Struct wasmtime::StructType

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pub struct StructType { /* private fields */ }
Expand description

The type of a WebAssembly struct.

WebAssembly structs are a static, fixed-length, ordered sequence of fields. Fields are named by index, not an identifier. Each field is mutable or constant and stores unpacked Vals or packed 8-/16-bit integers.

§Subtyping and Equality

StructType does not implement Eq, because reference types have a subtyping relationship, and so 99.99% of the time you actually want to check whether one type matches (i.e. is a subtype of) another type. You can use the StructType::matches method to perform these types of checks. If, however, you are in that 0.01% scenario where you need to check precise equality between types, you can use the StructType::eq method.

Implementations§

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impl StructType

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pub fn new( engine: &Engine, fields: impl IntoIterator<Item = FieldType>, ) -> Result<Self>

Construct a new StructType with the given field types.

This StructType will be final and without a supertype.

The result will be associated with the given engine, and attempts to use it with other engines will panic (for example, checking whether it is a subtype of another struct type that is associated with a different engine).

Returns an error if the number of fields exceeds the implementation limit.

§Panics

Panics if any given field type is not associated with the given engine.

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pub fn with_finality_and_supertype( engine: &Engine, finality: Finality, supertype: Option<&Self>, fields: impl IntoIterator<Item = FieldType>, ) -> Result<Self>

Construct a new StructType with the given finality, supertype, and fields.

The result will be associated with the given engine, and attempts to use it with other engines will panic (for example, checking whether it is a subtype of another struct type that is associated with a different engine).

Returns an error if the number of fields exceeds the implementation limit, if the supertype is final, or if this type does not match the supertype.

§Panics

Panics if any given field type is not associated with the given engine.

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pub fn engine(&self) -> &Engine

Get the engine that this struct type is associated with.

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pub fn finality(&self) -> Finality

Get the finality of this struct type.

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pub fn supertype(&self) -> Option<Self>

Get the supertype of this struct type, if any.

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

Get the ith field type.

Returns None if i is out of bounds.

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pub fn fields(&self) -> impl ExactSizeIterator<Item = FieldType> + '_

Returns the list of field types for this function.

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

Does this struct type match the other struct type?

That is, is this function type a subtype of the other struct type?

§Panics

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

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pub fn eq(a: &StructType, b: &StructType) -> bool

Is struct type a precisely equal to struct type b?

Returns false even if a is a subtype of b or vice versa, if they are not exactly the same struct type.

§Panics

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

Trait Implementations§

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impl Clone for StructType

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fn clone(&self) -> StructType

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for StructType

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

Formats the value using the given formatter. Read more
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impl Display for StructType

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

Formats the value using the given formatter. Read more
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impl From<StructType> for HeapType

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fn from(s: StructType) -> Self

Converts to this type from the input type.
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impl Hash for StructType

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts 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 more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts 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
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.