# Source code for rdflib.query

    from __future__ import annotations

    import itertools
    import types
    import warnings
    from io import BytesIO
    from typing import (
        IO,
        TYPE_CHECKING,
        Any,
        BinaryIO,
        Dict,
        Iterator,
        List,
        Mapping,
        MutableSequence,
        Optional,
        Tuple,
        Union,
        cast,
        overload,
    )
    from urllib.parse import urlparse
    from urllib.request import url2pathname

    __all__ = [
        "Processor",
        "UpdateProcessor",
        "Result",
        "ResultRow",
        "ResultParser",
        "ResultSerializer",
        "ResultException",
        "EncodeOnlyUnicode",
    ]

    import rdflib.term

    if TYPE_CHECKING:
        from rdflib.graph import Graph, _TripleType
        from rdflib.plugins.sparql.sparql import Query, Update
        from rdflib.term import Identifier, Variable

    class Processor:
        """
        Query plugin interface.

        This module is useful for those wanting to write a query processor
        that can plugin to rdf. If you are wanting to execute a query you
        likely want to do so through the Graph class query method.

        """

        def __init__(self, graph: Graph):
            pass

        # type error: Missing return statement

        def query(  # type: ignore[empty-body]
            self,
            strOrQuery: Union[str, Query],  # noqa: N803
            initBindings: Mapping[str, Identifier] = {},  # noqa: N803
            initNs: Mapping[str, Any] = {},  # noqa: N803
            DEBUG: bool = False,  # noqa: N803
        ) -> Mapping[str, Any]:
            pass

    class UpdateProcessor:
        """
        Update plugin interface.

        This module is useful for those wanting to write an update
        processor that can plugin to rdflib. If you are wanting to execute
        an update statement you likely want to do so through the Graph
        class update method.

        .. versionadded:: 4.0

        """

        def __init__(self, graph: Graph):
            pass

        def update(
            self,
            strOrQuery: Union[str, Update],  # noqa: N803
            initBindings: Mapping[str, Identifier] = {},  # noqa: N803
            initNs: Mapping[str, Any] = {},  # noqa: N803
        ) -> None:
            pass

    class ResultException(Exception):  # noqa: N818
        pass

    class EncodeOnlyUnicode:
        """
        This is a crappy work-around for
        http://bugs.python.org/issue11649

        """

        def __init__(self, stream: BinaryIO):
            self.__stream = stream

        def write(self, arg):
            if isinstance(arg, str):
                self.__stream.write(arg.encode("utf-8"))
            else:
                self.__stream.write(arg)

        def __getattr__(self, name: str) -> Any:
            return getattr(self.__stream, name)

    class ResultRow(Tuple[rdflib.term.Identifier, ...]):
        """
        a single result row
        allows accessing bindings as attributes or with []

        >>> from rdflib import URIRef, Variable
        >>> rr=ResultRow({ Variable('a'): URIRef('urn:cake') }, [Variable('a')])

        >>> rr[0]
        rdflib.term.URIRef('urn:cake')
        >>> rr[1]
        Traceback (most recent call last):
            ...
        IndexError: tuple index out of range

        >>> rr.a
        rdflib.term.URIRef('urn:cake')
        >>> rr.b
        Traceback (most recent call last):
            ...
        AttributeError: b

        >>> rr['a']
        rdflib.term.URIRef('urn:cake')
        >>> rr['b']
        Traceback (most recent call last):
            ...
        KeyError: 'b'

        >>> rr[Variable('a')]
        rdflib.term.URIRef('urn:cake')

        .. versionadded:: 4.0

        """

        labels: Mapping[str, int]

        def __new__(cls, values: Mapping[Variable, Identifier], labels: List[Variable]):
            # type error: Value of type variable "Self" of "__new__" of "tuple" cannot be "ResultRow"  [type-var]
            # type error: Generator has incompatible item type "Optional[Identifier]"; expected "_T_co"  [misc]
            instance = super(ResultRow, cls).__new__(cls, (values.get(v) for v in labels))  # type: ignore[type-var, misc, unused-ignore]
            instance.labels = dict((str(x[1]), x[0]) for x in enumerate(labels))
            return instance

        def __getattr__(self, name: str) -> Identifier:
            if name not in self.labels:
                raise AttributeError(name)
            return tuple.__getitem__(self, self.labels[name])

        # type error: Signature of "__getitem__" incompatible with supertype "tuple"
        # type error: Signature of "__getitem__" incompatible with supertype "Sequence"

        def __getitem__(self, name: Union[str, int, Any]) -> Identifier:  # type: ignore[override]
            try:
                # type error: Invalid index type "Union[str, int, Any]" for "tuple"; expected type "int"
                return tuple.__getitem__(self, name)  # type: ignore[index]
            except TypeError:
                if name in self.labels:
                    # type error: Invalid index type "Union[str, int, slice, Any]" for "Mapping[str, int]"; expected type "str"
                    return tuple.__getitem__(self, self.labels[name])  # type: ignore[index]
                if str(name) in self.labels:  # passing in variable object
                    return tuple.__getitem__(self, self.labels[str(name)])
                raise KeyError(name)

        @overload
        def get(self, name: str, default: Identifier) -> Identifier: ...

        @overload
        def get(
            self, name: str, default: Optional[Identifier] = ...
        ) -> Optional[Identifier]: ...

        def get(
            self, name: str, default: Optional[Identifier] = None
        ) -> Optional[Identifier]:
            try:
                return self[name]
            except KeyError:
                return default

        def asdict(self) -> Dict[str, Identifier]:
            return dict((v, self[v]) for v in self.labels if self[v] is not None)

    class Result:
        """
        A common class for representing query result.

        There is a bit of magic here that makes this appear like different
        Python objects, depending on the type of result.

        If the type is "SELECT", iterating will yield lists of ResultRow objects

        If the type is "ASK", iterating will yield a single bool (or
        bool(result) will return the same bool)

        If the type is "CONSTRUCT" or "DESCRIBE" iterating will yield the
        triples.

        len(result) also works.

        """

        def __init__(self, type_: str):
            if type_ not in ("CONSTRUCT", "DESCRIBE", "SELECT", "ASK"):
                raise ResultException("Unknown Result type: %s" % type_)

            self.type = type_
            #: variables contained in the result.
            self.vars: Optional[List[Variable]] = None
            self._bindings: MutableSequence[Mapping[Variable, Identifier]] = None  # type: ignore[assignment]
            self._genbindings: Optional[Iterator[Mapping[Variable, Identifier]]] = None
            self.askAnswer: Optional[bool] = None
            self.graph: Optional[Graph] = None

        @property
        def bindings(self) -> MutableSequence[Mapping[Variable, Identifier]]:
            """
            a list of variable bindings as dicts
            """
            if self._genbindings:
                self._bindings += list(self._genbindings)
                self._genbindings = None

            return self._bindings

        @bindings.setter
        def bindings(
            self,
            b: Union[
                MutableSequence[Mapping[Variable, Identifier]],
                Iterator[Mapping[Variable, Identifier]],
            ],
        ) -> None:
            if isinstance(b, (types.GeneratorType, itertools.islice)):
                self._genbindings = b
                self._bindings = []
            else:
                # type error: Incompatible types in assignment (expression has type "Union[MutableSequence[Mapping[Variable, Identifier]], Iterator[Mapping[Variable, Identifier]]]", variable has type "MutableSequence[Mapping[Variable, Identifier]]")
                self._bindings = b  # type: ignore[assignment]

        @staticmethod
        def parse(
            source: Optional[IO] = None,
            format: Optional[str] = None,
            content_type: Optional[str] = None,
            **kwargs: Any,
        ) -> Result:
            from rdflib import plugin

            if format:
                plugin_key = format
            elif content_type:
                plugin_key = content_type.split(";", 1)[0]
            else:
                plugin_key = "xml"

            parser = plugin.get(plugin_key, ResultParser)()

            # type error: Argument 1 to "parse" of "ResultParser" has incompatible type "Optional[IO[Any]]"; expected "IO[Any]"
            return parser.parse(
                source, content_type=content_type, **kwargs  # type:ignore[arg-type]
            )

        def serialize(
            self,
            destination: Optional[Union[str, IO]] = None,
            encoding: str = "utf-8",
            format: str = "xml",
            **args: Any,
        ) -> Optional[bytes]:
            """
            Serialize the query result.

            The :code:`format` argument determines the Serializer class to use.

            - csv: :class:`~rdflib.plugins.sparql.results.csvresults.CSVResultSerializer`
            - json: :class:`~rdflib.plugins.sparql.results.jsonresults.JSONResultSerializer`
            - txt: :class:`~rdflib.plugins.sparql.results.txtresults.TXTResultSerializer`
            - xml: :class:`~rdflib.plugins.sparql.results.xmlresults.XMLResultSerializer`

            :param destination: Path of file output or BufferedIOBase object to write the output to.
            :param encoding: Encoding of output.
            :param format: One of ['csv', 'json', 'txt', xml']
            :param args:
            :return: bytes
            """
            if self.type in ("CONSTRUCT", "DESCRIBE"):
                # type error: Item "None" of "Optional[Graph]" has no attribute "serialize"
                # type error: Incompatible return value type (got "Union[bytes, str, Graph, Any]", expected "Optional[bytes]")
                return self.graph.serialize(  # type: ignore[union-attr,return-value]
                    destination, encoding=encoding, format=format, **args
                )

            """stolen wholesale from graph.serialize"""
            from rdflib import plugin

            serializer = plugin.get(format, ResultSerializer)(self)
            if destination is None:
                streamb: BytesIO = BytesIO()
                stream2 = EncodeOnlyUnicode(streamb)  # TODO: Remove the need for this
                # TODO: All QueryResult serializers should write to a Bytes Stream.
                # type error: Argument 1 to "serialize" of "ResultSerializer" has incompatible type "EncodeOnlyUnicode"; expected "IO[Any]"
                serializer.serialize(stream2, encoding=encoding, **args)  # type: ignore[arg-type]
                return streamb.getvalue()
            if hasattr(destination, "write"):
                stream = cast(IO[bytes], destination)
                serializer.serialize(stream, encoding=encoding, **args)
            else:
                location = cast(str, destination)
                scheme, netloc, path, params, query, fragment = urlparse(location)
                if scheme == "file":
                    if netloc != "":
                        raise ValueError(
                            f"the file URI {location!r} has an authority component which is not supported"
                        )
                    os_path = url2pathname(path)
                else:
                    os_path = location
                with open(os_path, "wb") as stream:
                    serializer.serialize(stream, encoding=encoding, **args)
            return None

        def __len__(self) -> int:
            if self.type == "ASK":
                return 1
            elif self.type == "SELECT":
                return len(self.bindings)
            else:
                # type error: Argument 1 to "len" has incompatible type "Optional[Graph]"; expected "Sized"
                return len(self.graph)  # type: ignore[arg-type]

        def __bool__(self) -> bool:
            if self.type == "ASK":
                # type error: Incompatible return value type (got "Optional[bool]", expected "bool")
                return self.askAnswer  # type: ignore[return-value]
            else:
                return len(self) > 0

        def __iter__(
            self,
        ) -> Iterator[Union[_TripleType, bool, ResultRow]]:
            if self.type in ("CONSTRUCT", "DESCRIBE"):
                # type error: Item "None" of "Optional[Graph]" has no attribute "__iter__" (not iterable)
                for t in self.graph:  # type: ignore[union-attr]
                    yield t
            elif self.type == "ASK":
                # type error: Incompatible types in "yield" (actual type "Optional[bool]", expected type "Union[Tuple[Identifier, Identifier, Identifier], bool, ResultRow]")  [misc]
                yield self.askAnswer  # type: ignore[misc]
            elif self.type == "SELECT":
                # this iterates over ResultRows of variable bindings

                if self._genbindings:
                    for b in self._genbindings:
                        if b:  # don't add a result row in case of empty binding {}
                            self._bindings.append(b)
                            # type error: Argument 2 to "ResultRow" has incompatible type "Optional[List[Variable]]"; expected "List[Variable]"
                            yield ResultRow(b, self.vars)  # type: ignore[arg-type]
                    self._genbindings = None
                else:
                    for b in self._bindings:
                        if b:  # don't add a result row in case of empty binding {}
                            # type error: Argument 2 to "ResultRow" has incompatible type "Optional[List[Variable]]"; expected "List[Variable]"
                            yield ResultRow(b, self.vars)  # type: ignore[arg-type]

        def __getattr__(self, name: str) -> Any:
            if self.type in ("CONSTRUCT", "DESCRIBE") and self.graph is not None:
                # type error: "Graph" has no attribute "__getattr__"
                return self.graph.__getattr__(self, name)  # type: ignore[attr-defined]
            elif self.type == "SELECT" and name == "result":
                warnings.warn(
                    "accessing the 'result' attribute is deprecated."
                    " Iterate over the object instead.",
                    DeprecationWarning,
                    stacklevel=2,
                )
                # copied from __iter__, above
                # type error: Item "None" of "Optional[List[Variable]]" has no attribute "__iter__" (not iterable)
                return [(tuple(b[v] for v in self.vars)) for b in self.bindings]  # type: ignore[union-attr]
            else:
                raise AttributeError("'%s' object has no attribute '%s'" % (self, name))

        def __eq__(self, other: Any) -> bool:
            try:
                if self.type != other.type:
                    return False
                if self.type == "ASK":
                    return self.askAnswer == other.askAnswer
                elif self.type == "SELECT":
                    return self.vars == other.vars and self.bindings == other.bindings
                else:
                    return self.graph == other.graph
            except Exception:
                return False

    class ResultParser:

        def __init__(self):
            pass

        # type error: Missing return statement

        def parse(self, source: IO, **kwargs: Any) -> Result:  # type: ignore[empty-body]
            """return a Result object"""
            pass  # abstract

    class ResultSerializer:

        def __init__(self, result: Result):
            self.result = result

        def serialize(self, stream: IO, encoding: str = "utf-8", **kwargs: Any) -> None:
            """return a string properly serialized"""
            pass  # abstract