Lib/xmlcore/dom/xmlbuilder.py

   1 """Implementation of the DOM Level 3 'LS-Load' feature."""
   2
   3 import copy
   4 import xmlcore.dom
   5
   6 from xmlcore.dom.NodeFilter import NodeFilter
   7
   8
   9 __all__ = ["DOMBuilder", "DOMEntityResolver", "DOMInputSource"]
  10
  11
  12 class Options:
  13     """Features object that has variables set for each DOMBuilder feature.
  14
  15     The DOMBuilder class uses an instance of this class to pass settings to
  16     the ExpatBuilder class.
  17     """
  18
  19     # Note that the DOMBuilder class in LoadSave constrains which of these
  20     # values can be set using the DOM Level 3 LoadSave feature.
  21
  22     namespaces = 1
  23     namespace_declarations = True
  24     validation = False
  25     external_parameter_entities = True
  26     external_general_entities = True
  27     external_dtd_subset = True
  28     validate_if_schema = False
  29     validate = False
  30     datatype_normalization = False
  31     create_entity_ref_nodes = True
  32     entities = True
  33     whitespace_in_element_content = True
  34     cdata_sections = True
  35     comments = True
  36     charset_overrides_xml_encoding = True
  37     infoset = False
  38     supported_mediatypes_only = False
  39
  40     errorHandler = None
  41     filter = None
  42
  43
  44 class DOMBuilder:
  45     entityResolver = None
  46     errorHandler = None
  47     filter = None
  48
  49     ACTION_REPLACE = 1
  50     ACTION_APPEND_AS_CHILDREN = 2
  51     ACTION_INSERT_AFTER = 3
  52     ACTION_INSERT_BEFORE = 4
  53
  54     _legal_actions = (ACTION_REPLACE, ACTION_APPEND_AS_CHILDREN,
  55                       ACTION_INSERT_AFTER, ACTION_INSERT_BEFORE)
  56
  57     def __init__(self):
  58         self._options = Options()
  59
  60     def _get_entityResolver(self):
  61         return self.entityResolver
  62     def _set_entityResolver(self, entityResolver):
  63         self.entityResolver = entityResolver
  64
  65     def _get_errorHandler(self):
  66         return self.errorHandler
  67     def _set_errorHandler(self, errorHandler):
  68         self.errorHandler = errorHandler
  69
  70     def _get_filter(self):
  71         return self.filter
  72     def _set_filter(self, filter):
  73         self.filter = filter
  74
  75     def setFeature(self, name, state):
  76         if self.supportsFeature(name):
  77             state = state and 1 or 0
  78             try:
  79                 settings = self._settings[(_name_xform(name), state)]
  80             except KeyError:
  81                 raise xmlcore.dom.NotSupportedErr(
  82                     "unsupported feature: %r" % (name,))
  83             else:
  84                 for name, value in settings:
  85                     setattr(self._options, name, value)
  86         else:
  87             raise xmlcore.dom.NotFoundErr("unknown feature: " + repr(name))
  88
  89     def supportsFeature(self, name):
  90         return hasattr(self._options, _name_xform(name))
  91
  92     def canSetFeature(self, name, state):
  93         key = (_name_xform(name), state and 1 or 0)
  94         return self._settings.has_key(key)
  95
  96     # This dictionary maps from (feature,value) to a list of
  97     # (option,value) pairs that should be set on the Options object.
  98     # If a (feature,value) setting is not in this dictionary, it is
  99     # not supported by the DOMBuilder.
 100     #
 101     _settings = {
 102         ("namespace_declarations", 0): [
 103             ("namespace_declarations", 0)],
 104         ("namespace_declarations", 1): [
 105             ("namespace_declarations", 1)],
 106         ("validation", 0): [
 107             ("validation", 0)],
 108         ("external_general_entities", 0): [
 109             ("external_general_entities", 0)],
 110         ("external_general_entities", 1): [
 111             ("external_general_entities", 1)],
 112         ("external_parameter_entities", 0): [
 113             ("external_parameter_entities", 0)],
 114         ("external_parameter_entities", 1): [
 115             ("external_parameter_entities", 1)],
 116         ("validate_if_schema", 0): [
 117             ("validate_if_schema", 0)],
 118         ("create_entity_ref_nodes", 0): [
 119             ("create_entity_ref_nodes", 0)],
 120         ("create_entity_ref_nodes", 1): [
 121             ("create_entity_ref_nodes", 1)],
 122         ("entities", 0): [
 123             ("create_entity_ref_nodes", 0),
 124             ("entities", 0)],
 125         ("entities", 1): [
 126             ("entities", 1)],
 127         ("whitespace_in_element_content", 0): [
 128             ("whitespace_in_element_content", 0)],
 129         ("whitespace_in_element_content", 1): [
 130             ("whitespace_in_element_content", 1)],
 131         ("cdata_sections", 0): [
 132             ("cdata_sections", 0)],
 133         ("cdata_sections", 1): [
 134             ("cdata_sections", 1)],
 135         ("comments", 0): [
 136             ("comments", 0)],
 137         ("comments", 1): [
 138             ("comments", 1)],
 139         ("charset_overrides_xml_encoding", 0): [
 140             ("charset_overrides_xml_encoding", 0)],
 141         ("charset_overrides_xml_encoding", 1): [
 142             ("charset_overrides_xml_encoding", 1)],
 143         ("infoset", 0): [],
 144         ("infoset", 1): [
 145             ("namespace_declarations", 0),
 146             ("validate_if_schema", 0),
 147             ("create_entity_ref_nodes", 0),
 148             ("entities", 0),
 149             ("cdata_sections", 0),
 150             ("datatype_normalization", 1),
 151             ("whitespace_in_element_content", 1),
 152             ("comments", 1),
 153             ("charset_overrides_xml_encoding", 1)],
 154         ("supported_mediatypes_only", 0): [
 155             ("supported_mediatypes_only", 0)],
 156         ("namespaces", 0): [
 157             ("namespaces", 0)],
 158         ("namespaces", 1): [
 159             ("namespaces", 1)],
 160     }
 161
 162     def getFeature(self, name):
 163         xname = _name_xform(name)
 164         try:
 165             return getattr(self._options, xname)
 166         except AttributeError:
 167             if name == "infoset":
 168                 options = self._options
 169                 return (options.datatype_normalization
 170                         and options.whitespace_in_element_content
 171                         and options.comments
 172                         and options.charset_overrides_xml_encoding
 173                         and not (options.namespace_declarations
 174                                  or options.validate_if_schema
 175                                  or options.create_entity_ref_nodes
 176                                  or options.entities
 177                                  or options.cdata_sections))
 178             raise xmlcore.dom.NotFoundErr("feature %s not known" % repr(name))
 179
 180     def parseURI(self, uri):
 181         if self.entityResolver:
 182             input = self.entityResolver.resolveEntity(None, uri)
 183         else:
 184             input = DOMEntityResolver().resolveEntity(None, uri)
 185         return self.parse(input)
 186
 187     def parse(self, input):
 188         options = copy.copy(self._options)
 189         options.filter = self.filter
 190         options.errorHandler = self.errorHandler
 191         fp = input.byteStream
 192         if fp is None and options.systemId:
 193             import urllib2
 194             fp = urllib2.urlopen(input.systemId)
 195         return self._parse_bytestream(fp, options)
 196
 197     def parseWithContext(self, input, cnode, action):
 198         if action not in self._legal_actions:
 199             raise ValueError("not a legal action")
 200         raise NotImplementedError("Haven't written this yet...")
 201
 202     def _parse_bytestream(self, stream, options):
 203         import xmlcore.dom.expatbuilder
 204         builder = xmlcore.dom.expatbuilder.makeBuilder(options)
 205         return builder.parseFile(stream)
 206
 207
 208 def _name_xform(name):
 209     return name.lower().replace('-', '_')
 210
 211
 212 class DOMEntityResolver(object):
 213     __slots__ = '_opener',
 214
 215     def resolveEntity(self, publicId, systemId):
 216         assert systemId is not None
 217         source = DOMInputSource()
 218         source.publicId = publicId
 219         source.systemId = systemId
 220         source.byteStream = self._get_opener().open(systemId)
 221
 222         # determine the encoding if the transport provided it
 223         source.encoding = self._guess_media_encoding(source)
 224
 225         # determine the base URI is we can
 226         import posixpath, urlparse
 227         parts = urlparse.urlparse(systemId)
 228         scheme, netloc, path, params, query, fragment = parts
 229         # XXX should we check the scheme here as well?
 230         if path and not path.endswith("/"):
 231             path = posixpath.dirname(path) + "/"
 232             parts = scheme, netloc, path, params, query, fragment
 233             source.baseURI = urlparse.urlunparse(parts)
 234
 235         return source
 236
 237     def _get_opener(self):
 238         try:
 239             return self._opener
 240         except AttributeError:
 241             self._opener = self._create_opener()
 242             return self._opener
 243
 244     def _create_opener(self):
 245         import urllib2
 246         return urllib2.build_opener()
 247
 248     def _guess_media_encoding(self, source):
 249         info = source.byteStream.info()
 250         if info.has_key("Content-Type"):
 251             for param in info.getplist():
 252                 if param.startswith("charset="):
 253                     return param.split("=", 1)[1].lower()
 254
 255
 256 class DOMInputSource(object):
 257     __slots__ = ('byteStream', 'characterStream', 'stringData',
 258                  'encoding', 'publicId', 'systemId', 'baseURI')
 259
 260     def __init__(self):
 261         self.byteStream = None
 262         self.characterStream = None
 263         self.stringData = None
 264         self.encoding = None
 265         self.publicId = None
 266         self.systemId = None
 267         self.baseURI = None
 268
 269     def _get_byteStream(self):
 270         return self.byteStream
 271     def _set_byteStream(self, byteStream):
 272         self.byteStream = byteStream
 273
 274     def _get_characterStream(self):
 275         return self.characterStream
 276     def _set_characterStream(self, characterStream):
 277         self.characterStream = characterStream
 278
 279     def _get_stringData(self):
 280         return self.stringData
 281     def _set_stringData(self, data):
 282         self.stringData = data
 283
 284     def _get_encoding(self):
 285         return self.encoding
 286     def _set_encoding(self, encoding):
 287         self.encoding = encoding
 288
 289     def _get_publicId(self):
 290         return self.publicId
 291     def _set_publicId(self, publicId):
 292         self.publicId = publicId
 293
 294     def _get_systemId(self):
 295         return self.systemId
 296     def _set_systemId(self, systemId):
 297         self.systemId = systemId
 298
 299     def _get_baseURI(self):
 300         return self.baseURI
 301     def _set_baseURI(self, uri):
 302         self.baseURI = uri
 303
 304
 305 class DOMBuilderFilter:
 306     """Element filter which can be used to tailor construction of
 307     a DOM instance.
 308     """
 309
 310     # There's really no need for this class; concrete implementations
 311     # should just implement the endElement() and startElement()
 312     # methods as appropriate.  Using this makes it easy to only
 313     # implement one of them.
 314
 315     FILTER_ACCEPT = 1
 316     FILTER_REJECT = 2
 317     FILTER_SKIP = 3
 318     FILTER_INTERRUPT = 4
 319
 320     whatToShow = NodeFilter.SHOW_ALL
 321
 322     def _get_whatToShow(self):
 323         return self.whatToShow
 324
 325     def acceptNode(self, element):
 326         return self.FILTER_ACCEPT
 327
 328     def startContainer(self, element):
 329         return self.FILTER_ACCEPT
 330
 331 del NodeFilter
 332
 333
 334 class DocumentLS:
 335     """Mixin to create documents that conform to the load/save spec."""
 336
 337     async = False
 338
 339     def _get_async(self):
 340         return False
 341     def _set_async(self, async):
 342         if async:
 343             raise xmlcore.dom.NotSupportedErr(
 344                 "asynchronous document loading is not supported")
 345
 346     def abort(self):
 347         # What does it mean to "clear" a document?  Does the
 348         # documentElement disappear?
 349         raise NotImplementedError(
 350             "haven't figured out what this means yet")
 351
 352     def load(self, uri):
 353         raise NotImplementedError("haven't written this yet")
 354
 355     def loadXML(self, source):
 356         raise NotImplementedError("haven't written this yet")
 357
 358     def saveXML(self, snode):
 359         if snode is None:
 360             snode = self
 361         elif snode.ownerDocument is not self:
 362             raise xmlcore.dom.WrongDocumentErr()
 363         return snode.toxml()
 364
 365
 366 class DOMImplementationLS:
 367     MODE_SYNCHRONOUS = 1
 368     MODE_ASYNCHRONOUS = 2
 369
 370     def createDOMBuilder(self, mode, schemaType):
 371         if schemaType is not None:
 372             raise xmlcore.dom.NotSupportedErr(
 373                 "schemaType not yet supported")
 374         if mode == self.MODE_SYNCHRONOUS:
 375             return DOMBuilder()
 376         if mode == self.MODE_ASYNCHRONOUS:
 377             raise xmlcore.dom.NotSupportedErr(
 378                 "asynchronous builders are not supported")
 379         raise ValueError("unknown value for mode")
 380
 381     def createDOMWriter(self):
 382         raise NotImplementedError(
 383             "the writer interface hasn't been written yet!")
 384
 385     def createDOMInputSource(self):
 386         return DOMInputSource()