tokenization_cpm.py

# coding=utf-8
# Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
#
# 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
#
#     http://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.
"""Tokenization classes."""
import os
import unicodedata
from shutil import copyfile
from typing import Any, Dict, List, Optional, Tuple

import sentencepiece as spm

from ...tokenization_utils import AddedToken, PreTrainedTokenizer
from ...utils import SPIECE_UNDERLINE, logging


logger = logging.get_logger(__name__)

VOCAB_FILES_NAMES = {"vocab_file": "spiece.model"}

PRETRAINED_VOCAB_FILES_MAP = {
    "vocab_file": {
        "TsinghuaAI/CPM-Generate": "https://huggingface.co/TsinghuaAI/CPM-Generate/resolve/main/spiece.model",
    }
}


class CpmTokenizer(PreTrainedTokenizer):
    """Runs pre-tokenization with Jieba segmentation tool. It is used in CPM models."""

    def __init__(
        self,
        vocab_file,
        do_lower_case=False,
        remove_space=True,
        keep_accents=False,
        bos_token="<s>",
        eos_token="</s>",
        unk_token="<unk>",
        sep_token="<sep>",
        pad_token="<pad>",
        cls_token="<cls>",
        mask_token="<mask>",
        additional_special_tokens=["<eop>", "<eod>"],
        sp_model_kwargs: Optional[Dict[str, Any]] = None,
        **kwargs,
    ) -> None:
        """
        Construct a CPM tokenizer. Based on [Jieba](https://pypi.org/project/jieba/) and
        [SentencePiece](https://github.com/google/sentencepiece).

        This tokenizer inherits from [`PreTrainedTokenizer`] which contains most of the main methods. Users should
        refer to this superclass for more information regarding those methods.

        Args:
            vocab_file (`str`):
                [SentencePiece](https://github.com/google/sentencepiece) file (generally has a .spm extension) that
                contains the vocabulary necessary to instantiate a tokenizer.
            do_lower_case (`bool`, *optional*, defaults to `True`):
                Whether to lowercase the input when tokenizing.
            remove_space (`bool`, *optional*, defaults to `True`):
                Whether to strip the text when tokenizing (removing excess spaces before and after the string).
            keep_accents (`bool`, *optional*, defaults to `False`):
                Whether to keep accents when tokenizing.
            bos_token (`str`, *optional*, defaults to `"<s>"`):
                The beginning of sequence token that was used during pretraining. Can be used a sequence classifier
                token.

                <Tip>

                When building a sequence using special tokens, this is not the token that is used for the beginning of
                sequence. The token used is the `cls_token`.

                </Tip>

            eos_token (`str`, *optional*, defaults to `"</s>"`):
                The end of sequence token.

                <Tip>

                When building a sequence using special tokens, this is not the token that is used for the end of
                sequence. The token used is the `sep_token`.

                </Tip>

            unk_token (`str`, *optional*, defaults to `"<unk>"`):
                The unknown token. A token that is not in the vocabulary cannot be converted to an ID and is set to be
                this token instead.
            sep_token (`str`, *optional*, defaults to `"<sep>"`):
                The separator token, which is used when building a sequence from multiple sequences, e.g. two sequences
                for sequence classification or for a text and a question for question answering. It is also used as the
                last token of a sequence built with special tokens.
            pad_token (`str`, *optional*, defaults to `"<pad>"`):
                The token used for padding, for example when batching sequences of different lengths.
            cls_token (`str`, *optional*, defaults to `"<cls>"`):
                The classifier token which is used when doing sequence classification (classification of the whole
                sequence instead of per-token classification). It is the first token of the sequence when built with
                special tokens.
            mask_token (`str`, *optional*, defaults to `"<mask>"`):
                The token used for masking values. This is the token used when training this model with masked language
                modeling. This is the token which the model will try to predict.
            additional_special_tokens (`List[str]`, *optional*, defaults to `["<eop>", "<eod>"]`):
                Additional special tokens used by the tokenizer.

        Attributes:
            sp_model (`SentencePieceProcessor`):
                The *SentencePiece* processor that is used for every conversion (string, tokens and IDs).
        """
        # Mask token behave like a normal word, i.e. include the space before it
        mask_token = AddedToken(mask_token, lstrip=True, rstrip=False) if isinstance(mask_token, str) else mask_token

        self.sp_model_kwargs = {} if sp_model_kwargs is None else sp_model_kwargs

        super().__init__(
            do_lower_case=do_lower_case,
            remove_space=remove_space,
            keep_accents=keep_accents,
            bos_token=bos_token,
            eos_token=eos_token,
            unk_token=unk_token,
            sep_token=sep_token,
            pad_token=pad_token,
            cls_token=cls_token,
            mask_token=mask_token,
            additional_special_tokens=additional_special_tokens,
            sp_model_kwargs=self.sp_model_kwargs,
            **kwargs,
        )

        self._pad_token_type_id = 3

        self.do_lower_case = do_lower_case
        self.remove_space = remove_space
        self.keep_accents = keep_accents
        self.vocab_file = vocab_file

        self.sp_model = spm.SentencePieceProcessor(**self.sp_model_kwargs)
        self.sp_model.Load(vocab_file)

        try:
            import jieba
        except ModuleNotFoundError as error:
            raise error.__class__(
                "You need to install jieba to use CpmTokenizer or CpmTokenizerFast. "
                "See https://pypi.org/project/jieba/ for installation."
            )
        self.jieba = jieba
        self.translator = str.maketrans(" \n", "\u2582\u2583")

    @property
    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.vocab_size
    def vocab_size(self):
        return len(self.sp_model)

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.get_vocab
    def get_vocab(self):
        vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
        vocab.update(self.added_tokens_encoder)
        return vocab

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.__getstate__
    def __getstate__(self):
        state = self.__dict__.copy()
        state["sp_model"] = None
        return state

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.__setstate__
    def __setstate__(self, d):
        self.__dict__ = d

        # for backward compatibility
        if not hasattr(self, "sp_model_kwargs"):
            self.sp_model_kwargs = {}

        self.sp_model = spm.SentencePieceProcessor(**self.sp_model_kwargs)
        self.sp_model.Load(self.vocab_file)

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.preprocess_text
    def preprocess_text(self, inputs):
        if self.remove_space:
            outputs = " ".join(inputs.strip().split())
        else:
            outputs = inputs
        outputs = outputs.replace("``", '"').replace("''", '"')

        if not self.keep_accents:
            outputs = unicodedata.normalize("NFKD", outputs)
            outputs = "".join([c for c in outputs if not unicodedata.combining(c)])
        if self.do_lower_case:
            outputs = outputs.lower()

        return outputs

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer._tokenize
    def _tokenize(self, text: str) -> List[str]:
        """Tokenize a string."""
        text = self.preprocess_text(text)
        pieces = self.sp_model.encode(text, out_type=str)
        new_pieces = []
        for piece in pieces:
            if len(piece) > 1 and piece[-1] == str(",") and piece[-2].isdigit():
                cur_pieces = self.sp_model.EncodeAsPieces(piece[:-1].replace(SPIECE_UNDERLINE, ""))
                if piece[0] != SPIECE_UNDERLINE and cur_pieces[0][0] == SPIECE_UNDERLINE:
                    if len(cur_pieces[0]) == 1:
                        cur_pieces = cur_pieces[1:]
                    else:
                        cur_pieces[0] = cur_pieces[0][1:]
                cur_pieces.append(piece[-1])
                new_pieces.extend(cur_pieces)
            else:
                new_pieces.append(piece)

        return new_pieces

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer._convert_token_to_id
    def _convert_token_to_id(self, token):
        """Converts a token (str) in an id using the vocab."""
        return self.sp_model.PieceToId(token)

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer._convert_id_to_token
    def _convert_id_to_token(self, index):
        """Converts an index (integer) in a token (str) using the vocab."""
        return self.sp_model.IdToPiece(index)

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.convert_tokens_to_string
    def convert_tokens_to_string(self, tokens):
        """Converts a sequence of tokens (strings for sub-words) in a single string."""
        out_string = "".join(tokens).replace(SPIECE_UNDERLINE, " ").strip()
        return out_string

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.build_inputs_with_special_tokens
    def build_inputs_with_special_tokens(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
    ) -> List[int]:
        """
        Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and
        adding special tokens. An XLNet sequence has the following format:

        - single sequence: `X <sep> <cls>`
        - pair of sequences: `A <sep> B <sep> <cls>`

        Args:
            token_ids_0 (`List[int]`):
                List of IDs to which the special tokens will be added.
            token_ids_1 (`List[int]`, *optional*):
                Optional second list of IDs for sequence pairs.

        Returns:
            `List[int]`: List of [input IDs](../glossary#input-ids) with the appropriate special tokens.
        """
        sep = [self.sep_token_id]
        cls = [self.cls_token_id]
        if token_ids_1 is None:
            return token_ids_0 + sep + cls
        return token_ids_0 + sep + token_ids_1 + sep + cls

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.get_special_tokens_mask
    def get_special_tokens_mask(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None, already_has_special_tokens: bool = False
    ) -> List[int]:
        """
        Retrieve sequence ids from a token list that has no special tokens added. This method is called when adding
        special tokens using the tokenizer `prepare_for_model` method.

        Args:
            token_ids_0 (`List[int]`):
                List of IDs.
            token_ids_1 (`List[int]`, *optional*):
                Optional second list of IDs for sequence pairs.
            already_has_special_tokens (`bool`, *optional*, defaults to `False`):
                Whether or not the token list is already formatted with special tokens for the model.

        Returns:
            `List[int]`: A list of integers in the range [0, 1]: 1 for a special token, 0 for a sequence token.
        """

        if already_has_special_tokens:
            return super().get_special_tokens_mask(
                token_ids_0=token_ids_0, token_ids_1=token_ids_1, already_has_special_tokens=True
            )

        if token_ids_1 is not None:
            return ([0] * len(token_ids_0)) + [1] + ([0] * len(token_ids_1)) + [1, 1]
        return ([0] * len(token_ids_0)) + [1, 1]

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.create_token_type_ids_from_sequences
    def create_token_type_ids_from_sequences(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
    ) -> List[int]:
        """
        Create a mask from the two sequences passed to be used in a sequence-pair classification task. An XLNet
        sequence pair mask has the following format:

        ```
        0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1
        | first sequence    | second sequence |
        ```

        If `token_ids_1` is `None`, this method only returns the first portion of the mask (0s).

        Args:
            token_ids_0 (`List[int]`):
                List of IDs.
            token_ids_1 (`List[int]`, *optional*):
                Optional second list of IDs for sequence pairs.

        Returns:
            `List[int]`: List of [token type IDs](../glossary#token-type-ids) according to the given sequence(s).
        """
        sep = [self.sep_token_id]
        cls_segment_id = [2]

        if token_ids_1 is None:
            return len(token_ids_0 + sep) * [0] + cls_segment_id
        return len(token_ids_0 + sep) * [0] + len(token_ids_1 + sep) * [1] + cls_segment_id

    # Copied from transformers.models.xlnet.tokenization_xlnet.XLNetTokenizer.save_vocabulary
    def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
        if not os.path.isdir(save_directory):
            logger.error(f"Vocabulary path ({save_directory}) should be a directory")
            return
        out_vocab_file = os.path.join(
            save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["vocab_file"]
        )

        if os.path.abspath(self.vocab_file) != os.path.abspath(out_vocab_file) and os.path.isfile(self.vocab_file):
            copyfile(self.vocab_file, out_vocab_file)
        elif not os.path.isfile(self.vocab_file):
            with open(out_vocab_file, "wb") as fi:
                content_spiece_model = self.sp_model.serialized_model_proto()
                fi.write(content_spiece_model)

        return (out_vocab_file,)

    def _decode(self, *args, **kwargs):
        text = super()._decode(*args, **kwargs)
        text = text.replace(" ", "").replace("\u2582", " ").replace("\u2583", "\n")
        return text