third_party/markdown/util.py

   1 # -*- coding: utf-8 -*-
   2 # markdown is released under the BSD license
   3 # Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
   4 # Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
   5 # Copyright 2004 Manfred Stienstra (the original version)
   6 #
   7 # All rights reserved.
   8 #
   9 # Redistribution and use in source and binary forms, with or without
  10 # modification, are permitted provided that the following conditions are met:
  11 #
  12 # *   Redistributions of source code must retain the above copyright
  13 #     notice, this list of conditions and the following disclaimer.
  14 # *   Redistributions in binary form must reproduce the above copyright
  15 #     notice, this list of conditions and the following disclaimer in the
  16 #     documentation and/or other materials provided with the distribution.
  17 # *   Neither the name of the <organization> nor the
  18 #     names of its contributors may be used to endorse or promote products
  19 #     derived from this software without specific prior written permission.
  20 #
  21 # THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
  22 # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24 # DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
  25 # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  30 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31 # POSSIBILITY OF SUCH DAMAGE.
  32
  33
  34 from __future__ import unicode_literals
  35 import re
  36 import sys
  37
  38
  39 """
  40 Python 3 Stuff
  41 =============================================================================
  42 """
  43 PY3 = sys.version_info[0] == 3
  44
  45 if PY3:
  46     string_type = str
  47     text_type = str
  48     int2str = chr
  49 else:
  50     string_type = basestring
  51     text_type = unicode
  52     int2str = unichr
  53
  54
  55 """
  56 Constants you might want to modify
  57 -----------------------------------------------------------------------------
  58 """
  59
  60 BLOCK_LEVEL_ELEMENTS = re.compile("^(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul"
  61                                   "|script|noscript|form|fieldset|iframe|math"
  62                                   "|hr|hr/|style|li|dt|dd|thead|tbody"
  63                                   "|tr|th|td|section|footer|header|group|figure"
  64                                   "|figcaption|aside|article|canvas|output"
  65                                   "|progress|video)$", re.IGNORECASE)
  66 # Placeholders
  67 STX = '\u0002'  # Use STX ("Start of text") for start-of-placeholder
  68 ETX = '\u0003'  # Use ETX ("End of text") for end-of-placeholder
  69 INLINE_PLACEHOLDER_PREFIX = STX+"klzzwxh:"
  70 INLINE_PLACEHOLDER = INLINE_PLACEHOLDER_PREFIX + "%s" + ETX
  71 INLINE_PLACEHOLDER_RE = re.compile(INLINE_PLACEHOLDER % r'([0-9]{4})')
  72 AMP_SUBSTITUTE = STX+"amp"+ETX
  73
  74 """
  75 Constants you probably do not need to change
  76 -----------------------------------------------------------------------------
  77 """
  78
  79 RTL_BIDI_RANGES = ( ('\u0590', '\u07FF'),
  80                      # Hebrew (0590-05FF), Arabic (0600-06FF),
  81                      # Syriac (0700-074F), Arabic supplement (0750-077F),
  82                      # Thaana (0780-07BF), Nko (07C0-07FF).
  83                     ('\u2D30', '\u2D7F'), # Tifinagh
  84                     )
  85
  86 # Extensions should use "markdown.util.etree" instead of "etree" (or do `from
  87 # markdown.util import etree`).  Do not import it by yourself.
  88
  89 try: # Is the C implemenation of ElementTree available?
  90     import xml.etree.cElementTree as etree
  91     from xml.etree.ElementTree import Comment
  92     # Serializers (including ours) test with non-c Comment
  93     etree.test_comment = Comment
  94     if etree.VERSION < "1.0.5":
  95         raise RuntimeError("cElementTree version 1.0.5 or higher is required.")
  96 except (ImportError, RuntimeError):
  97     # Use the Python implementation of ElementTree?
  98     import xml.etree.ElementTree as etree
  99     if etree.VERSION < "1.1":
 100         raise RuntimeError("ElementTree version 1.1 or higher is required")
 101
 102
 103 """
 104 AUXILIARY GLOBAL FUNCTIONS
 105 =============================================================================
 106 """
 107
 108
 109 def isBlockLevel(tag):
 110     """Check if the tag is a block level HTML tag."""
 111     if isinstance(tag, string_type):
 112         return BLOCK_LEVEL_ELEMENTS.match(tag)
 113     # Some ElementTree tags are not strings, so return False.
 114     return False
 115
 116 """
 117 MISC AUXILIARY CLASSES
 118 =============================================================================
 119 """
 120
 121 class AtomicString(text_type):
 122     """A string which should not be further processed."""
 123     pass
 124
 125
 126 class Processor(object):
 127     def __init__(self, markdown_instance=None):
 128         if markdown_instance:
 129             self.markdown = markdown_instance
 130
 131
 132 class HtmlStash(object):
 133     """
 134     This class is used for stashing HTML objects that we extract
 135     in the beginning and replace with place-holders.
 136     """
 137
 138     def __init__ (self):
 139         """ Create a HtmlStash. """
 140         self.html_counter = 0 # for counting inline html segments
 141         self.rawHtmlBlocks=[]
 142
 143     def store(self, html, safe=False):
 144         """
 145         Saves an HTML segment for later reinsertion.  Returns a
 146         placeholder string that needs to be inserted into the
 147         document.
 148
 149         Keyword arguments:
 150
 151         * html: an html segment
 152         * safe: label an html segment as safe for safemode
 153
 154         Returns : a placeholder string
 155
 156         """
 157         self.rawHtmlBlocks.append((html, safe))
 158         placeholder = self.get_placeholder(self.html_counter)
 159         self.html_counter += 1
 160         return placeholder
 161
 162     def reset(self):
 163         self.html_counter = 0
 164         self.rawHtmlBlocks = []
 165
 166     def get_placeholder(self, key):
 167         return "%swzxhzdk:%d%s" % (STX, key, ETX)
 168