Trait CustomRegistryValue

Source

pub trait CustomRegistryValue:
    CustomRegistryKind
    + Any
    + Send
    + Sync
    + Debug {
    // Required methods
    fn kind_name() -> &'static str
       where Self: Sized;
    fn to_value(&self) -> Result<Value, String>;

    // Provided methods
    fn from_value(_value: &Value) -> Result<Self, String>
       where Self: Sized { ... }
    fn from_bytes(_bytes: &[u8], format: &str) -> Result<Self, String>
       where Self: Sized { ... }
    fn from_path(path: &Path) -> Result<Self, String>
       where Self: Sized { ... }
    fn export_to_bytes(&self, format: &str) -> Result<Vec<u8>, String> { ... }
    fn known_import_formats() -> Vec<ExtensionWithMime>
       where Self: Sized { ... }
    fn known_export_formats() -> Vec<ExtensionWithMime>
       where Self: Sized { ... }
}

Expand description

A registry handle type owned by a downstream crate.

Implement this, then a #[bind(handle)] argument or a #[register_binding(returns_handle)] return of that type crosses the binding boundary as a registry id instead of being serialized as JSON, the same treatment the built-in big types get but without an entry in the macro crate’s list of them. Derive CustomRegistryEntity to accept it as a #[bind(handle)] argument.

Registering the type with crate::register_custom_registry_kind! is optional and adds what needs a name rather than a Rust type: RegistryItemKind::from_str resolution, RegistryItem::load_from_path / RegistryItem::load_from_bytes, and the format lists. Unregistered, a value still stores, resolves by id and exports.

Send + Sync are load-bearing: the registry lives in a static in the wasm hosts, so AppState has to stay Sync.