1# markdown is released under the BSD license
2# Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
3# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
4# Copyright 2004 Manfred Stienstra (the original version)
5#
6# All rights reserved.
7#
8# Redistribution and use in source and binary forms, with or without
9# modification, are permitted provided that the following conditions are met:
10#
11# *   Redistributions of source code must retain the above copyright
12#     notice, this list of conditions and the following disclaimer.
13# *   Redistributions in binary form must reproduce the above copyright
14#     notice, this list of conditions and the following disclaimer in the
15#     documentation and/or other materials provided with the distribution.
16# *   Neither the name of the <organization> nor the
17#     names of its contributors may be used to endorse or promote products
18#     derived from this software without specific prior written permission.
19#
20# THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
21# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
22# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
23# DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
24# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30# POSSIBILITY OF SUCH DAMAGE.
31
32
33from __future__ import unicode_literals
34from __future__ import absolute_import
35from . import util
36from . import odict
37
38class State(list):
39    """ Track the current and nested state of the parser.
40
41    This utility class is used to track the state of the BlockParser and
42    support multiple levels if nesting. It's just a simple API wrapped around
43    a list. Each time a state is set, that state is appended to the end of the
44    list. Each time a state is reset, that state is removed from the end of
45    the list.
46
47    Therefore, each time a state is set for a nested block, that state must be
48    reset when we back out of that level of nesting or the state could be
49    corrupted.
50
51    While all the methods of a list object are available, only the three
52    defined below need be used.
53
54    """
55
56    def set(self, state):
57        """ Set a new state. """
58        self.append(state)
59
60    def reset(self):
61        """ Step back one step in nested state. """
62        self.pop()
63
64    def isstate(self, state):
65        """ Test that top (current) level is of given state. """
66        if len(self):
67            return self[-1] == state
68        else:
69            return False
70
71class BlockParser:
72    """ Parse Markdown blocks into an ElementTree object.
73
74    A wrapper class that stitches the various BlockProcessors together,
75    looping through them and creating an ElementTree object.
76    """
77
78    def __init__(self, markdown):
79        self.blockprocessors = odict.OrderedDict()
80        self.state = State()
81        self.markdown = markdown
82
83    def parseDocument(self, lines):
84        """ Parse a markdown document into an ElementTree.
85
86        Given a list of lines, an ElementTree object (not just a parent Element)
87        is created and the root element is passed to the parser as the parent.
88        The ElementTree object is returned.
89
90        This should only be called on an entire document, not pieces.
91
92        """
93        # Create a ElementTree from the lines
94        self.root = util.etree.Element(self.markdown.doc_tag)
95        self.parseChunk(self.root, '\n'.join(lines))
96        return util.etree.ElementTree(self.root)
97
98    def parseChunk(self, parent, text):
99        """ Parse a chunk of markdown text and attach to given etree node.
100
101        While the ``text`` argument is generally assumed to contain multiple
102        blocks which will be split on blank lines, it could contain only one
103        block. Generally, this method would be called by extensions when
104        block parsing is required.
105
106        The ``parent`` etree Element passed in is altered in place.
107        Nothing is returned.
108
109        """
110        self.parseBlocks(parent, text.split('\n\n'))
111
112    def parseBlocks(self, parent, blocks):
113        """ Process blocks of markdown text and attach to given etree node.
114
115        Given a list of ``blocks``, each blockprocessor is stepped through
116        until there are no blocks left. While an extension could potentially
117        call this method directly, it's generally expected to be used internally.
118
119        This is a public method as an extension may need to add/alter additional
120        BlockProcessors which call this method to recursively parse a nested
121        block.
122
123        """
124        while blocks:
125            for processor in self.blockprocessors.values():
126                if processor.test(parent, blocks[0]):
127                    if processor.run(parent, blocks) is not False:
128                        # run returns True or None
129                        break
130
131
132