WorldWind Kotlin/earth.worldwind.layer.cache/BlobStore

BlobStore

URI-keyed binary blob store. Persists arbitrary HTTP-fetched payloads (3D Tiles content, future generic asset caches) under a single content key.

Distinct from TileStore / FeatureStore: those are pyramid- or feature-shaped. This one is a flat string-keyed key/value store, the right shape for any cache whose entries are independent URLs rather than a coordinate grid. The first user is 3D Tiles (earth.worldwind.layer.ogc3d.Ogc3dTilesLayer) — each tile's content URI keys into one row.

Persistence backend is platform-dependent (GeoPackage extension table on JVM/Android, IndexedDB on JS, file blobs on iOS), all reached through earth.worldwind.util.ContentManager.openBlobStore.

The store stores both the raw payload bytes and a small metadata envelope (BlobEntry.contentType, BlobEntry.etag, BlobEntry.lastModified) so the layer can skip magic-byte detection when the server returned a known content type and so future revalidation (If-None-Match / If-Modified-Since) can be wired without a schema migration.

Inheritors

GpkgBlobStore

NoOpBlobStore

Functions

clear

abstract suspend fun clear()

Drop every entry. Schema is preserved so subsequent puts succeed.

get

abstract suspend fun get(uri: String): BlobEntry?

Fetch a previously-stored blob. Null when uri is not in the cache.

put

abstract suspend fun put(uri: String, bytes: ByteArray, contentType: String? = null, etag: String? = null, lastModified: Instant? = null, responseUrl: String? = null)

Persist or replace the blob for uri. contentType is whatever the server returned (e.g. application/octet-stream, model/gltf-binary); null when unknown. etag and lastModified are conditional-fetch metadata the layer can consult on a future revalidation request. responseUrl is the post-redirect URL the body was actually served from — replayed via BlobEntry.responseUrl on cache hits so callers can resolve relative URIs against the body's true origin. Null when same as uri / unknown.

remove

abstract suspend fun remove(uri: String)

Drop one entry. No-op when uri is absent.

sizeBytes

abstract suspend fun sizeBytes(): Long

Total stored payload size in bytes. Excludes metadata + schema overhead; close approximation suitable for budget reporting, not exact accounting.