Struct ObjectPresenceFilter 

pub struct ObjectPresenceFilter<Src: BlockMetadata> { /* private fields */ }

G2→G4 filter: async presence check for object storage destinations.

Unlike PresenceFilter which checks local BlockRegistry synchronously, this filter queries object storage (S3, etc.) asynchronously via a PresenceChecker implementation.

Duplicate Prevention

When a PendingTracker is configured, this filter also checks for blocks that are currently in-flight through the pipeline before querying object storage.

Performance

This policy returns Either::Right(BoxFuture) since it requires async I/O. The pending tracker check is done synchronously first to avoid unnecessary object storage queries.

Example

let object_ops: Arc<dyn ObjectBlockOps> = ...;
let checker = Arc::new(S3PresenceChecker::new(object_ops));
let tracker = Arc::new(PendingTracker::new());
let filter = ObjectPresenceFilter::<G2>::new(checker)
    .with_pending_tracker(tracker);
// Blocks already in object storage OR in-flight will be filtered out

Implementations

impl<Src: BlockMetadata> ObjectPresenceFilter<Src>

pub fn new(presence_checker: Arc<dyn PresenceChecker>) -> Self

Create a new object presence filter.

pub fn with_pending_tracker(self, tracker: Arc<PendingTracker>) -> Self

Add a pending tracker for duplicate prevention.

When set, blocks that are currently in-flight (passed policy but not yet stored in object storage) will be filtered out.

pub fn pending_tracker(&self) -> Option<&Arc<PendingTracker>>

Get a reference to the pending tracker if configured.

Trait Implementations

impl<Src: BlockMetadata> OffloadPolicy<Src> for ObjectPresenceFilter<Src>

fn name(&self) -> &str

Unique name for this policy (for logging/debugging).

fn evaluate<'a>(&'a self, ctx: &'a EvalContext<Src>) -> PolicyFuture<'a>

Evaluate whether a block should be offloaded.

fn evaluate_batch<'a>( &'a self, contexts: &'a [EvalContext<Src>], ) -> PolicyBatchFuture<'a>

Batch evaluate multiple blocks.