source: python/trunk/Lib/xml/sax/xmlreader.py

Last change on this file was 391, checked in by dmik, 11 years ago

python: Merge vendor 2.7.6 to trunk.
  • Property svn:eol-style set to native
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Line 
1"""An XML Reader is the SAX 2 name for an XML parser. XML Parsers
2should be based on this code. """
3
4import handler
5
6from _exceptions import SAXNotSupportedException, SAXNotRecognizedException
7
8
9# ===== XMLREADER =====
10
11class XMLReader:
12 """Interface for reading an XML document using callbacks.
13
14 XMLReader is the interface that an XML parser's SAX2 driver must
15 implement. This interface allows an application to set and query
16 features and properties in the parser, to register event handlers
17 for document processing, and to initiate a document parse.
18
19 All SAX interfaces are assumed to be synchronous: the parse
20 methods must not return until parsing is complete, and readers
21 must wait for an event-handler callback to return before reporting
22 the next event."""
23
24 def __init__(self):
25 self._cont_handler = handler.ContentHandler()
26 self._dtd_handler = handler.DTDHandler()
27 self._ent_handler = handler.EntityResolver()
28 self._err_handler = handler.ErrorHandler()
29
30 def parse(self, source):
31 "Parse an XML document from a system identifier or an InputSource."
32 raise NotImplementedError("This method must be implemented!")
33
34 def getContentHandler(self):
35 "Returns the current ContentHandler."
36 return self._cont_handler
37
38 def setContentHandler(self, handler):
39 "Registers a new object to receive document content events."
40 self._cont_handler = handler
41
42 def getDTDHandler(self):
43 "Returns the current DTD handler."
44 return self._dtd_handler
45
46 def setDTDHandler(self, handler):
47 "Register an object to receive basic DTD-related events."
48 self._dtd_handler = handler
49
50 def getEntityResolver(self):
51 "Returns the current EntityResolver."
52 return self._ent_handler
53
54 def setEntityResolver(self, resolver):
55 "Register an object to resolve external entities."
56 self._ent_handler = resolver
57
58 def getErrorHandler(self):
59 "Returns the current ErrorHandler."
60 return self._err_handler
61
62 def setErrorHandler(self, handler):
63 "Register an object to receive error-message events."
64 self._err_handler = handler
65
66 def setLocale(self, locale):
67 """Allow an application to set the locale for errors and warnings.
68
69 SAX parsers are not required to provide localization for errors
70 and warnings; if they cannot support the requested locale,
71 however, they must raise a SAX exception. Applications may
72 request a locale change in the middle of a parse."""
73 raise SAXNotSupportedException("Locale support not implemented")
74
75 def getFeature(self, name):
76 "Looks up and returns the state of a SAX2 feature."
77 raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
78
79 def setFeature(self, name, state):
80 "Sets the state of a SAX2 feature."
81 raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
82
83 def getProperty(self, name):
84 "Looks up and returns the value of a SAX2 property."
85 raise SAXNotRecognizedException("Property '%s' not recognized" % name)
86
87 def setProperty(self, name, value):
88 "Sets the value of a SAX2 property."
89 raise SAXNotRecognizedException("Property '%s' not recognized" % name)
90
91class IncrementalParser(XMLReader):
92 """This interface adds three extra methods to the XMLReader
93 interface that allow XML parsers to support incremental
94 parsing. Support for this interface is optional, since not all
95 underlying XML parsers support this functionality.
96
97 When the parser is instantiated it is ready to begin accepting
98 data from the feed method immediately. After parsing has been
99 finished with a call to close the reset method must be called to
100 make the parser ready to accept new data, either from feed or
101 using the parse method.
102
103 Note that these methods must _not_ be called during parsing, that
104 is, after parse has been called and before it returns.
105
106 By default, the class also implements the parse method of the XMLReader
107 interface using the feed, close and reset methods of the
108 IncrementalParser interface as a convenience to SAX 2.0 driver
109 writers."""
110
111 def __init__(self, bufsize=2**16):
112 self._bufsize = bufsize
113 XMLReader.__init__(self)
114
115 def parse(self, source):
116 import saxutils
117 source = saxutils.prepare_input_source(source)
118
119 self.prepareParser(source)
120 file = source.getByteStream()
121 buffer = file.read(self._bufsize)
122 while buffer != "":
123 self.feed(buffer)
124 buffer = file.read(self._bufsize)
125 self.close()
126
127 def feed(self, data):
128 """This method gives the raw XML data in the data parameter to
129 the parser and makes it parse the data, emitting the
130 corresponding events. It is allowed for XML constructs to be
131 split across several calls to feed.
132
133 feed may raise SAXException."""
134 raise NotImplementedError("This method must be implemented!")
135
136 def prepareParser(self, source):
137 """This method is called by the parse implementation to allow
138 the SAX 2.0 driver to prepare itself for parsing."""
139 raise NotImplementedError("prepareParser must be overridden!")
140
141 def close(self):
142 """This method is called when the entire XML document has been
143 passed to the parser through the feed method, to notify the
144 parser that there are no more data. This allows the parser to
145 do the final checks on the document and empty the internal
146 data buffer.
147
148 The parser will not be ready to parse another document until
149 the reset method has been called.
150
151 close may raise SAXException."""
152 raise NotImplementedError("This method must be implemented!")
153
154 def reset(self):
155 """This method is called after close has been called to reset
156 the parser so that it is ready to parse new documents. The
157 results of calling parse or feed after close without calling
158 reset are undefined."""
159 raise NotImplementedError("This method must be implemented!")
160
161# ===== LOCATOR =====
162
163class Locator:
164 """Interface for associating a SAX event with a document
165 location. A locator object will return valid results only during
166 calls to DocumentHandler methods; at any other time, the
167 results are unpredictable."""
168
169 def getColumnNumber(self):
170 "Return the column number where the current event ends."
171 return -1
172
173 def getLineNumber(self):
174 "Return the line number where the current event ends."
175 return -1
176
177 def getPublicId(self):
178 "Return the public identifier for the current event."
179 return None
180
181 def getSystemId(self):
182 "Return the system identifier for the current event."
183 return None
184
185# ===== INPUTSOURCE =====
186
187class InputSource:
188 """Encapsulation of the information needed by the XMLReader to
189 read entities.
190
191 This class may include information about the public identifier,
192 system identifier, byte stream (possibly with character encoding
193 information) and/or the character stream of an entity.
194
195 Applications will create objects of this class for use in the
196 XMLReader.parse method and for returning from
197 EntityResolver.resolveEntity.
198
199 An InputSource belongs to the application, the XMLReader is not
200 allowed to modify InputSource objects passed to it from the
201 application, although it may make copies and modify those."""
202
203 def __init__(self, system_id = None):
204 self.__system_id = system_id
205 self.__public_id = None
206 self.__encoding = None
207 self.__bytefile = None
208 self.__charfile = None
209
210 def setPublicId(self, public_id):
211 "Sets the public identifier of this InputSource."
212 self.__public_id = public_id
213
214 def getPublicId(self):
215 "Returns the public identifier of this InputSource."
216 return self.__public_id
217
218 def setSystemId(self, system_id):
219 "Sets the system identifier of this InputSource."
220 self.__system_id = system_id
221
222 def getSystemId(self):
223 "Returns the system identifier of this InputSource."
224 return self.__system_id
225
226 def setEncoding(self, encoding):
227 """Sets the character encoding of this InputSource.
228
229 The encoding must be a string acceptable for an XML encoding
230 declaration (see section 4.3.3 of the XML recommendation).
231
232 The encoding attribute of the InputSource is ignored if the
233 InputSource also contains a character stream."""
234 self.__encoding = encoding
235
236 def getEncoding(self):
237 "Get the character encoding of this InputSource."
238 return self.__encoding
239
240 def setByteStream(self, bytefile):
241 """Set the byte stream (a Python file-like object which does
242 not perform byte-to-character conversion) for this input
243 source.
244
245 The SAX parser will ignore this if there is also a character
246 stream specified, but it will use a byte stream in preference
247 to opening a URI connection itself.
248
249 If the application knows the character encoding of the byte
250 stream, it should set it with the setEncoding method."""
251 self.__bytefile = bytefile
252
253 def getByteStream(self):
254 """Get the byte stream for this input source.
255
256 The getEncoding method will return the character encoding for
257 this byte stream, or None if unknown."""
258 return self.__bytefile
259
260 def setCharacterStream(self, charfile):
261 """Set the character stream for this input source. (The stream
262 must be a Python 2.0 Unicode-wrapped file-like that performs
263 conversion to Unicode strings.)
264
265 If there is a character stream specified, the SAX parser will
266 ignore any byte stream and will not attempt to open a URI
267 connection to the system identifier."""
268 self.__charfile = charfile
269
270 def getCharacterStream(self):
271 "Get the character stream for this input source."
272 return self.__charfile
273
274# ===== ATTRIBUTESIMPL =====
275
276class AttributesImpl:
277
278 def __init__(self, attrs):
279 """Non-NS-aware implementation.
280
281 attrs should be of the form {name : value}."""
282 self._attrs = attrs
283
284 def getLength(self):
285 return len(self._attrs)
286
287 def getType(self, name):
288 return "CDATA"
289
290 def getValue(self, name):
291 return self._attrs[name]
292
293 def getValueByQName(self, name):
294 return self._attrs[name]
295
296 def getNameByQName(self, name):
297 if not name in self._attrs:
298 raise KeyError, name
299 return name
300
301 def getQNameByName(self, name):
302 if not name in self._attrs:
303 raise KeyError, name
304 return name
305
306 def getNames(self):
307 return self._attrs.keys()
308
309 def getQNames(self):
310 return self._attrs.keys()
311
312 def __len__(self):
313 return len(self._attrs)
314
315 def __getitem__(self, name):
316 return self._attrs[name]
317
318 def keys(self):
319 return self._attrs.keys()
320
321 def has_key(self, name):
322 return name in self._attrs
323
324 def __contains__(self, name):
325 return name in self._attrs
326
327 def get(self, name, alternative=None):
328 return self._attrs.get(name, alternative)
329
330 def copy(self):
331 return self.__class__(self._attrs)
332
333 def items(self):
334 return self._attrs.items()
335
336 def values(self):
337 return self._attrs.values()
338
339# ===== ATTRIBUTESNSIMPL =====
340
341class AttributesNSImpl(AttributesImpl):
342
343 def __init__(self, attrs, qnames):
344 """NS-aware implementation.
345
346 attrs should be of the form {(ns_uri, lname): value, ...}.
347 qnames of the form {(ns_uri, lname): qname, ...}."""
348 self._attrs = attrs
349 self._qnames = qnames
350
351 def getValueByQName(self, name):
352 for (nsname, qname) in self._qnames.items():
353 if qname == name:
354 return self._attrs[nsname]
355
356 raise KeyError, name
357
358 def getNameByQName(self, name):
359 for (nsname, qname) in self._qnames.items():
360 if qname == name:
361 return nsname
362
363 raise KeyError, name
364
365 def getQNameByName(self, name):
366 return self._qnames[name]
367
368 def getQNames(self):
369 return self._qnames.values()
370
371 def copy(self):
372 return self.__class__(self._attrs, self._qnames)
373
374
375def _test():
376 XMLReader()
377 IncrementalParser()
378 Locator()
379
380if __name__ == "__main__":
381 _test()
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