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markup.py

Last change on this file was 1012, checked in by cmlenz, 15 years ago
Ported [1011] to 0.5.x branch.
Property svn:eol-style set to `native`
File size: 13.3 KB

Line
1	# -- coding: utf-8 --
2	#
3	# Copyright (C) 2006-2008 Edgewall Software
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://genshi.edgewall.org/wiki/License.
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://genshi.edgewall.org/log/.
13
14	"""Markup templating engine."""
15
16	from itertools import chain
17
18	from genshi.core import Attrs, Markup, Namespace, Stream, StreamEventKind
19	from genshi.core import START, END, START_NS, END_NS, TEXT, PI, COMMENT
20	from genshi.input import XMLParser
21	from genshi.template.base import BadDirectiveError, Template, \
22	TemplateSyntaxError, _apply_directives, \
23	EXEC, INCLUDE, SUB
24	from genshi.template.eval import Suite
25	from genshi.template.interpolation import interpolate
26	from genshi.template.directives import *
27	from genshi.template.text import NewTextTemplate
28
29	__all__ = ['MarkupTemplate']
30	__docformat__ = 'restructuredtext en'
31
32
33	class MarkupTemplate(Template):
34	"""Implementation of the template language for XML-based templates.
35
36	>>> tmpl = MarkupTemplate('''<ul xmlns:py="http://genshi.edgewall.org/">
37	... <li py:for="item in items">${item}</li>
38	... </ul>''')
39	>>> print tmpl.generate(items=[1, 2, 3])
40	<ul>
41	<li>1</li><li>2</li><li>3</li>
42	</ul>
43	"""
44
45	DIRECTIVE_NAMESPACE = Namespace('http://genshi.edgewall.org/')
46	XINCLUDE_NAMESPACE = Namespace('http://www.w3.org/2001/XInclude')
47
48	directives = [('def', DefDirective),
49	('match', MatchDirective),
50	('when', WhenDirective),
51	('otherwise', OtherwiseDirective),
52	('for', ForDirective),
53	('if', IfDirective),
54	('choose', ChooseDirective),
55	('with', WithDirective),
56	('replace', ReplaceDirective),
57	('content', ContentDirective),
58	('attrs', AttrsDirective),
59	('strip', StripDirective)]
60	serializer = 'xml'
61	_number_conv = Markup
62
63	def _init_filters(self):
64	Template._init_filters(self)
65	# Make sure the include filter comes after the match filter
66	if self.loader:
67	self.filters.remove(self._include)
68	self.filters += [self._match]
69	if self.loader:
70	self.filters.append(self._include)
71
72	def _parse(self, source, encoding):
73	streams = [[]] # stacked lists of events of the "compiled" template
74	dirmap = {} # temporary mapping of directives to elements
75	ns_prefix = {}
76	depth = 0
77	fallbacks = []
78	includes = []
79
80	if not isinstance(source, Stream):
81	source = XMLParser(source, filename=self.filename,
82	encoding=encoding)
83
84	for kind, data, pos in source:
85	stream = streams[-1]
86
87	if kind is START_NS:
88	# Strip out the namespace declaration for template directives
89	prefix, uri = data
90	ns_prefix[prefix] = uri
91	if uri not in (self.DIRECTIVE_NAMESPACE,
92	self.XINCLUDE_NAMESPACE):
93	stream.append((kind, data, pos))
94
95	elif kind is END_NS:
96	uri = ns_prefix.pop(data, None)
97	if uri and uri not in (self.DIRECTIVE_NAMESPACE,
98	self.XINCLUDE_NAMESPACE):
99	stream.append((kind, data, pos))
100
101	elif kind is START:
102	# Record any directive attributes in start tags
103	tag, attrs = data
104	directives = []
105	strip = False
106
107	if tag in self.DIRECTIVE_NAMESPACE:
108	cls = self._dir_by_name.get(tag.localname)
109	if cls is None:
110	raise BadDirectiveError(tag.localname, self.filepath,
111	pos[1])
112	args = dict([(name.localname, value) for name, value
113	in attrs if not name.namespace])
114	directives.append((cls, args, ns_prefix.copy(), pos))
115	strip = True
116
117	new_attrs = []
118	for name, value in attrs:
119	if name in self.DIRECTIVE_NAMESPACE:
120	cls = self._dir_by_name.get(name.localname)
121	if cls is None:
122	raise BadDirectiveError(name.localname,
123	self.filepath, pos[1])
124	directives.append((cls, value, ns_prefix.copy(), pos))
125	else:
126	if value:
127	value = list(interpolate(value, self.filepath,
128	pos[1], pos[2],
129	lookup=self.lookup))
130	if len(value) == 1 and value[0][0] is TEXT:
131	value = value[0][1]
132	else:
133	value = [(TEXT, u'', pos)]
134	new_attrs.append((name, value))
135	new_attrs = Attrs(new_attrs)
136
137	if directives:
138	index = self._dir_order.index
139	directives.sort(lambda a, b: cmp(index(a[0]), index(b[0])))
140	dirmap[(depth, tag)] = (directives, len(stream), strip)
141
142	if tag in self.XINCLUDE_NAMESPACE:
143	if tag.localname == 'include':
144	include_href = new_attrs.get('href')
145	if not include_href:
146	raise TemplateSyntaxError('Include misses required '
147	'attribute "href"',
148	self.filepath, *pos[1:])
149	includes.append((include_href, new_attrs.get('parse')))
150	streams.append([])
151	elif tag.localname == 'fallback':
152	streams.append([])
153	fallbacks.append(streams[-1])
154
155	else:
156	stream.append((kind, (tag, new_attrs), pos))
157
158	depth += 1
159
160	elif kind is END:
161	depth -= 1
162
163	if fallbacks and data == self.XINCLUDE_NAMESPACE['fallback']:
164	assert streams.pop() is fallbacks[-1]
165	elif data == self.XINCLUDE_NAMESPACE['include']:
166	fallback = None
167	if len(fallbacks) == len(includes):
168	fallback = fallbacks.pop()
169	streams.pop() # discard anything between the include tags
170	# and the fallback element
171	stream = streams[-1]
172	href, parse = includes.pop()
173	try:
174	cls = {
175	'xml': MarkupTemplate,
176	'text': NewTextTemplate
177	}[parse or 'xml']
178	except KeyError:
179	raise TemplateSyntaxError('Invalid value for "parse" '
180	'attribute of include',
181	self.filepath, *pos[1:])
182	stream.append((INCLUDE, (href, cls, fallback), pos))
183	else:
184	stream.append((kind, data, pos))
185
186	# If there have have directive attributes with the corresponding
187	# start tag, move the events inbetween into a "subprogram"
188	if (depth, data) in dirmap:
189	directives, start_offset, strip = dirmap.pop((depth, data))
190	substream = stream[start_offset:]
191	if strip:
192	substream = substream[1:-1]
193	stream[start_offset:] = [(SUB, (directives, substream),
194	pos)]
195
196	elif kind is PI and data[0] == 'python':
197	if not self.allow_exec:
198	raise TemplateSyntaxError('Python code blocks not allowed',
199	self.filepath, *pos[1:])
200	try:
201	suite = Suite(data[1], self.filepath, pos[1],
202	lookup=self.lookup)
203	except SyntaxError, err:
204	raise TemplateSyntaxError(err, self.filepath,
205	pos[1] + (err.lineno or 1) - 1,
206	pos[2] + (err.offset or 0))
207	stream.append((EXEC, suite, pos))
208
209	elif kind is TEXT:
210	for kind, data, pos in interpolate(data, self.filepath, pos[1],
211	pos[2], lookup=self.lookup):
212	stream.append((kind, data, pos))
213
214	elif kind is COMMENT:
215	if not data.lstrip().startswith('!'):
216	stream.append((kind, data, pos))
217
218	else:
219	stream.append((kind, data, pos))
220
221	assert len(streams) == 1
222	return streams[0]
223
224	def _match(self, stream, ctxt, start=0, end=None, **vars):
225	"""Internal stream filter that applies any defined match templates
226	to the stream.
227	"""
228	match_templates = ctxt._match_templates
229
230	tail = []
231	def _strip(stream):
232	depth = 1
233	while 1:
234	event = stream.next()
235	if event[0] is START:
236	depth += 1
237	elif event[0] is END:
238	depth -= 1
239	if depth > 0:
240	yield event
241	else:
242	tail[:] = [event]
243	break
244
245	for event in stream:
246
247	# We (currently) only care about start and end events for matching
248	# We might care about namespace events in the future, though
249	if not match_templates or (event[0] is not START and
250	event[0] is not END):
251	yield event
252	continue
253
254	for idx, (test, path, template, hints, namespaces, directives) \
255	in enumerate(match_templates):
256	if idx < start or end is not None and idx >= end:
257	continue
258
259	if test(event, namespaces, ctxt) is True:
260	if 'match_once' in hints:
261	del match_templates[idx]
262	idx -= 1
263
264	# Let the remaining match templates know about the event so
265	# they get a chance to update their internal state
266	for test in [mt[0] for mt in match_templates[idx + 1:]]:
267	test(event, namespaces, ctxt, updateonly=True)
268
269	# Consume and store all events until an end event
270	# corresponding to this start event is encountered
271	pre_end = idx + 1
272	if 'match_once' not in hints and 'not_recursive' in hints:
273	pre_end -= 1
274	inner = _strip(stream)
275	if pre_end > 0:
276	inner = self._match(inner, ctxt, end=pre_end)
277	content = self._include(chain([event], inner, tail), ctxt)
278	if 'not_buffered' not in hints:
279	content = list(content)
280
281	# Make the select() function available in the body of the
282	# match template
283	selected = [False]
284	def select(path):
285	selected[0] = True
286	return Stream(content).select(path, namespaces, ctxt)
287	vars = dict(select=select)
288
289	# Recursively process the output
290	template = _apply_directives(template, directives, ctxt,
291	**vars)
292	for event in self._match(
293	self._exec(
294	self._eval(
295	self._flatten(template, ctxt, **vars),
296	ctxt, **vars),
297	ctxt, **vars),
298	ctxt, start=idx + 1, **vars):
299	yield event
300
301	# If the match template did not actually call select to
302	# consume the matched stream, the original events need to
303	# be consumed here or they'll get appended to the output
304	if not selected[0]:
305	for event in content:
306	pass
307
308	# Let the remaining match templates know about the last
309	# event in the matched content, so they can update their
310	# internal state accordingly
311	for test in [mt[0] for mt in match_templates]:
312	test(tail[0], namespaces, ctxt, updateonly=True)
313
314	break
315
316	else: # no matches
317	yield event

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source: branches/stable/0.5.x/genshi/template/markup.py

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