Struct sp_runtime_interface::pass_by::Enum[][src]

pub struct Enum<T: Copy + Into<u8> + TryFrom<u8>>(_);

The implementation of the pass by enum strategy. This strategy uses an u8 internally to pass the enum between wasm and the host. So, this strategy only supports enums with unit variants.

Use this type as associated type for PassBy to implement this strategy for a type.

This type expects the type that wants to implement this strategy as generic parameter. Besides that the type needs to implement TryFrom<u8> and From<Self> for u8.

PassByEnum is a derive macro to implement this strategy.

Example

#[derive(Clone, Copy)]
enum Test {
    Test1,
    Test2,
}

impl From<Test> for u8 {
    fn from(val: Test) -> u8 {
        match val {
            Test::Test1 => 0,
            Test::Test2 => 1,
        }
    }
}

impl std::convert::TryFrom<u8> for Test {
    type Error = ();

    fn try_from(val: u8) -> Result<Test, ()> {
        match val {
            0 => Ok(Test::Test1),
            1 => Ok(Test::Test2),
            _ => Err(()),
        }
    }
}

impl PassBy for Test {
    type PassBy = Enum<Self>;
}

Trait Implementations

impl<T: Copy + Into<u8> + TryFrom<u8>> PassByImpl<T> for Enum<T>[src]

impl<T: Copy + Into<u8> + TryFrom<u8>> RIType for Enum<T>[src]

The type is passed as u8.

The value is corresponds to the discriminant of the variant.

type FFIType = u8

The ffi type that is used to represent Self.

Auto Trait Implementations

impl<T> RefUnwindSafe for Enum<T> where
    T: RefUnwindSafe

impl<T> Send for Enum<T> where
    T: Send

impl<T> Sync for Enum<T> where
    T: Sync

impl<T> Unpin for Enum<T> where
    T: Unpin

impl<T> UnwindSafe for Enum<T> where
    T: UnwindSafe

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
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impl<T> Borrow<T> for T where
    T: ?Sized
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impl<T> BorrowMut<T> for T where
    T: ?Sized
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impl<T> From<T> for T[src]

impl<T> Instrument for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
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impl<T> MaybeRefUnwindSafe for T where
    T: RefUnwindSafe
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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.

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.

impl<V, T> VZip<V> for T where
    V: MultiLane<T>, 
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