codec.py

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from .core import encode, decode, alabel, ulabel, IDNAError
import codecs
import re
from typing import Tuple, Optional
 
_unicode_dots_re = re.compile('[\u002e\u3002\uff0e\uff61]')
 
class Codec(codecs.Codec):
 
    def encode(self, data: str, errors: str = 'strict') -> Tuple[bytes, int]:
        if errors != 'strict':
            raise IDNAError('Unsupported error handling \"{}\"'.format(errors))
 
        if not data:
            return b"", 0
 
        return encode(data), len(data)
 
    def decode(self, data: bytes, errors: str = 'strict') -> Tuple[str, int]:
        if errors != 'strict':
            raise IDNAError('Unsupported error handling \"{}\"'.format(errors))
 
        if not data:
            return '', 0
 
        return decode(data), len(data)
 
class IncrementalEncoder(codecs.BufferedIncrementalEncoder):
    def _buffer_encode(self, data: str, errors: str, final: bool) -> Tuple[str, int]:  # type: ignore
        if errors != 'strict':
            raise IDNAError('Unsupported error handling \"{}\"'.format(errors))
 
        if not data:
            return "", 0
 
        labels = _unicode_dots_re.split(data)
        trailing_dot = ''
        if labels:
            if not labels[-1]:
                trailing_dot = '.'
                del labels[-1]
            elif not final:
                # Keep potentially unfinished label until the next call
                del labels[-1]
                if labels:
                    trailing_dot = '.'
 
        result = []
        size = 0
        for label in labels:
            result.append(alabel(label))
            if size:
                size += 1
            size += len(label)
 
        # Join with U+002E
        result_str = '.'.join(result) + trailing_dot  # type: ignore
        size += len(trailing_dot)
        return result_str, size
 
class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
    def _buffer_decode(self, data: str, errors: str, final: bool) -> Tuple[str, int]:  # type: ignore
        if errors != 'strict':
            raise IDNAError('Unsupported error handling \"{}\"'.format(errors))
 
        if not data:
            return ('', 0)
 
        labels = _unicode_dots_re.split(data)
        trailing_dot = ''
        if labels:
            if not labels[-1]:
                trailing_dot = '.'
                del labels[-1]
            elif not final:
                # Keep potentially unfinished label until the next call
                del labels[-1]
                if labels:
                    trailing_dot = '.'
 
        result = []
        size = 0
        for label in labels:
            result.append(ulabel(label))
            if size:
                size += 1
            size += len(label)
 
        result_str = '.'.join(result) + trailing_dot
        size += len(trailing_dot)
        return (result_str, size)
 
 
class StreamWriter(Codec, codecs.StreamWriter):
    pass
 
 
class StreamReader(Codec, codecs.StreamReader):
    pass
 
 
def getregentry() -> codecs.CodecInfo:
    # Compatibility as a search_function for codecs.register()
    return codecs.CodecInfo(
        name='idna',
        encode=Codec().encode,  # type: ignore
        decode=Codec().decode,  # type: ignore
        incrementalencoder=IncrementalEncoder,
        incrementaldecoder=IncrementalDecoder,
        streamwriter=StreamWriter,
        streamreader=StreamReader,
    )