reader.py

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

# Copyright (c) 2020, Sandflow Consulting LLC
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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'''IMSC reader'''

import io
import logging
import typing
import xml.etree.ElementTree as et

import ttconv.imsc.elements as imsc_elements
import ttconv.model as model

LOGGER = logging.getLogger(__name__)


def to_model(data_file: typing.BinaryIO, _config=None, progress_callback=lambda _: None) -> typing.Optional[model.ContentDocument]:
  '''Convers an IMSC document to the data model'''

  text_stream = io.TextIOWrapper(data_file, encoding='utf-8')
  xml_element = et.parse(text_stream).getroot()

  if not imsc_elements.TTElement.is_instance(xml_element):
    LOGGER.fatal("A tt element is not the root element")
    return None

  tt_element = imsc_elements.TTElement.from_xml(None, xml_element, progress_callback)

  if tt_element is None:
    LOGGER.fatal("Invalid TT element")
    return None 

  return tt_element.doc