Viewing file:  expatreader.py (10.87 KB) -rw-r--r--
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"""
SAX driver for the Pyexpat C module. This driver works with
pyexpat.__version__ == '2.22'.
"""
version = "0.20"
from xml.sax._exceptions import *
# xml.parsers.expat does not raise ImportError in Jython
import sys
if sys.platform[:4] == "java":
raise SAXReaderNotAvailable("expat not available in Java", None)
del sys
try:
from xml.parsers import expat
except ImportError:
raise SAXReaderNotAvailable("expat not supported", None)
else:
if not hasattr(expat, "ParserCreate"):
raise SAXReaderNotAvailable("expat not supported", None)
from xml.sax import xmlreader, saxutils, handler
AttributesImpl = xmlreader.AttributesImpl
AttributesNSImpl = xmlreader.AttributesNSImpl
import string
import weakref
# --- ExpatLocator
class ExpatLocator(xmlreader.Locator):
"""Locator for use with the ExpatParser class.
This uses a weak reference to the parser object to avoid creating
a circular reference between the parser and the content handler.
"""
def __init__(self, parser):
self._ref = weakref.ref(parser)
def getColumnNumber(self):
parser = self._ref()
if parser is None or parser._parser is None:
return None
return parser._parser.ErrorColumnNumber
def getLineNumber(self):
parser = self._ref()
if parser is None or parser._parser is None:
return 1
return parser._parser.ErrorLineNumber
def getPublicId(self):
parser = self._ref()
if parser is None:
return None
return parser._source.getPublicId()
def getSystemId(self):
parser = self._ref()
if parser is None:
return None
return parser._source.getSystemId()
# --- ExpatParser
class ExpatParser(xmlreader.IncrementalParser, xmlreader.Locator):
"SAX driver for the Pyexpat C module."
def __init__(self, namespaceHandling=0, bufsize=2**16-20):
xmlreader.IncrementalParser.__init__(self, bufsize)
self._source = xmlreader.InputSource()
self._parser = None
self._namespaces = namespaceHandling
self._lex_handler_prop = None
self._parsing = 0
self._entity_stack = []
self._ns_stack = []
# XMLReader methods
def parse(self, source):
"Parse an XML document from a URL or an InputSource."
source = saxutils.prepare_input_source(source)
self._source = source
self.reset()
self._cont_handler.setDocumentLocator(ExpatLocator(self))
xmlreader.IncrementalParser.parse(self, source)
def prepareParser(self, source):
if source.getSystemId() != None:
self._parser.SetBase(source.getSystemId())
# Redefined setContentHandle to allow changing handlers during parsing
def setContentHandler(self, handler):
xmlreader.IncrementalParser.setContentHandler(self, handler)
if self._parsing:
self._reset_cont_handler()
def getFeature(self, name):
if name == handler.feature_namespaces:
return self._namespaces
raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
def setFeature(self, name, state):
if self._parsing:
raise SAXNotSupportedException("Cannot set features while parsing")
if name == handler.feature_namespaces:
self._namespaces = state
else:
raise SAXNotRecognizedException("Feature '%s' not recognized" %
name)
def getProperty(self, name):
if name == handler.property_lexical_handler:
return self._lex_handler_prop
raise SAXNotRecognizedException("Property '%s' not recognized" % name)
def setProperty(self, name, value):
if name == handler.property_lexical_handler:
self._lex_handler_prop = value
if self._parsing:
self._reset_lex_handler_prop()
else:
raise SAXNotRecognizedException("Property '%s' not recognized" % name)
# IncrementalParser methods
def feed(self, data, isFinal = 0):
if not self._parsing:
self.reset()
self._parsing = 1
self._cont_handler.startDocument()
try:
# The isFinal parameter is internal to the expat reader.
# If it is set to true, expat will check validity of the entire
# document. When feeding chunks, they are not normally final -
# except when invoked from close.
self._parser.Parse(data, isFinal)
except expat.error:
error_code = self._parser.ErrorCode
exc = SAXParseException(expat.ErrorString(error_code), None, self)
# FIXME: when to invoke error()?
self._err_handler.fatalError(exc)
def close(self):
if self._entity_stack:
# If we are completing an external entity, do nothing here
return
self.feed("", isFinal = 1)
self._cont_handler.endDocument()
self._parsing = 0
# break cycle created by expat handlers pointing to our methods
self._parser = None
def _reset_cont_handler(self):
self._parser.ProcessingInstructionHandler = \
self._cont_handler.processingInstruction
self._parser.CharacterDataHandler = self._cont_handler.characters
def _reset_lex_handler_prop(self):
self._parser.CommentHandler = self._lex_handler_prop.comment
self._parser.StartCdataSectionHandler = self._lex_handler_prop.startCDATA
self._parser.EndCdataSectionHandler = self._lex_handler_prop.endCDATA
def reset(self):
if self._namespaces:
self._parser = expat.ParserCreate(None, " ")
self._parser.StartElementHandler = self.start_element_ns
self._parser.EndElementHandler = self.end_element_ns
else:
self._parser = expat.ParserCreate()
self._parser.StartElementHandler = self.start_element
self._parser.EndElementHandler = self.end_element
self._reset_cont_handler()
self._parser.UnparsedEntityDeclHandler = self.unparsed_entity_decl
self._parser.NotationDeclHandler = self.notation_decl
self._parser.StartNamespaceDeclHandler = self.start_namespace_decl
self._parser.EndNamespaceDeclHandler = self.end_namespace_decl
self._decl_handler_prop = None
if self._lex_handler_prop:
self._reset_lex_handler_prop()
# self._parser.DefaultHandler =
# self._parser.DefaultHandlerExpand =
# self._parser.NotStandaloneHandler =
self._parser.ExternalEntityRefHandler = self.external_entity_ref
self._parsing = 0
self._entity_stack = []
# Locator methods
def getColumnNumber(self):
if self._parser is None:
return None
return self._parser.ErrorColumnNumber
def getLineNumber(self):
if self._parser is None:
return 1
return self._parser.ErrorLineNumber
def getPublicId(self):
return self._source.getPublicId()
def getSystemId(self):
return self._source.getSystemId()
# event handlers
def start_element(self, name, attrs):
self._cont_handler.startElement(name, AttributesImpl(attrs))
def end_element(self, name):
self._cont_handler.endElement(name)
def start_element_ns(self, name, attrs):
pair = string.split(name)
if len(pair) == 1:
pair = (None, name)
qname = name
else:
pair = tuple(pair)
qname = pair[1]
if self._ns_stack:
prefix = self._ns_stack[-1][pair[0]][-1]
if prefix:
qname = "%s:%s" % (prefix, pair[1])
newattrs = {}
qnames = {}
for (aname, value) in attrs.items():
apair = string.split(aname)
if len(apair) == 1:
apair = (None, aname)
aqname = aname
else:
apair = tuple(apair)
# XXX need to guess the prefix
prefix = self._ns_stack[-1][apair[0]][-1]
aqname = "%s:%s" % (prefix, apair[1])
newattrs[apair] = value
qnames[apair] = aqname
self._cont_handler.startElementNS(pair, qname,
AttributesNSImpl(newattrs, qnames))
def end_element_ns(self, name):
pair = string.split(name)
if len(pair) == 1:
pair = (None, name)
qname = name
else:
pair = tuple(pair)
qname = pair[1]
if self._ns_stack:
prefix = self._ns_stack[-1][pair[0]][-1]
if prefix:
qname = "%s:%s" % (prefix, pair[1])
self._cont_handler.endElementNS(pair, qname)
# this is not used (call directly to ContentHandler)
def processing_instruction(self, target, data):
self._cont_handler.processingInstruction(target, data)
# this is not used (call directly to ContentHandler)
def character_data(self, data):
self._cont_handler.characters(data)
def start_namespace_decl(self, prefix, uri):
if self._ns_stack:
d = self._ns_stack[-1].copy()
if d.has_key(uri):
L = d[uri][:]
d[uri] = L
L.append(prefix)
else:
d[uri] = [prefix]
else:
d = {uri: [prefix]}
self._ns_stack.append(d)
self._cont_handler.startPrefixMapping(prefix, uri)
def end_namespace_decl(self, prefix):
del self._ns_stack[-1]
self._cont_handler.endPrefixMapping(prefix)
def unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
self._dtd_handler.unparsedEntityDecl(name, pubid, sysid, notation_name)
def notation_decl(self, name, base, sysid, pubid):
self._dtd_handler.notationDecl(name, pubid, sysid)
def external_entity_ref(self, context, base, sysid, pubid):
source = self._ent_handler.resolveEntity(pubid, sysid)
source = saxutils.prepare_input_source(source,
self._source.getSystemId() or
"")
self._entity_stack.append((self._parser, self._source))
self._parser = self._parser.ExternalEntityParserCreate(context)
self._source = source
try:
xmlreader.IncrementalParser.parse(self, source)
except:
return 0 # FIXME: save error info here?
(self._parser, self._source) = self._entity_stack[-1]
del self._entity_stack[-1]
return 1
# ---
def create_parser(*args, **kwargs):
return apply(ExpatParser, args, kwargs)
# ---
if __name__ == "__main__":
import xml.sax
p = create_parser()
p.setContentHandler(xml.sax.XMLGenerator())
p.setErrorHandler(xml.sax.ErrorHandler())
p.parse("../../../hamlet.xml")
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