Crate goods

source · []
Expand description

Asset loader.

Asset and AssetField derive macros

Creates structures to act as two loading stages of asset and implement asset using those. First stages must be deserializable with serde. All fields with #[external] must implement AssetField<External>. Which has blanket impl for Asset implementors and some wrappers, like Option<A> and Arc<[A]> where A: Asset. All fields with #[container] attribute must implement AssetField<Container>. It can be derived using derive(AssetField). They can in turn contain fields with #[external] and #[container] attributes. Also implemented for wrappers like Option<A> and Arc<[A]>. All fields without special attributes of the target struct must implement DeserializeOwned. All fields transiently with #[external] attribute will be replaced with id for first stage struct and AssetResults for second stage. Second stages will have AssetResults fields in place of the assets.


/// Simple deserializable type. Included as-is into generated types for `#[derive(Asset)]` and #[derive(AssetField)].
#[derive(Clone, serde::Deserialize)]
struct Foo;

/// Trivial asset type.
#[derive(Clone, Asset)]
#[asset(name = "bar")]
struct Bar;

/// Asset field type. `AssetField<Container>` implementation is generated, but not `Asset` implementation.
/// Fields of types with `#[derive(AssetField)]` attribute are not replaced by uuids as external assets.
#[derive(Clone, AssetField)]
struct Baz;

/// Asset structure. Implements Asset trait using
/// two generated structures are intermediate phases.
#[derive(Clone, Asset)]
#[asset(name = "assetstruct")]
struct AssetStruct {
    /// Deserializable types are inlined into asset as is.
    foo: Foo,

    /// `AssetField<External>` is implemented for all `Asset` implementors.
    /// Deserialized as `AssetId` and loaded recursively.
    bar: Bar,

    /// Container fields are deserialized similar to types that derive `Asset`.
    /// If there is no external asset somewhere in hierarchy, decoded `Baz` is structurally equivalent to `Baz`.
    baz: Baz,



Type for unique asset identification. There are 2^64-1 valid values of this type that should be enough for now.

Virtual storage for all available assets.

Builder for Loader. Allows configure asset loader with required Sources.

AssetId augmented with type information, specifying which asset type is referenced.


Error type used by derive-macro.


An asset type that can be built from decoded representation.

Asset building trait. Users should implement this trait for at least single choice of B. But it is highly recommended to implement this trait for wide choices of B for improved composability. Because composite asset will implement AssetBuild<B> only for such types B for which all components implement AssetBuild<B>.

This trait is used by code generated by Asset and AssetField derive macros. Types must implement AssetField in order to be usable as field types in structures that derive Asset or AssetField.

This trait is AssetBuild but for AssetField implementations.

Simple assets have no dependencies. For this reason their decode function is always sync and do not take Loader argument.

Trivial assets have no dependencies and do not require building. They are decoded directly from bytes. And thus they implement AssetBuild<B> for any B.

Derive Macros