Struct Instance
pub struct Instance(/* private fields */);
Expand description
An instantiated component.
This type represents an instantiated Component
.
Instances have exports which can be accessed through functions such as
Instance::get_func
or Instance::get_export
. Instances are owned by a
Store
and all methods require a handle to the store.
Component instances are created through
Linker::instantiate
and its family of
methods.
This type is similar to the core wasm version
wasmtime::Instance
except that it represents an
instantiated component instead of an instantiated module.
Implementations§
§impl Instance
impl Instance
pub fn get_func(
&self,
store: impl AsContextMut,
name: impl InstanceExportLookup,
) -> Option<Func>
pub fn get_func( &self, store: impl AsContextMut, name: impl InstanceExportLookup, ) -> Option<Func>
Looks up an exported function by name within this Instance
.
The store
argument provided must be the store that this instance
lives within and the name
argument is the lookup key by which to find
the exported function. If the function is found then Some
is returned
and otherwise None
is returned.
The name
here can be a string such as &str
or it can be a
ComponentExportIndex
which is loaded prior from a Component
.
§Panics
Panics if store
does not own this instance.
§Examples
Looking up a function which is exported from the root of a component:
use wasmtime::{Engine, Store};
use wasmtime::component::{Component, Linker};
let engine = Engine::default();
let component = Component::new(
&engine,
r#"
(component
(core module $m
(func (export "f"))
)
(core instance $i (instantiate $m))
(func (export "f")
(canon lift (core func $i "f")))
)
"#,
)?;
// Look up the function by name
let mut store = Store::new(&engine, ());
let instance = Linker::new(&engine).instantiate(&mut store, &component)?;
let func = instance.get_func(&mut store, "f").unwrap();
// The function can also be looked up by an index via a precomputed index.
let (_, export) = component.export_index(None, "f").unwrap();
let func = instance.get_func(&mut store, &export).unwrap();
Looking up a function which is exported from a nested instance:
use wasmtime::{Engine, Store};
use wasmtime::component::{Component, Linker};
let engine = Engine::default();
let component = Component::new(
&engine,
r#"
(component
(core module $m
(func (export "f"))
)
(core instance $i (instantiate $m))
(func $f
(canon lift (core func $i "f")))
(instance $i
(export "f" (func $f)))
(export "i" (instance $i))
)
"#,
)?;
// First look up the exported instance, then use that to lookup the
// exported function.
let (_, instance_index) = component.export_index(None, "i").unwrap();
let (_, func_index) = component.export_index(Some(&instance_index), "f").unwrap();
// Then use `func_index` at runtime.
let mut store = Store::new(&engine, ());
let instance = Linker::new(&engine).instantiate(&mut store, &component)?;
let func = instance.get_func(&mut store, &func_index).unwrap();
// Alternatively the `instance` can be used directly in conjunction with
// the `get_export` method.
let instance_index = instance.get_export(&mut store, None, "i").unwrap();
let func_index = instance.get_export(&mut store, Some(&instance_index), "f").unwrap();
let func = instance.get_func(&mut store, &func_index).unwrap();
pub fn get_typed_func<Params, Results>(
&self,
store: impl AsContextMut,
name: impl InstanceExportLookup,
) -> Result<TypedFunc<Params, Results>, Error>
pub fn get_typed_func<Params, Results>( &self, store: impl AsContextMut, name: impl InstanceExportLookup, ) -> Result<TypedFunc<Params, Results>, Error>
Looks up an exported Func
value by name and with its type.
This function is a convenience wrapper over Instance::get_func
and
Func::typed
. For more information see the linked documentation.
Returns an error if name
isn’t a function export or if the export’s
type did not match Params
or Results
§Panics
Panics if store
does not own this instance.
pub fn get_module(
&self,
store: impl AsContextMut,
name: impl InstanceExportLookup,
) -> Option<Module>
pub fn get_module( &self, store: impl AsContextMut, name: impl InstanceExportLookup, ) -> Option<Module>
Looks up an exported module by name within this Instance
.
The store
argument provided must be the store that this instance
lives within and the name
argument is the lookup key by which to find
the exported module. If the module is found then Some
is returned
and otherwise None
is returned.
The name
here can be a string such as &str
or it can be a
ComponentExportIndex
which is loaded prior from a Component
.
For some examples see Instance::get_func
for loading values from a
component.
§Panics
Panics if store
does not own this instance.
pub fn get_resource(
&self,
store: impl AsContextMut,
name: impl InstanceExportLookup,
) -> Option<ResourceType>
pub fn get_resource( &self, store: impl AsContextMut, name: impl InstanceExportLookup, ) -> Option<ResourceType>
Looks up an exported resource type by name within this Instance
.
The store
argument provided must be the store that this instance
lives within and the name
argument is the lookup key by which to find
the exported resource. If the resource is found then Some
is returned
and otherwise None
is returned.
The name
here can be a string such as &str
or it can be a
ComponentExportIndex
which is loaded prior from a Component
.
For some examples see Instance::get_func
for loading values from a
component.
§Panics
Panics if store
does not own this instance.
pub fn get_export(
&self,
store: impl AsContextMut,
instance: Option<&ComponentExportIndex>,
name: &str,
) -> Option<ComponentExportIndex>
pub fn get_export( &self, store: impl AsContextMut, instance: Option<&ComponentExportIndex>, name: &str, ) -> Option<ComponentExportIndex>
A methods similar to Component::export_index
except for this
instance.
This method will lookup the name
provided within the instance
provided and return a ComponentExportIndex
which can be used to
pass to other get_*
functions like Instance::get_func
.
§Panics
Panics if store
does not own this instance.
Trait Implementations§
Auto Trait Implementations§
impl Freeze for Instance
impl RefUnwindSafe for Instance
impl Send for Instance
impl Sync for Instance
impl Unpin for Instance
impl UnwindSafe for Instance
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> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<T> Instrument for T
impl<T> Instrument for T
Source§fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
Source§fn in_current_span(self) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
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