Trait Transport 

pub trait Transport: Send + Sync {
    // Required methods
    fn upload_pack(&self, bytes: &[u8], key: &PackKey) -> TransportResult<()>;
    fn download_pack(&self, key: &PackKey) -> TransportResult<Vec<u8>>;
    fn pack_exists(&self, key: &PackKey) -> TransportResult<bool>;
    fn update_ref(
        &self,
        name: &str,
        condition: RefWriteCondition,
        hash: &Hash,
    ) -> TransportResult<()>;
    fn read_ref(&self, name: &str) -> TransportResult<Option<Hash>>;
    fn list_refs(&self, prefix: &str) -> TransportResult<Vec<Ref>>;

    // Provided method
    fn write_ref(&self, name: &str, hash: &Hash) -> TransportResult<()> { ... }
}

The mkit transport vtable.

Every transport (memory, file, HTTP, S3, SSH) implements this trait. Methods are synchronous and take &self; transports that need interior mutability (e.g. connection pools) MUST use a Mutex / RwLock internally. This keeps the trait object-safe.

All implementations MUST honour the retry policy in SPEC-TRANSPORT §7 internally OR document that the caller is responsible — the abstract trait takes no position. The is_retryable and BackoffIterator helpers are provided for implementations that embed the policy.

Required Methods

fn upload_pack(&self, bytes: &[u8], key: &PackKey) -> TransportResult<()>

Upload a pack. The digest is computed by the caller (BLAKE3 of the full pack bytes) and used as the object key — servers MAY dedupe on this key.

fn download_pack(&self, key: &PackKey) -> TransportResult<Vec<u8>>

Download a pack by its digest.

Returns TransportError::PackNotFound if the remote does not hold this digest.

fn pack_exists(&self, key: &PackKey) -> TransportResult<bool>

HEAD-check a pack. Cheaper than Self::download_pack on network transports.

fn update_ref( &self, name: &str, condition: RefWriteCondition, hash: &Hash, ) -> TransportResult<()>

CAS ref write. See RefWriteCondition.

On .missing / .match CAS failure, returns TransportError::RefConflict. Callers retrying after a timeout MUST follow up with Self::read_ref to confirm whether the first attempt actually landed (SPEC-TRANSPORT §7).

fn read_ref(&self, name: &str) -> TransportResult<Option<Hash>>

Read the current value of a ref, or None if it does not exist.

fn list_refs(&self, prefix: &str) -> TransportResult<Vec<Ref>>

List refs whose full name starts with prefix. Returned names have prefix stripped per SPEC-REFS §4. An empty prefix lists every ref.

Provided Methods

fn write_ref(&self, name: &str, hash: &Hash) -> TransportResult<()>

Unconditional ref write — equivalent to update_ref(name, RefWriteCondition::Any, hash).

Default impl delegates to Self::update_ref so transports only implement one entry point.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors