content: #  Copyright (c) ZenML GmbH 2021. All Rights Reserved.
  #
  #  Licensed under the Apache License, Version 2.0 (the "License");
  #  you may not use this file except in compliance with the License.
  #  You may obtain a copy of the License at:
  #
  #       https://www.apache.org/licenses/LICENSE-2.0
  #
  #  Unless required by applicable law or agreed to in writing, software
  #  distributed under the License is distributed on an "AS IS" BASIS,
  #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
  #  or implied. See the License for the specific language governing
  #  permissions and limitations under the License.
  """Implementation of the Huggingface tokenizer materializer."""
  
  import os
  from typing import Any, ClassVar, Tuple, Type
  
  from transformers import AutoTokenizer
  from transformers.tokenization_utils_base import (
      PreTrainedTokenizerBase,
  )
  
  from zenml.enums import ArtifactType
  from zenml.materializers.base_materializer import BaseMaterializer
  from zenml.utils import io_utils
  
  DEFAULT_TOKENIZER_DIR = "hf_tokenizer"
  
  
  class HFTokenizerMaterializer(BaseMaterializer):
      """Materializer to read tokenizer to and from huggingface tokenizer."""
  
      ASSOCIATED_TYPES: ClassVar[Tuple[Type[Any], ...]] = (
          PreTrainedTokenizerBase,
      )
      ASSOCIATED_ARTIFACT_TYPE: ClassVar[ArtifactType] = ArtifactType.MODEL
  
      def load(self, data_type: Type[Any]) -> PreTrainedTokenizerBase:
          """Reads Tokenizer.
  
          Args:
              data_type: The type of the tokenizer to read.
  
          Returns:
              The tokenizer read from the specified dir.
          """
          with self.get_temporary_directory(delete_at_exit=True) as temp_dir:
              io_utils.copy_dir(
                  os.path.join(self.uri, DEFAULT_TOKENIZER_DIR), temp_dir
              )
              return AutoTokenizer.from_pretrained(temp_dir)
  
      def save(self, tokenizer: Type[Any]) -> None:
          """Writes a Tokenizer to the specified dir.
  
          Args:
              tokenizer: The HFTokenizer to write.
          """
          with self.get_temporary_directory(delete_at_exit=True) as temp_dir:
              tokenizer.save_pretrained(temp_dir)
              io_utils.copy_dir(
                  temp_dir,
                  os.path.join(self.uri, DEFAULT_TOKENIZER_DIR),
              )
  