# Source code for rdflib.parser

    """
    Parser plugin interface.

    This module defines the parser plugin interface and contains other
    related parser support code.

    The module is mainly useful for those wanting to write a parser that
    can plugin to rdflib. If you are wanting to invoke a parser you likely
    want to do so through the Graph class parse method.

    """

    import codecs
    import os
    import pathlib
    import sys

    from io import BytesIO, TextIOBase, TextIOWrapper, StringIO, BufferedIOBase
    from typing import Any, Dict, Optional, Union

    from urllib.request import Request
    from urllib.request import url2pathname
    from urllib.request import urlopen
    from urllib.error import HTTPError

    from xml.sax import xmlreader

    from rdflib import __version__
    from rdflib.term import URIRef
    from rdflib.namespace import Namespace

    __all__ = [
        "Parser",
        "InputSource",
        "StringInputSource",
        "URLInputSource",
        "FileInputSource",
        "PythonInputSource",
    ]

    class Parser(object):
        __slots__ = ()

        def __init__(self):
            pass

        def parse(self, source, sink):
            pass

    class BytesIOWrapper(BufferedIOBase):
        __slots__ = ("wrapped", "encoded", "encoding")

        def __init__(self, wrapped: str, encoding="utf-8"):
            super(BytesIOWrapper, self).__init__()
            self.wrapped = wrapped
            self.encoding = encoding
            self.encoded = None

        def read(self, *args, **kwargs):
            if self.encoded is None:
                b, blen = codecs.getencoder(self.encoding)(self.wrapped)
                self.encoded = BytesIO(b)
            return self.encoded.read(*args, **kwargs)

        def read1(self, *args, **kwargs):
            if self.encoded is None:
                b = codecs.getencoder(self.encoding)(self.wrapped)
                self.encoded = BytesIO(b)
            return self.encoded.read1(*args, **kwargs)

        def readinto(self, *args, **kwargs):
            raise NotImplementedError()

        def readinto1(self, *args, **kwargs):
            raise NotImplementedError()

        def write(self, *args, **kwargs):
            raise NotImplementedError()

    class InputSource(xmlreader.InputSource, object):
        """
        TODO:
        """

        def __init__(self, system_id=None):
            xmlreader.InputSource.__init__(self, system_id=system_id)
            self.content_type = None
            self.auto_close = False  # see Graph.parse(), true if opened by us

        def close(self):
            c = self.getCharacterStream()
            if c and hasattr(c, "close"):
                try:
                    c.close()
                except Exception:
                    pass
            f = self.getByteStream()
            if f and hasattr(f, "close"):
                try:
                    f.close()
                except Exception:
                    pass

    class PythonInputSource(InputSource):
        """
        Constructs an RDFLib Parser InputSource from a Python data structure,
        for example, loaded from JSON with json.load or json.loads:

        >>> import json
        >>> as_string = \"\"\"{
        ...   "@context" : {"ex" : "http://example.com/ns#"},
        ...   "@graph": [{"@type": "ex:item", "@id": "#example"}]
        ... }\"\"\"
        >>> as_python = json.loads(as_string)
        >>> source = create_input_source(data=as_python)
        >>> isinstance(source, PythonInputSource)
        True
        """

        def __init__(self, data, system_id=None):
            self.content_type = None
            self.auto_close = False  # see Graph.parse(), true if opened by us
            self.public_id = None
            self.system_id = system_id
            self.data = data

        def getPublicId(self):
            return self.public_id

        def setPublicId(self, public_id):
            self.public_id = public_id

        def getSystemId(self):
            return self.system_id

        def setSystemId(self, system_id):
            self.system_id = system_id

        def close(self):
            self.data = None

    class StringInputSource(InputSource):
        """
        Constructs an RDFLib Parser InputSource from a Python String or Bytes
        """

        def __init__(self, value, encoding="utf-8", system_id=None):
            super(StringInputSource, self).__init__(system_id)
            if isinstance(value, str):
                stream = StringIO(value)
                self.setCharacterStream(stream)
                self.setEncoding(encoding)
                b_stream = BytesIOWrapper(value, encoding)
                self.setByteStream(b_stream)
            else:
                stream = BytesIO(value)
                self.setByteStream(stream)
                c_stream = TextIOWrapper(stream, encoding)
                self.setCharacterStream(c_stream)
                self.setEncoding(c_stream.encoding)

    headers = {
        "User-agent": "rdflib-%s (http://rdflib.net/; eikeon@eikeon.com)" % __version__
    }

    class URLInputSource(InputSource):
        """
        TODO:
        """

        def __init__(self, system_id=None, format=None):
            super(URLInputSource, self).__init__(system_id)
            self.url = system_id

            # copy headers to change
            myheaders = dict(headers)
            if format == "application/rdf+xml":
                myheaders["Accept"] = "application/rdf+xml, */*;q=0.1"
            elif format == "n3":
                myheaders["Accept"] = "text/n3, */*;q=0.1"
            elif format == "turtle":
                myheaders["Accept"] = "text/turtle,application/x-turtle, */*;q=0.1"
            elif format == "nt":
                myheaders["Accept"] = "text/plain, */*;q=0.1"
            elif format == "json-ld":
                myheaders[
                    "Accept"
                ] = "application/ld+json, application/json;q=0.9, */*;q=0.1"
            else:
                myheaders["Accept"] = (
                    "application/rdf+xml,text/rdf+n3;q=0.9,"
                    + "application/xhtml+xml;q=0.5, */*;q=0.1"
                )

            req = Request(system_id, None, myheaders)

            def _urlopen(req: Request):
                try:
                    return urlopen(req)
                except HTTPError as ex:
                    # 308 (Permanent Redirect) is not supported by current python version(s)
                    # See https://bugs.python.org/issue40321
                    # This custom error handling should be removed once all
                    # supported versions of python support 308.
                    if ex.code == 308:
                        req.full_url = ex.headers.get("Location")
                        return _urlopen(req)
                    else:
                        raise

            file = _urlopen(req)
            # Fix for issue 130 https://github.com/RDFLib/rdflib/issues/130
            self.url = file.geturl()  # in case redirections took place
            self.setPublicId(self.url)
            self.content_type = file.info().get("content-type")
            if self.content_type is not None:
                self.content_type = self.content_type.split(";", 1)[0]
            self.setByteStream(file)
            # TODO: self.setEncoding(encoding)
            self.response_info = file.info()  # a mimetools.Message instance

        def __repr__(self):
            return self.url

    class FileInputSource(InputSource):

        def __init__(self, file):
            base = pathlib.Path.cwd().as_uri()
            system_id = URIRef(pathlib.Path(file.name).absolute().as_uri(), base=base)
            super(FileInputSource, self).__init__(system_id)
            self.file = file
            if isinstance(file, TextIOBase):  # Python3 unicode fp
                self.setCharacterStream(file)
                self.setEncoding(file.encoding)
                try:
                    b = file.buffer
                    self.setByteStream(b)
                except (AttributeError, LookupError):
                    self.setByteStream(file)
            else:
                self.setByteStream(file)

                # We cannot set characterStream here because
                # we do not know the Raw Bytes File encoding.

        def __repr__(self):
            return repr(self.file)

    def create_input_source(
        source=None,
        publicID=None,
        location=None,
        file=None,
        data: Optional[Union[str, bytes, bytearray, Dict[Any, Any]]] = None,
        format=None,
    ):
        """
        Return an appropriate InputSource instance for the given
        parameters.
        """

        # test that exactly one of source, location, file, and data is not None.
        non_empty_arguments = list(
            filter(
                lambda v: v is not None,
                [source, location, file, data],
            )
        )

        if len(non_empty_arguments) != 1:
            raise ValueError(
                "exactly one of source, location, file or data must be given",
            )

        input_source = None

        if source is not None:
            if isinstance(source, InputSource):
                input_source = source
            else:
                if isinstance(source, str):
                    location = source
                elif isinstance(source, pathlib.PurePath):
                    location = str(source)
                elif isinstance(source, bytes):
                    data = source
                elif hasattr(source, "read") and not isinstance(source, Namespace):
                    f = source
                    input_source = InputSource()
                    if hasattr(source, "encoding"):
                        input_source.setCharacterStream(source)
                        input_source.setEncoding(source.encoding)
                        try:
                            b = file.buffer
                            input_source.setByteStream(b)
                        except (AttributeError, LookupError):
                            input_source.setByteStream(source)
                    else:
                        input_source.setByteStream(f)
                    if f is sys.stdin:
                        input_source.setSystemId("file:///dev/stdin")
                    elif hasattr(f, "name"):
                        input_source.setSystemId(f.name)
                else:
                    raise Exception(
                        "Unexpected type '%s' for source '%s'" % (type(source), source)
                    )

        absolute_location = None  # Further to fix for issue 130

        auto_close = False  # make sure we close all file handles we open

        if location is not None:
            (
                absolute_location,
                auto_close,
                file,
                input_source,
            ) = _create_input_source_from_location(
                file=file,
                format=format,
                input_source=input_source,
                location=location,
            )

        if file is not None:
            input_source = FileInputSource(file)

        if data is not None:
            if isinstance(data, dict):
                input_source = PythonInputSource(data)
                auto_close = True
            elif isinstance(data, (str, bytes, bytearray)):
                input_source = StringInputSource(data)
                auto_close = True
            else:
                raise RuntimeError(f"parse data can only str, or bytes. not: {type(data)}")

        if input_source is None:
            raise Exception("could not create InputSource")
        else:
            input_source.auto_close |= auto_close
            if publicID is not None:  # Further to fix for issue 130
                input_source.setPublicId(publicID)
            # Further to fix for issue 130
            elif input_source.getPublicId() is None:
                input_source.setPublicId(absolute_location or "")
            return input_source

    def _create_input_source_from_location(file, format, input_source, location):
        # Fix for Windows problem https://github.com/RDFLib/rdflib/issues/145 and
        # https://github.com/RDFLib/rdflib/issues/1430
        # NOTE: using pathlib.Path.exists on a URL fails on windows as it is not a
        # valid path. However os.path.exists() returns false for a URL on windows
        # which is why it is being used instead.
        if os.path.exists(location):
            location = pathlib.Path(location).absolute().as_uri()

        base = pathlib.Path.cwd().as_uri()

        absolute_location = URIRef(location, base=base)

        if absolute_location.startswith("file:///"):
            filename = url2pathname(absolute_location.replace("file:///", "/"))
            file = open(filename, "rb")
        else:
            input_source = URLInputSource(absolute_location, format)

        auto_close = True
        # publicID = publicID or absolute_location  # Further to fix
        # for issue 130

        return absolute_location, auto_close, file, input_source