Struct ExnType

pub struct ExnType { /* private fields */ }

A WebAssembly exception-object signature type.

This type captures the signature of an exception object. Note that the WebAssembly standard does not define concrete types in the heap-type lattice between exn (any exception object – the top type) and noexn (the uninhabited bottom type). Wasmtime defines concrete types based on the signature – that is, the function type that describes the signature of the exception payload values – rather than the tag. The tag is a per-instance nominal entity (similar to a memory or a table) and is associated only with particular exception objects.

Implementations

impl ExnType

pub fn new( engine: &Engine, fields: impl IntoIterator<Item = ValType>, ) -> Result<ExnType, Error>

Create a new ExnType.

This function creates a new exception object type with the given signature, i.e., list of payload value types. This signature implies a tag type, and when instantiated at runtime, it must be associated with a tag of that type.

pub fn from_tag_type(tag: &TagType) -> Result<ExnType, Error>

Create a new ExnType from an existing TagType.

This function creates a new exception object type with the signature represented by the tag. The signature must have no result values, i.e., must be of the form (T1, T2, ...) -> ().

pub fn tag_type(&self) -> TagType

Get the tag type that this exception type is associated with.

pub fn field(&self, i: usize) -> Option<FieldType>

Get the ith field type.

Returns None if i is out of bounds.

pub fn fields(&self) -> impl ExactSizeIterator

Returns the list of field types for this function.

pub fn engine(&self) -> &Engine

Get the engine that this exception type is associated with.

pub fn matches(&self, other: &ExnType) -> bool

Does this exception type match the other exception type?

That is, is this exception type a subtype of the other exception type?

Panics

Panics if either type is associated with a different engine from the other.

Trait Implementations

impl Clone for ExnType

fn clone(&self) -> ExnType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExnType

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

Formats the value using the given formatter.

impl Display for ExnType

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

Formats the value using the given formatter.

impl From<ExnType> for HeapType

fn from(e: ExnType) -> HeapType

Converts to this type from the input type.

impl Hash for ExnType

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.