Struct Stage 

pub struct Stage { /* private fields */ }

Where a run keeps what it is about to replace.

Implementations

impl Stage

pub fn new(backup_root: &Utf8Path) -> Result<Self, AppError>

Open the backup store under backup_root.

Errors

Any I/O error creating the store.

pub fn backup_path(&self, digest: &Sha256) -> Utf8PathBuf

Where one backed-up digest is kept.

pub fn back_up( &self, destination: &Utf8Path, ) -> Result<Option<Sha256>, AppError>

Copy an existing destination into the store, returning its digest.

None means the destination does not exist, which is what tells a recovery to remove it rather than restore it.

Errors

Any I/O error reading the destination or writing the copy.

pub fn restore( &self, digest: &Sha256, destination: &Utf8Path, ) -> Result<(), AppError>

Put a backed-up copy back at destination.

Errors

AppError::Unrecovered when the copy is gone, and any I/O error of the write.

pub fn write( destination: &Utf8Path, bytes: &[u8], ) -> Result<Utf8PathBuf, AppError>

Write bytes to a scratch file beside destination.

The scratch file is created exclusively, so a path already there — a symlink included — refuses rather than being followed.

Errors

Any I/O error creating the parent, the scratch file, or syncing it.

pub fn replace( scratch: &Utf8Path, destination: &Utf8Path, ) -> Result<(), AppError>

Rename a staged file over its destination and sync the directory.

Errors

Any I/O error of the rename or the sync. The scratch file is removed on failure, so a retry is not blocked by its own leftover.

pub fn discard(scratch: &Utf8Path)

Drop a staged file that will not be used.

Trait Implementations

impl Clone for Stage

fn clone(&self) -> Stage

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Stage

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.