Module sidecar 

xattr/sidecar metadata – SyncSignature, dirty flags, JSON fallback. Xattr/sidecar metadata – SyncSignature, MerkleSignature, dir_hash.

Metadata/dirty-flag management via xattr (primary) with JSON sidecar fallback.

Structs

AsyncSidecar

Background thread for non-blocking dirty flag I/O

SyncSignature

File sync signature stored in xattr/sidecar for change detection

Constants

XATTR_EMBEDDING

xattr key for embedding metadata (model, dimensions, chunk count).

XATTR_ENRICHMENT

xattr key for LLM enrichment data (Dublin Core, APP envelope).

XATTR_FILE_SIMILARITY

xattr key for file-level similarity fingerprint.

XATTR_MEDIA_META

xattr key for extracted media metadata (EXIF, ID3, PDF info).

XATTR_SIMILARITY

xattr key for similarity metadata (SimHash, entropy class).

Functions

clear_dir_hash

Clear a stored directory hash (invalidation).

get_dir_hash

Retrieve a stored directory hash from xattr.

get_merkle_signature

Retrieve a stored Merkle signature from xattr or per-target index

get_metadata

Retrieve a metadata value by key from xattr or sidecar fallback

get_sidecar_path

Compute the .foxing_meta sidecar path for a given file

get_sync_signature

Retrieve the stored sync signature for a file

is_dirty

Check if a file has the dirty flag set (indicates an in-progress copy)

remove_metadata

Remove a metadata key from both xattr namespaces and sidecar

set_dir_hash

Store a directory-level Merkle hash via xattr on the target directory.

set_dirty_flag

Set or clear the dirty flag on a file

set_merkle_signature

Store a Merkle signature in xattr (small files) or per-target index (large files)

set_metadata

Store a metadata key-value pair via xattr (primary) or JSON sidecar (fallback)

set_metadata_batch

Write multiple metadata keys. Uses xattr per-key (kernel can’t batch), but avoids sidecar entirely unless xattr is unsupported.

set_sync_signature

Store a sync signature in the file’s xattr/sidecar metadata