Struct wasmtime::ExternRef

pub struct ExternRef { /* private fields */ }

Available on crate feature runtime only.

Represents an opaque reference to any data within WebAssembly.

Implementations

impl ExternRef

pub fn new<T>(value: T) -> ExternRef

where T: 'static + Any + Send + Sync,

Creates a new instance of ExternRef wrapping the given value.

pub fn data(&self) -> &dyn Any

Get the underlying data for this ExternRef.

pub fn strong_count(&self) -> usize

Get the strong reference count for this ExternRef.

Note that this loads the reference count with a SeqCst ordering to synchronize with other threads.

pub fn ptr_eq(&self, other: &ExternRef) -> bool

Does this ExternRef point to the same inner value as other?

This is only pointer equality, and does not run any inner value’s Eq implementation.

pub unsafe fn from_raw(raw: *mut c_void) -> Option<ExternRef>

Creates a new strongly-owned ExternRef from the raw value provided.

This is intended to be used in conjunction with Func::new_unchecked, Func::call_unchecked, and ValRaw with its externref field.

This function assumes that raw is an externref value which is currently rooted within the Store.

Unsafety

This function is particularly unsafe because raw not only must be a valid externref value produced prior by to_raw but it must also be correctly rooted within the store. When arguments are provided to a callback with Func::new_unchecked, for example, or returned via Func::call_unchecked, if a GC is performed within the store then floating externref values are not rooted and will be GC’d, meaning that this function will no longer be safe to call with the values cleaned up. This function must be invoked before possible GC operations can happen (such as calling wasm).

When in doubt try to not use this. Instead use the safe Rust APIs of TypedFunc and friends.

pub unsafe fn to_raw(&self, store: impl AsContextMut) -> *mut c_void

Converts this ExternRef to a raw value suitable to store within a ValRaw.

Unsafety

Produces a raw value which is only safe to pass into a store if a GC doesn’t happen between when the value is produce and when it’s passed into the store.

Trait Implementations

impl Clone for ExternRef

fn clone(&self) -> ExternRef

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExternRef

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<ExternRef> for Ref

fn from(e: ExternRef) -> Ref

Converts to this type from the input type.

impl From<ExternRef> for Val

fn from(val: ExternRef) -> Val

Converts to this type from the input type.

impl Pointer for ExternRef

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl WasmTy for ExternRef