facet-rs / facet / 15085905564

use crate::FunctionPointerDef;

use super::Shape;

/// Describes all pointer types

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]

#[repr(C)]

pub enum PointerType<'shape> {

    /// Describees bound const and mut references (`&`/`&mut`)

    Reference(ValuePointerType<'shape>),

    /// Describes raw pointers

    ///

    /// Dereferencing invalid raw pointers may lead to undefined behavior

    Raw(ValuePointerType<'shape>),

    /// Describes function pointers

    Function(FunctionPointerDef),

}

/// Describes the raw/reference pointer

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]

#[repr(C)]

#[non_exhaustive]

pub struct ValuePointerType<'shape> {

    /// Is the pointer mutable or not.

    pub mutable: bool,

    /// Describes whether the pointer is wider or not

    ///

    /// Note: if the pointer is wide, then the `target` shape will have `ShapeLayout::Unsized`, and

    /// the vtables of the target shape will expect the pointer to _this_ pointer, rather than the

    /// resulting address of unsized data. This is because wide pointer's metadata information is

    /// an undefined implementation detail, at this current moment.

    ///

    /// See: <https://github.com/rust-lang/rust/issues/81513>

    pub wide: bool,

    /// Shape of the pointer's pointee

    ///

    /// This needs to be indirect (behind a function), in order to allow recursive types without

    /// overflowing the const-eval system.

    pub target: fn() -> &'shape Shape<'shape>,

}

impl<'shape> ValuePointerType<'shape> {

    /// Returns the shape of the pointer's pointee.

}