cpython/Lib/xml/sax/xmlreader.py

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"""An XML Reader is the SAX 2 name for an XML parser. XML Parsers
should be based on this code. """
import handler
# ===== XMLREADER =====
class XMLReader:
def __init__(self):
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self._cont_handler = handler.ContentHandler()
#self._dtd_handler = handler.DTDHandler()
#self._ent_handler = handler.EntityResolver()
self._err_handler = handler.ErrorHandler()
def parse(self, source):
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"Parse an XML document from a system identifier or an InputSource."
raise NotImplementedError("This method must be implemented!")
def getContentHandler(self):
"Returns the current ContentHandler."
return self._cont_handler
def setContentHandler(self, handler):
"Registers a new object to receive document content events."
self._cont_handler = handler
def getDTDHandler(self):
"Returns the current DTD handler."
return self._dtd_handler
def setDTDHandler(self, handler):
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"Register an object to receive basic DTD-related events."
self._dtd_handler = handler
def getEntityResolver(self):
"Returns the current EntityResolver."
return self._ent_handler
def setEntityResolver(self, resolver):
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"Register an object to resolve external entities."
self._ent_handler = resolver
def getErrorHandler(self):
"Returns the current ErrorHandler."
return self._err_handler
def setErrorHandler(self, handler):
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"Register an object to receive error-message events."
self._err_handler = handler
def setLocale(self, locale):
"""Allow an application to set the locale for errors and warnings.
SAX parsers are not required to provide localization for errors
and warnings; if they cannot support the requested locale,
however, they must throw a SAX exception. Applications may
request a locale change in the middle of a parse."""
raise SAXNotSupportedException("Locale support not implemented")
def getFeature(self, name):
"Looks up and returns the state of a SAX2 feature."
raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
def setFeature(self, name, state):
"Sets the state of a SAX2 feature."
raise SAXNotRecognizedException("Feature '%s' not recognized" % name)
def getProperty(self, name):
"Looks up and returns the value of a SAX2 property."
raise SAXNotRecognizedException("Property '%s' not recognized" % name)
def setProperty(self, name, value):
"Sets the value of a SAX2 property."
raise SAXNotRecognizedException("Property '%s' not recognized" % name)
class IncrementalParser(XMLReader):
"""This interface adds three extra methods to the XMLReader
interface that allow XML parsers to support incremental
parsing. Support for this interface is optional, since not all
underlying XML parsers support this functionality.
When the parser is instantiated it is ready to begin accepting
data from the feed method immediately. After parsing has been
finished with a call to close the reset method must be called to
make the parser ready to accept new data, either from feed or
using the parse method.
Note that these methods must _not_ be called during parsing, that
is, after parse has been called and before it returns.
By default, the class also implements the parse method of the XMLReader
interface using the feed, close and reset methods of the
IncrementalParser interface as a convenience to SAX 2.0 driver
writers."""
def __init__(self, bufsize=2**16):
self._bufsize = bufsize
XMLReader.__init__(self)
def _parseOpenFile(self, source):
buffer = source.read(self._bufsize)
while buffer != "":
self.feed(buffer)
buffer = source.read(self._bufsize)
self.close()
self.reset()
def parse(self, source):
if hasattr(source, "read"):
self._parseOpenFile(source)
else:
#FIXME: how to recognize if it is a URL instead of filename?
self.prepareParser(source)
file = open(source)
self._parseOpenFile(file)
file.close()
def feed(self, data):
"""This method gives the raw XML data in the data parameter to
the parser and makes it parse the data, emitting the
corresponding events. It is allowed for XML constructs to be
split across several calls to feed.
feed may raise SAXException."""
raise NotImplementedError("This method must be implemented!")
def prepareParser(self, source):
"""This method is called by the parse implementation to allow
the SAX 2.0 driver to prepare itself for parsing."""
raise NotImplementedError("prepareParser must be overridden!")
def close(self):
"""This method is called when the entire XML document has been
passed to the parser through the feed method, to notify the
parser that there are no more data. This allows the parser to
do the final checks on the document and empty the internal
data buffer.
The parser will not be ready to parse another document until
the reset method has been called.
close may raise SAXException."""
raise NotImplementedError("This method must be implemented!")
def reset(self):
"""This method is called after close has been called to reset
the parser so that it is ready to parse new documents. The
results of calling parse or feed after close without calling
reset are undefined."""
raise NotImplementedError("This method must be implemented!")
# ===== LOCATOR =====
class Locator:
"""Interface for associating a SAX event with a document
location. A locator object will return valid results only during
calls to DocumentHandler methods; at any other time, the
results are unpredictable."""
def getColumnNumber(self):
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"Return the column number where the current event ends."
return -1
def getLineNumber(self):
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"Return the line number where the current event ends."
return -1
def getPublicId(self):
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"Return the public identifier for the current event."
return None
def getSystemId(self):
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"Return the system identifier for the current event."
return None
# --- AttributesImpl
class AttributesImpl:
def __init__(self, attrs, rawnames):
self._attrs = attrs
self._rawnames = rawnames
def getLength(self):
return len(self._attrs)
def getType(self, name):
return "CDATA"
def getValue(self, name):
return self._attrs[name]
def getValueByQName(self, name):
return self._attrs[self._rawnames[name]]
def getNameByQName(self, name):
return self._rawnames[name]
def getNames(self):
return self._attrs.keys()
def getQNames(self):
return self._rawnames.keys()
def __len__(self):
return len(self._attrs)
def __getitem__(self, name):
return self._attrs[name]
def keys(self):
return self._attrs.keys()
def has_key(self, name):
return self._attrs.has_key(name)
def get(self, name, alternative=None):
return self._attrs.get(name, alternative)
def copy(self):
return self.__class__(self._attrs, self._rawnames)
def items(self):
return self._attrs.items()
def values(self):
return self._attrs.values()
def _test():
XMLReader()
IncrementalParser()
Locator()
AttributesImpl()
if __name__ == "__main__":
_test()