Trait abi_stable::pointer_trait::AsMutPtr

source ·

pub unsafe trait AsMutPtr: AsPtr {
    // Required method
    fn as_mut_ptr(&mut self) -> *mut Self::PtrTarget;

    // Provided method
    fn as_rmut(&mut self) -> RMut<'_, Self::PtrTarget> { ... }
}

Expand description

For getting a mutable raw pointer to the value that this points to.

§Safety

The implementor of this trait must return a pointer to the same data as DerefMut::deref_mut, without constructing a &mut Self::Target in as_mut_ptr (or any function it calls).

The implementor of this trait must not override the defaulted methods.

§Example

use abi_stable::{
    erased_types::interfaces::DEIteratorInterface,
    pointer_trait::{
        PK_MutReference,
        AsPtr, AsMutPtr, CanTransmuteElement, GetPointerKind, TransmuteElement,
    },
    sabi_types::RMut,
    DynTrait,
};

fn main() {
    let mut iter = 0..=5;
    let reff: DynTrait<QuxMut<()>, DEIteratorInterface<_>> =
        DynTrait::from_ptr(QuxMut::new(&mut iter)).interface(DEIteratorInterface::NEW);
     
    assert_eq!(reff.collect::<Vec<u32>>(), [0, 1, 2, 3, 4, 5]);

    assert_eq!(iter.next(), None);
}


#[derive(Debug)]
#[repr(transparent)]
struct QuxMut<'a, T>(RMut<'a, T>);

impl<'a, T> QuxMut<'a, T> {
    pub fn new(reff: &'a mut T) -> Self {
        Self(RMut::new(reff))
    }
}

unsafe impl<T> GetPointerKind for QuxMut<'_, T> {
    type PtrTarget = T;
    type Kind = PK_MutReference;
}

unsafe impl<'a, T: 'a, U: 'a> CanTransmuteElement<U> for QuxMut<'a, T> {
    type TransmutedPtr = QuxMut<'a, U>;
     
    unsafe fn transmute_element_(self) -> Self::TransmutedPtr {
        QuxMut(self.0.transmute_element_())
    }
}

unsafe impl<T> AsPtr for QuxMut<'_, T> {
    fn as_ptr(&self) -> *const T {
        self.0.as_ptr()
    }
}

unsafe impl<T> AsMutPtr for QuxMut<'_, T> {
    fn as_mut_ptr(&mut self) -> *mut T {
        self.0.as_mut_ptr()
    }
}