Class FilterVisibilityController

Lib/xml/dom/expatbuilder.py:453–508

Wrapper around a DOMBuilderFilter which implements the checks to make the whatToShow filter attribute work.

_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,
        }