Trait LayerAttach

Source

pub trait LayerAttach:
    'static
    + Send
    + Sync {
    type Error: Into<Box<dyn Error + Send + Sync + 'static>>;
    type Layer: LayerIo;

    // Required method
    fn attach(
        self,
        lower_layer_metadata: Option<DiskLayerMetadata>,
    ) -> impl Future<Output = Result<Self::Layer, Self::Error>> + Send;
}

Expand description

Transition a layer from an unattached type-state, into an attached type-state, capable of performing LayerIo.

Layers which do not require a type-state transition on-attach (e.g: those which are pre-initialized with a fixed set of metadata) can simply implement LayerIo directly, and leverage the blanket-impl of impl<T: LayerIo> LayerAttach for T which simply returns Self during the state transition.

Required Associated Types§

Source

type Error: Into<Box<dyn Error + Send + Sync + 'static>>

Error returned if on attach failure.

Source

type Layer: LayerIo

Object implementating LayerIo after being attached.

Required Methods§

Source

fn attach( self, lower_layer_metadata: Option<DiskLayerMetadata>, ) -> impl Future<Output = Result<Self::Layer, Self::Error>> + Send

Invoked when the layer is being attached to a layer stack.

If the layer is being attached on-top of an existing layer, lower_layer_metadata can be used to initialize and/or reconfigure the layer using the properties of the layer is is being stacked on-top of.