wasmtime::component

Struct ResourceTable

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pub struct ResourceTable { /* private fields */ }
Available on crate features runtime and component-model only.
Expand description

The ResourceTable type maps a Resource<T> to its T.

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impl ResourceTable

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pub fn new() -> Self

Create an empty table

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pub fn with_capacity(capacity: usize) -> Self

Create an empty table with at least the specified capacity.

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pub fn push<T>(&mut self, entry: T) -> Result<Resource<T>, ResourceTableError>
where T: Send + 'static,

Inserts a new value T into this table, returning a corresponding Resource<T> which can be used to refer to it after it was inserted.

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pub fn push_child<T, U>( &mut self, entry: T, parent: &Resource<U>, ) -> Result<Resource<T>, ResourceTableError>
where T: Send + 'static, U: 'static,

Insert a resource at the next available index, and track that it has a parent resource.

The parent must exist to create a child. All children resources must be destroyed before a parent can be destroyed - otherwise ResourceTable::delete will fail with ResourceTableError::HasChildren.

Parent-child relationships are tracked inside the table to ensure that a parent resource is not deleted while it has live children. This allows child resources to hold “references” to a parent by table index, to avoid needing e.g. an Arc<Mutex<parent>> and the associated locking overhead and design issues, such as child existence extending lifetime of parent referent even after parent resource is destroyed, possibility for deadlocks.

Parent-child relationships may not be modified once created. There is no way to observe these relationships through the ResourceTable methods except for erroring on deletion, or the std::fmt::Debug impl.

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pub fn get<T: Any + Sized>( &self, key: &Resource<T>, ) -> Result<&T, ResourceTableError>

Get an immutable reference to a resource of a given type at a given index.

Multiple shared references can be borrowed at any given time.

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pub fn get_mut<T: Any + Sized>( &mut self, key: &Resource<T>, ) -> Result<&mut T, ResourceTableError>

Get an mutable reference to a resource of a given type at a given index.

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pub fn get_any_mut( &mut self, key: u32, ) -> Result<&mut dyn Any, ResourceTableError>

Returns the raw Any at the key index provided.

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pub fn delete<T>( &mut self, resource: Resource<T>, ) -> Result<T, ResourceTableError>
where T: Any,

Same as delete, but typed

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pub fn iter_entries<'a, T>( &'a mut self, map: HashMap<u32, T>, ) -> impl Iterator<Item = (Result<&'a mut dyn Any, ResourceTableError>, T)>

Available on crate feature std only.

Zip the values of the map with mutable references to table entries corresponding to each key. As the keys in the HashMap are unique, this iterator can give mutable references with the same lifetime as the mutable reference to the ResourceTable.

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pub fn iter_children<T>( &self, parent: &Resource<T>, ) -> Result<impl Iterator<Item = &(dyn Any + Send)>, ResourceTableError>
where T: 'static,

Iterate over all children belonging to the provided parent

Trait Implementations§

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impl Debug for ResourceTable

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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 Default for ResourceTable

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fn default() -> Self

Returns the “default value” for a type. 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> 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, 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.