Struct RwImage 

pub struct RwImage { /* private fields */ }

An open read-write LimniFS image.

Implementations

impl RwImage

pub fn open(path: &Path, config: WriteConfig) -> Result<Self, WriteError>

Open an existing image for read-write access. Parses the manifest, mmaps the slabs, and builds the path index.

Errors

Returns WriteError if the manifest cannot be parsed or the slab files cannot be opened.

pub fn create_new(path: &Path, config: WriteConfig) -> Self

Create a new empty RW image. The first commit produces the on-disk manifest + slabs.

pub fn add_file(&mut self, path: &str, data: &[u8]) -> Result<u64, WriteError>

Add a new file to the image. The plaintext is staged for the next commit; no I/O happens until then.

Errors

Returns WriteError only if internal allocation fails.

pub fn update_file(&mut self, path: &str, data: &[u8]) -> Result<(), WriteError>

Update an existing file. The old inode is marked superseded; old drops remain in slabs until the next turnover.

Errors

Returns WriteError if the path doesn’t exist.

pub fn delete_file(&mut self, path: &str) -> Result<(), WriteError>

Delete a file. The inode is removed from the path index; old drops remain until the next turnover.

Errors

Returns WriteError if the path doesn’t exist.

pub fn read_file(&self, path: &str) -> Result<Vec<u8>, WriteError>

Read a file’s plaintext from the in-memory state. Only available for images that have been opened.

Errors

Returns WriteError if the image was not opened, the path is unknown, or the slab is missing/corrupt.

pub fn pending_changes(&self) -> usize

Number of pending (uncommitted) changes.

pub fn needs_turnover(&self) -> bool

Check if auto-turnover should trigger based on the config’s turnover_threshold.

pub fn mode(&self) -> &ImageMode

Get the image mode (RO vs RW sub-mode).

pub fn commit(&self) -> Result<WriteArtifact, WriteError>

Commit pending changes. Materializes the live tree (if any), overlays pending writes, rebuilds the image with the configured codecs, and writes the new manifest + slabs.

Crash safety: writes the WAL with planned operations before the manifest swap. If the swap is interrupted, the WAL survives and is replayed on the next open, restoring the user’s pending writes. On successful swap, the WAL is unlinked.

Errors

Returns WriteError on I/O or serialization failure.

pub fn turnover(&self) -> Result<WriteArtifact, WriteError>

Turnover: rebuild the current live tree with the configured codecs. Pending changes are dropped — this is a hygiene operation, not a commit.

Errors

Returns WriteError on I/O or serialization failure.