"""
PRE-PROCESSORS
=============================================================================
Preprocessors work on source text before we start doing anything too
complicated.
"""
from __future__ import absolute_import
from __future__ import unicode_literals
from . import util
from . import odict
import re
def build_preprocessors(md_instance, **kwargs):
""" Build the default set of preprocessors used by Markdown. """
preprocessors = odict.OrderedDict()
preprocessors['normalize_whitespace'] = NormalizeWhitespace(md_instance)
if md_instance.safeMode != 'escape':
preprocessors["html_block"] = HtmlBlockPreprocessor(md_instance)
preprocessors["reference"] = ReferencePreprocessor(md_instance)
return preprocessors
class Preprocessor(util.Processor):
"""
Preprocessors are run after the text is broken into lines.
Each preprocessor implements a "run" method that takes a pointer to a
list of lines of the document, modifies it as necessary and returns
either the same pointer or a pointer to a new list.
Preprocessors must extend markdown.Preprocessor.
"""
def run(self, lines):
"""
Each subclass of Preprocessor should override the `run` method, which
takes the document as a list of strings split by newlines and returns
the (possibly modified) list of lines.
"""
pass # pragma: no cover
class NormalizeWhitespace(Preprocessor):
""" Normalize whitespace for consistant parsing. """
def run(self, lines):
source = '\n'.join(lines)
source = source.replace(util.STX, "").replace(util.ETX, "")
source = source.replace("\r\n", "\n").replace("\r", "\n") + "\n\n"
source = source.expandtabs(self.markdown.tab_length)
source = re.sub(r'(?<=\n) +\n', '\n', source)
return source.split('\n')
class HtmlBlockPreprocessor(Preprocessor):
"""Remove html blocks from the text and store them for later retrieval."""
right_tag_patterns = ["</%s>", "%s>"]
attrs_pattern = r"""
\s+(?P<attr>[^>"'/= ]+)=(?P<q>['"])(?P<value>.*?)(?P=q) # attr="value"
| # OR
\s+(?P<attr1>[^>"'/= ]+)=(?P<value1>[^> ]+) # attr=value
| # OR
\s+(?P<attr2>[^>"'/= ]+) # attr
"""
left_tag_pattern = r'^\<(?P<tag>[^> ]+)(?P<attrs>(%s)*)\s*\/?\>?' % \
attrs_pattern
attrs_re = re.compile(attrs_pattern, re.VERBOSE)
left_tag_re = re.compile(left_tag_pattern, re.VERBOSE)
markdown_in_raw = False
def _get_left_tag(self, block):
m = self.left_tag_re.match(block)
if m:
tag = m.group('tag')
raw_attrs = m.group('attrs')
attrs = {}
if raw_attrs:
for ma in self.attrs_re.finditer(raw_attrs):
if ma.group('attr'):
if ma.group('value'):
attrs[ma.group('attr').strip()] = ma.group('value')
else:
attrs[ma.group('attr').strip()] = ""
elif ma.group('attr1'):
if ma.group('value1'):
attrs[ma.group('attr1').strip()] = ma.group(
'value1'
)
else:
attrs[ma.group('attr1').strip()] = ""
elif ma.group('attr2'):
attrs[ma.group('attr2').strip()] = ""
return tag, len(m.group(0)), attrs
else:
tag = block[1:].split(">", 1)[0].lower()
return tag, len(tag)+2, {}
def _recursive_tagfind(self, ltag, rtag, start_index, block):
while 1:
i = block.find(rtag, start_index)
if i == -1:
return -1
j = block.find(ltag, start_index)
# if no ltag, or rtag found before another ltag, return index
if (j > i or j == -1):
return i + len(rtag)
# another ltag found before rtag, use end of ltag as starting
# point and search again
j = block.find('>', j)
start_index = self._recursive_tagfind(ltag, rtag, j + 1, block)
if start_index == -1:
# HTML potentially malformed- ltag has no corresponding
# rtag
return -1
def _get_right_tag(self, left_tag, left_index, block):
for p in self.right_tag_patterns:
tag = p % left_tag
i = self._recursive_tagfind(
"<%s" % left_tag, tag, left_index, block
)
if i > 2:
return tag.lstrip("<").rstrip(">"), i
return block.rstrip()[-left_index:-1].lower(), len(block)
def _equal_tags(self, left_tag, right_tag):
if left_tag[0] in ['?', '@', '%']: # handle PHP, etc.
return True
if ("/" + left_tag) == right_tag:
return True
if (right_tag == "--" and left_tag == "--"):
return True
elif left_tag == right_tag[1:] and right_tag[0] == "/":
return True
else:
return False
def _is_oneliner(self, tag):
return (tag in ['hr', 'hr/'])
def _stringindex_to_listindex(self, stringindex, items):
"""
Same effect as concatenating the strings in items,
finding the character to which stringindex refers in that string,
and returning the index of the item in which that character resides.
"""
items.append('dummy')
i, count = 0, 0
while count <= stringindex:
count += len(items[i])
i += 1
return i - 1
def _nested_markdown_in_html(self, items):
"""Find and process html child elements of the given element block."""
for i, item in enumerate(items):
if self.left_tag_re.match(item):
left_tag, left_index, attrs = \
self._get_left_tag(''.join(items[i:]))
right_tag, data_index = self._get_right_tag(
left_tag, left_index, ''.join(items[i:]))
right_listindex = \
self._stringindex_to_listindex(data_index, items[i:]) + i
if 'markdown' in attrs.keys():
items[i] = items[i][left_index:] # remove opening tag
placeholder = self.markdown.htmlStash.store_tag(
left_tag, attrs, i + 1, right_listindex + 1)
items.insert(i, placeholder)
if len(items) - right_listindex <= 1: # last nest, no tail
right_listindex -= 1
items[right_listindex] = items[right_listindex][
:-len(right_tag) - 2] # remove closing tag
else: # raw html
if len(items) - right_listindex <= 1: # last element
right_listindex -= 1
if right_listindex <= i:
right_listindex = i + 1
placeholder = self.markdown.htmlStash.store('\n\n'.join(
items[i:right_listindex]))
del items[i:right_listindex]
items.insert(i, placeholder)
return items
def run(self, lines):
text = "\n".join(lines)
new_blocks = []
text = text.rsplit("\n\n")
items = []
left_tag = ''
right_tag = ''
in_tag = False # flag
while text:
block = text[0]
if block.startswith("\n"):
block = block[1:]
text = text[1:]
if block.startswith("\n"):
block = block[1:]
if not in_tag:
if block.startswith("<") and len(block.strip()) > 1:
if block[1:4] == "!--":
# is a comment block
left_tag, left_index, attrs = "--", 2, {}
else:
left_tag, left_index, attrs = self._get_left_tag(block)
right_tag, data_index = self._get_right_tag(left_tag,
left_index,
block)
# keep checking conditions below and maybe just append
if data_index < len(block) and (util.isBlockLevel(left_tag) or left_tag == '--'):
text.insert(0, block[data_index:])
block = block[:data_index]
if not (util.isBlockLevel(left_tag) or block[1] in ["!", "?", "@", "%"]):
new_blocks.append(block)
continue
if self._is_oneliner(left_tag):
new_blocks.append(block.strip())
continue
if block.rstrip().endswith(">") \
and self._equal_tags(left_tag, right_tag):
if self.markdown_in_raw and 'markdown' in attrs.keys():
block = block[left_index:-len(right_tag) - 2]
new_blocks.append(self.markdown.htmlStash.
store_tag(left_tag, attrs, 0, 2))
new_blocks.extend([block])
else:
new_blocks.append(
self.markdown.htmlStash.store(block.strip()))
continue
else:
# if is block level tag and is not complete
if (not self._equal_tags(left_tag, right_tag)) and \
(util.isBlockLevel(left_tag) or left_tag == "--"):
items.append(block.strip())
in_tag = True
else:
new_blocks.append(
self.markdown.htmlStash.store(block.strip())
)
continue
else:
new_blocks.append(block)
else:
items.append(block)
# Need to evaluate all items so we can calculate relative to the left index.
right_tag, data_index = self._get_right_tag(left_tag, left_index, ''.join(items))
# Adjust data_index: relative to items -> relative to last block
prev_block_length = 0
for item in items[:-1]:
prev_block_length += len(item)
data_index -= prev_block_length
if self._equal_tags(left_tag, right_tag):
# if find closing tag
if data_index < len(block):
# we have more text after right_tag
items[-1] = block[:data_index]
text.insert(0, block[data_index:])
in_tag = False
if self.markdown_in_raw and 'markdown' in attrs.keys():
items[0] = items[0][left_index:]
items[-1] = items[-1][:-len(right_tag) - 2]
if items[len(items) - 1]: # not a newline/empty string
right_index = len(items) + 3
else:
right_index = len(items) + 2
new_blocks.append(self.markdown.htmlStash.store_tag(
left_tag, attrs, 0, right_index))
placeholderslen = len(self.markdown.htmlStash.tag_data)
new_blocks.extend(
self._nested_markdown_in_html(items))
nests = len(self.markdown.htmlStash.tag_data) - \
placeholderslen
self.markdown.htmlStash.tag_data[-1 - nests][
'right_index'] += nests - 2
else:
new_blocks.append(
self.markdown.htmlStash.store('\n\n'.join(items)))
items = []
if items:
if self.markdown_in_raw and 'markdown' in attrs.keys():
items[0] = items[0][left_index:]
items[-1] = items[-1][:-len(right_tag) - 2]
if items[len(items) - 1]: # not a newline/empty string
right_index = len(items) + 3
else:
right_index = len(items) + 2
new_blocks.append(
self.markdown.htmlStash.store_tag(
left_tag, attrs, 0, right_index))
placeholderslen = len(self.markdown.htmlStash.tag_data)
new_blocks.extend(self._nested_markdown_in_html(items))
nests = len(self.markdown.htmlStash.tag_data) - placeholderslen
self.markdown.htmlStash.tag_data[-1 - nests][
'right_index'] += nests - 2
else:
new_blocks.append(
self.markdown.htmlStash.store('\n\n'.join(items)))
new_blocks.append('\n')
new_text = "\n\n".join(new_blocks)
return new_text.split("\n")
class ReferencePreprocessor(Preprocessor):
""" Remove reference definitions from text and store for later use. """
TITLE = r'[ ]*(\"(.*)\"|\'(.*)\'|\((.*)\))[ ]*'
RE = re.compile(
r'^[ ]{0,3}\[([^\]]*)\]:\s*([^ ]*)[ ]*(%s)?$' % TITLE, re.DOTALL
)
TITLE_RE = re.compile(r'^%s$' % TITLE)
def run(self, lines):
new_text = []
while lines:
line = lines.pop(0)
m = self.RE.match(line)
if m:
id = m.group(1).strip().lower()
link = m.group(2).lstrip('<').rstrip('>')
t = m.group(5) or m.group(6) or m.group(7)
if not t:
# Check next line for title
tm = self.TITLE_RE.match(lines[0])
if tm:
lines.pop(0)
t = tm.group(2) or tm.group(3) or tm.group(4)
self.markdown.references[id] = (link, t)
else:
new_text.append(line)
return new_text # + "\n"