350 lines
12 KiB
Python
350 lines
12 KiB
Python
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import xml.sax
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import xml.sax.handler
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START_ELEMENT = "START_ELEMENT"
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END_ELEMENT = "END_ELEMENT"
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COMMENT = "COMMENT"
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START_DOCUMENT = "START_DOCUMENT"
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END_DOCUMENT = "END_DOCUMENT"
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PROCESSING_INSTRUCTION = "PROCESSING_INSTRUCTION"
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IGNORABLE_WHITESPACE = "IGNORABLE_WHITESPACE"
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CHARACTERS = "CHARACTERS"
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class PullDOM(xml.sax.ContentHandler):
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_locator = None
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document = None
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def __init__(self, documentFactory=None):
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from xml.dom import XML_NAMESPACE
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self.documentFactory = documentFactory
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self.firstEvent = [None, None]
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self.lastEvent = self.firstEvent
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self.elementStack = []
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self.push = self.elementStack.append
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try:
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self.pop = self.elementStack.pop
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except AttributeError:
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# use class' pop instead
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pass
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self._ns_contexts = [{XML_NAMESPACE:'xml'}] # contains uri -> prefix dicts
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self._current_context = self._ns_contexts[-1]
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self.pending_events = []
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def pop(self):
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result = self.elementStack[-1]
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del self.elementStack[-1]
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return result
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def setDocumentLocator(self, locator):
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self._locator = locator
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def startPrefixMapping(self, prefix, uri):
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if not hasattr(self, '_xmlns_attrs'):
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self._xmlns_attrs = []
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self._xmlns_attrs.append((prefix or 'xmlns', uri))
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self._ns_contexts.append(self._current_context.copy())
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self._current_context[uri] = prefix or None
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def endPrefixMapping(self, prefix):
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self._current_context = self._ns_contexts.pop()
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def startElementNS(self, name, tagName , attrs):
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# Retrieve xml namespace declaration attributes.
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xmlns_uri = 'http://www.w3.org/2000/xmlns/'
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xmlns_attrs = getattr(self, '_xmlns_attrs', None)
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if xmlns_attrs is not None:
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for aname, value in xmlns_attrs:
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attrs._attrs[(xmlns_uri, aname)] = value
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self._xmlns_attrs = []
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uri, localname = name
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if uri:
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# When using namespaces, the reader may or may not
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# provide us with the original name. If not, create
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# *a* valid tagName from the current context.
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if tagName is None:
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prefix = self._current_context[uri]
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if prefix:
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tagName = prefix + ":" + localname
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else:
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tagName = localname
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if self.document:
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node = self.document.createElementNS(uri, tagName)
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else:
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node = self.buildDocument(uri, tagName)
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else:
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# When the tagname is not prefixed, it just appears as
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# localname
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if self.document:
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node = self.document.createElement(localname)
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else:
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node = self.buildDocument(None, localname)
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for aname,value in attrs.items():
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a_uri, a_localname = aname
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if a_uri == xmlns_uri:
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if a_localname == 'xmlns':
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qname = a_localname
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else:
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qname = 'xmlns:' + a_localname
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attr = self.document.createAttributeNS(a_uri, qname)
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node.setAttributeNodeNS(attr)
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elif a_uri:
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prefix = self._current_context[a_uri]
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if prefix:
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qname = prefix + ":" + a_localname
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else:
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qname = a_localname
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attr = self.document.createAttributeNS(a_uri, qname)
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node.setAttributeNodeNS(attr)
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else:
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attr = self.document.createAttribute(a_localname)
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node.setAttributeNode(attr)
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attr.value = value
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self.lastEvent[1] = [(START_ELEMENT, node), None]
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self.lastEvent = self.lastEvent[1]
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self.push(node)
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def endElementNS(self, name, tagName):
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self.lastEvent[1] = [(END_ELEMENT, self.pop()), None]
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self.lastEvent = self.lastEvent[1]
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def startElement(self, name, attrs):
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if self.document:
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node = self.document.createElement(name)
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else:
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node = self.buildDocument(None, name)
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for aname,value in attrs.items():
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attr = self.document.createAttribute(aname)
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attr.value = value
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node.setAttributeNode(attr)
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self.lastEvent[1] = [(START_ELEMENT, node), None]
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self.lastEvent = self.lastEvent[1]
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self.push(node)
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def endElement(self, name):
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self.lastEvent[1] = [(END_ELEMENT, self.pop()), None]
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self.lastEvent = self.lastEvent[1]
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def comment(self, s):
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if self.document:
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node = self.document.createComment(s)
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self.lastEvent[1] = [(COMMENT, node), None]
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self.lastEvent = self.lastEvent[1]
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else:
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event = [(COMMENT, s), None]
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self.pending_events.append(event)
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def processingInstruction(self, target, data):
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if self.document:
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node = self.document.createProcessingInstruction(target, data)
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self.lastEvent[1] = [(PROCESSING_INSTRUCTION, node), None]
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self.lastEvent = self.lastEvent[1]
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else:
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event = [(PROCESSING_INSTRUCTION, target, data), None]
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self.pending_events.append(event)
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def ignorableWhitespace(self, chars):
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node = self.document.createTextNode(chars)
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self.lastEvent[1] = [(IGNORABLE_WHITESPACE, node), None]
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self.lastEvent = self.lastEvent[1]
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def characters(self, chars):
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node = self.document.createTextNode(chars)
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self.lastEvent[1] = [(CHARACTERS, node), None]
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self.lastEvent = self.lastEvent[1]
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def startDocument(self):
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if self.documentFactory is None:
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import xml.dom.minidom
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self.documentFactory = xml.dom.minidom.Document.implementation
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def buildDocument(self, uri, tagname):
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# Can't do that in startDocument, since we need the tagname
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# XXX: obtain DocumentType
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node = self.documentFactory.createDocument(uri, tagname, None)
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self.document = node
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self.lastEvent[1] = [(START_DOCUMENT, node), None]
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self.lastEvent = self.lastEvent[1]
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self.push(node)
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# Put everything we have seen so far into the document
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for e in self.pending_events:
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if e[0][0] == PROCESSING_INSTRUCTION:
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_,target,data = e[0]
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n = self.document.createProcessingInstruction(target, data)
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e[0] = (PROCESSING_INSTRUCTION, n)
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elif e[0][0] == COMMENT:
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n = self.document.createComment(e[0][1])
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e[0] = (COMMENT, n)
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else:
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raise AssertionError("Unknown pending event ",e[0][0])
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self.lastEvent[1] = e
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self.lastEvent = e
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self.pending_events = None
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return node.firstChild
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def endDocument(self):
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self.lastEvent[1] = [(END_DOCUMENT, self.document), None]
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self.pop()
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def clear(self):
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"clear(): Explicitly release parsing structures"
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self.document = None
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class ErrorHandler:
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def warning(self, exception):
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print(exception)
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def error(self, exception):
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raise exception
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def fatalError(self, exception):
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raise exception
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class DOMEventStream:
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def __init__(self, stream, parser, bufsize):
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self.stream = stream
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self.parser = parser
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self.bufsize = bufsize
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if not hasattr(self.parser, 'feed'):
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self.getEvent = self._slurp
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self.reset()
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def reset(self):
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self.pulldom = PullDOM()
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# This content handler relies on namespace support
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self.parser.setFeature(xml.sax.handler.feature_namespaces, 1)
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self.parser.setContentHandler(self.pulldom)
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def __getitem__(self, pos):
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import warnings
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warnings.warn(
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"DOMEventStream's __getitem__ method ignores 'pos' parameter. "
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"Use iterator protocol instead.",
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DeprecationWarning,
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stacklevel=2
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)
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rc = self.getEvent()
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if rc:
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return rc
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raise IndexError
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def __next__(self):
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rc = self.getEvent()
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if rc:
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return rc
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raise StopIteration
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def __iter__(self):
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return self
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def expandNode(self, node):
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event = self.getEvent()
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parents = [node]
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while event:
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token, cur_node = event
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if cur_node is node:
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return
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if token != END_ELEMENT:
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parents[-1].appendChild(cur_node)
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if token == START_ELEMENT:
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parents.append(cur_node)
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elif token == END_ELEMENT:
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del parents[-1]
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event = self.getEvent()
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def getEvent(self):
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# use IncrementalParser interface, so we get the desired
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# pull effect
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if not self.pulldom.firstEvent[1]:
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self.pulldom.lastEvent = self.pulldom.firstEvent
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while not self.pulldom.firstEvent[1]:
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buf = self.stream.read(self.bufsize)
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if not buf:
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self.parser.close()
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return None
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self.parser.feed(buf)
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rc = self.pulldom.firstEvent[1][0]
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self.pulldom.firstEvent[1] = self.pulldom.firstEvent[1][1]
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return rc
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def _slurp(self):
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""" Fallback replacement for getEvent() using the
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standard SAX2 interface, which means we slurp the
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SAX events into memory (no performance gain, but
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we are compatible to all SAX parsers).
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"""
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self.parser.parse(self.stream)
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self.getEvent = self._emit
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return self._emit()
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def _emit(self):
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""" Fallback replacement for getEvent() that emits
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the events that _slurp() read previously.
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"""
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rc = self.pulldom.firstEvent[1][0]
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self.pulldom.firstEvent[1] = self.pulldom.firstEvent[1][1]
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return rc
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def clear(self):
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"""clear(): Explicitly release parsing objects"""
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self.pulldom.clear()
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del self.pulldom
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self.parser = None
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self.stream = None
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class SAX2DOM(PullDOM):
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def startElementNS(self, name, tagName , attrs):
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PullDOM.startElementNS(self, name, tagName, attrs)
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curNode = self.elementStack[-1]
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parentNode = self.elementStack[-2]
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parentNode.appendChild(curNode)
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def startElement(self, name, attrs):
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PullDOM.startElement(self, name, attrs)
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curNode = self.elementStack[-1]
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parentNode = self.elementStack[-2]
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parentNode.appendChild(curNode)
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def processingInstruction(self, target, data):
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PullDOM.processingInstruction(self, target, data)
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node = self.lastEvent[0][1]
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parentNode = self.elementStack[-1]
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parentNode.appendChild(node)
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def ignorableWhitespace(self, chars):
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PullDOM.ignorableWhitespace(self, chars)
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node = self.lastEvent[0][1]
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parentNode = self.elementStack[-1]
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parentNode.appendChild(node)
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def characters(self, chars):
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PullDOM.characters(self, chars)
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node = self.lastEvent[0][1]
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parentNode = self.elementStack[-1]
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parentNode.appendChild(node)
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default_bufsize = (2 ** 14) - 20
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def parse(stream_or_string, parser=None, bufsize=None):
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if bufsize is None:
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bufsize = default_bufsize
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if isinstance(stream_or_string, str):
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stream = open(stream_or_string, 'rb')
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else:
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stream = stream_or_string
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if not parser:
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parser = xml.sax.make_parser()
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return DOMEventStream(stream, parser, bufsize)
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def parseString(string, parser=None):
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from io import StringIO
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bufsize = len(string)
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buf = StringIO(string)
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if not parser:
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parser = xml.sax.make_parser()
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return DOMEventStream(buf, parser, bufsize)
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