AppPkg/Applications/Python/Python-2.7.2/Lib/xml/sax/handler.py

   1 """
   2 This module contains the core classes of version 2.0 of SAX for Python.
   3 This file provides only default classes with absolutely minimum
   4 functionality, from which drivers and applications can be subclassed.
   5
   6 Many of these classes are empty and are included only as documentation
   7 of the interfaces.
   8
   9 $Id$
  10 """
  11
  12 version = '2.0beta'
  13
  14 #============================================================================
  15 #
  16 # HANDLER INTERFACES
  17 #
  18 #============================================================================
  19
  20 # ===== ERRORHANDLER =====
  21
  22 class ErrorHandler:
  23     """Basic interface for SAX error handlers.
  24
  25     If you create an object that implements this interface, then
  26     register the object with your XMLReader, the parser will call the
  27     methods in your object to report all warnings and errors. There
  28     are three levels of errors available: warnings, (possibly)
  29     recoverable errors, and unrecoverable errors. All methods take a
  30     SAXParseException as the only parameter."""
  31
  32     def error(self, exception):
  33         "Handle a recoverable error."
  34         raise exception
  35
  36     def fatalError(self, exception):
  37         "Handle a non-recoverable error."
  38         raise exception
  39
  40     def warning(self, exception):
  41         "Handle a warning."
  42         print exception
  43
  44
  45 # ===== CONTENTHANDLER =====
  46
  47 class ContentHandler:
  48     """Interface for receiving logical document content events.
  49
  50     This is the main callback interface in SAX, and the one most
  51     important to applications. The order of events in this interface
  52     mirrors the order of the information in the document."""
  53
  54     def __init__(self):
  55         self._locator = None
  56
  57     def setDocumentLocator(self, locator):
  58         """Called by the parser to give the application a locator for
  59         locating the origin of document events.
  60
  61         SAX parsers are strongly encouraged (though not absolutely
  62         required) to supply a locator: if it does so, it must supply
  63         the locator to the application by invoking this method before
  64         invoking any of the other methods in the DocumentHandler
  65         interface.
  66
  67         The locator allows the application to determine the end
  68         position of any document-related event, even if the parser is
  69         not reporting an error. Typically, the application will use
  70         this information for reporting its own errors (such as
  71         character content that does not match an application's
  72         business rules). The information returned by the locator is
  73         probably not sufficient for use with a search engine.
  74
  75         Note that the locator will return correct information only
  76         during the invocation of the events in this interface. The
  77         application should not attempt to use it at any other time."""
  78         self._locator = locator
  79
  80     def startDocument(self):
  81         """Receive notification of the beginning of a document.
  82
  83         The SAX parser will invoke this method only once, before any
  84         other methods in this interface or in DTDHandler (except for
  85         setDocumentLocator)."""
  86
  87     def endDocument(self):
  88         """Receive notification of the end of a document.
  89
  90         The SAX parser will invoke this method only once, and it will
  91         be the last method invoked during the parse. The parser shall
  92         not invoke this method until it has either abandoned parsing
  93         (because of an unrecoverable error) or reached the end of
  94         input."""
  95
  96     def startPrefixMapping(self, prefix, uri):
  97         """Begin the scope of a prefix-URI Namespace mapping.
  98
  99         The information from this event is not necessary for normal
 100         Namespace processing: the SAX XML reader will automatically
 101         replace prefixes for element and attribute names when the
 102         http://xml.org/sax/features/namespaces feature is true (the
 103         default).
 104
 105         There are cases, however, when applications need to use
 106         prefixes in character data or in attribute values, where they
 107         cannot safely be expanded automatically; the
 108         start/endPrefixMapping event supplies the information to the
 109         application to expand prefixes in those contexts itself, if
 110         necessary.
 111
 112         Note that start/endPrefixMapping events are not guaranteed to
 113         be properly nested relative to each-other: all
 114         startPrefixMapping events will occur before the corresponding
 115         startElement event, and all endPrefixMapping events will occur
 116         after the corresponding endElement event, but their order is
 117         not guaranteed."""
 118
 119     def endPrefixMapping(self, prefix):
 120         """End the scope of a prefix-URI mapping.
 121
 122         See startPrefixMapping for details. This event will always
 123         occur after the corresponding endElement event, but the order
 124         of endPrefixMapping events is not otherwise guaranteed."""
 125
 126     def startElement(self, name, attrs):
 127         """Signals the start of an element in non-namespace mode.
 128
 129         The name parameter contains the raw XML 1.0 name of the
 130         element type as a string and the attrs parameter holds an
 131         instance of the Attributes class containing the attributes of
 132         the element."""
 133
 134     def endElement(self, name):
 135         """Signals the end of an element in non-namespace mode.
 136
 137         The name parameter contains the name of the element type, just
 138         as with the startElement event."""
 139
 140     def startElementNS(self, name, qname, attrs):
 141         """Signals the start of an element in namespace mode.
 142
 143         The name parameter contains the name of the element type as a
 144         (uri, localname) tuple, the qname parameter the raw XML 1.0
 145         name used in the source document, and the attrs parameter
 146         holds an instance of the Attributes class containing the
 147         attributes of the element.
 148
 149         The uri part of the name tuple is None for elements which have
 150         no namespace."""
 151
 152     def endElementNS(self, name, qname):
 153         """Signals the end of an element in namespace mode.
 154
 155         The name parameter contains the name of the element type, just
 156         as with the startElementNS event."""
 157
 158     def characters(self, content):
 159         """Receive notification of character data.
 160
 161         The Parser will call this method to report each chunk of
 162         character data. SAX parsers may return all contiguous
 163         character data in a single chunk, or they may split it into
 164         several chunks; however, all of the characters in any single
 165         event must come from the same external entity so that the
 166         Locator provides useful information."""
 167
 168     def ignorableWhitespace(self, whitespace):
 169         """Receive notification of ignorable whitespace in element content.
 170
 171         Validating Parsers must use this method to report each chunk
 172         of ignorable whitespace (see the W3C XML 1.0 recommendation,
 173         section 2.10): non-validating parsers may also use this method
 174         if they are capable of parsing and using content models.
 175
 176         SAX parsers may return all contiguous whitespace in a single
 177         chunk, or they may split it into several chunks; however, all
 178         of the characters in any single event must come from the same
 179         external entity, so that the Locator provides useful
 180         information."""
 181
 182     def processingInstruction(self, target, data):
 183         """Receive notification of a processing instruction.
 184
 185         The Parser will invoke this method once for each processing
 186         instruction found: note that processing instructions may occur
 187         before or after the main document element.
 188
 189         A SAX parser should never report an XML declaration (XML 1.0,
 190         section 2.8) or a text declaration (XML 1.0, section 4.3.1)
 191         using this method."""
 192
 193     def skippedEntity(self, name):
 194         """Receive notification of a skipped entity.
 195
 196         The Parser will invoke this method once for each entity
 197         skipped. Non-validating processors may skip entities if they
 198         have not seen the declarations (because, for example, the
 199         entity was declared in an external DTD subset). All processors
 200         may skip external entities, depending on the values of the
 201         http://xml.org/sax/features/external-general-entities and the
 202         http://xml.org/sax/features/external-parameter-entities
 203         properties."""
 204
 205
 206 # ===== DTDHandler =====
 207
 208 class DTDHandler:
 209     """Handle DTD events.
 210
 211     This interface specifies only those DTD events required for basic
 212     parsing (unparsed entities and attributes)."""
 213
 214     def notationDecl(self, name, publicId, systemId):
 215         "Handle a notation declaration event."
 216
 217     def unparsedEntityDecl(self, name, publicId, systemId, ndata):
 218         "Handle an unparsed entity declaration event."
 219
 220
 221 # ===== ENTITYRESOLVER =====
 222
 223 class EntityResolver:
 224     """Basic interface for resolving entities. If you create an object
 225     implementing this interface, then register the object with your
 226     Parser, the parser will call the method in your object to
 227     resolve all external entities. Note that DefaultHandler implements
 228     this interface with the default behaviour."""
 229
 230     def resolveEntity(self, publicId, systemId):
 231         """Resolve the system identifier of an entity and return either
 232         the system identifier to read from as a string, or an InputSource
 233         to read from."""
 234         return systemId
 235
 236
 237 #============================================================================
 238 #
 239 # CORE FEATURES
 240 #
 241 #============================================================================
 242
 243 feature_namespaces = "http://xml.org/sax/features/namespaces"
 244 # true: Perform Namespace processing (default).
 245 # false: Optionally do not perform Namespace processing
 246 #        (implies namespace-prefixes).
 247 # access: (parsing) read-only; (not parsing) read/write
 248
 249 feature_namespace_prefixes = "http://xml.org/sax/features/namespace-prefixes"
 250 # true: Report the original prefixed names and attributes used for Namespace
 251 #       declarations.
 252 # false: Do not report attributes used for Namespace declarations, and
 253 #        optionally do not report original prefixed names (default).
 254 # access: (parsing) read-only; (not parsing) read/write
 255
 256 feature_string_interning = "http://xml.org/sax/features/string-interning"
 257 # true: All element names, prefixes, attribute names, Namespace URIs, and
 258 #       local names are interned using the built-in intern function.
 259 # false: Names are not necessarily interned, although they may be (default).
 260 # access: (parsing) read-only; (not parsing) read/write
 261
 262 feature_validation = "http://xml.org/sax/features/validation"
 263 # true: Report all validation errors (implies external-general-entities and
 264 #       external-parameter-entities).
 265 # false: Do not report validation errors.
 266 # access: (parsing) read-only; (not parsing) read/write
 267
 268 feature_external_ges = "http://xml.org/sax/features/external-general-entities"
 269 # true: Include all external general (text) entities.
 270 # false: Do not include external general entities.
 271 # access: (parsing) read-only; (not parsing) read/write
 272
 273 feature_external_pes = "http://xml.org/sax/features/external-parameter-entities"
 274 # true: Include all external parameter entities, including the external
 275 #       DTD subset.
 276 # false: Do not include any external parameter entities, even the external
 277 #        DTD subset.
 278 # access: (parsing) read-only; (not parsing) read/write
 279
 280 all_features = [feature_namespaces,
 281                 feature_namespace_prefixes,
 282                 feature_string_interning,
 283                 feature_validation,
 284                 feature_external_ges,
 285                 feature_external_pes]
 286
 287
 288 #============================================================================
 289 #
 290 # CORE PROPERTIES
 291 #
 292 #============================================================================
 293
 294 property_lexical_handler = "http://xml.org/sax/properties/lexical-handler"
 295 # data type: xml.sax.sax2lib.LexicalHandler
 296 # description: An optional extension handler for lexical events like comments.
 297 # access: read/write
 298
 299 property_declaration_handler = "http://xml.org/sax/properties/declaration-handler"
 300 # data type: xml.sax.sax2lib.DeclHandler
 301 # description: An optional extension handler for DTD-related events other
 302 #              than notations and unparsed entities.
 303 # access: read/write
 304
 305 property_dom_node = "http://xml.org/sax/properties/dom-node"
 306 # data type: org.w3c.dom.Node
 307 # description: When parsing, the current DOM node being visited if this is
 308 #              a DOM iterator; when not parsing, the root DOM node for
 309 #              iteration.
 310 # access: (parsing) read-only; (not parsing) read/write
 311
 312 property_xml_string = "http://xml.org/sax/properties/xml-string"
 313 # data type: String
 314 # description: The literal string of characters that was the source for
 315 #              the current event.
 316 # access: read-only
 317
 318 property_encoding = "http://www.python.org/sax/properties/encoding"
 319 # data type: String
 320 # description: The name of the encoding to assume for input data.
 321 # access: write: set the encoding, e.g. established by a higher-level
 322 #                protocol. May change during parsing (e.g. after
 323 #                processing a META tag)
 324 #         read:  return the current encoding (possibly established through
 325 #                auto-detection.
 326 # initial value: UTF-8
 327 #
 328
 329 property_interning_dict = "http://www.python.org/sax/properties/interning-dict"
 330 # data type: Dictionary
 331 # description: The dictionary used to intern common strings in the document
 332 # access: write: Request that the parser uses a specific dictionary, to
 333 #                allow interning across different documents
 334 #         read:  return the current interning dictionary, or None
 335 #
 336
 337 all_properties = [property_lexical_handler,
 338                   property_dom_node,
 339                   property_declaration_handler,
 340                   property_xml_string,
 341                   property_encoding,
 342                   property_interning_dict]