Paul Prescod <paul@prescod.net>:

W3C DOM implementation for Python.

Lib/xml/dom/pulldom.py

+import minidom
+import types
+import string
+import sys
+import pyexpat
+from xml.sax import ExpatParser
+
+#todo: SAX2/namespace handling
+
+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:
+    def __init__( self ):
+        self.firstEvent=[None,None]
+        self.lastEvent=self.firstEvent
+
+    def setDocumentLocator( self, locator ): pass
+
+    def startElement( self, tagName , attrs  ):
+        if not hasattr( self, "curNode" ):
+            # FIXME: hack!
+            self.startDocument( )
+
+        node = self.document.createElement( tagName ) #FIXME namespaces!
+        for attr in attrs.keys():
+            node.setAttribute( attr, attrs[attr] )
+        
+        parent=self.curNode
+        node.parentNode = parent
+        if parent.childNodes:
+            node.previousSibling=parent.childNodes[-1]
+            node.previousSibling.nextSibling=node
+        self.curNode = node
+        # FIXME: do I have to screen namespace attributes
+        self.lastEvent[1]=[(START_ELEMENT, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (START_ELEMENT, node) )
+
+    def endElement( self, name ):
+        node = self.curNode
+        self.lastEvent[1]=[(END_ELEMENT, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (END_ELEMENT, node ))
+        self.curNode = node.parentNode
+
+    def comment( self, s):
+        node = self.document.createComment ( s )
+        parent=self.curNode
+        node.parentNode=parent
+        if parent.childNodes:
+            node.previousSibling=parent.childNodes[-1]
+            node.previousSibling.nextSibling=node
+        self.lastEvent[1]=[(COMMENT, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (COMMENT, node ))
+
+    def processingInstruction( self, target, data ):
+        node = self.document.createProcessingInstruction( target, data )
+        #self.appendChild( node )
+        
+        parent=self.curNode
+        node.parentNode=parent
+        if parent.childNodes:
+            node.previousSibling=parent.childNodes[-1]
+            node.previousSibling.nextSibling=node
+        self.lastEvent[1]=[(PROCESSING_INSTRUCTION, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (PROCESSING_INSTRUCTION, node) )
+
+    def ignorableWhitespace( self, chars ):
+        node = self.document.createTextNode( chars[start:start+length] )
+        parent=self.curNode
+        node.parentNode=parent
+        if parent.childNodes:
+            node.previousSibling=parent.childNodes[-1]
+            node.previousSibling.nextSibling=node
+        self.lastEvent[1]=[(IGNORABLE_WHITESPACE, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (IGNORABLE_WHITESPACE, node))
+
+    def characters( self, chars ):
+        node = self.document.createTextNode( chars )
+        node.parentNode=self.curNode
+        self.lastEvent[1]=[(CHARACTERS, node), None ]
+        self.lastEvent=self.lastEvent[1]
+
+    def startDocument( self ):
+        node = self.curNode = self.document = minidom.Document()
+        node.parentNode=None
+        self.lastEvent[1]=[(START_DOCUMENT, node), None ]
+        self.lastEvent=self.lastEvent[1]
+        #self.events.append( (START_DOCUMENT, node) )
+            
+    def endDocument( self ):
+        assert( not self.curNode.parentNode )
+        for node in self.curNode.childNodes:
+                if node.nodeType==node.ELEMENT_NODE:
+                        self.document.documentElement = node
+        #if not self.document.documentElement:
+        #        raise Error, "No document element"
+
+        self.lastEvent[1]=[(END_DOCUMENT, node), None ]
+        #self.events.append( (END_DOCUMENT, self.curNode) )
+
+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()
+        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()
+        while event:
+            token,cur_node=event
+            if cur_node is node: return
+            
+            if token !=END_ELEMENT:
+                cur_node.parentNode.childNodes.append( cur_node )
+            event=self.getEvent()
+        if node.nodeType==minidom.Node.DOCUMENT_NODE:
+            for child in node.childNodes:
+                if child.nodeType==minidom.Node.ELEMENT_NODE:
+                    node.documentElement=child
+
+    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:
+                #FIXME: why doesn't Expat close work?
+                #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
+
+# FIXME: sax2
+#def _getParser( ):
+ #   from xml.sax.saxexts import make_parser
+    # expat doesn't report errors properly! Figure it out
+  #  return make_parser()
+   # return make_parser("xml.sax.drivers.drv_xmllib")
+
+
+        
+def _getParser():
+     return ExpatParser()
+
+default_bufsize=(2**14)-20
+# FIXME: move into sax package for common usage
+def parse( stream_or_string, parser=None, bufsize=default_bufsize ):
+    if type( stream_or_string ) == type( "" ):
+        stream=open( stream_or_string )
+    else:
+        stream=stream_or_string
+    if not parser: 
+        parser=_getParser()
+    return DOMEventStream( stream, parser, bufsize )
+
+def parseString( string, parser=None ):
+    try:
+        import cStringIO
+        stringio=cStringIO.StringIO
+    except ImportError:
+        import StringIO
+        stringio=StringIO.StringIO
+        
+    bufsize=len( string )
+    stringio( string )
+    parser=_getParser()
+    return DOMEventStream( buf, parser, bufsize )
+
+#FIXME: Use Lars' instead!!!
+class SAX_expat:
+    "SAX driver for the Pyexpat C module."
+
+    def __init__(self):
+        self.parser=pyexpat.ParserCreate()
+        self.started=0
+
+    def setDocumentHandler( self, handler ):
+        self.parser.StartElementHandler = handler.startElement
+        self.parser.EndElementHandler = handler.endElement
+        self.parser.CharacterDataHandler = handler.datachars
+        self.parser.ProcessingInstructionHandler = handler.processingInstruction
+        self.doc_handler=handler
+
+    def setErrorHandler( self, handler ):
+        self.err_handler=handler
+
+    # --- Locator methods. Only usable after errors.
+
+    def getLineNumber(self):
+        return self.parser.ErrorLineNumber
+
+    def getColumnNumber(self):
+        return self.parser.ErrorColumnNumber    
+
+    # --- Internal
+
+    def __report_error(self):
+        msg=pyexpat.ErrorString(self.parser.ErrorCode)
+        self.err_handler.fatalError(msg)
+
+    # --- EXPERIMENTAL PYTHON SAX EXTENSIONS
+        
+    def get_parser_name(self):
+        return "pyexpat"
+
+    def get_parser_version(self):
+        return "Unknown"
+
+    def get_driver_version(self):
+        return version
+    
+    def is_validating(self):
+        return 0
+
+    def is_dtd_reading(self):
+        return 0
+
+    def reset(self):
+        self.parser=pyexpat.ParserCreate()
+        self.parser.StartElementHandler = self.startElement
+        self.parser.EndElementHandler = self.endElement
+        self.parser.CharacterDataHandler = self.characters
+        self.parser.ProcessingInstructionHandler = self.processingInstruction
+    
+    def feed(self,data):
+        if not self.started:
+            self.doc_handler.startDocument()
+            self.started=1  
+        if not self.parser.Parse(data):
+            self.__report_error()
+
+    def close(self):
+        if not self.parser.Parse("",1):
+            self.__report_error()
+        self.doc_handler.endDocument()
+        self.parser = None