Struct ResourceAny

pub struct ResourceAny { /* private fields */ }

Expand description

Representation of a resource in the component model, either a guest-defined or a host-defined resource.

This type is similar to Resource except that it can be used to represent any resource, either host or guest. This type cannot be directly constructed and is only available if the guest returns it to the host (e.g. a function returning a guest-defined resource) or by a conversion from Resource via ResourceAny::try_from_resource. This type also does not carry a static type parameter T for example and does not have as much information about its type. This means that it’s possible to get runtime type-errors when using this type because it cannot statically prevent mismatching resource types.

Like Resource this type represents either an own or a borrow resource internally. Unlike Resource, however, a ResourceAny must always be explicitly destroyed with the ResourceAny::resource_drop method. This will update internal dynamic state tracking and invoke the WebAssembly-defined destructor for a resource, if any.

Note that it is required to call resource_drop for all instances of ResourceAny: even borrows. Both borrows and own handles have state associated with them that must be discarded by the time they’re done being used.

Implementations§

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impl ResourceAny

pub fn try_from_resource<T>( resource: Resource<T>, store: impl AsContextMut, ) -> Result<ResourceAny, Error>
where T: 'static,

Attempts to convert an imported Resource into ResourceAny.

resource is the resource to convert.
store is the store to place the returned resource into.

The returned ResourceAny will not have a destructor attached to it meaning that if resource_drop is called then it will not invoked a host-defined destructor. This is similar to how Resource<T> does not have a destructor associated with it.

§Errors

This method will return an error if resource has already been “taken” and has ownership transferred elsewhere which can happen in situations such as when it’s already lowered into a component.

pub fn try_into_resource<T>( self, store: impl AsContextMut, ) -> Result<Resource<T>, Error>
where T: 'static,

See Resource::try_from_resource_any

pub fn ty(&self) -> ResourceType

Returns the corresponding type associated with this resource, either a host-defined type or a guest-defined type.

This can be compared against ResourceType::host for example to see if it’s a host-resource or against a type extracted with Instance::get_resource to see if it’s a guest-defined resource.

pub fn owned(&self) -> bool

Returns whether this is an owned resource, and if not it’s a borrowed resource.

pub fn resource_drop(self, store: impl AsContextMut) -> Result<(), Error>

Destroy this resource and release any state associated with it.

This is required to be called (or the async version) for all instances of ResourceAny to ensure that state associated with this resource is properly cleaned up. For owned resources this may execute the guest-defined destructor if applicable (or the host-defined destructor if one was specified).