization.
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Each `Treeprocessor` implements a `run` method that takes a pointer to an
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`Element` and modifies it as necessary.
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`Treeprocessors` must extend `markdown.Treeprocessor`.
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"""
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def run(self, root: etree.Element) -> etree.Element | None:
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"""
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Subclasses of `Treeprocessor` should implement a `run` method, which
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takes a root `Element`. This method can return another `Element`
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object, and the existing root `Element` will be replaced, or it can
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modify the current tree and return `None`.
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"""
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pass # pragma: no cover
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class InlineProcessor(Treeprocessor):
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"""
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A `Treeprocessor` that traverses a tree, applying inline patterns.
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"""
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def __init__(self, md: Markdown):
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self.__placeholder_prefix = util.INLINE_PLACEHOLDER_PREFIX
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self.__placeholder_suffix = util.ETX
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self.__placeholder_length = 4 + len(self.__placeholder_prefix) \
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+ len(self.__placeholder_suffix)
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self.__placeholder_re = util.INLINE_PLACEHOLDER_RE
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self.md = md
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self.inlinePatterns = md.inlinePatterns
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self.ancestors: list[str] = []
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def __makePlaceholder(self, type: str) -> tuple[str, str]:
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""" Generate a placeholder """
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id = "%04d" % len(self.stashed_nodes)
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hash = util.INLINE_PLACEHOLDER % id
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return hash, id
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def __findPlaceholder(self, data: str, index: int) -> tuple[str | None, int]:
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"""
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Extract id from data string, start from index.
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Arguments:
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data: String.
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index: Index, from which we start search.
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Returns:
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Placeholder id and string index, after the found placeholder.
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"""
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m = self.__placeholder_re.search(data, index)
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if m:
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return m.group(1), m.end()
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else:
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return None, index + 1
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def __stashNode(self, node: etree.Element | str, type: str) -> str:
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""" Add node to stash. """
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placeholder, id = self.__makePlaceholder(type)
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self.stashed_nodes[id] = node
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return placeholder
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def __handleInline(self, data: str, patternIndex: int = 0) -> str:
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"""
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Process string with inline patterns and replace it with placeholders.
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Arguments:
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data: A line of Markdown text.
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patternIndex: The index of the `inlinePattern` to start with.
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Returns:
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String with placeholders.
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"""
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if not isinstance(data, util.AtomicString):
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startIndex = 0
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count = len(self.inlinePatterns)
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while patternIndex < count:
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data, matched, startIndex = self.__applyPattern(
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self.inlinePatterns[patternIndex], data, patternIndex, startIndex
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)
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if not matched:
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patternIndex += 1
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return data
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def __processElementText(self, node: etree.Element, subnode: etree.Element, isText: bool = True) -> None:
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"""
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Process placeholders in `Element.text` or `Element.tail`
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of Elements popped from `self.stashed_nodes`.
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Arguments:
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node: Parent node.
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subnode: Processing node.
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isText: Boolean variable, True - it's text, False - it's a tail.
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"""
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if isText:
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text = subnode.text
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subnode.text = None
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else:
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text = subnode.tail
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subnode.tail = None
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childResult = self.__processPlaceholders(text, subnode, isText)
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if not isText and node is not subnode:
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pos = list(node).index(subnode) + 1
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else:
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pos = 0
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childResult.reverse()
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for newChild in childResult:
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node.insert(pos, newChild[0])
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def __processPlaceholders(
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self,
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data: str | None,
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parent: etree.Element,
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isText: bool = True
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) -> list[tuple[etree.Element, list[str]]]:
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"""
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Process string with placeholders and generate `ElementTree` tree.
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Arguments:
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data: String with placeholders instead of `ElementTree` elements.
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parent: Element, which contains processing inline data.
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isText: Boolean variable, True - it's text, False - it's a tail.
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Returns:
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List with `ElementTree` elements with applied inline patterns.
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"""
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def linkText(text: str | None) -> None:
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if text:
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if result:
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if result[-1][0].tail:
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result[-1][0].tail += text
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else:
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result[-1][0].tail = text
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elif not isText:
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if parent.tail:
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parent.tail += text
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else:
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parent.tail = text
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else:
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if parent.text:
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parent.text += text
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else:
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parent.text = text
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result = []
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strartIndex = 0
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while data:
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index = data.find(self.__placeholder_prefix, strartIndex)
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if index != -1:
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id, phEndIndex = self.__findPlaceholder(data, index)
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if id in self.stashed_nodes:
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node = self.stashed_nodes.get(id)
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if index > 0:
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text = data[strartIndex:index]
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linkText(text)
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if not isinstance(node, str): # it's Element
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for child in [node] + list(node):
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if child.tail:
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if child.tail.strip():
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self.__processElementText(
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node, child, False
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)
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if child.text:
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if child.text.strip():
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self.__processElementText(child, child)
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else: # it's just a string
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linkText(node)
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strartIndex = phEndIndex
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continue
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strartIndex = phEndIndex
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result.append((node, self.ancestors[:]))
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else: # wrong placeholder
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end = index + len(self.__placeholder_prefix)
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linkText(data[strartIndex:end])
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strartIndex = end
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else:
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text = data[strartIndex:]
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if isinstance(data, util.AtomicString):
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# We don't want to loose the `AtomicString`
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text = util.AtomicString(text)
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linkText(text)
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data = ""
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return result
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def __applyPattern(
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self,
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pattern: inlinepatterns.Pattern,
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data: str,
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patternIndex: int,
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startIndex: int = 0
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) -> tuple[str, bool, int]:
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"""
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Check if the line fits the pattern, create the necessary
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elements, add it to `stashed_nodes`.
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Arguments:
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data: The text to be processed.
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pattern: The pattern to be checked.
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patternIndex: Index of current pattern.
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startIndex: String index, from which we start searching.
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Returns:
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String with placeholders instead of `ElementTree` elements.
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"""
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new_style = isinstance(pattern, inlinepatterns.InlineProcessor)
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for exclude in pattern.ANCESTOR_EXCLUDES:
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if exclude.lower() in self.ancestors:
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return data, False, 0
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if new_style:
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match = None
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# Since `handleMatch` may reject our first match,
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# we iterate over the buffer looking for matches
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# until we can't find any more.
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for match in pattern.getCompiledRegExp().finditer(data, startIndex):
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node, start, end = pattern.handleMatch(match, data)
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if start is None or end is None:
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startIndex += match.end(0)
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match = None
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continue
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break
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else: # pragma: no cover
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match = pattern.getCompiledRegExp().match(data[startIndex:])
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leftData = data[:startIndex]
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if not match:
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return data, False, 0
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if not new_style: # pragma: no cover
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node = pattern.handleMatch(match)
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start = match.start(0)
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end = match.end(0)
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if node is None:
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return data, True, end
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if not isinstance(node, str):
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if not isinstance(node.text, util.AtomicString):
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# We need to process current node too
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for child in [node] + list(node):
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if not isString(node):
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if child.text:
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self.ancestors.append(child.tag.lower())
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child.text = self.__handleInline(
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child.text, patternIndex + 1
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)
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self.ancestors.pop()
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if child.tail:
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child.tail = self.__handleInline(
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child.tail, patternIndex
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)
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placeholder = self.__stashNode(node, pattern.type())
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if new_style:
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return "{}{}{}".format(data[:start],
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placeholder, data[end:]), True, 0
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else: # pragma: no cover
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return "{}{}{}{}".format(leftData,
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match.group(1),
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placeholder, match.groups()[-1]), True, 0
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def __build_ancestors(self, parent: etree.Element | None, parents: list[str]) -> None:
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"""Build the ancestor list."""
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ancestors = []
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while parent is not None:
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if parent is not None:
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ancestors.append(parent.tag.lower())
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parent = self.parent_map.get(parent)
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ancestors.reverse()
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parents.extend(ancestors)
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def run(self, tree: etree.Element, ancestors: list[str] | None = None) -> etree.Element:
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"""Apply inline patterns to a parsed Markdown tree.
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Iterate over `Element`, find elements with inline tag, apply inline
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patterns and append newly created Elements to tree. To avoid further
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processing of string with inline patterns, instead of normal string,
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use subclass [`AtomicString`][markdown.util.AtomicString]:
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node.text = markdown.util.AtomicString("This will not be processed.")
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Arguments:
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tree: `Element` object, representing Markdown tree.
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ancestors: List of parent tag names that precede the tree node (if needed).
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Returns:
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An element tree object with applied inline patterns.
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"""
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self.stashed_nodes: dict[str, etree.Element | str] = {}
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# Ensure a valid parent list, but copy passed in lists
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# to ensure we don't have the user accidentally change it on us.
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tree_parents = [] if ancestors is None else ancestors[:]
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self.parent_map = {c: p for p in tree.iter() for c in p}
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stack = [(tree, tree_parents)]
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while stack:
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currElement, parents = stack.pop()
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self.ancestors = parents
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self.__build_ancestors(currElement, self.ancestors)
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insertQueue = []
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for child in currElement:
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if child.text and not isinstance(
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child.text, util.AtomicString
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):
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self.ancestors.append(child.tag.lower())
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text = child.text
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child.text = None
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lst = self.__processPlaceholders(
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self.__handleInline(text), child
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)
|
||
|
|
for item in lst:
|
||
|
|
self.parent_map[item[0]] = child
|
||
|
|
stack += lst
|
||
|
|
insertQueue.append((child, lst))
|
||
|
|
self.ancestors.pop()
|
||
|
|
if child.tail:
|
||
|
|
tail = self.__handleInline(child.tail)
|
||
|
|
dumby = etree.Element('d')
|
||
|
|
child.tail = None
|
||
|
|
tailResult = self.__processPlaceholders(tail, dumby, False)
|
||
|
|
if dumby.tail:
|
||
|
|
child.tail = dumby.tail
|
||
|
|
pos = list(currElement).index(child) + 1
|
||
|
|
tailResult.reverse()
|
||
|
|
for newChild in tailResult:
|
||
|
|
self.parent_map[newChild[0]] = currElement
|
||
|
|
currElement.insert(pos, newChild[0])
|
||
|
|
if len(child):
|
||
|
|
self.parent_map[child] = currElement
|
||
|
|
stack.append((child, self.ancestors[:]))
|
||
|
|
|
||
|
|
for element, lst in insertQueue:
|
||
|
|
for i, obj in enumerate(lst):
|
||
|
|
newChild = obj[0]
|
||
|
|
element.insert(i, newChild)
|
||
|
|
return tree
|
||
|
|
|
||
|
|
|
||
|
|
class PrettifyTreeprocessor(Treeprocessor):
|
||
|
|
""" Add line breaks to the html document. """
|
||
|
|
|
||
|
|
def _prettifyETree(self, elem: etree.Element) -> None:
|
||
|
|
""" Recursively add line breaks to `ElementTree` children. """
|
||
|
|
|
||
|
|
i = "\n"
|
||
|
|
if self.md.is_block_level(elem.tag) and elem.tag not in ['code', 'pre']:
|
||
|
|
if (not elem.text or not elem.text.strip()) \
|
||
|
|
and len(elem) and self.md.is_block_level(elem[0].tag):
|
||
|
|
elem.text = i
|
||
|
|
for e in elem:
|
||
|
|
if self.md.is_block_level(e.tag):
|
||
|
|
self._prettifyETree(e)
|
||
|
|
if not elem.tail or not elem.tail.strip():
|
||
|
|
elem.tail = i
|
||
|
|
|
||
|
|
def run(self, root: etree.Element) -> None:
|
||
|
|
""" Add line breaks to `Element` object and its children. """
|
||
|
|
|
||
|
|
self._prettifyETree(root)
|
||
|
|
# Do `<br />`'s separately as they are often in the middle of
|
||
|
|
# inline content and missed by `_prettifyETree`.
|
||
|
|
brs = root.iter('br')
|
||
|
|
for br in brs:
|
||
|
|
if not br.tail or not br.tail.strip():
|
||
|
|
br.tail = '\n'
|
||
|
|
else:
|
||
|
|
br.tail = '\n%s' % br.tail
|
||
|
|
# Clean up extra empty lines at end of code blocks.
|
||
|
|
pres = root.iter('pre')
|
||
|
|
for pre in pres:
|
||
|
|
if len(pre) and pre[0].tag == 'code':
|
||
|
|
code = pre[0]
|
||
|
|
# Only prettify code containing text only
|
||
|
|
if not len(code) and code.text is not None:
|
||
|
|
code.text = util.AtomicString(code.text.rstrip() + '\n')
|
||
|
|
|
||
|
|
|
||
|
|
class UnescapeTreeprocessor(Treeprocessor):
|
||
|
|
""" Restore escaped chars """
|
||
|
|
|
||
|
|
RE = re.compile(r'{}(\d+){}'.format(util.STX, util.ETX))
|
||
|
|
|
||
|
|
def _unescape(self, m: re.Match[str]) -> str:
|
||
|
|
return chr(int(m.group(1)))
|
||
|
|
|
||
|
|
def unescape(self, text: str) -> str:
|
||
|
|
return self.RE.sub(self._unescape, text)
|
||
|
|
|
||
|
|
def run(self, root: etree.Element) -> None:
|
||
|
|
""" Loop over all elements and unescape all text. """
|
||
|
|
for elem in root.iter():
|
||
|
|
# Unescape text content
|
||
|
|
if elem.text and not elem.tag == 'code':
|
||
|
|
elem.text = self.unescape(elem.text)
|
||
|
|
# Unescape tail content
|
||
|
|
if elem.tail:
|
||
|
|
elem.tail = self.unescape(elem.tail)
|
||
|
|
# Unescape attribute values
|
||
|
|
for key, value in elem.items():
|
||
|
|
elem.set(key, self.unescape(value))
|