Module repository

To support clients implementing the Repository trait in a ::wasm_bindgen environment, we need to deal with an extern "C" interface, as that is what ::wasm_bindgen supports:

This looks something like this:

#[wasm_bindgen]
extern "C" {
    pub type CipherRepository;

    #[wasm_bindgen(method, catch)]
    async fn get(this: &CipherRepository, id: String) -> Result<JsValue, JsValue>;
}

As you can see, this has a few limitations:

• The type must be known at compile time, so we cannot use generics directly, which means we can’t use the existing Repository trait directly.
• The return type must be JsValue, so we need to convert our types to and from JsValue.

To facilitate this, we provide some utilities:

• WasmRepository trait, which defines the methods as we expect them to come from ::wasm_bindgen, using JsValue. This is generic and should be implemented for each concrete repository we define, but the implementation should be very straightforward.
• WasmRepositoryChannel struct, which wraps a WasmRepository in a ThreadBoundRunner and implements the Repository trait. This has a few special considerations:
  • It uses [tsify::serde_wasm_bindgen] to convert between JsValue and our types, so we can use the existing Repository trait.
  • It runs the calls in a thread-bound manner, so we can safely call the WasmRepository methods from any thread.
• The create_wasm_repository macro, defines the ::wasm_bindgen interface and implements the WasmRepository trait for you.

Macros

create_wasm_repository 🔒

This macro generates a ::wasm_bindgen interface for a repository type, and provides the implementation of WasmRepository and a way to convert it into something that implements the Repository trait.

Structs

WasmRepositoryChannel 🔒

This struct wraps a WasmRepository in a ThreadBoundRunner to allow it to be used as a Repository in a thread-safe manner. It implements the Repository trait directly, by converting the values as needed with [tsify::serde_wasm_bindgen].

Constants

UNIT 🔒

Traits

WasmRepository 🔒

This trait defines the methods that a ::wasm_bindgen repository must implement. The trait itself exists to provide a generic way of handling the ::wasm_bindgen interface, which is !Send + !Sync, and only deals with JsValue.

Functions

convert_result 🔒

Converts a Result<JsValue, JsValue> to a typed Result<T, RepositoryError> using [tsify::serde_wasm_bindgen]

run_convert 🔒

Utility function that runs a closure in a thread-bound manner, and converts the Result from Result<JsValue, JsValue> to a typed Result<T, RepositoryError>.