Mercurial > genshi > genshi-test

comparison markup/output.py @ 1:821114ec4f69

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Initial import.
author cmlenz
date Sat, 03 Jun 2006 07:16:01 +0000
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children 4cbebb15a834
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0:20f3417d4171 1:821114ec4f69
1 # -*- coding: utf-8 -*-
2 #
3 # Copyright (C) 2006 Christopher Lenz
4 # All rights reserved.
5 #
6 # This software is licensed as described in the file COPYING, which
7 # you should have received as part of this distribution. The terms
8 # are also available at http://trac.edgewall.com/license.html.
9 #
10 # This software consists of voluntary contributions made by many
11 # individuals. For the exact contribution history, see the revision
12 # history and logs, available at http://projects.edgewall.com/trac/.
13
14 """This module provides different kinds of serialization methods for XML event
15 streams.
16 """
17
18 try:
19 frozenset
20 except NameError:
21 from sets import ImmutableSet as frozenset
22
23 from markup.core import Markup, QName, Stream
24 from markup.filters import WhitespaceFilter
25
26 __all__ = ['Serializer', 'XMLSerializer', 'HTMLSerializer']
27
28
29 class Serializer(object):
30 """Base class for serializers."""
31
32 def serialize(self, stream):
33 raise NotImplementedError
34
35
36 class XMLSerializer(Serializer):
37 """Produces XML text from an event stream.
38
39 >>> from markup.builder import tag
40 >>> elem = tag.DIV(tag.A(href='foo'), tag.BR, tag.HR(noshade=True))
41 >>> print ''.join(XMLSerializer().serialize(elem.generate()))
42 <div><a href="foo"/><br/><hr noshade="True"/></div>
43 """
44
45 def serialize(self, stream):
46 ns_attrib = []
47 ns_mapping = {}
48
49 stream = PushbackIterator(stream)
50 for kind, data, pos in stream:
51
52 if kind is Stream.DOCTYPE:
53 # FIXME: what if there's no system or public ID in the input?
54 yield Markup('<!DOCTYPE %s "%s" "%s">\n' % data)
55
56 elif kind is Stream.START_NS:
57 prefix, uri = data
58 if uri not in ns_mapping:
59 ns_mapping[uri] = prefix
60 if not prefix:
61 ns_attrib.append((QName('xmlns'), uri))
62 else:
63 ns_attrib.append((QName('xmlns:%s' % prefix), uri))
64
65 elif kind is Stream.START:
66 tag, attrib = data
67
68 tagname = tag.localname
69 if tag.namespace:
70 try:
71 prefix = ns_mapping[tag.namespace]
72 if prefix:
73 tagname = prefix + ':' + tag.localname
74 except KeyError:
75 ns_attrib.append((QName('xmlns'), tag.namespace))
76 buf = ['<', tagname]
77
78 if ns_attrib:
79 attrib.extend(ns_attrib)
80 ns_attrib = []
81 for attr, value in attrib:
82 attrname = attr.localname
83 if attr.namespace:
84 try:
85 prefix = ns_mapping[attr.namespace]
86 except KeyError:
87 # FIXME: synthesize a prefix for the attribute?
88 prefix = ''
89 if prefix:
90 attrname = prefix + ':' + attrname
91 buf.append(' %s="%s"' % (attrname, Markup.escape(value)))
92
93 kind, data, pos = stream.next()
94 if kind is Stream.END:
95 buf.append('/>')
96 else:
97 buf.append('>')
98 stream.pushback((kind, data, pos))
99
100 yield Markup(''.join(buf))
101
102 elif kind is Stream.END:
103 tag = data
104 tagname = tag.localname
105 if tag.namespace:
106 prefix = ns_mapping[tag.namespace]
107 if prefix:
108 tagname = prefix + ':' + tag.localname
109 yield Markup('</%s>' % tagname)
110
111 elif kind is Stream.TEXT:
112 yield Markup.escape(data, quotes=False)
113
114
115 class HTMLSerializer(Serializer):
116 """Produces HTML text from an event stream.
117
118 >>> from markup.builder import tag
119 >>> elem = tag.DIV(tag.A(href='foo'), tag.BR, tag.HR(noshade=True))
120 >>> print ''.join(HTMLSerializer().serialize(elem.generate()))
121 <div><a href="foo"></a><br><hr noshade></div>
122 """
123
124 NAMESPACE = 'http://www.w3.org/1999/xhtml'
125
126 _EMPTY_ELEMS = frozenset(['area', 'base', 'basefont', 'br', 'col', 'frame',
127 'hr', 'img', 'input', 'isindex', 'link', 'meta',
128 'param'])
129 _BOOLEAN_ATTRS = frozenset(['selected', 'checked', 'compact', 'declare',
130 'defer', 'disabled', 'ismap', 'multiple',
131 'nohref', 'noresize', 'noshade', 'nowrap'])
132
133 def serialize(self, stream):
134 ns_mapping = {}
135
136 stream = PushbackIterator(stream)
137 for kind, data, pos in stream:
138
139 if kind is Stream.DOCTYPE:
140 yield Markup('<!DOCTYPE %s "%s" "%s">\n' % data)
141
142 elif kind is Stream.START_NS:
143 prefix, uri = data
144 if uri not in ns_mapping:
145 ns_mapping[uri] = prefix
146
147 elif kind is Stream.START:
148 tag, attrib = data
149 if tag.namespace and tag.namespace != self.NAMESPACE:
150 continue # not in the HTML namespace, so don't emit
151 buf = ['<', tag.localname]
152 for attr, value in attrib:
153 if attr.namespace and attr.namespace != self.NAMESPACE:
154 continue # not in the HTML namespace, so don't emit
155 if attr.localname in self._BOOLEAN_ATTRS:
156 if value:
157 buf.append(' %s' % attr.localname)
158 else:
159 buf.append(' %s="%s"' % (attr.localname,
160 Markup.escape(value)))
161
162 if tag.localname in self._EMPTY_ELEMS:
163 kind, data, pos = stream.next()
164 if kind is not Stream.END:
165 stream.pushback((kind, data, pos))
166
167 yield Markup(''.join(buf + ['>']))
168
169 elif kind is Stream.END:
170 tag = data
171 if tag.namespace and tag.namespace != self.NAMESPACE:
172 continue # not in the HTML namespace, so don't emit
173 yield Markup('</%s>' % tag.localname)
174
175 elif kind is Stream.TEXT:
176 yield Markup.escape(data, quotes=False)
177
178
179 class PushbackIterator(object):
180 """A simple wrapper for iterators that allows pushing items back on the
181 queue via the `pushback()` method.
182
183 That can effectively be used to peek at the next item."""
184 __slots__ = ['iterable', 'buf']
185
186 def __init__(self, iterable):
187 self.iterable = iter(iterable)
188 self.buf = []
189
190 def __iter__(self):
191 return self
192
193 def next(self):
194 if self.buf:
195 return self.buf.pop(0)
196 return self.iterable.next()
197
198 def pushback(self, item):
199 self.buf.append(item)
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