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import re |
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import string |
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from .util import escape_url |
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PREVENT_BACKSLASH = r'(?<!\\)(?:\\\\)*' |
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PUNCTUATION = r'[' + re.escape(string.punctuation) + r']' |
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LINK_LABEL = r'(?:[^\\\[\]]|\\.){0,500}' |
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LINK_BRACKET_START = re.compile(r'[ \t]*\n?[ \t]*<') |
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LINK_BRACKET_RE = re.compile(r'<([^<>\n\\\x00]*)>') |
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LINK_HREF_BLOCK_RE = re.compile(r'[ \t]*\n?[ \t]*([^\s]+)(?:\s|$)') |
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LINK_HREF_INLINE_RE = re.compile( |
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r'[ \t]*\n?[ \t]*([^ \t\n]*?)(?:[ \t\n]|' |
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r'(?:' + PREVENT_BACKSLASH + r'\)))' |
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) |
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LINK_TITLE_RE = re.compile( |
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r'[ \t\n]+(' |
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r'"(?:\\' + PUNCTUATION + r'|[^"\x00])*"|' |
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r"'(?:\\" + PUNCTUATION + r"|[^'\x00])*'" |
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r')' |
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) |
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PAREN_END_RE = re.compile(r'\s*\)') |
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HTML_TAGNAME = r'[A-Za-z][A-Za-z0-9-]*' |
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HTML_ATTRIBUTES = ( |
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r'(?:\s+[A-Za-z_:][A-Za-z0-9_.:-]*' |
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r'(?:\s*=\s*(?:[^ !"\'=<>`]+|\'[^\']*?\'|"[^\"]*?"))?)*' |
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) |
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BLOCK_TAGS = ( |
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'address', 'article', 'aside', 'base', 'basefont', 'blockquote', |
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'body', 'caption', 'center', 'col', 'colgroup', 'dd', 'details', |
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'dialog', 'dir', 'div', 'dl', 'dt', 'fieldset', 'figcaption', |
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'figure', 'footer', 'form', 'frame', 'frameset', 'h1', 'h2', 'h3', |
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'h4', 'h5', 'h6', 'head', 'header', 'hr', 'html', 'iframe', |
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'legend', 'li', 'link', 'main', 'menu', 'menuitem', 'meta', 'nav', |
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'noframes', 'ol', 'optgroup', 'option', 'p', 'param', 'section', |
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'source', 'summary', 'table', 'tbody', 'td', 'tfoot', 'th', 'thead', |
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'title', 'tr', 'track', 'ul' |
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) |
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PRE_TAGS = ('pre', 'script', 'style', 'textarea') |
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_INLINE_LINK_LABEL_RE = re.compile(LINK_LABEL + r'\]') |
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_INLINE_SQUARE_BRACKET_RE = re.compile(PREVENT_BACKSLASH + r'[\[\]]') |
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_ESCAPE_CHAR_RE = re.compile(r'\\(' + PUNCTUATION + r')') |
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def unescape_char(text): |
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return _ESCAPE_CHAR_RE.sub(r'\1', text) |
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def parse_link_text(src, pos): |
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level = 1 |
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found = False |
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start_pos = pos |
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while pos < len(src): |
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m = _INLINE_SQUARE_BRACKET_RE.search(src, pos) |
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if not m: |
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break |
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pos = m.end() |
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marker = m.group(0) |
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if marker == ']': |
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level -= 1 |
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if level == 0: |
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found = True |
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break |
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else: |
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level += 1 |
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if found: |
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text = src[start_pos:pos-1] |
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return text, pos |
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return None, None |
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def parse_link_label(src, start_pos): |
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m = _INLINE_LINK_LABEL_RE.match(src, start_pos) |
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if m: |
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label = m.group(0)[:-1] |
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return label, m.end() |
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return None, None |
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def parse_link_href(src, start_pos, block=False): |
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m = LINK_BRACKET_START.match(src, start_pos) |
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if m: |
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start_pos = m.end() - 1 |
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m = LINK_BRACKET_RE.match(src, start_pos) |
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if m: |
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return m.group(1), m.end() |
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return None, None |
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if block: |
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m = LINK_HREF_BLOCK_RE.match(src, start_pos) |
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else: |
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m = LINK_HREF_INLINE_RE.match(src, start_pos) |
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if not m: |
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return None, None |
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end_pos = m.end() |
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href = m.group(1) |
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if block and src[end_pos - 1] == href[-1]: |
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return href, end_pos |
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return href, end_pos - 1 |
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def parse_link_title(src, start_pos, max_pos): |
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m = LINK_TITLE_RE.match(src, start_pos, max_pos) |
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if m: |
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title = m.group(1)[1:-1] |
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title = unescape_char(title) |
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return title, m.end() |
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return None, None |
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def parse_link(src, pos): |
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href, href_pos = parse_link_href(src, pos) |
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if href is None: |
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return None, None |
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title, title_pos = parse_link_title(src, href_pos, len(src)) |
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next_pos = title_pos or href_pos |
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m = PAREN_END_RE.match(src, next_pos) |
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if not m: |
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return None, None |
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href = unescape_char(href) |
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attrs = {'url': escape_url(href)} |
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if title: |
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attrs['title'] = title |
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return attrs, m.end() |
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