Check in a simple pure-python based Markdown previewer.

third_party/Python-Markdown/markdown/util.py

Index: third_party/Python-Markdown/markdown/util.py
diff --git a/third_party/markdown/util.py b/third_party/Python-Markdown/markdown/util.py
similarity index 51%
copy from third_party/markdown/util.py
copy to third_party/Python-Markdown/markdown/util.py
index 97f7679700a0a680816f0f92790c78e48270c7ca..d3d48f099940521431520bbc42eb466fd099e1fb 100644
--- a/third_party/markdown/util.py
+++ b/third_party/Python-Markdown/markdown/util.py
@@ -1,36 +1,4 @@
 # -*- coding: utf-8 -*-
-# markdown is released under the BSD license
-# Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
-# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
-# Copyright 2004 Manfred Stienstra (the original version)
-# 
-# All rights reserved.
-# 
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are met:
-# 
-# *   Redistributions of source code must retain the above copyright
-#     notice, this list of conditions and the following disclaimer.
-# *   Redistributions in binary form must reproduce the above copyright
-#     notice, this list of conditions and the following disclaimer in the
-#     documentation and/or other materials provided with the distribution.
-# *   Neither the name of the <organization> nor the
-#     names of its contributors may be used to endorse or promote products
-#     derived from this software without specific prior written permission.
-# 
-# THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
-# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-# DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
-# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-# POSSIBILITY OF SUCH DAMAGE.
-
-
 from __future__ import unicode_literals
 import re
 import sys
@@ -42,14 +10,14 @@ Python 3 Stuff
 """
 PY3 = sys.version_info[0] == 3
 
-if PY3:
+if PY3:  # pragma: no cover
     string_type = str
     text_type = str
     int2str = chr
-else:
-    string_type = basestring
-    text_type = unicode
-    int2str = unichr
+else:  # pragma: no cover
+    string_type = basestring   # noqa
+    text_type = unicode        # noqa
+    int2str = unichr           # noqa
 
 
 """
@@ -57,43 +25,53 @@ Constants you might want to modify
 -----------------------------------------------------------------------------
 """
 
-BLOCK_LEVEL_ELEMENTS = re.compile("^(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul"
-                                  "|script|noscript|form|fieldset|iframe|math"
-                                  "|hr|hr/|style|li|dt|dd|thead|tbody"
-                                  "|tr|th|td|section|footer|header|group|figure"
-                                  "|figcaption|aside|article|canvas|output"
-                                  "|progress|video)$", re.IGNORECASE)
+
+BLOCK_LEVEL_ELEMENTS = re.compile(
+    "^(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul"
+    "|script|noscript|form|fieldset|iframe|math"
+    "|hr|hr/|style|li|dt|dd|thead|tbody"
+    "|tr|th|td|section|footer|header|group|figure"
+    "|figcaption|aside|article|canvas|output"
+    "|progress|video|nav)$",
+    re.IGNORECASE
+)
 # Placeholders
 STX = '\u0002'  # Use STX ("Start of text") for start-of-placeholder
 ETX = '\u0003'  # Use ETX ("End of text") for end-of-placeholder
 INLINE_PLACEHOLDER_PREFIX = STX+"klzzwxh:"
 INLINE_PLACEHOLDER = INLINE_PLACEHOLDER_PREFIX + "%s" + ETX
-INLINE_PLACEHOLDER_RE = re.compile(INLINE_PLACEHOLDER % r'([0-9]{4})')
+INLINE_PLACEHOLDER_RE = re.compile(INLINE_PLACEHOLDER % r'([0-9]+)')
 AMP_SUBSTITUTE = STX+"amp"+ETX
+HTML_PLACEHOLDER = STX + "wzxhzdk:%s" + ETX
+HTML_PLACEHOLDER_RE = re.compile(HTML_PLACEHOLDER % r'([0-9]+)')
+TAG_PLACEHOLDER = STX + "hzzhzkh:%s" + ETX
+
 
 """
 Constants you probably do not need to change
 -----------------------------------------------------------------------------
 """
 
-RTL_BIDI_RANGES = ( ('\u0590', '\u07FF'),
-                     # Hebrew (0590-05FF), Arabic (0600-06FF),
-                     # Syriac (0700-074F), Arabic supplement (0750-077F),
-                     # Thaana (0780-07BF), Nko (07C0-07FF).
-                    ('\u2D30', '\u2D7F'), # Tifinagh
-                    )
+RTL_BIDI_RANGES = (
+    ('\u0590', '\u07FF'),
+    # Hebrew (0590-05FF), Arabic (0600-06FF),
+    # Syriac (0700-074F), Arabic supplement (0750-077F),
+    # Thaana (0780-07BF), Nko (07C0-07FF).
+    ('\u2D30', '\u2D7F')  # Tifinagh
+)
 
 # Extensions should use "markdown.util.etree" instead of "etree" (or do `from
 # markdown.util import etree`).  Do not import it by yourself.
 
-try: # Is the C implemenation of ElementTree available?
+try:  # pragma: no cover
+    # Is the C implementation of ElementTree available?
     import xml.etree.cElementTree as etree
     from xml.etree.ElementTree import Comment
     # Serializers (including ours) test with non-c Comment
     etree.test_comment = Comment
     if etree.VERSION < "1.0.5":
         raise RuntimeError("cElementTree version 1.0.5 or higher is required.")
-except (ImportError, RuntimeError):
+except (ImportError, RuntimeError):  # pragma: no cover
     # Use the Python implementation of ElementTree?
     import xml.etree.ElementTree as etree
     if etree.VERSION < "1.1":
@@ -113,11 +91,32 @@ def isBlockLevel(tag):
     # Some ElementTree tags are not strings, so return False.
     return False
 
+
+def parseBoolValue(value, fail_on_errors=True, preserve_none=False):
+    """Parses a string representing bool value. If parsing was successful,
+       returns True or False. If preserve_none=True, returns True, False,
+       or None. If parsing was not successful, raises  ValueError, or, if
+       fail_on_errors=False, returns None."""
+    if not isinstance(value, string_type):
+        if preserve_none and value is None:
+            return value
+        return bool(value)
+    elif preserve_none and value.lower() == 'none':
+        return None
+    elif value.lower() in ('true', 'yes', 'y', 'on', '1'):
+        return True
+    elif value.lower() in ('false', 'no', 'n', 'off', '0', 'none'):
+        return False
+    elif fail_on_errors:
+        raise ValueError('Cannot parse bool value: %r' % value)
+
+
 """
 MISC AUXILIARY CLASSES
 =============================================================================
 """
 
+
 class AtomicString(text_type):
     """A string which should not be further processed."""
     pass
@@ -135,10 +134,12 @@ class HtmlStash(object):
     in the beginning and replace with place-holders.
     """
 
-    def __init__ (self):
+    def __init__(self):
         """ Create a HtmlStash. """
-        self.html_counter = 0 # for counting inline html segments
-        self.rawHtmlBlocks=[]
+        self.html_counter = 0  # for counting inline html segments
+        self.rawHtmlBlocks = []
+        self.tag_counter = 0
+        self.tag_data = []  # list of dictionaries in the order tags appear
 
     def store(self, html, safe=False):
         """
@@ -164,5 +165,13 @@ class HtmlStash(object):
         self.rawHtmlBlocks = []
 
     def get_placeholder(self, key):
-        return "%swzxhzdk:%d%s" % (STX, key, ETX)
-
+        return HTML_PLACEHOLDER % key
+
+    def store_tag(self, tag, attrs, left_index, right_index):
+        """Store tag data and return a placeholder."""
+        self.tag_data.append({'tag': tag, 'attrs': attrs,
+                              'left_index': left_index,
+                              'right_index': right_index})
+        placeholder = TAG_PLACEHOLDER % str(self.tag_counter)
+        self.tag_counter += 1  # equal to the tag's index in self.tag_data
+        return placeholder