codingutf8 2022 the facebook ai research team s 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 orglicenseslicense2 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 construct an nllb tokenizer adapted from robertatokenizer and xlnettokenizer based on sentencepiecehttps github comgooglesentencepiece the tokenization method is tokens eos language code for source language documents and language code tokens eos for target language documents examples python from transformers import nllbtokenizer tokenizer nllbtokenizer frompretrained facebooknllb200distilled600m srclangenglatn tgtlangfralatn exampleenglishphrase un chief says there is no military solution in syria expectedtranslationfrench le chef de l onu affirme qu il n y a pas de solution militaire en syrie inputs tokenizerexampleenglishphrase texttargetexpectedtranslationfrench returntensorspt args vocabfile str path to the vocabulary file bostoken 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 clstoken tip eostoken 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 septoken tip septoken str optional defaults to s 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 clstoken str optional defaults to s the classifier token which is used when doing sequence classification classification of the whole sequence instead of pertoken classification it is the first token of the sequence when built with special tokens unktoken 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 padtoken str optional defaults to pad the token used for padding for example when batching sequences of different lengths masktoken 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 tokenizerfile str optional the path to a tokenizer file to use instead of the vocab file srclang str optional the language to use as source language for translation tgtlang str optional the language to use as target language for translation spmodelkwargs dictstr str additional keyword arguments to pass to the model initialization mask token behave like a normal word i e include the space before it original fairseq vocab and spm vocab must be aligned vocab 0 1 2 3 4 5 6 7 8 9 fairseq s pad s unk an n m t k a spm unk s s an n m t k a s mimic fairseq tokentoid alignment for the first 4 token the first real token has position 4 in the original fairseq vocab and position 3 in the spm vocab only add those special tokens if they are not already there for backward compatibility retrieve sequence ids from a token list that has no special tokens added this method is called when adding special tokens using the tokenizer prepareformodel method args tokenids0 listint list of ids tokenids1 listint optional optional second list of ids for sequence pairs alreadyhasspecialtokens bool optional defaults to false whether or not the token list is already formatted with special tokens for the model returns listint a list of integers in the range 0 1 1 for a special token 0 for a sequence token build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and adding special tokens an nllb sequence has the following format where x represents the sequence inputids for encoder x eos srclangcode decoderinputids for decoder x eos tgtlangcode bos is never used pairs of sequences are not the expected use case but they will be handled without a separator args tokenids0 listint list of ids to which the special tokens will be added tokenids1 listint optional optional second list of ids for sequence pairs returns listint list of input ids glossaryinputids with the appropriate special tokens we don t expect to process pairs but leave the pair logic for api consistency create a mask from the two sequences passed to be used in a sequencepair classification task nllb does not make use of token type ids therefore a list of zeros is returned args tokenids0 listint list of ids tokenids1 listint optional optional second list of ids for sequence pairs returns listint list of zeros used by translation pipeline to prepare inputs for the generate function if srclang is none or tgtlang is none raise valueerrortranslation requires a srclang and a tgtlang for this model self srclang srclang inputs selfrawinputs addspecialtokenstrue returntensorsreturntensors extrakwargs tgtlangid self converttokenstoidstgtlang inputsforcedbostokenid tgtlangid return inputs def getvocabself vocab self convertidstotokensi i for i in rangeself vocabsize vocab updateself addedtokensencoder return vocab def tokenizeself text str liststr return self spmodel encodetext outtypestr def converttokentoidself token need to return unknown token if the sp model returned 0 converts an index integer in a token str using the vocab if index in self fairseqidstotokens return self fairseqidstotokensindex return self spmodel idtopieceindex self fairseqoffset def converttokenstostringself tokens reset the special tokens to the source lang setting in legacy mode no prefix and suffixeos srclangcode in default mode prefixsrclangcode suffix eos reset the special tokens to the target lang setting in legacy mode no prefix and suffixeos tgtlangcode in default mode prefixtgtlangcode suffix eos coding utf 8 2022 the facebook ai research team s 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 fmt skip construct an nllb tokenizer adapted from robertatokenizer and xlnettokenizer based on sentencepiece https github com google sentencepiece the tokenization method is tokens eos language code for source language documents and language code tokens eos for target language documents examples python from transformers import nllbtokenizer tokenizer nllbtokenizer from_pretrained facebook nllb 200 distilled 600m src_lang eng_latn tgt_lang fra_latn example_english_phrase un chief says there is no military solution in syria expected_translation_french le chef de l onu affirme qu il n y a pas de solution militaire en syrie inputs tokenizer example_english_phrase text_target expected_translation_french return_tensors pt args vocab_file str path to the vocabulary file 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 sep_token str optional defaults to s 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 cls_token str optional defaults to s 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 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 pad_token str optional defaults to pad the token used for padding for example when batching sequences of different lengths 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 tokenizer_file str optional the path to a tokenizer file to use instead of the vocab file src_lang str optional the language to use as source language for translation tgt_lang str optional the language to use as target language for translation sp_model_kwargs dict str str additional keyword arguments to pass to the model initialization mask token behave like a normal word i e include the space before it original fairseq vocab and spm vocab must be aligned vocab 0 1 2 3 4 5 6 7 8 9 fairseq s pad s unk an n m t k a spm unk s s an n m t k a s mimic fairseq token to id alignment for the first 4 token the first real token has position 4 in the original fairseq vocab and position 3 in the spm vocab only add those special tokens if they are not already there for backward compatibility plus 1 for the mask token 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 build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and adding special tokens an nllb sequence has the following format where x represents the sequence input_ids for encoder x eos src_lang_code decoder_input_ids for decoder x eos tgt_lang_code bos is never used pairs of sequences are not the expected use case but they will be handled without a separator 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 we don t expect to process pairs but leave the pair logic for api consistency create a mask from the two sequences passed to be used in a sequence pair classification task nllb does not make use of token type ids therefore a list of zeros is returned 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 zeros used by translation pipeline to prepare inputs for the generate function converts a token str in an id using the vocab need to return unknown token if the sp model returned 0 converts an index integer in a token str using the vocab converts a sequence of tokens strings for sub words in a single string reset the special tokens to the source lang setting in legacy mode no prefix and suffix eos src_lang_code in default mode prefix src_lang_code suffix eos reset the special tokens to the target lang setting in legacy mode no prefix and suffix eos tgt_lang_code in default mode prefix tgt_lang_code suffix eos
import os
from shutil import copyfile
from typing import Any, Dict, List, Optional, Tuple

import sentencepiece as spm

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


logger = logging.get_logger(__name__)

SPIECE_UNDERLINE = "▁"

VOCAB_FILES_NAMES = {"vocab_file": "sentencepiece.bpe.model"}

PRETRAINED_VOCAB_FILES_MAP = {
    "vocab_file": {
        "facebook/nllb-200-distilled-600M": (
            "https://huggingface.co/facebook/nllb-200-distilled-600M/blob/main/sentencepiece.bpe.model"
        ),
    }
}

PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
    "facebook/nllb-200-distilled-600M": 1024,
}

FAIRSEQ_LANGUAGE_CODES = ['ace_Arab', 'ace_Latn', 'acm_Arab', 'acq_Arab', 'aeb_Arab', 'afr_Latn', 'ajp_Arab', 'aka_Latn', 'amh_Ethi', 'apc_Arab', 'arb_Arab', 'ars_Arab', 'ary_Arab', 'arz_Arab', 'asm_Beng', 'ast_Latn', 'awa_Deva', 'ayr_Latn', 'azb_Arab', 'azj_Latn', 'bak_Cyrl', 'bam_Latn', 'ban_Latn', 'bel_Cyrl', 'bem_Latn', 'ben_Beng', 'bho_Deva', 'bjn_Arab', 'bjn_Latn', 'bod_Tibt', 'bos_Latn', 'bug_Latn', 'bul_Cyrl', 'cat_Latn', 'ceb_Latn', 'ces_Latn', 'cjk_Latn', 'ckb_Arab', 'crh_Latn', 'cym_Latn', 'dan_Latn', 'deu_Latn', 'dik_Latn', 'dyu_Latn', 'dzo_Tibt', 'ell_Grek', 'eng_Latn', 'epo_Latn', 'est_Latn', 'eus_Latn', 'ewe_Latn', 'fao_Latn', 'pes_Arab', 'fij_Latn', 'fin_Latn', 'fon_Latn', 'fra_Latn', 'fur_Latn', 'fuv_Latn', 'gla_Latn', 'gle_Latn', 'glg_Latn', 'grn_Latn', 'guj_Gujr', 'hat_Latn', 'hau_Latn', 'heb_Hebr', 'hin_Deva', 'hne_Deva', 'hrv_Latn', 'hun_Latn', 'hye_Armn', 'ibo_Latn', 'ilo_Latn', 'ind_Latn', 'isl_Latn', 'ita_Latn', 'jav_Latn', 'jpn_Jpan', 'kab_Latn', 'kac_Latn', 'kam_Latn', 'kan_Knda', 'kas_Arab', 'kas_Deva', 'kat_Geor', 'knc_Arab', 'knc_Latn', 'kaz_Cyrl', 'kbp_Latn', 'kea_Latn', 'khm_Khmr', 'kik_Latn', 'kin_Latn', 'kir_Cyrl', 'kmb_Latn', 'kon_Latn', 'kor_Hang', 'kmr_Latn', 'lao_Laoo', 'lvs_Latn', 'lij_Latn', 'lim_Latn', 'lin_Latn', 'lit_Latn', 'lmo_Latn', 'ltg_Latn', 'ltz_Latn', 'lua_Latn', 'lug_Latn', 'luo_Latn', 'lus_Latn', 'mag_Deva', 'mai_Deva', 'mal_Mlym', 'mar_Deva', 'min_Latn', 'mkd_Cyrl', 'plt_Latn', 'mlt_Latn', 'mni_Beng', 'khk_Cyrl', 'mos_Latn', 'mri_Latn', 'zsm_Latn', 'mya_Mymr', 'nld_Latn', 'nno_Latn', 'nob_Latn', 'npi_Deva', 'nso_Latn', 'nus_Latn', 'nya_Latn', 'oci_Latn', 'gaz_Latn', 'ory_Orya', 'pag_Latn', 'pan_Guru', 'pap_Latn', 'pol_Latn', 'por_Latn', 'prs_Arab', 'pbt_Arab', 'quy_Latn', 'ron_Latn', 'run_Latn', 'rus_Cyrl', 'sag_Latn', 'san_Deva', 'sat_Beng', 'scn_Latn', 'shn_Mymr', 'sin_Sinh', 'slk_Latn', 'slv_Latn', 'smo_Latn', 'sna_Latn', 'snd_Arab', 'som_Latn', 'sot_Latn', 'spa_Latn', 'als_Latn', 'srd_Latn', 'srp_Cyrl', 'ssw_Latn', 'sun_Latn', 'swe_Latn', 'swh_Latn', 'szl_Latn', 'tam_Taml', 'tat_Cyrl', 'tel_Telu', 'tgk_Cyrl', 'tgl_Latn', 'tha_Thai', 'tir_Ethi', 'taq_Latn', 'taq_Tfng', 'tpi_Latn', 'tsn_Latn', 'tso_Latn', 'tuk_Latn', 'tum_Latn', 'tur_Latn', 'twi_Latn', 'tzm_Tfng', 'uig_Arab', 'ukr_Cyrl', 'umb_Latn', 'urd_Arab', 'uzn_Latn', 'vec_Latn', 'vie_Latn', 'war_Latn', 'wol_Latn', 'xho_Latn', 'ydd_Hebr', 'yor_Latn', 'yue_Hant', 'zho_Hans', 'zho_Hant', 'zul_Latn']  


class NllbTokenizer(PreTrainedTokenizer):
    

    vocab_files_names = VOCAB_FILES_NAMES
    max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
    pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
    model_input_names = ["input_ids", "attention_mask"]

    prefix_tokens: List[int] = []
    suffix_tokens: List[int] = []

    def __init__(
        self,
        vocab_file,
        bos_token="<s>",
        eos_token="</s>",
        sep_token="</s>",
        cls_token="<s>",
        unk_token="<unk>",
        pad_token="<pad>",
        mask_token="<mask>",
        tokenizer_file=None,
        src_lang=None,
        tgt_lang=None,
        sp_model_kwargs: Optional[Dict[str, Any]] = None,
        additional_special_tokens=None,
        legacy_behaviour=False,
        **kwargs,
    ):
        
        mask_token = (
            AddedToken(mask_token, normalized=True, lstrip=True, special=True)
            if isinstance(mask_token, str)
            else mask_token
        )

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

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

        
        self.fairseq_tokens_to_ids = {"<s>": 0, "<pad>": 1, "</s>": 2, "<unk>": 3}

        
        self.fairseq_offset = 1

        self.sp_model_size = len(self.sp_model)
        self.lang_code_to_id = {
            code: self.sp_model_size + i + self.fairseq_offset for i, code in enumerate(FAIRSEQ_LANGUAGE_CODES)
        }
        self.id_to_lang_code = {v: k for k, v in self.lang_code_to_id.items()}
        self.fairseq_tokens_to_ids["<mask>"] = len(self.sp_model) + len(self.lang_code_to_id) + self.fairseq_offset

        self.fairseq_tokens_to_ids.update(self.lang_code_to_id)
        self.fairseq_ids_to_tokens = {v: k for k, v in self.fairseq_tokens_to_ids.items()}

        self._src_lang = src_lang if src_lang is not None else "eng_Latn"
        self.cur_lang_code_id = self.lang_code_to_id[self._src_lang]

        _additional_special_tokens = list(self.lang_code_to_id.keys())

        if additional_special_tokens is not None:
            
            _additional_special_tokens.extend(
                [t for t in additional_special_tokens if t not in _additional_special_tokens]
            )

        super().__init__(
            bos_token=bos_token,
            eos_token=eos_token,
            unk_token=unk_token,
            sep_token=sep_token,
            cls_token=cls_token,
            pad_token=pad_token,
            mask_token=mask_token,
            tokenizer_file=tokenizer_file,
            src_lang=src_lang,
            tgt_lang=tgt_lang,
            additional_special_tokens=_additional_special_tokens,
            sp_model_kwargs=self.sp_model_kwargs,
            legacy_behaviour=legacy_behaviour,
            **kwargs,
        )

        self.tgt_lang = tgt_lang
        self.set_src_lang_special_tokens(self._src_lang)

    def __getstate__(self):
        state = self.__dict__.copy()
        state["sp_model"] = None
        state["sp_model_proto"] = self.sp_model.serialized_model_proto()
        return state

    def __setstate__(self, d):
        self.__dict__ = d

        
        if not hasattr(self, "sp_model_kwargs"):
            self.sp_model_kwargs = {}

        self.sp_model = spm.SentencePieceProcessor(**self.sp_model_kwargs)
        self.sp_model.LoadFromSerializedProto(self.sp_model_proto)

    @property
    def vocab_size(self):
        return len(self.sp_model) + len(self.lang_code_to_id) + self.fairseq_offset + 1  

    @property
    def src_lang(self) -> str:
        return self._src_lang

    @src_lang.setter
    def src_lang(self, new_src_lang: str) -> None:
        self._src_lang = new_src_lang
        self.set_src_lang_special_tokens(self._src_lang)

    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]:
        

        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
            )

        prefix_ones = [1] * len(self.prefix_tokens)
        suffix_ones = [1] * len(self.suffix_tokens)
        if token_ids_1 is None:
            return prefix_ones + ([0] * len(token_ids_0)) + suffix_ones
        return prefix_ones + ([0] * len(token_ids_0)) + ([0] * len(token_ids_1)) + suffix_ones

    def build_inputs_with_special_tokens(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
    ) -> List[int]:
        
        if token_ids_1 is None:
            return self.prefix_tokens + token_ids_0 + self.suffix_tokens
        
        return self.prefix_tokens + token_ids_0 + token_ids_1 + self.suffix_tokens

    def create_token_type_ids_from_sequences(
        self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
    ) -> List[int]:
        

        sep = [self.sep_token_id]
        cls = [self.cls_token_id]

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

    def _build_translation_inputs(
        self, raw_inputs, return_tensors: str, src_lang: Optional[str], tgt_lang: Optional[str], **extra_kwargs
    ):
        
        if src_lang is None or tgt_lang is None:
            raise ValueError("Translation requires a `src_lang` and a `tgt_lang` for this model")
        self.src_lang = src_lang
        inputs = self(raw_inputs, add_special_tokens=True, return_tensors=return_tensors, **extra_kwargs)
        tgt_lang_id = self.convert_tokens_to_ids(tgt_lang)
        inputs["forced_bos_token_id"] = tgt_lang_id
        return inputs

    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

    def _tokenize(self, text: str) -> List[str]:
        return self.sp_model.encode(text, out_type=str)

    def _convert_token_to_id(self, token):
        
        if token in self.fairseq_tokens_to_ids:
            return self.fairseq_tokens_to_ids[token]
        spm_id = self.sp_model.PieceToId(token)

        
        return spm_id + self.fairseq_offset if spm_id else self.unk_token_id

    def _convert_id_to_token(self, index):
        
        if index in self.fairseq_ids_to_tokens:
            return self.fairseq_ids_to_tokens[index]
        return self.sp_model.IdToPiece(index - self.fairseq_offset)

    def convert_tokens_to_string(self, tokens):
        
        out_string = "".join(tokens).replace(SPIECE_UNDERLINE, " ").strip()
        return out_string

    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 prepare_seq2seq_batch(
        self,
        src_texts: List[str],
        src_lang: str = "eng_Latn",
        tgt_texts: Optional[List[str]] = None,
        tgt_lang: str = "fra_Latn",
        **kwargs,
    ) -> BatchEncoding:
        self.src_lang = src_lang
        self.tgt_lang = tgt_lang
        return super().prepare_seq2seq_batch(src_texts, tgt_texts, **kwargs)

    def _switch_to_input_mode(self):
        return self.set_src_lang_special_tokens(self.src_lang)

    def _switch_to_target_mode(self):
        return self.set_tgt_lang_special_tokens(self.tgt_lang)

    def set_src_lang_special_tokens(self, src_lang) -> None:
        
        self.cur_lang_code = self.lang_code_to_id[src_lang]
        if self.legacy_behaviour:
            self.prefix_tokens = []
            self.suffix_tokens = [self.eos_token_id, self.cur_lang_code]
        else:
            self.prefix_tokens = [self.cur_lang_code]
            self.suffix_tokens = [self.eos_token_id]

    def set_tgt_lang_special_tokens(self, lang: str) -> None:
        
        self.cur_lang_code = self.lang_code_to_id[lang]
        if self.legacy_behaviour:
            self.prefix_tokens = []
            self.suffix_tokens = [self.eos_token_id, self.cur_lang_code]
        else:
            self.prefix_tokens = [self.cur_lang_code]
            self.suffix_tokens = [self.eos_token_id]