Lib/xml/dom/minidom.py

"""\
minidom.py -- a lightweight DOM implementation based on SAX.

parse( "foo.xml" )

parseString( "<foo><bar/></foo>" )

Todo:
=====
 * convenience methods for getting elements and text.
 * more testing
 * bring some of the writer and linearizer code into conformance with this
        interface
 * SAX 2 namespaces
"""

import string
_string = string
del string

# localize the types, and allow support for Unicode values if available:
import types
_TupleType = types.TupleType
try:
    _StringTypes = (types.StringType, types.UnicodeType)
except AttributeError:
    _StringTypes = (types.StringType,)
del types


class Node:
    ELEMENT_NODE                = 1
    ATTRIBUTE_NODE              = 2
    TEXT_NODE                   = 3
    CDATA_SECTION_NODE          = 4
    ENTITY_REFERENCE_NODE       = 5
    ENTITY_NODE                 = 6
    PROCESSING_INSTRUCTION_NODE = 7
    COMMENT_NODE                = 8
    DOCUMENT_NODE               = 9
    DOCUMENT_TYPE_NODE          = 10
    DOCUMENT_FRAGMENT_NODE      = 11
    NOTATION_NODE               = 12

    allnodes = {}
    _debug = 0
    _makeParentNodes = 1
    debug = None

    def __init__(self):
        self.childNodes = []
        if Node._debug:
            index = repr(id(self)) + repr(self.__class__)
            Node.allnodes[index] = repr(self.__dict__)
            if Node.debug is None:
                Node.debug = _get_StringIO()
                #open( "debug4.out", "w" )
            Node.debug.write("create %s\n" % index)

    def __getattr__(self, key):
        if key[0:2] == "__":
            raise AttributeError
        # getattr should never call getattr!
        if self.__dict__.has_key("inGetAttr"):
            del self.inGetAttr
            raise AttributeError, key

        prefix, attrname = key[:5], key[5:]
        if prefix == "_get_":
            self.inGetAttr = 1
            if hasattr(self, attrname):
                del self.inGetAttr
                return (lambda self=self, attrname=attrname:
                                getattr(self, attrname))
            else:
                del self.inGetAttr
                raise AttributeError, key
        else:
            self.inGetAttr = 1
            try:
                func = getattr(self, "_get_" + key)
            except AttributeError:
                raise AttributeError, key
            del self.inGetAttr
            return func()

    def __nonzero__(self):
        return 1

    def toxml(self):
        writer = _get_StringIO()
        self.writexml(writer)
        return writer.getvalue()

    def hasChildNodes(self):
        if self.childNodes:
            return 1
        else:
            return 0

    def _get_firstChild(self):
        if self.childNodes:
            return self.childNodes[0]

    def _get_lastChild(self):
        if self.childNodes:
            return self.childNodes[-1]

    def insertBefore(self, newChild, refChild):
        if refChild is None:
            self.appendChild(newChild)
        else:
            index = self.childNodes.index(refChild)
            self.childNodes.insert(index, newChild)
            newChild.nextSibling = refChild
            refChild.previousSibling = newChild
            if index:
                node = self.childNodes[index-1]
                node.nextSibling = newChild
                newChild.previousSibling = node
            else:
                newChild.previousSibling = None
            if self._makeParentNodes:
                newChild.parentNode = self
        return newChild

    def appendChild(self, node):
        if self.childNodes:
            last = self.lastChild
            node.previousSibling = last
            last.nextSibling = node
        else:
            node.previousSibling = None
        node.nextSibling = None
        self.childNodes.append(node)
        if self._makeParentNodes:
            node.parentNode = self
        return node

    def replaceChild(self, newChild, oldChild):
        if newChild is oldChild:
            return
        index = self.childNodes.index(oldChild)
        self.childNodes[index] = newChild
        if self._makeParentNodes:
            newChild.parentNode = self
            oldChild.parentNode = None
        newChild.nextSibling = oldChild.nextSibling
        newChild.previousSibling = oldChild.previousSibling
        oldChild.newChild = None
        oldChild.previousSibling = None
        return oldChild

    def removeChild(self, oldChild):
        self.childNodes.remove(oldChild)
        if self._makeParentNodes:
            oldChild.parentNode = None
        return oldChild

    def normalize(self):
        if len(self.childNodes) > 1:
            L = [self.childNodes[0]]
            for child in self.childNodes[1:]:
                if (  child.nodeType == Node.TEXT_NODE
                      and L[-1].nodeType == child.nodeType):
                    # collapse text node
                    node = L[-1]
                    node.data = node.nodeValue = node.data + child.data
                    node.nextSibling = child.nextSibling
                    child.unlink()
                else:
                    L[-1].nextSibling = child
                    child.previousSibling = L[-1]
                    L.append(child)
                    child.normalize()
            self.childNodes = L
        elif self.childNodes:
            # exactly one child -- just recurse
            self.childNodes[0].normalize()

    def cloneNode(self, deep):
        import new
        clone = new.instance(self.__class__, self.__dict__.copy())
        if self._makeParentNodes:
            clone.parentNode = None
        clone.childNodes = []
        if deep:
            for child in self.childNodes:
                clone.appendChild(child.cloneNode(1))
        return clone

    def unlink(self):
        self.parentNode = None
        for child in self.childNodes:
            child.unlink()
        self.childNodes = None
        self.previousSibling = None
        self.nextSibling = None
        if Node._debug:
            index = repr(id(self)) + repr(self.__class__)
            self.debug.write("Deleting: %s\n" % index)
            del Node.allnodes[index]

def _write_data(writer, data):
    "Writes datachars to writer."
    replace = _string.replace
    data = replace(data, "&", "&amp;")
    data = replace(data, "<", "&lt;")
    data = replace(data, "\"", "&quot;")
    data = replace(data, ">", "&gt;")
    writer.write(data)

def _getElementsByTagNameHelper(parent, name, rc):
    for node in parent.childNodes:
        if node.nodeType == Node.ELEMENT_NODE and \
            (name == "*" or node.tagName == name):
            rc.append(node)
        _getElementsByTagNameHelper(node, name, rc)
    return rc

def _getElementsByTagNameNSHelper(parent, nsURI, localName, rc):
    for node in parent.childNodes:
        if node.nodeType == Node.ELEMENT_NODE:
            if ((localName == "*" or node.tagName == localName) and
                (nsURI == "*" or node.namespaceURI == nsURI)):
                rc.append(node)
            _getElementsByTagNameNSHelper(node, name, rc)

class Attr(Node):
    nodeType = Node.ATTRIBUTE_NODE
    attributes = None
    ownerElement = None

    def __init__(self, qName, namespaceURI="", localName=None, prefix=None):
        # skip setattr for performance
        d = self.__dict__
        d["localName"] = localName or qName
        d["nodeName"] = d["name"] = qName
        d["namespaceURI"] = namespaceURI
        d["prefix"] = prefix
        Node.__init__(self)
        # nodeValue and value are set elsewhere

    def __setattr__(self, name, value):
        if name in ("value", "nodeValue"):
            self.__dict__["value"] = self.__dict__["nodeValue"] = value
        else:
            self.__dict__[name] = value

    def cloneNode(self, deep):
        clone = Node.cloneNode(self, deep)
        if clone.__dict__.has_key("ownerElement"):
            del clone.ownerElement
        return clone

class AttributeList:
    """The attribute list is a transient interface to the underlying
    dictionaries.  Mutations here will change the underlying element's
    dictionary"""

    def __init__(self, attrs, attrsNS):
        self._attrs = attrs
        self._attrsNS = attrsNS
        self.length = len(self._attrs)

    def item(self, index):
        try:
            return self[self.keys()[index]]
        except IndexError:
            return None

    def items(self):
        L = []
        for node in self._attrs.values():
            L.append((node.tagName, node.value))
        return L

    def itemsNS(self):
        L = []
        for node in self._attrs.values():
            L.append(((node.URI, node.localName), node.value))
        return L

    def keys(self):
        return self._attrs.keys()

    def keysNS(self):
        return self._attrsNS.keys()

    def values(self):
        return self._attrs.values()

    def __len__(self):
        return self.length

    def __cmp__(self, other):
        if self._attrs is getattr(other, "_attrs", None):
            return 0
        else:
            return cmp(id(self), id(other))

    #FIXME: is it appropriate to return .value?
    def __getitem__(self, attname_or_tuple):
        if type(attname_or_tuple) is _TupleType:
            return self._attrsNS[attname_or_tuple]
        else:
            return self._attrs[attname_or_tuple]

    # same as set
    def __setitem__(self, attname, value):
        if type(value) in _StringTypes:
            node = Attr(attname)
            node.value = value
        else:
            if not isinstance(value, Attr):
                raise TypeError, "value must be a string or Attr object"
            node = value
        old = self._attrs.get(attname, None)
        if old:
            old.unlink()
        self._attrs[node.name] = node
        self._attrsNS[(node.namespaceURI, node.localName)] = node

    def __delitem__(self, attname_or_tuple):
        node = self[attname_or_tuple]
        node.unlink()
        del self._attrs[node.name]
        del self._attrsNS[(node.namespaceURI, node.localName)]

class Element(Node):
    nodeType = Node.ELEMENT_NODE
    nextSibling = None
    previousSibling = None

    def __init__(self, tagName, namespaceURI="", prefix="",
                 localName=None):
        Node.__init__(self)
        self.tagName = self.nodeName = tagName
        self.localName = localName or tagName
        self.prefix = prefix
        self.namespaceURI = namespaceURI
        self.nodeValue = None

        self._attrs = {}   # attributes are double-indexed:
        self._attrsNS = {} #    tagName -> Attribute
                           #    URI,localName -> Attribute
                           # in the future: consider lazy generation
                           # of attribute objects this is too tricky
                           # for now because of headaches with
                           # namespaces.

    def cloneNode(self, deep):
        clone = Node.cloneNode(self, deep)
        clone._attrs = {}
        clone._attrsNS = {}
        for attr in self._attrs.values():
            node = attr.cloneNode(1)
            clone._attrs[node.name] = node
            clone._attrsNS[(node.namespaceURI, node.localName)] = node
            node.ownerElement = clone
        return clone

    def unlink(self):
        for attr in self._attrs.values():
            attr.unlink()
        self._attrs = None
        self._attrsNS = None
        Node.unlink(self)

    def getAttribute(self, attname):
        return self._attrs[attname].value

    def getAttributeNS(self, namespaceURI, localName):
        return self._attrsNS[(namespaceURI, localName)].value

    def setAttribute(self, attname, value):
        attr = Attr(attname)
        # for performance
        attr.__dict__["value"] = attr.__dict__["nodeValue"] = value
        self.setAttributeNode(attr)

    def setAttributeNS(self, namespaceURI, qualifiedName, value):
        prefix, localname = _nssplit(qualifiedName)
        # for performance
        attr = Attr(qualifiedName, namespaceURI, localname, prefix)
        attr.__dict__["value"] = attr.__dict__["nodeValue"] = value
        self.setAttributeNode(attr)

    def getAttributeNode(self, attrname):
        return self._attrs.get(attrname)

    def getAttributeNodeNS(self, namespaceURI, localName):
        return self._attrsNS[(namespaceURI, localName)]

    def setAttributeNode(self, attr):
        if attr.ownerElement not in (None, self):
            raise ValueError, "attribute node already owned"
        old = self._attrs.get(attr.name, None)
        if old:
            old.unlink()
        self._attrs[attr.name] = attr
        self._attrsNS[(attr.namespaceURI, attr.localName)] = attr

        # This creates a circular reference, but Element.unlink()
        # breaks the cycle since the references to the attribute
        # dictionaries are tossed.
        attr.ownerElement = self

        if old is not attr:
            # It might have already been part of this node, in which case
            # it doesn't represent a change, and should not be returned.
            return old

    def removeAttribute(self, name):
        attr = self._attrs[name]
        self.removeAttributeNode(attr)

    def removeAttributeNS(self, namespaceURI, localName):
        attr = self._attrsNS[(namespaceURI, localName)]
        self.removeAttributeNode(attr)

    def removeAttributeNode(self, node):
        node.unlink()
        del self._attrs[node.name]
        del self._attrsNS[(node.namespaceURI, node.localName)]

    def getElementsByTagName(self, name):
        return _getElementsByTagNameHelper(self, name, [])

    def getElementsByTagNameNS(self, namespaceURI, localName):
        _getElementsByTagNameNSHelper(self, namespaceURI, localName, [])

    def __repr__(self):
        return "<DOM Element: %s at %s>" % (self.tagName, id(self))

    def writexml(self, writer):
        writer.write("<" + self.tagName)

        attrs = self._get_attributes()
        a_names = attrs.keys()
        a_names.sort()

        for a_name in a_names:
            writer.write(" %s=\"" % a_name)
            _write_data(writer, attrs[a_name].value)
            writer.write("\"")
        if self.childNodes:
            writer.write(">")
            for node in self.childNodes:
                node.writexml(writer)
            writer.write("</%s>" % self.tagName)
        else:
            writer.write("/>")

    def _get_attributes(self):
        return AttributeList(self._attrs, self._attrsNS)

class Comment(Node):
    nodeType = Node.COMMENT_NODE
    nodeName = "#comment"
    attributes = None

    def __init__(self, data):
        Node.__init__(self)
        self.data = self.nodeValue = data

    def writexml(self, writer):
        writer.write("<!--%s-->" % self.data)

class ProcessingInstruction(Node):
    nodeType = Node.PROCESSING_INSTRUCTION_NODE
    attributes = None

    def __init__(self, target, data):
        Node.__init__(self)
        self.target = self.nodeName = target
        self.data = self.nodeValue = data

    def writexml(self, writer):
        writer.write("<?%s %s?>" % (self.target, self.data))

class Text(Node):
    nodeType = Node.TEXT_NODE
    nodeName = "#text"
    attributes = None

    def __init__(self, data):
        Node.__init__(self)
        self.data = self.nodeValue = data

    def __repr__(self):
        if len(self.data) > 10:
            dotdotdot = "..."
        else:
            dotdotdot = ""
        return "<DOM Text node \"%s%s\">" % (self.data[0:10], dotdotdot)

    def writexml(self, writer):
        _write_data(writer, self.data)

def _nssplit(qualifiedName):
    fields = _string.split(qualifiedName, ':', 1)
    if len(fields) == 2:
        return fields
    elif len(fields) == 1:
        return ('', fields[0])

class Document(Node):
    nodeType = Node.DOCUMENT_NODE
    nodeName = "#document"
    nodeValue = None
    attributes = None
    documentElement = None

    def appendChild(self, node):
        if node.nodeType == Node.ELEMENT_NODE:
            if self.documentElement:
                raise TypeError, "Two document elements disallowed"
            else:
                self.documentElement = node
        return Node.appendChild(self, node)

    createElement = Element

    createTextNode = Text

    createComment = Comment

    createProcessingInstruction = ProcessingInstruction

    createAttribute = Attr

    def createElementNS(self, namespaceURI, qualifiedName):
        prefix, localName = _nssplit(qualifiedName)
        return self.createElement(qualifiedName, namespaceURI,
                                  prefix, localName)

    def createAttributeNS(self, namespaceURI, qualifiedName):
        prefix, localName = _nssplit(qualifiedName)
        return self.createAttribute(qualifiedName, namespaceURI,
                                    localName, prefix)

    def getElementsByTagNameNS(self, namespaceURI, localName):
        _getElementsByTagNameNSHelper(self, namespaceURI, localName)

    def unlink(self):
        self.documentElement = None
        Node.unlink(self)

    def getElementsByTagName(self, name):
        rc = []
        _getElementsByTagNameHelper(self, name, rc)
        return rc

    def writexml(self, writer):
        for node in self.childNodes:
            node.writexml(writer)

def _get_StringIO():
    try:
        from cStringIO import StringIO
    except ImportError:
        from StringIO import StringIO
    return StringIO()

def _doparse(func, args, kwargs):
    events = apply(func, args, kwargs)
    toktype, rootNode = events.getEvent()
    events.expandNode(rootNode)
    return rootNode

def parse(*args, **kwargs):
    "Parse a file into a DOM by filename or file object"
    from xml.dom import pulldom
    return _doparse(pulldom.parse, args, kwargs)

def parseString(*args, **kwargs):
    "Parse a file into a DOM from a string"
    from xml.dom import pulldom
    return _doparse(pulldom.parseString, args, kwargs)