Gets the starting line number of the start-tag of root

root_sourceline.py

def root_sourceline(source, resolver=None):
    """Gets the starting line number of the start-tag of root

    :param source:
    :type source: file name/path, file object, file-like object, URL
    :param etree.Resolver resolver: custom resolver
    :return: (line number, column)
    :rtype: tuple
    """
    if hasattr(source, 'read'):
        # We have a read() method, so it's a file-like object
        buffer = io.StringIO(source.read())
    elif os.path.exists(source):
        # path to a file
        buffer = io.StringIO(open(source, 'r').read())
    else:
        # We expect a string here
        buffer = io.StringIO(source)

    import xml.sax.handler

    class MyContentHandler(xml.sax.handler.ContentHandler):
        def __init__(self):
            ContentHandler.__init__(self)
            # initialize your handler
            self.root = None

        def startElement(self, name, attrs):
            if isinstance(self.root, tuple):
                return
            loc = self._locator
            if loc is not None:
                line, col = loc.getLineNumber(), loc.getColumnNumber()
            else:
                line, col = None, None
            self.root = (line, col)

    parser = xml.sax.make_parser()
    handler = MyContentHandler()
    parser.setContentHandler(handler)
    parser.parse(source)
    return handler.root