# Source code for itemadapter.utils

    import warnings

    from types import MappingProxyType
    from typing import Any

    from itemadapter._imports import attr, pydantic

    __all__ = ["is_item", "get_field_meta_from_class"]

    def _is_attrs_class(obj: Any) -> bool:
        if attr is None:
            return False
        return attr.has(obj)

    def _is_pydantic_model(obj: Any) -> bool:
        if pydantic is None:
            return False
        return issubclass(obj, pydantic.BaseModel)

    def _get_pydantic_model_metadata(item_model: Any, field_name: str) -> MappingProxyType:
        metadata = {}
        field = item_model.__fields__[field_name].field_info

        for attribute in [
            "alias",
            "title",
            "description",
            "const",
            "gt",
            "ge",
            "lt",
            "le",
            "multiple_of",
            "min_items",
            "max_items",
            "min_length",
            "max_length",
            "regex",
        ]:
            value = getattr(field, attribute)
            if value is not None:
                metadata[attribute] = value
        if not field.allow_mutation:
            metadata["allow_mutation"] = field.allow_mutation
        metadata.update(field.extra)

        return MappingProxyType(metadata)

    def is_item(obj: Any) -> bool:
        """Return True if the given object belongs to one of the supported types, False otherwise.

        Alias for ItemAdapter.is_item
        """
        from itemadapter.adapter import ItemAdapter

        return ItemAdapter.is_item(obj)

    def get_field_meta_from_class(item_class: type, field_name: str) -> MappingProxyType:
        """Return a read-only mapping with metadata for the given field name, within the given
        item class. If there is no metadata for the field, or the item class does not support
        field metadata, an empty object is returned.

        Field metadata is taken from different sources, depending on the item type:
        * scrapy.item.Item: corresponding scrapy.item.Field object
        * dataclass items: "metadata" attribute for the corresponding field
        * attrs items: "metadata" attribute for the corresponding field
        * pydantic models: corresponding pydantic.field.FieldInfo/ModelField object

        The returned value is an instance of types.MappingProxyType, i.e. a dynamic read-only view
        of the original mapping, which gets automatically updated if the original mapping changes.
        """

        from itemadapter.adapter import ItemAdapter

        return ItemAdapter.get_field_meta_from_class(item_class, field_name)

    # deprecated

    def is_dataclass_instance(obj: Any) -> bool:
        warnings.warn(
            "itemadapter.utils.is_dataclass_instance is deprecated"
            " and it will be removed in a future version",
            category=DeprecationWarning,
            stacklevel=2,
        )
        from itemadapter.adapter import DataclassAdapter

        return DataclassAdapter.is_item(obj)

    def is_attrs_instance(obj: Any) -> bool:
        warnings.warn(
            "itemadapter.utils.is_attrs_instance is deprecated"
            " and it will be removed in a future version",
            category=DeprecationWarning,
            stacklevel=2,
        )
        from itemadapter.adapter import AttrsAdapter

        return AttrsAdapter.is_item(obj)

    def is_pydantic_instance(obj: Any) -> bool:
        warnings.warn(
            "itemadapter.utils.is_pydantic_instance is deprecated"
            " and it will be removed in a future version",
            category=DeprecationWarning,
            stacklevel=2,
        )
        from itemadapter.adapter import PydanticAdapter

        return PydanticAdapter.is_item(obj)

    def is_scrapy_item(obj: Any) -> bool:
        warnings.warn(
            "itemadapter.utils.is_scrapy_item is deprecated"
            " and it will be removed in a future version",
            category=DeprecationWarning,
            stacklevel=2,
        )
        from itemadapter.adapter import ScrapyItemAdapter

        return ScrapyItemAdapter.is_item(obj)