Struct Optional

pub struct Optional<T: TypeMarker>(/* private fields */);

The FIDL type T:optional where T is a vector, string, handle, or client/server end.

Trait Implementations

impl<T: TypeMarker, D: ResourceDialect> Decode<Optional<T>, D> for Option<T::Owned>

where T::Owned: Decode<T, D>,

fn new_empty() -> Self

Creates a valid instance of Self. The specific value does not matter, since it will be overwritten by decode.

unsafe fn decode( &mut self, decoder: &mut Decoder<'_, D>, offset: usize, depth: Depth, ) -> Result<()>

Decodes an object of type T from the decoder’s buffers into self.

impl<T: TypeMarker, E: Encode<T, D>, D: ResourceDialect> Encode<Optional<T>, D> for Option<E>

unsafe fn encode( self, encoder: &mut Encoder<'_, D>, offset: usize, depth: Depth, ) -> Result<()>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID.

impl<T: ResourceTypeMarker + TypeMarker> ResourceTypeMarker for Optional<T>

type Borrowed<'a> = Option<<T as ResourceTypeMarker>::Borrowed<'a>>

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &mut Self::Owned. There are three cases:

fn take_or_borrow(value: &mut <Self as TypeMarker>::Owned) -> Self::Borrowed<'_>

Cheaply converts from &mut Self::Owned to Self::Borrowed. For HandleBased types this is “take” (it returns an owned handle and replaces value with Handle::invalid), and for all other types it is “borrow” (just converts from one reference to another).

impl<T: TypeMarker> TypeMarker for Optional<T>

type Owned = Option<<T as TypeMarker>::Owned>

The owned Rust type which this FIDL type decodes into.

fn inline_align(context: Context) -> usize

Returns the minimum required alignment of the inline portion of the encoded object. It must be a (nonzero) power of two.

fn inline_size(context: Context) -> usize

Returns the size of the inline portion of the encoded object, including padding for alignment. Must be a multiple of inline_align.

fn encode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and encoding requires no validation. When true, we can optimize encoding arrays and vectors of Self::Owned to a single memcpy.

fn decode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and decoding requires no validation. When true, we can optimize decoding arrays and vectors of Self::Owned to a single memcpy.

impl<T: ValueTypeMarker> ValueTypeMarker for Optional<T>

type Borrowed<'a> = Option<<T as ValueTypeMarker>::Borrowed<'a>>

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &Self::Owned. There are three cases:

fn borrow(value: &Self::Owned) -> Self::Borrowed<'_>

Cheaply converts from &Self::Owned to Self::Borrowed.