"""Facility to use the Expat parser to load a minidom instance

from a string or file.

This avoids all the overhead of SAX and pulldom to gain performance.

"""

# Warning!

#

# This module is tightly bound to the implementation details of the

# minidom DOM and can't be used with other DOM implementations.  This

# is due, in part, to a lack of appropriate methods in the DOM (there is

# no way to create Entity and Notation nodes via the DOM Level 2

# interface), and for performance.  The later is the cause of some fairly

# cryptic code.

#

# Performance hacks:

#

#   -  .character_data_handler() has an extra case in which continuing

#      data is appended to an existing Text node; this can be a

#      speedup since pyexpat can break up character data into multiple

#      callbacks even though we set the buffer_text attribute on the

#      parser.  This also gives us the advantage that we don't need a

#      separate normalization pass.

#

#   -  Determining that a node exists is done using an identity comparison

#      with None rather than a truth test; this avoids searching for and

#      calling any methods on the node object if it exists.  (A rather

#      nice speedup is achieved this way as well!)

from xml.dom import xmlbuilder, minidom, Node

from xml.dom import EMPTY_NAMESPACE, EMPTY_PREFIX, XMLNS_NAMESPACE

from xml.parsers import expat

from xml.dom.minidom import _append_child, _set_attribute_node

from xml.dom.NodeFilter import NodeFilter

from xml.dom.minicompat import *

TEXT_NODE = Node.TEXT_NODE

CDATA_SECTION_NODE = Node.CDATA_SECTION_NODE

DOCUMENT_NODE = Node.DOCUMENT_NODE

FILTER_ACCEPT = xmlbuilder.DOMBuilderFilter.FILTER_ACCEPT

FILTER_REJECT = xmlbuilder.DOMBuilderFilter.FILTER_REJECT

FILTER_SKIP = xmlbuilder.DOMBuilderFilter.FILTER_SKIP

FILTER_INTERRUPT = xmlbuilder.DOMBuilderFilter.FILTER_INTERRUPT

theDOMImplementation = minidom.getDOMImplementation()

# Expat typename -> TypeInfo

_typeinfo_map = {

    "CDATA":    minidom.TypeInfo(None, "cdata"),

    "ENUM":     minidom.TypeInfo(None, "enumeration"),

    "ENTITY":   minidom.TypeInfo(None, "entity"),

    "ENTITIES": minidom.TypeInfo(None, "entities"),

    "ID":       minidom.TypeInfo(None, "id"),

    "IDREF":    minidom.TypeInfo(None, "idref"),

    "IDREFS":   minidom.TypeInfo(None, "idrefs"),

    "NMTOKEN":  minidom.TypeInfo(None, "nmtoken"),

    "NMTOKENS": minidom.TypeInfo(None, "nmtokens"),

    }

class ElementInfo(object):

    __slots__ = '_attr_info', '_model', 'tagName'

    def __init__(self, tagName, model=None):

        self.tagName = tagName

        self._attr_info = []

        self._model = model

    def __getstate__(self):

        return self._attr_info, self._model, self.tagName

    def __setstate__(self, state):

        self._attr_info, self._model, self.tagName = state

    def getAttributeType(self, aname):

        for info in self._attr_info:

            if info[1] == aname:

                t = info[-2]

                if t[0] == "(":

                    return _typeinfo_map["ENUM"]

                else:

                    return _typeinfo_map[info[-2]]

        return minidom._no_type

    def getAttributeTypeNS(self, namespaceURI, localName):

        return minidom._no_type

    def isElementContent(self):

        if self._model:

            type = self._model[0]

            return type not in (expat.model.XML_CTYPE_ANY,

                                expat.model.XML_CTYPE_MIXED)

        else:

            return False

    def isEmpty(self):

        if self._model:

            return self._model[0] == expat.model.XML_CTYPE_EMPTY

        else:

            return False

    def isId(self, aname):

        for info in self._attr_info:

            if info[1] == aname:

                return info[-2] == "ID"

        return False

    def isIdNS(self, euri, ename, auri, aname):

        # not sure this is meaningful

        return self.isId((auri, aname))

def _intern(builder, s):

    return builder._intern_setdefault(s, s)

def _parse_ns_name(builder, name):

    assert ' ' in name

    parts = name.split(' ')

    intern = builder._intern_setdefault

    if len(parts) == 3:

        uri, localname, prefix = parts

        prefix = intern(prefix, prefix)

        qname = "%s:%s" % (prefix, localname)

        qname = intern(qname, qname)

        localname = intern(localname, localname)

    else:

        uri, localname = parts

        prefix = EMPTY_PREFIX

        qname = localname = intern(localname, localname)

    return intern(uri, uri), localname, prefix, qname

class ExpatBuilder:

    """Document builder that uses Expat to build a ParsedXML.DOM document

    instance."""

    def __init__(self, options=None):

        if options is None:

            options = xmlbuilder.Options()

        self._options = options

        if self._options.filter is not None:

            self._filter = FilterVisibilityController(self._options.filter)

        else:

            self._filter = None

            # This *really* doesn't do anything in this case, so

            # override it with something fast & minimal.

            self._finish_start_element = id

        self._parser = None

        self.reset()

    def createParser(self):

        """Create a new parser object."""

        return expat.ParserCreate()

    def getParser(self):

        """Return the parser object, creating a new one if needed."""

        if not self._parser:

            self._parser = self.createParser()

            self._intern_setdefault = self._parser.intern.setdefault

            self._parser.buffer_text = True

            self._parser.ordered_attributes = True

            self._parser.specified_attributes = True

            self.install(self._parser)

        return self._parser

    def reset(self):

        """Free all data structures used during DOM construction."""

        self.document = theDOMImplementation.createDocument(

            EMPTY_NAMESPACE, None, None)

        self.curNode = self.document

        self._elem_info = self.document._elem_info

        self._cdata = False

    def install(self, parser):

        """Install the callbacks needed to build the DOM into the parser."""

        # This creates circular references!

        parser.StartDoctypeDeclHandler = self.start_doctype_decl_handler

        parser.StartElementHandler = self.first_element_handler

        parser.EndElementHandler = self.end_element_handler

        parser.ProcessingInstructionHandler = self.pi_handler

        if self._options.entities:

            parser.EntityDeclHandler = self.entity_decl_handler

        parser.NotationDeclHandler = self.notation_decl_handler

        if self._options.comments:

            parser.CommentHandler = self.comment_handler

        if self._options.cdata_sections:

            parser.StartCdataSectionHandler = self.start_cdata_section_handler

            parser.EndCdataSectionHandler = self.end_cdata_section_handler

            parser.CharacterDataHandler = self.character_data_handler_cdata

        else:

            parser.CharacterDataHandler = self.character_data_handler

        parser.ExternalEntityRefHandler = self.external_entity_ref_handler

        parser.XmlDeclHandler = self.xml_decl_handler

        parser.ElementDeclHandler = self.element_decl_handler

        parser.AttlistDeclHandler = self.attlist_decl_handler

    def parseFile(self, file):

        """Parse a document from a file object, returning the document

        node."""

        parser = self.getParser()

        first_buffer = True

        try:

            while 1:

                buffer = file.read(16*1024)

                if not buffer:

                    break

                parser.Parse(buffer, 0)

                if first_buffer and self.document.documentElement:

                    self._setup_subset(buffer)

                first_buffer = False

            parser.Parse("", True)

        except ParseEscape:

            pass

        doc = self.document

        self.reset()

        self._parser = None

        return doc

    def parseString(self, string):

        """Parse a document from a string, returning the document node."""

        parser = self.getParser()

        try:

            parser.Parse(string, True)

            self._setup_subset(string)

        except ParseEscape:

            pass

        doc = self.document

        self.reset()

        self._parser = None

        return doc

    def _setup_subset(self, buffer):

        """Load the internal subset if there might be one."""

        if self.document.doctype:

            extractor = InternalSubsetExtractor()

            extractor.parseString(buffer)

            subset = extractor.getSubset()

            self.document.doctype.internalSubset = subset

    def start_doctype_decl_handler(self, doctypeName, systemId, publicId,

                                   has_internal_subset):

        doctype = self.document.implementation.createDocumentType(

            doctypeName, publicId, systemId)

        doctype.ownerDocument = self.document

        self.document.childNodes.append(doctype)

        self.document.doctype = doctype

        if self._filter and self._filter.acceptNode(doctype) == FILTER_REJECT:

            self.document.doctype = None

            del self.document.childNodes[-1]

            doctype = None

            self._parser.EntityDeclHandler = None

            self._parser.NotationDeclHandler = None

        if has_internal_subset:

            if doctype is not None:

                doctype.entities._seq = []

                doctype.notations._seq = []

            self._parser.CommentHandler = None

            self._parser.ProcessingInstructionHandler = None

            self._parser.EndDoctypeDeclHandler = self.end_doctype_decl_handler

    def end_doctype_decl_handler(self):

        if self._options.comments:

            self._parser.CommentHandler = self.comment_handler

        self._parser.ProcessingInstructionHandler = self.pi_handler

        if not (self._elem_info or self._filter):

            self._finish_end_element = id

    def pi_handler(self, target, data):

        node = self.document.createProcessingInstruction(target, data)

        _append_child(self.curNode, node)

        if self._filter and self._filter.acceptNode(node) == FILTER_REJECT:

            self.curNode.removeChild(node)

    def character_data_handler_cdata(self, data):

        childNodes = self.curNode.childNodes

        if self._cdata:

            if (  self._cdata_continue

                  and childNodes[-1].nodeType == CDATA_SECTION_NODE):

                childNodes[-1].appendData(data)

                return

            node = self.document.createCDATASection(data)

            self._cdata_continue = True

        elif childNodes and childNodes[-1].nodeType == TEXT_NODE:

            node = childNodes[-1]

            value = node.data + data

            d = node.__dict__

            d['data'] = d['nodeValue'] = value

            return

        else:

            node = minidom.Text()

            d = node.__dict__

            d['data'] = d['nodeValue'] = data

            d['ownerDocument'] = self.document

        _append_child(self.curNode, node)

    def character_data_handler(self, data):

        childNodes = self.curNode.childNodes

        if childNodes and childNodes[-1].nodeType == TEXT_NODE:

            node = childNodes[-1]

            d = node.__dict__

            d['data'] = d['nodeValue'] = node.data + data

            return

        node = minidom.Text()

        d = node.__dict__

        d['data'] = d['nodeValue'] = node.data + data

        d['ownerDocument'] = self.document

        _append_child(self.curNode, node)

    def entity_decl_handler(self, entityName, is_parameter_entity, value,

                            base, systemId, publicId, notationName):

        if is_parameter_entity:

            # we don't care about parameter entities for the DOM

            return

        if not self._options.entities:

            return

        node = self.document._create_entity(entityName, publicId,

                                            systemId, notationName)

        if value is not None:

            # internal entity

            # node *should* be readonly, but we'll cheat

            child = self.document.createTextNode(value)

            node.childNodes.append(child)

        self.document.doctype.entities._seq.append(node)

        if self._filter and self._filter.acceptNode(node) == FILTER_REJECT:

            del self.document.doctype.entities._seq[-1]

    def notation_decl_handler(self, notationName, base, systemId, publicId):

        node = self.document._create_notation(notationName, publicId, systemId)

        self.document.doctype.notations._seq.append(node)

        if self._filter and self._filter.acceptNode(node) == FILTER_ACCEPT:

            del self.document.doctype.notations._seq[-1]

    def comment_handler(self, data):

        node = self.document.createComment(data)

        _append_child(self.curNode, node)

        if self._filter and self._filter.acceptNode(node) == FILTER_REJECT:

            self.curNode.removeChild(node)

    def start_cdata_section_handler(self):

        self._cdata = True

        self._cdata_continue = False

    def end_cdata_section_handler(self):

        self._cdata = False

        self._cdata_continue = False

    def external_entity_ref_handler(self, context, base, systemId, publicId):

        return 1

    def first_element_handler(self, name, attributes):

        if self._filter is None and not self._elem_info:

            self._finish_end_element = id

        self.getParser().StartElementHandler = self.start_element_handler

        self.start_element_handler(name, attributes)

    def start_element_handler(self, name, attributes):

        node = self.document.createElement(name)

        _append_child(self.curNode, node)

        self.curNode = node

        if attributes:

            for i in range(0, len(attributes), 2):

                a = minidom.Attr(attributes[i], EMPTY_NAMESPACE,

                                 None, EMPTY_PREFIX)

                value = attributes[i+1]

                d = a.childNodes[0].__dict__

                d['data'] = d['nodeValue'] = value

                d = a.__dict__

                d['value'] = d['nodeValue'] = value

                d['ownerDocument'] = self.document

                _set_attribute_node(node, a)

        if node is not self.document.documentElement:

            self._finish_start_element(node)

    def _finish_start_element(self, node):

        if self._filter:

            # To be general, we'd have to call isSameNode(), but this

            # is sufficient for minidom:

            if node is self.document.documentElement:

                return

            filt = self._filter.startContainer(node)

            if filt == FILTER_REJECT:

                # ignore this node & all descendents

                Rejecter(self)

            elif filt == FILTER_SKIP:

                # ignore this node, but make it's children become

                # children of the parent node

                Skipper(self)

            else:

                return

            self.curNode = node.parentNode

            node.parentNode.removeChild(node)

            node.unlink()

    # If this ever changes, Namespaces.end_element_handler() needs to

    # be changed to match.

    #

    def end_element_handler(self, name):

        curNode = self.curNode

        self.curNode = curNode.parentNode

        self._finish_end_element(curNode)

    def _finish_end_element(self, curNode):

        info = self._elem_info.get(curNode.tagName)

        if info:

            self._handle_white_text_nodes(curNode, info)

        if self._filter:

            if curNode is self.document.documentElement:

                return

            if self._filter.acceptNode(curNode) == FILTER_REJECT:

                self.curNode.removeChild(curNode)

                curNode.unlink()

    def _handle_white_text_nodes(self, node, info):

        if (self._options.whitespace_in_element_content

            or not info.isElementContent()):

            return

        # We have element type information and should remove ignorable

        # whitespace; identify for text nodes which contain only

        # whitespace.

        L = []

        for child in node.childNodes:

            if child.nodeType == TEXT_NODE and not child.data.strip():

                L.append(child)

        # Remove ignorable whitespace from the tree.

        for child in L:

            node.removeChild(child)

    def element_decl_handler(self, name, model):

        info = self._elem_info.get(name)

        if info is None:

            self._elem_info[name] = ElementInfo(name, model)

        else:

            assert info._model is None

            info._model = model

    def attlist_decl_handler(self, elem, name, type, default, required):

        info = self._elem_info.get(elem)

        if info is None:

            info = ElementInfo(elem)

            self._elem_info[elem] = info

        info._attr_info.append(

            [None, name, None, None, default, 0, type, required])

    def xml_decl_handler(self, version, encoding, standalone):

        self.document.version = version

        self.document.encoding = encoding

        # This is still a little ugly, thanks to the pyexpat API. ;-(

        if standalone >= 0:

            if standalone:

                self.document.standalone = True

            else:

                self.document.standalone = False

# Don't include FILTER_INTERRUPT, since that's checked separately

# where allowed.

_ALLOWED_FILTER_RETURNS = (FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP)

class FilterVisibilityController(object):

    """Wrapper around a DOMBuilderFilter which implements the checks

    to make the whatToShow filter attribute work."""

    __slots__ = 'filter',

    def __init__(self, filter):

        self.filter = filter

    def startContainer(self, node):

        mask = self._nodetype_mask[node.nodeType]

        if self.filter.whatToShow & mask:

            val = self.filter.startContainer(node)

            if val == FILTER_INTERRUPT:

                raise ParseEscape

            if val not in _ALLOWED_FILTER_RETURNS:

                raise ValueError, \

                      "startContainer() returned illegal value: " + repr(val)

            return val

        else:

            return FILTER_ACCEPT

    def acceptNode(self, node):

        mask = self._nodetype_mask[node.nodeType]

        if self.filter.whatToShow & mask:

            val = self.filter.acceptNode(node)

            if val == FILTER_INTERRUPT:

                raise ParseEscape

            if val == FILTER_SKIP:

                # move all child nodes to the parent, and remove this node

                parent = node.parentNode

                for child in node.childNodes[:]:

                    parent.appendChild(child)

                # node is handled by the caller

                return FILTER_REJECT

            if val not in _ALLOWED_FILTER_RETURNS:

                raise ValueError, \

                      "acceptNode() returned illegal value: " + repr(val)

            return val

        else:

            return FILTER_ACCEPT

    _nodetype_mask = {

        Node.ELEMENT_NODE:                NodeFilter.SHOW_ELEMENT,

        Node.ATTRIBUTE_NODE:              NodeFilter.SHOW_ATTRIBUTE,

        Node.TEXT_NODE:                   NodeFilter.SHOW_TEXT,

        Node.CDATA_SECTION_NODE:          NodeFilter.SHOW_CDATA_SECTION,

        Node.ENTITY_REFERENCE_NODE:       NodeFilter.SHOW_ENTITY_REFERENCE,

        Node.ENTITY_NODE:                 NodeFilter.SHOW_ENTITY,

        Node.PROCESSING_INSTRUCTION_NODE: NodeFilter.SHOW_PROCESSING_INSTRUCTION,

        Node.COMMENT_NODE:                NodeFilter.SHOW_COMMENT,

        Node.DOCUMENT_NODE:               NodeFilter.SHOW_DOCUMENT,

        Node.DOCUMENT_TYPE_NODE:          NodeFilter.SHOW_DOCUMENT_TYPE,

        Node.DOCUMENT_FRAGMENT_NODE:      NodeFilter.SHOW_DOCUMENT_FRAGMENT,

        Node.NOTATION_NODE:               NodeFilter.SHOW_NOTATION,

        }

class FilterCrutch(object):

    __slots__ = '_builder', '_level', '_old_start', '_old_end'

    def __init__(self, builder):

        self._level = 0

        self._builder = builder

        parser = builder._parser

        self._old_start = parser.StartElementHandler