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third_party/markdown/extensions/fenced_code.py

+# 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.
+
+
+"""
+Fenced Code Extension for Python Markdown
+=========================================
+
+This extension adds Fenced Code Blocks to Python-Markdown.
+
+    >>> import markdown
+    >>> text = '''
+    ... A paragraph before a fenced code block:
+    ...
+    ... ~~~
+    ... Fenced code block
+    ... ~~~
+    ... '''
+    >>> html = markdown.markdown(text, extensions=['fenced_code'])
+    >>> print html
+    <p>A paragraph before a fenced code block:</p>
+    <pre><code>Fenced code block
+    </code></pre>
+
+Works with safe_mode also (we check this because we are using the HtmlStash):
+
+    >>> print markdown.markdown(text, extensions=['fenced_code'], safe_mode='replace')
+    <p>A paragraph before a fenced code block:</p>
+    <pre><code>Fenced code block
+    </code></pre>
+
+Include tilde's in a code block and wrap with blank lines:
+
+    >>> text = '''
+    ... ~~~~~~~~
+    ...
+    ... ~~~~
+    ... ~~~~~~~~'''
+    >>> print markdown.markdown(text, extensions=['fenced_code'])
+    <pre><code>
+    ~~~~
+    </code></pre>
+
+Language tags:
+
+    >>> text = '''
+    ... ~~~~{.python}
+    ... # Some python code
+    ... ~~~~'''
+    >>> print markdown.markdown(text, extensions=['fenced_code'])
+    <pre><code class="python"># Some python code
+    </code></pre>
+
+Optionally backticks instead of tildes as per how github's code block markdown is identified:
+
+    >>> text = '''
+    ... `````
+    ... # Arbitrary code
+    ... ~~~~~ # these tildes will not close the block
+    ... `````'''
+    >>> print markdown.markdown(text, extensions=['fenced_code'])
+    <pre><code># Arbitrary code
+    ~~~~~ # these tildes will not close the block
+    </code></pre>
+
+Copyright 2007-2008 [Waylan Limberg](http://achinghead.com/).
+
+Project website: <http://packages.python.org/Markdown/extensions/fenced_code_blocks.html>
+Contact: markdown@freewisdom.org
+
+License: BSD (see ../docs/LICENSE for details)
+
+Dependencies:
+* [Python 2.4+](http://python.org)
+* [Markdown 2.0+](http://packages.python.org/Markdown/)
+* [Pygments (optional)](http://pygments.org)
+
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+from . import Extension
+from ..preprocessors import Preprocessor
+from .codehilite import CodeHilite, CodeHiliteExtension
+import re
+
+# Global vars
+FENCED_BLOCK_RE = re.compile( \
+    r'(?P<fence>^(?:~{3,}|`{3,}))[ ]*(\{?\.?(?P<lang>[a-zA-Z0-9_+-]*)\}?)?[ ]*\n(?P<code>.*?)(?<=\n)(?P=fence)[ ]*$',
+    re.MULTILINE|re.DOTALL
+    )
+CODE_WRAP = '<pre><code%s>%s</code></pre>'
+LANG_TAG = ' class="%s"'
+
+class FencedCodeExtension(Extension):
+
+    def extendMarkdown(self, md, md_globals):
+        """ Add FencedBlockPreprocessor to the Markdown instance. """
+        md.registerExtension(self)
+
+        md.preprocessors.add('fenced_code_block',
+                                 FencedBlockPreprocessor(md),
+                                 ">normalize_whitespace")
+
+
+class FencedBlockPreprocessor(Preprocessor):
+
+    def __init__(self, md):
+        super(FencedBlockPreprocessor, self).__init__(md)
+
+        self.checked_for_codehilite = False
+        self.codehilite_conf = {}
+
+    def run(self, lines):
+        """ Match and store Fenced Code Blocks in the HtmlStash. """
+
+        # Check for code hilite extension
+        if not self.checked_for_codehilite:
+            for ext in self.markdown.registeredExtensions:
+                if isinstance(ext, CodeHiliteExtension):
+                    self.codehilite_conf = ext.config
+                    break
+
+            self.checked_for_codehilite = True
+
+        text = "\n".join(lines)
+        while 1:
+            m = FENCED_BLOCK_RE.search(text)
+            if m:
+                lang = ''
+                if m.group('lang'):
+                    lang = LANG_TAG % m.group('lang')
+
+                # If config is not empty, then the codehighlite extension
+                # is enabled, so we call it to highlite the code
+                if self.codehilite_conf:
+                    highliter = CodeHilite(m.group('code'),
+                            linenums=self.codehilite_conf['linenums'][0],
+                            guess_lang=self.codehilite_conf['guess_lang'][0],
+                            css_class=self.codehilite_conf['css_class'][0],
+                            style=self.codehilite_conf['pygments_style'][0],
+                            lang=(m.group('lang') or None),
+                            noclasses=self.codehilite_conf['noclasses'][0])
+
+                    code = highliter.hilite()
+                else:
+                    code = CODE_WRAP % (lang, self._escape(m.group('code')))
+
+                placeholder = self.markdown.htmlStash.store(code, safe=True)
+                text = '%s\n%s\n%s'% (text[:m.start()], placeholder, text[m.end():])
+            else:
+                break
+        return text.split("\n")
+
+    def _escape(self, txt):
+        """ basic html escaping """
+        txt = txt.replace('&', '&amp;')
+        txt = txt.replace('<', '&lt;')
+        txt = txt.replace('>', '&gt;')
+        txt = txt.replace('"', '&quot;')
+        return txt
+
+
+def makeExtension(configs=None):
+    return FencedCodeExtension(configs=configs)