Trait FromFFIValue 

pub trait FromFFIValue<'a>: RIType {
    type Owned;

    // Required methods
    fn from_ffi_value(
        context: &mut dyn FunctionContext,
        arg: Self::FFIType,
    ) -> Result<Self::Owned>;
    fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner;

    // Provided method
    fn write_back_into_runtime(
        _value: Self::Owned,
        _context: &mut dyn FunctionContext,
        _arg: Self::FFIType,
    ) -> Result<()> { ... }
}

A type used as a parameter in a host function. Can be created from an FFI value.

Implementations are safe to assume that the arg given to from_ffi_value is only generated by the corresponding wasm::IntoFFIValue implementation.

Required Associated Types

type Owned

The owned inner type.

Required Methods

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

Creates Self::Owned from the given arg received through the FFI boundary from the runtime.

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

Creates Self::Inner from an owned value.

Provided Methods

fn write_back_into_runtime( _value: Self::Owned, _context: &mut dyn FunctionContext, _arg: Self::FFIType, ) -> Result<()>

Write back a modified value back into the runtime’s memory.

Only makes sense for parameters like e.g. &mut [u8].

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<'a> FromFFIValue<'a> for bool

Available on non-substrate_runtime only.

type Owned = bool

fn from_ffi_value(_: &mut dyn FunctionContext, arg: u32) -> Result<bool>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for i8

Available on non-substrate_runtime only.

type Owned = i8

fn from_ffi_value(_: &mut dyn FunctionContext, arg: i32) -> Result<i8>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for i16

Available on non-substrate_runtime only.

type Owned = i16

fn from_ffi_value(_: &mut dyn FunctionContext, arg: i32) -> Result<i16>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for i32

Available on non-substrate_runtime only.

type Owned = i32

fn from_ffi_value(_: &mut dyn FunctionContext, arg: i32) -> Result<i32>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for i64

Available on non-substrate_runtime only.

type Owned = i64

fn from_ffi_value(_: &mut dyn FunctionContext, arg: i64) -> Result<i64>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for u8

Available on non-substrate_runtime only.

type Owned = u8

fn from_ffi_value(_: &mut dyn FunctionContext, arg: u32) -> Result<u8>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for u16

Available on non-substrate_runtime only.

type Owned = u16

fn from_ffi_value(_: &mut dyn FunctionContext, arg: u32) -> Result<u16>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for u32

Available on non-substrate_runtime only.

type Owned = u32

fn from_ffi_value(_: &mut dyn FunctionContext, arg: u32) -> Result<u32>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

impl<'a> FromFFIValue<'a> for u64

Available on non-substrate_runtime only.

type Owned = u64

fn from_ffi_value(_: &mut dyn FunctionContext, arg: u64) -> Result<u64>

fn take_from_owned(owned: &'a mut Self::Owned) -> Self::Inner

Implementors

impl<'a> FromFFIValue<'a> for PassFatPointerAndRead<&'a str>

Available on non-substrate_runtime only.

type Owned = String

impl<'a> FromFFIValue<'a> for PassFatPointerAndRead<&'a [u8]>

Available on non-substrate_runtime only.

type Owned = Vec<u8>

impl<'a> FromFFIValue<'a> for PassFatPointerAndRead<Vec<u8>>

Available on non-substrate_runtime only.

type Owned = Vec<u8>

impl<'a> FromFFIValue<'a> for PassFatPointerAndReadWrite<&'a mut [u8]>

Available on non-substrate_runtime only.

type Owned = Vec<u8>

impl<'a, T, U> FromFFIValue<'a> for PassAs<T, U>

where U: RIType + FromFFIValue<'a> + Primitive, T: TryFrom<<U as FromFFIValue<'a>>::Owned> + Copy,

Available on non-substrate_runtime only.

type Owned = T

impl<'a, T, const N: usize> FromFFIValue<'a> for PassPointerAndRead<&'a T, N>

where T: From<[u8; N]>,

Available on non-substrate_runtime only.

type Owned = T

impl<'a, T, const N: usize> FromFFIValue<'a> for PassPointerAndReadCopy<T, N>

where T: From<[u8; N]> + Copy,

Available on non-substrate_runtime only.

type Owned = T

impl<'a, T, const N: usize> FromFFIValue<'a> for PassPointerAndWrite<&'a mut T, N>

where T: Default + AsRef<[u8]>,

Available on non-substrate_runtime only.

type Owned = T

impl<'a, T: Decode> FromFFIValue<'a> for PassFatPointerAndDecode<T>

Available on non-substrate_runtime only.

type Owned = Option<T>

impl<'a, T: Decode> FromFFIValue<'a> for PassFatPointerAndDecodeSlice<&'a [T]>

Available on non-substrate_runtime only.

type Owned = Vec<T>

impl<'a, T: PointerType> FromFFIValue<'a> for Pointer<T>

Available on non-substrate_runtime only.

type Owned = Pointer<T>