447 lines
15 KiB
Python
447 lines
15 KiB
Python
"""
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SAX driver for the pyexpat C module. This driver works with
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pyexpat.__version__ == '2.22'.
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"""
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version = "0.20"
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from xml.sax._exceptions import *
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from xml.sax.handler import feature_validation, feature_namespaces
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from xml.sax.handler import feature_namespace_prefixes
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from xml.sax.handler import feature_external_ges, feature_external_pes
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from xml.sax.handler import feature_string_interning
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from xml.sax.handler import property_xml_string, property_interning_dict
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# xml.parsers.expat does not raise ImportError in Jython
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import sys
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if sys.platform[:4] == "java":
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raise SAXReaderNotAvailable("expat not available in Java", None)
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del sys
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try:
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from xml.parsers import expat
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except ImportError:
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raise SAXReaderNotAvailable("expat not supported", None)
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else:
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if not hasattr(expat, "ParserCreate"):
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raise SAXReaderNotAvailable("expat not supported", None)
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from xml.sax import xmlreader, saxutils, handler
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AttributesImpl = xmlreader.AttributesImpl
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AttributesNSImpl = xmlreader.AttributesNSImpl
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# If we're using a sufficiently recent version of Python, we can use
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# weak references to avoid cycles between the parser and content
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# handler, otherwise we'll just have to pretend.
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try:
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import _weakref
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except ImportError:
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def _mkproxy(o):
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return o
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else:
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import weakref
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_mkproxy = weakref.proxy
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del weakref, _weakref
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class _ClosedParser:
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pass
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# --- ExpatLocator
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class ExpatLocator(xmlreader.Locator):
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"""Locator for use with the ExpatParser class.
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This uses a weak reference to the parser object to avoid creating
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a circular reference between the parser and the content handler.
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"""
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def __init__(self, parser):
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self._ref = _mkproxy(parser)
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def getColumnNumber(self):
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parser = self._ref
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if parser._parser is None:
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return None
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return parser._parser.ErrorColumnNumber
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def getLineNumber(self):
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parser = self._ref
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if parser._parser is None:
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return 1
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return parser._parser.ErrorLineNumber
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def getPublicId(self):
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parser = self._ref
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if parser is None:
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return None
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return parser._source.getPublicId()
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def getSystemId(self):
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parser = self._ref
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if parser is None:
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return None
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return parser._source.getSystemId()
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# --- ExpatParser
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class ExpatParser(xmlreader.IncrementalParser, xmlreader.Locator):
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"""SAX driver for the pyexpat C module."""
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def __init__(self, namespaceHandling=0, bufsize=2**16-20):
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xmlreader.IncrementalParser.__init__(self, bufsize)
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self._source = xmlreader.InputSource()
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self._parser = None
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self._namespaces = namespaceHandling
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self._lex_handler_prop = None
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self._parsing = 0
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self._entity_stack = []
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self._external_ges = 1
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self._interning = None
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# XMLReader methods
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def parse(self, source):
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"Parse an XML document from a URL or an InputSource."
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source = saxutils.prepare_input_source(source)
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self._source = source
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try:
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self.reset()
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self._cont_handler.setDocumentLocator(ExpatLocator(self))
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xmlreader.IncrementalParser.parse(self, source)
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except:
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# bpo-30264: Close the source on error to not leak resources:
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# xml.sax.parse() doesn't give access to the underlying parser
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# to the caller
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self._close_source()
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raise
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def prepareParser(self, source):
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if source.getSystemId() is not None:
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self._parser.SetBase(source.getSystemId())
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# Redefined setContentHandler to allow changing handlers during parsing
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def setContentHandler(self, handler):
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xmlreader.IncrementalParser.setContentHandler(self, handler)
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if self._parsing:
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self._reset_cont_handler()
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def getFeature(self, name):
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if name == feature_namespaces:
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return self._namespaces
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elif name == feature_string_interning:
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return self._interning is not None
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elif name in (feature_validation, feature_external_pes,
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feature_namespace_prefixes):
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return 0
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elif name == feature_external_ges:
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return self._external_ges
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raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
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def setFeature(self, name, state):
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if self._parsing:
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raise SAXNotSupportedException("Cannot set features while parsing")
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if name == feature_namespaces:
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self._namespaces = state
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elif name == feature_external_ges:
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self._external_ges = state
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elif name == feature_string_interning:
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if state:
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if self._interning is None:
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self._interning = {}
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else:
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self._interning = None
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elif name == feature_validation:
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if state:
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raise SAXNotSupportedException(
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"expat does not support validation")
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elif name == feature_external_pes:
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if state:
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raise SAXNotSupportedException(
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"expat does not read external parameter entities")
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elif name == feature_namespace_prefixes:
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if state:
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raise SAXNotSupportedException(
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"expat does not report namespace prefixes")
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else:
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raise SAXNotRecognizedException(
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"Feature '%s' not recognized" % name)
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def getProperty(self, name):
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if name == handler.property_lexical_handler:
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return self._lex_handler_prop
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elif name == property_interning_dict:
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return self._interning
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elif name == property_xml_string:
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if self._parser:
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if hasattr(self._parser, "GetInputContext"):
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return self._parser.GetInputContext()
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else:
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raise SAXNotRecognizedException(
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"This version of expat does not support getting"
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" the XML string")
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else:
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raise SAXNotSupportedException(
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"XML string cannot be returned when not parsing")
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raise SAXNotRecognizedException("Property '%s' not recognized" % name)
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def setProperty(self, name, value):
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if name == handler.property_lexical_handler:
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self._lex_handler_prop = value
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if self._parsing:
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self._reset_lex_handler_prop()
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elif name == property_interning_dict:
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self._interning = value
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elif name == property_xml_string:
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raise SAXNotSupportedException("Property '%s' cannot be set" %
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name)
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else:
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raise SAXNotRecognizedException("Property '%s' not recognized" %
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name)
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# IncrementalParser methods
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def feed(self, data, isFinal = 0):
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if not self._parsing:
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self.reset()
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self._parsing = 1
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self._cont_handler.startDocument()
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try:
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# The isFinal parameter is internal to the expat reader.
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# If it is set to true, expat will check validity of the entire
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# document. When feeding chunks, they are not normally final -
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# except when invoked from close.
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self._parser.Parse(data, isFinal)
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except expat.error as e:
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exc = SAXParseException(expat.ErrorString(e.code), e, self)
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# FIXME: when to invoke error()?
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self._err_handler.fatalError(exc)
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def _close_source(self):
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source = self._source
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try:
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file = source.getCharacterStream()
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if file is not None:
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file.close()
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finally:
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file = source.getByteStream()
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if file is not None:
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file.close()
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def close(self):
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if (self._entity_stack or self._parser is None or
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isinstance(self._parser, _ClosedParser)):
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# If we are completing an external entity, do nothing here
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return
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try:
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self.feed("", isFinal = 1)
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self._cont_handler.endDocument()
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self._parsing = 0
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# break cycle created by expat handlers pointing to our methods
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self._parser = None
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finally:
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self._parsing = 0
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if self._parser is not None:
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# Keep ErrorColumnNumber and ErrorLineNumber after closing.
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parser = _ClosedParser()
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parser.ErrorColumnNumber = self._parser.ErrorColumnNumber
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parser.ErrorLineNumber = self._parser.ErrorLineNumber
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self._parser = parser
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self._close_source()
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def _reset_cont_handler(self):
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self._parser.ProcessingInstructionHandler = \
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self._cont_handler.processingInstruction
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self._parser.CharacterDataHandler = self._cont_handler.characters
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def _reset_lex_handler_prop(self):
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lex = self._lex_handler_prop
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parser = self._parser
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if lex is None:
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parser.CommentHandler = None
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parser.StartCdataSectionHandler = None
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parser.EndCdataSectionHandler = None
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parser.StartDoctypeDeclHandler = None
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parser.EndDoctypeDeclHandler = None
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else:
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parser.CommentHandler = lex.comment
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parser.StartCdataSectionHandler = lex.startCDATA
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parser.EndCdataSectionHandler = lex.endCDATA
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parser.StartDoctypeDeclHandler = self.start_doctype_decl
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parser.EndDoctypeDeclHandler = lex.endDTD
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def reset(self):
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if self._namespaces:
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self._parser = expat.ParserCreate(self._source.getEncoding(), " ",
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intern=self._interning)
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self._parser.namespace_prefixes = 1
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self._parser.StartElementHandler = self.start_element_ns
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self._parser.EndElementHandler = self.end_element_ns
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else:
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self._parser = expat.ParserCreate(self._source.getEncoding(),
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intern = self._interning)
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self._parser.StartElementHandler = self.start_element
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self._parser.EndElementHandler = self.end_element
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self._reset_cont_handler()
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self._parser.UnparsedEntityDeclHandler = self.unparsed_entity_decl
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self._parser.NotationDeclHandler = self.notation_decl
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self._parser.StartNamespaceDeclHandler = self.start_namespace_decl
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self._parser.EndNamespaceDeclHandler = self.end_namespace_decl
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self._decl_handler_prop = None
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if self._lex_handler_prop:
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self._reset_lex_handler_prop()
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# self._parser.DefaultHandler =
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# self._parser.DefaultHandlerExpand =
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# self._parser.NotStandaloneHandler =
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self._parser.ExternalEntityRefHandler = self.external_entity_ref
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try:
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self._parser.SkippedEntityHandler = self.skipped_entity_handler
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except AttributeError:
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# This pyexpat does not support SkippedEntity
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pass
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self._parser.SetParamEntityParsing(
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expat.XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE)
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self._parsing = 0
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self._entity_stack = []
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# Locator methods
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def getColumnNumber(self):
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if self._parser is None:
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return None
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return self._parser.ErrorColumnNumber
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def getLineNumber(self):
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if self._parser is None:
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return 1
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return self._parser.ErrorLineNumber
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def getPublicId(self):
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return self._source.getPublicId()
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def getSystemId(self):
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return self._source.getSystemId()
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# event handlers
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def start_element(self, name, attrs):
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self._cont_handler.startElement(name, AttributesImpl(attrs))
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def end_element(self, name):
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self._cont_handler.endElement(name)
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def start_element_ns(self, name, attrs):
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pair = name.split()
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if len(pair) == 1:
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# no namespace
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pair = (None, name)
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elif len(pair) == 3:
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pair = pair[0], pair[1]
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else:
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# default namespace
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pair = tuple(pair)
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newattrs = {}
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qnames = {}
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for (aname, value) in attrs.items():
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parts = aname.split()
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length = len(parts)
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if length == 1:
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# no namespace
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qname = aname
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apair = (None, aname)
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elif length == 3:
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qname = "%s:%s" % (parts[2], parts[1])
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apair = parts[0], parts[1]
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else:
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# default namespace
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qname = parts[1]
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apair = tuple(parts)
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newattrs[apair] = value
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qnames[apair] = qname
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self._cont_handler.startElementNS(pair, None,
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AttributesNSImpl(newattrs, qnames))
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def end_element_ns(self, name):
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pair = name.split()
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if len(pair) == 1:
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pair = (None, name)
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elif len(pair) == 3:
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pair = pair[0], pair[1]
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else:
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pair = tuple(pair)
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self._cont_handler.endElementNS(pair, None)
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# this is not used (call directly to ContentHandler)
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def processing_instruction(self, target, data):
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self._cont_handler.processingInstruction(target, data)
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# this is not used (call directly to ContentHandler)
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def character_data(self, data):
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self._cont_handler.characters(data)
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def start_namespace_decl(self, prefix, uri):
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self._cont_handler.startPrefixMapping(prefix, uri)
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def end_namespace_decl(self, prefix):
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self._cont_handler.endPrefixMapping(prefix)
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def start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
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self._lex_handler_prop.startDTD(name, pubid, sysid)
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def unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
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self._dtd_handler.unparsedEntityDecl(name, pubid, sysid, notation_name)
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def notation_decl(self, name, base, sysid, pubid):
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self._dtd_handler.notationDecl(name, pubid, sysid)
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def external_entity_ref(self, context, base, sysid, pubid):
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if not self._external_ges:
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return 1
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source = self._ent_handler.resolveEntity(pubid, sysid)
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source = saxutils.prepare_input_source(source,
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self._source.getSystemId() or
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"")
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self._entity_stack.append((self._parser, self._source))
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self._parser = self._parser.ExternalEntityParserCreate(context)
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self._source = source
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try:
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xmlreader.IncrementalParser.parse(self, source)
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except:
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return 0 # FIXME: save error info here?
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(self._parser, self._source) = self._entity_stack[-1]
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del self._entity_stack[-1]
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return 1
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def skipped_entity_handler(self, name, is_pe):
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if is_pe:
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# The SAX spec requires to report skipped PEs with a '%'
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name = '%'+name
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self._cont_handler.skippedEntity(name)
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# ---
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def create_parser(*args, **kwargs):
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return ExpatParser(*args, **kwargs)
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# ---
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if __name__ == "__main__":
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import xml.sax.saxutils
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p = create_parser()
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p.setContentHandler(xml.sax.saxutils.XMLGenerator())
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p.setErrorHandler(xml.sax.ErrorHandler())
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p.parse("http://www.ibiblio.org/xml/examples/shakespeare/hamlet.xml")
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