Module bindings

CoreCrypto FFI Details

Bindings

• WASM / TypeScript bindings are self-documented in [crypto-ffi/bindings/js/CoreCrypto.ts].
  • Please refer to your IDE of choice’s inlay hints or simply check out the TypeDoc-generated documentation on typescript
  • Naming convention wise, snake_case gets translated to the TS idiomatic camelCase for methods and PascalCase for classes/interfaces
• UniFFI-generated bindings (Swift, Kotlin) share the same characteristics in terms of naming convention translation.
  • The general convention is that the idiomatic Rust snake_case gets translated to the language’s idiomatic convention. Fortunately, for both Swift and Kotlin, the convention is camelCase for methods and PascalCase for classes/interfaces.

Naming conventions table

Item	Rust	Swift	Kotlin	TypeScript
Methods/Functions	snake_case	camelCase	camelCase	camelCase
Variables/Arguments	snake_case	camelCase	camelCase	camelCase
Classes/Interfaces	PascalCase	PascalCase	PascalCase	PascalCase

Types equivalence table

Rust	Swift	Kotlin	TypeScript
bool	Bool	Boolean	boolean
u8	UInt8	UByte	number
u16	UInt16	UShort	number
u32	UInt32	UInt	number
u64	UInt64	ULong	number
i8	Int8	Byte	number
i16	Int16	Short	number
i32	Int32	Int	number
i64	Int64	Long	number
f32	Float	Float	number
f64	Double	Double	number
String / &str	String	String	string
std::time::SystemTime	Date	java.time.Instant	Date
std::time::Duration	TimeInterval	java.time.Duration	number (in milliseconds)
Option<T>	Optional<T>	Optional<T>	T?
Vec<T>	Array<T>	List<T>	Array<T>
HashMap<String, T>	Dictionary<String, T>	Map<String, T>	Record<string, T>
()	nil	null	null
Result<T, E>	func placeholder() throws E -> T	T placeholder() throws E	function placeholder(): T // @throws E

Adding new APIs

1. Make your changes wherever applicable.
2. Make sure your new API is available on MlsCentral, while respecting encapsulation
   • For example, adding MlsConversation::hello() would mean exposing a new MlsCentral::conversation_hello(conversation_id: ConversationId)
3. Expose your new API on both crypto-ffi/src/[generic|wasm].rs.
4. Add the new APIs respecting the appropriate calling conventions defined above to
   • Kotlin/Android: crypto-ffi/bindings/jvm/src/main/kotlin/com/wire/crypto/client/[CoreCryptoCentral|E2eiClient|MLSClient].kt
   • TypeScript/Web: crypto-ffi/bindings/js/CoreCrypto.ts (Swift/iOS are automatically generated)
5. Add documentation for the new API in the bindings.
6. Add a test for the bindings. This is easily done by extending the existing test suite in crypto-ffi/bindings/js/test/CoreCrypto.test.ts. For example, see this commit.

Modules

• kotlin
• swift
• typescript