[DNM] feat(da): support fiber (not via c-node)

block/internal/da/fiber/types.go

@@ -0,0 +1,69 @@
+// Package fiber defines the Fiber DA backend interface and shared types.
+//
+// # Design Assumptions
+//
+//   - The sequencer trusts the encoder to eventually confirm blob inclusion.
+//     Upload returns after the blob is uploaded and the PFF transaction is
+//     broadcast, NOT after on-chain confirmation. This keeps the sequencer's
+//     write path fast (~2s per 128 MB blob).
+//
+//   - Callers are expected to batch/buffer their data into blobs sized for the
+//     protocol maximum (128 MiB - 5 byte header = 134,217,723 bytes).
+//     The interface accepts arbitrary sizes but the implementation may batch
+//     or reject oversized blobs.
+//
+//   - Confirmation/finality is intentionally omitted from the initial API.
+//     The sequencer does not need it; the read path (Listen + Download) is
+//     sufficient for full nodes. A Status or Confirm RPC can be added later
+//     if needed without breaking existing callers.
+//
+//   - Blob ordering is encoded in the blob data itself by the caller.
+//     The interface does not impose or guarantee ordering.
+//
+//   - The interface is the same whether the encoder runs in-process or as an
+//     external gRPC service. For in-process use, call the mock or real
+//     implementation directly; for external use, connect via gRPC.
+package fiber
+
+import (
+	"context"
+	"time"
+)
+
+// BlobID uniquely identifies an uploaded blob (version byte + 32-byte commitment).
+type BlobID []byte
+
+// UploadResult is returned by Upload after the blob is accepted.
+type UploadResult struct {
+	BlobID    BlobID
+	ExpiresAt time.Time
+}
+
+// BlobEvent is delivered via Listen when a blob is confirmed on-chain.
+type BlobEvent struct {
+	BlobID   BlobID
+	Height   uint64
+	DataSize uint64
+}
+
+// DA is the interface for interacting with the Fiber data availability layer.
+type DA interface {
+	// Upload submits a blob under the given namespace to the DA network.
+	// Returns after the blob is uploaded and the payment transaction is broadcast.
+	// Does NOT wait for on-chain confirmation (see package doc for rationale).
+	Upload(ctx context.Context, namespace []byte, data []byte) (UploadResult, error)
+
+	// Download retrieves and reconstructs a blob by its ID.
+	// Returns the original data that was passed to Upload.
+	Download(ctx context.Context, blobID BlobID) ([]byte, error)
+
+	// Listen streams confirmed blob events for the given namespace,
+	// starting at fromHeight.
+	//
+	// fromHeight == 0 starts the stream from the current chain head; any
+	// positive value replays events from that block forward so a
+	// subscriber can resume after a restart without missing blobs (the
+	// DA backend is expected to block, not error, on future heights).
+	// The returned channel is closed when ctx is cancelled.
+	Listen(ctx context.Context, namespace []byte, fromHeight uint64) (<-chan BlobEvent, error)
+}