# Copyright (c) 2001 - 2005
# Yuan Wang. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. Redistributions in any form must be accompanied by information on
# how to obtain complete source code for the X-Diff software and any
# accompanying software that uses the X-Diff software. The source code
# must either be included in the distribution or be available for no
# more than the cost of distribution plus a nominal fee, and must be
# freely redistributable under reasonable conditions. For an executable
# file, complete source code means the source code for all modules it
# contains. It does not include source code for modules or files that
# typically accompany the major components of the operating system on
# which the executable file runs.
# THIS SOFTWARE IS PROVIDED BY YUAN WANG "AS IS" AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT,
# ARE DISCLAIMED. IN NO EVENT SHALL YUAN WANG BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES LOSS OF USE, DATA, OR PROFITS OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
# IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
import XTree
import sys, hashlib
import xml.sax
_STACK_SIZE = 100
class ErrorHandler:
"""Basic interface for SAX error handlers. If you create an object
that implements this interface, then register the object with your
Parser, the parser will call the methods in your object to report
all warnings and errors. There are three levels of errors
available: warnings, (possibly) recoverable errors, and
unrecoverable errors. All methods take a SAXParseException as the
only parameter."""
def error(self, exception):
"Handle a recoverable error."
sys.stderr.write ("Error: %s\n" % exception)
def fatalError(self, exception):
"Handle a non-recoverable error."
sys.stderr.write ("Fatal error: %s\n" % exception)
raise xml.sax.SAXParseException
def warning(self, exception):
"Handle a warning."
sys.stderr.write ("Warning: %s\n" % exception)
# This is interesting
# http://www.virtuousprogrammer.com/?page_id=183
# http://docs.python.org/library/xml.sax.reader.html
# <code>XParser</code> parses an input XML document and constructs an
# <code>XTree</code>
# class XParser extends DefaultHandler implements LexicalHandler
class XParser(xml.sax.handler.ContentHandler):
# private XMLReader self._parser
# private XTree self._xtree
# private int self._idStack[], self._lsidStack[] # id and left sibling
# private long self._valueStack[]
# private int self._stackTop, self._currentNodeID
# private boolean self._readElement
# private StringBuffer self._elementBuffer
# Constructor.
def __init__(self):
xml.sax.handler.ContentHandler.__init__(self)
self._setValidation = False
self._setNameSpaces = True
self._setSchemaSupport = True
self._setSchemaFullSupport = False
self._setNameSpacePrefixes = True
self._readElement = False
self._xtree = None
# try:
self._parser = xml.sax.make_parser()
self._parser.setFeature(xml.sax.handler.feature_validation, \
self._setValidation)
self._parser.setFeature(xml.sax.handler.feature_namespaces, \
self._setNameSpaces)
self._parser.setFeature(xml.sax.handler.feature_namespace_prefixes, \
self._setNameSpacePrefixes)
#self._parser.setFeature("http://apache.org/xml/features/validation/schema", \
# self._setSchemaSupport)
#self._parser.setFeature("http://apache.org/xml/features/validation/schema-full-checking", \
# self._setSchemaFullSupport)
self._parser.setContentHandler(self)
# self._parser.setErrorHandler(self)
self._parser.setProperty(xml.sax.handler.property_lexical_handler, self)
# except xml.sax.SAXParseException as (errno, strerror): # swallowing exception FIXME
# print >>sys.stderr, "Exception: err no. %d\n%s" % (errno, strerror)
# sys.exit(1)
self._idStack = []
self._lsidStack = []
self._valueStack = []
self._stackTop = 0
self._currentNodeID = XTree.NULL_NODE
self._elementBuffer = ""
# Parse an XML document
# @param uri input XML document
# @return the created XTree
def parse(self, uri):
self._xtree = XTree.XTree()
self._idStack.append(XTree.NULL_NODE)
self._lsidStack.append(XTree.NULL_NODE)
# try:
self._parser.parse(uri)
# except xml.sax.SAXParseException as (errno, strerror):
# print >>sys.stderr, "Exception: err no. %d\n%s" % (errno, strerror)
# sys.exit(1)
return self._xtree
# Document handler methods
def startElement(self, local, attrs):
# if text is mixed with elements
if (len(self._elementBuffer) > 0):
text = str(self._elementBuffer).strip()
if (len(text) > 0):
# Original Java has long here, we have str. FIXME
value = hashlib.sha1(text).digest()
tid = self._xtree.addText(self._idStack[self._stackTop], self._lsidStack[self._stackTop], text, value)
self._lsidStack[self._stackTop] = tid
self._currentNodeID = tid
self._valueStack[self._stackTop] += value
eid = self._xtree.addElement(self._idStack[self._stackTop],
self._lsidStack[self._stackTop], local)
# Update last sibling info.
self._lsidStack[self._stackTop] = eid
# Push
self._stackTop += 1
self._idStack[self._stackTop] = eid
self._currentNodeID = eid
self._lsidStack[self._stackTop] = XTree.NULL_NODE
self._valueStack[self._stackTop] = hashlib.sha1(local).digest()
# Take care of attributes
if ((attrs != None) and (attrs.getLength() > 0)):
for i in range(attrs.getLength()):
name = attrs.getQName(i)
value = attrs.getValue(i)
namehash = hashlib.sha1(name).digest()
valuehash = hashlib.sha1(value).digest()
attrhash = namehash * namehash + \
valuehash * valuehash
aid = self._xtree.addAttribute(eid, self._lsidStack[self._stackTop], name, value, namehash, attrhash)
self._lsidStack[self._stackTop] = aid
self._currentNodeID = aid + 1
self._valueStack[self._stackTop] += attrhash * attrhash
self._readElement = True
self._elementBuffer = ""
def characters(self, ch):
self._elementBuffer += ch
def endElement(self, name):
if (self._readElement):
if (len(self._elementBuffer) > 0):
text = str(self._elementBuffer)
value = hashlib.sha1(text).digest()
self._currentNodeID = \
self._xtree.addText(self._idStack[self._stackTop],
self._lsidStack[self._stackTop],
text, value)
self._valueStack[self._stackTop] += value
else: # an empty element
self._currentNodeID = \
self._xtree.addText(self._idStack[self._stackTop], \
self._lsidStack[self._stackTop], \
"", 0)
self._readElement = False
else:
if (len(self._elementBuffer) > 0):
text = str(self._elementBuffer).strip()
# More text nodes before end of the element.
if (len(text) > 0):
value = hashlib.sha1(text).digest()
self._currentNodeID = \
self._xtree.addText(self._idStack[self._stackTop], \
self._lsidStack[self._stackTop], \
text, value)
self._valueStack[self._stackTop] += value
self._elementBuffer = ""
self._xtree.addHashValue(self._idStack[self._stackTop],
self._valueStack[self._stackTop])
self._valueStack[self._stackTop-1] += self._valueStack[self._stackTop] * \
self._valueStack[self._stackTop]
self._lsidStack[self._stackTop-1] = self._idStack[self._stackTop]
# Pop
self._stackTop -= 1
# End of document handler methods
# Lexical handler methods.
def startCDATA(self):
# The text node id should be the one next to the current
# node id.
textid = self._currentNodeID + 1
text = str(self._elementBuffer)
self._xtree.addCDATA(textid, len(text))
def endCDATA(self):
textid = self._currentNodeID + 1
text = str(self._elementBuffer)
self._xtree.addCDATA(textid, len(text))
# Following functions are not implemented.
def comment(self, ch):
pass
def startDTD(self, name, publicId, systemId):
pass
def endDTD(self):
pass
def startEntity(self, name):
pass
def endEntity(self, name):
pass
# End of lexical handler methods.
