Struct wiggle::UnsafeGuestSlice

pub struct UnsafeGuestSlice<'a, T> { /* private fields */ }

A smart pointer to an unsafe slice in guest memory.

Accessing guest memory (e.g., WebAssembly linear memory) is inherently unsafe. Even though this structure expects that we will have validated the addresses, lengths, and alignment, we must be extra careful to maintain the Rust borrowing guarantees if we hand out slices to the underlying memory. This is done in two ways:

• with shared memory (i.e., memory that may be accessed concurrently by multiple threads), we have no guarantee that the underlying data will not be changed; thus, we can only hand out slices unsafe-ly (TODO: eventually with UnsafeGuestSlice::as_slice, UnsafeGuestSlice::as_slice_mut)
• with non-shared memory, we can maintain the Rust slice guarantees, but only by manually performing borrow-checking of the underlying regions that are accessed; this kind of borrowing is wrapped up in the GuestSlice and GuestSliceMut smart pointers (see UnsafeGuestSlice::shared_borrow, UnsafeGuestSlice::mut_borrow).

Implementations

impl<'a, T> UnsafeGuestSlice<'a, T>

pub fn copy_from_slice(self, slice: &[T]) -> Result<(), GuestError>

where T: GuestTypeTransparent<'a> + Copy + 'a,

See GuestPtr::copy_from_slice.

pub fn len(&self) -> usize

Return the number of items in this slice.

pub fn is_shared_memory(&self) -> bool

Check if this slice comes from WebAssembly shared memory.

pub fn as_slice_mut(self) -> Result<Option<GuestSliceMut<'a, T>>, GuestError>

where T: GuestTypeTransparent<'a>,

See GuestPtr::as_slice_mut.

Trait Implementations

impl<T: Send> Send for UnsafeGuestSlice<'_, T>

impl<T: Sync> Sync for UnsafeGuestSlice<'_, T>