import xml.sax
import xml.sax.handler
import types
try:
_StringTypes = [types.StringType, types.UnicodeType]
except AttributeError:
_StringTypes = [types.StringType]
START_ELEMENT = "START_ELEMENT"
END_ELEMENT = "END_ELEMENT"
COMMENT = "COMMENT"
START_DOCUMENT = "START_DOCUMENT"
END_DOCUMENT = "END_DOCUMENT"
PROCESSING_INSTRUCTION = "PROCESSING_INSTRUCTION"
IGNORABLE_WHITESPACE = "IGNORABLE_WHITESPACE"
CHARACTERS = "CHARACTERS"
class PullDOM(xml.sax.ContentHandler):
_locator = None
document = None
def __init__(self, documentFactory=None):
self.documentFactory = documentFactory
self.firstEvent = [None, None]
self.lastEvent = self.firstEvent
self.elementStack = []
self.push = self.elementStack.append
try:
self.pop = self.elementStack.pop
except AttributeError:
# use class' pop instead
pass
self._ns_contexts = [{}] # contains uri -> prefix dicts
self._current_context = self._ns_contexts[-1]
self.pending_events = []
def pop(self):
result = self.elementStack[-1]
del self.elementStack[-1]
return result
def setDocumentLocator(self, locator):
self._locator = locator
def startPrefixMapping(self, prefix, uri):
self._ns_contexts.append(self._current_context.copy())
self._current_context[uri] = prefix or ''
def endPrefixMapping(self, prefix):
self._current_context = self._ns_contexts.pop()
def startElementNS(self, name, tagName , attrs):
uri, localname = name
if uri:
# When using namespaces, the reader may or may not
# provide us with the original name. If not, create
# *a* valid tagName from the current context.
if tagName is None:
prefix = self._current_context[uri]
if prefix:
tagName = prefix + ":" + localname
else:
tagName = localname
if self.document:
node = self.document.createElementNS(uri, tagName)
else:
node = self.buildDocument(uri, tagName)
else:
# When the tagname is not prefixed, it just appears as
# localname
if self.document:
node = self.document.createElement(localname)
else:
node = self.buildDocument(None, localname)
for aname,value in attrs.items():
a_uri, a_localname = aname
if a_uri:
prefix = self._current_context[a_uri]
if prefix:
qname = prefix + ":" + a_localname
else:
qname = a_localname
attr = self.document.createAttributeNS(a_uri, qname)
node.setAttributeNodeNS(attr)
else:
attr = self.document.createAttribute(a_localname)
node.setAttributeNode(attr)
attr.value = value
self.lastEvent[1] = [(START_ELEMENT, node), None]
self.lastEvent = self.lastEvent[1]
self.push(node)
def endElementNS(self, name, tagName):
self.lastEvent[1] = [(END_ELEMENT, self.pop()), None]
self.lastEvent = self.lastEvent[1]
def startElement(self, name, attrs):
if self.document:
node = self.document.createElement(name)
else:
node = self.buildDocument(None, name)
for aname,value in attrs.items():
attr = self.document.createAttribute(aname)
attr.value = value
node.setAttributeNode(attr)
self.lastEvent[1] = [(START_ELEMENT, node), None]
self.lastEvent = self.lastEvent[1]
self.push(node)
def endElement(self, name):
self.lastEvent[1] = [(END_ELEMENT, self.pop()), None]
self.lastEvent = self.lastEvent[1]
def comment(self, s):
if self.document:
node = self.document.createComment(s)
self.lastEvent[1] = [(COMMENT, node), None]
self.lastEvent = self.lastEvent[1]
else:
event = [(COMMENT, s), None]
self.pending_events.append(event)
def processingInstruction(self, target, data):
if self.document:
node = self.document.createProcessingInstruction(target, data)
self.lastEvent[1] = [(PROCESSING_INSTRUCTION, node), None]
self.lastEvent = self.lastEvent[1]
else:
event = [(PROCESSING_INSTRUCTION, target, data), None]
self.pending_events.append(event)
def ignorableWhitespace(self, chars):
node = self.document.createTextNode(chars)
self.lastEvent[1] = [(IGNORABLE_WHITESPACE, node), None]
self.lastEvent = self.lastEvent[1]
def characters(self, chars):
node = self.document.createTextNode(chars)
self.lastEvent[1] = [(CHARACTERS, node), None]
self.lastEvent = self.lastEvent[1]
def startDocument(self):
if self.documentFactory is None:
import xml.dom.minidom
self.documentFactory = xml.dom.minidom.Document.implementation
def buildDocument(self, uri, tagname):
# Can't do that in startDocument, since we need the tagname
# XXX: obtain DocumentType
node = self.documentFactory.createDocument(uri, tagname, None)
self.document = node
self.lastEvent[1] = [(START_DOCUMENT, node), None]
self.lastEvent = self.lastEvent[1]
self.push(node)
# Put everything we have seen so far into the document
for e in self.pending_events:
if e[0][0] == PROCESSING_INSTRUCTION:
_,target,data = e[0]
n = self.document.createProcessingInstruction(target, data)
e[0] = (PROCESSING_INSTRUCTION, n)
elif e[0][0] == COMMENT:
n = self.document.createComment(e[0][1])
e[0] = (COMMENT, n)
else:
raise AssertionError("Unknown pending event ",e[0][0])
self.lastEvent[1] = e
self.lastEvent = e
self.pending_events = None
return node.firstChild
def endDocument(self):
self.lastEvent[1] = [(END_DOCUMENT, self.document), None]
self.pop()
def clear(self):
"clear(): Explicitly release parsing structures"
self.document = None
class ErrorHandler:
def warning(self, exception):
print exception
def error(self, exception):
raise exception
def fatalError(self, exception):
raise exception
class DOMEventStream:
def __init__(self, stream, parser, bufsize):
self.stream = stream
self.parser = parser
self.bufsize = bufsize
self.reset()
def reset(self):
self.pulldom = PullDOM()
# This content handler relies on namespace support
self.parser.setFeature(xml.sax.handler.feature_namespaces, 1)
self.parser.setContentHandler(self.pulldom)
def __getitem__(self, pos):
rc = self.getEvent()
if rc:
return rc
raise IndexError
def expandNode(self, node):
event = self.getEvent()
parents = [node]
while event:
token, cur_node = event
if cur_node is node:
return
if token != END_ELEMENT:
parents[-1].appendChild(cur_node)
if token == START_ELEMENT:
parents.append(cur_node)
elif token == END_ELEMENT:
del parents[-1]
event = self.getEvent()
def getEvent(self):
if not self.pulldom.firstEvent[1]:
self.pulldom.lastEvent = self.pulldom.firstEvent
while not self.pulldom.firstEvent[1]:
buf = self.stream.read(self.bufsize)
if not buf:
self.parser.close()
return None
self.parser.feed(buf)
rc = self.pulldom.firstEvent[1][0]
self.pulldom.firstEvent[1] = self.pulldom.firstEvent[1][1]
return rc
def clear(self):
"clear(): Explicitly release parsing objects"
self.pulldom.clear()
del self.pulldom
self.parser = None
self.stream = None
class SAX2DOM(PullDOM):
def startElementNS(self, name, tagName , attrs):
PullDOM.startElementNS(self, name, tagName, attrs)
curNode = self.elementStack[-1]
parentNode = self.elementStack[-2]
parentNode.appendChild(curNode)
def startElement(self, name, attrs):
PullDOM.startElement(self, name, attrs)
curNode = self.elementStack[-1]
parentNode = self.elementStack[-2]
parentNode.appendChild(curNode)
def processingInstruction(self, target, data):
PullDOM.processingInstruction(self, target, data)
node = self.lastEvent[0][1]
parentNode = self.elementStack[-1]
parentNode.appendChild(node)
def ignorableWhitespace(self, chars):
PullDOM.ignorableWhitespace(self, chars)
node = self.lastEvent[0][1]
parentNode = self.elementStack[-1]
parentNode.appendChild(node)
def characters(self, chars):
PullDOM.characters(self, chars)
node = self.lastEvent[0][1]
parentNode = self.elementStack[-1]
parentNode.appendChild(node)
default_bufsize = (2 ** 14) - 20
def parse(stream_or_string, parser=None, bufsize=None):
if bufsize is None:
bufsize = default_bufsize
if type(stream_or_string) in _StringTypes:
stream = open(stream_or_string)
else:
stream = stream_or_string
if not parser:
parser = xml.sax.make_parser()
return DOMEventStream(stream, parser, bufsize)
def parseString(string, parser=None):
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
bufsize = len(string)
buf = StringIO(string)
if not parser:
parser = xml.sax.make_parser()
return DOMEventStream(buf, parser, bufsize)
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