Struct sp_runtime_interface::pass_by::Codec

pub struct Codec<T: Codec>(_);

The implementation of the pass by codec strategy. This strategy uses a SCALE encoded representation of the type between wasm and the host.

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.

PassByCodec is a derive macro to implement this strategy.

Example

#[derive(codec::Encode, codec::Decode)]
struct Test;

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

Trait Implementations

impl<T: Codec> PassByImpl<T> for Codec<T>

fn into_ffi_value(
    instance: T,
    context: &mut dyn FunctionContext
) -> Result<Self::FFIType>

Convert the given instance to the ffi value.

fn from_ffi_value(
    context: &mut dyn FunctionContext,
    arg: Self::FFIType
) -> Result<T>

Create T from the given ffi value.

impl<T: Codec> RIType for Codec<T>

The type is passed as u64.

The u64 value is build by length 32bit << 32 | pointer 32bit

Self is encoded and the length and the pointer are taken from the encoded vector.

type FFIType = u64

The ffi type that is used to represent Self.