pub struct Caller<'a, T> { /* private fields */ }
Expand description
A structure representing the caller’s context when creating a function
via Func::wrap
.
This structure can be taken as the first parameter of a closure passed to
Func::wrap
or other constructors, and serves two purposes:
-
First consumers can use
Caller<'_, T>
to get access toStoreContextMut<'_, T>
and/or get access toT
itself. This means that theCaller
type can serve as a proxy to the originalStore
itself and is used to satisfyAsContext
andAsContextMut
bounds. -
Second a
Caller
can be used as the name implies, learning about the caller’s context, namely it’s exported memory and exported functions. This allows functions which take pointers as arguments to easily read the memory the pointers point into, or if a function is expected to call malloc in the wasm module to reserve space for the output you can do that.
Host functions which want access to Store
-level state are
recommended to use this type.
Implementations§
source§impl<T> Caller<'_, T>
impl<T> Caller<'_, T>
sourcepub fn get_export(&mut self, name: &str) -> Option<Extern>
pub fn get_export(&mut self, name: &str) -> Option<Extern>
Looks up an export from the caller’s module by the name
given.
This is a low-level function that’s typically used to implement passing of pointers or indices between core Wasm instances, where the callee needs to consult the caller’s exports to perform memory management and resolve the references.
For comparison, in components, the component model handles translating arguments from one component instance to another and managing memory, so that callees don’t need to be aware of their callers, which promotes virtualizability of APIs.
§Return
If an export with the name
provided was found, then it is returned as an
Extern
. There are a number of situations, however, where the export may not
be available:
- The caller instance may not have an export named
name
- There may not be a caller available, for example if
Func
was called directly from host code.
It’s recommended to take care when calling this API and gracefully
handling a None
return value.
sourcepub fn data(&self) -> &T
pub fn data(&self) -> &T
Access the underlying data owned by this Store
.
Same as Store::data
sourcepub fn data_mut(&mut self) -> &mut T
pub fn data_mut(&mut self) -> &mut T
Access the underlying data owned by this Store
.
Same as Store::data_mut
sourcepub async fn gc_async(&mut self)where
T: Send,
pub async fn gc_async(&mut self)where
T: Send,
Perform garbage collection asynchronously.
Same as Store::gc_async
.
sourcepub fn get_fuel(&self) -> Result<u64>
pub fn get_fuel(&self) -> Result<u64>
Returns the remaining fuel in the store.
For more information see Store::get_fuel
sourcepub fn set_fuel(&mut self, fuel: u64) -> Result<()>
pub fn set_fuel(&mut self, fuel: u64) -> Result<()>
Set the amount of fuel in this store to be consumed when executing wasm code.
For more information see Store::set_fuel
sourcepub fn fuel_async_yield_interval(&mut self, interval: Option<u64>) -> Result<()>
pub fn fuel_async_yield_interval(&mut self, interval: Option<u64>) -> Result<()>
Configures this Store
to yield while executing futures every N units of fuel.
For more information see
Store::fuel_async_yield_interval
Trait Implementations§
source§impl<T> AsContext for Caller<'_, T>
impl<T> AsContext for Caller<'_, T>
source§fn as_context(&self) -> StoreContext<'_, T>
fn as_context(&self) -> StoreContext<'_, T>
source§impl<T> AsContextMut for Caller<'_, T>
impl<T> AsContextMut for Caller<'_, T>
source§fn as_context_mut(&mut self) -> StoreContextMut<'_, T>
fn as_context_mut(&mut self) -> StoreContextMut<'_, T>
Auto Trait Implementations§
impl<'a, T> Freeze for Caller<'a, T>
impl<'a, T> !RefUnwindSafe for Caller<'a, T>
impl<'a, T> Send for Caller<'a, T>where
T: Send,
impl<'a, T> Sync for Caller<'a, T>where
T: Sync,
impl<'a, T> Unpin for Caller<'a, T>
impl<'a, T> !UnwindSafe for Caller<'a, T>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more