Struct Staged 

struct Staged {
    scratch: PathBuf,
    path: PathBuf,
    committed: bool,
}

A file’s next contents, written and synced beside its final path but not yet renamed over it.

The shape didbot-pds’s write-ahead log gives its compaction: the replacement is built whole, 0600, at a scratch path, and one rename(2) makes it the file. A crash before the rename leaves the old file as it was, plus a scratch file the next write removes; a crash after it leaves the new one. The directory is synced after the rename, because on most filesystems a rename that has not been durably recorded in its parent can be undone by a power cut that kept the file it pointed at.

Dropped without commit, it removes its scratch file, so a save that fails partway leaves no private key under a name nothing reads.

Fields

scratch: PathBuf

path: PathBuf

committed: bool

Implementations

impl Staged

fn new(path: &Path, contents: &[u8]) -> Result<Self, StorageError>

Writes contents, 0600, to a scratch file beside path.

fn json<T: Serialize>(path: &Path, value: &T) -> Result<Self, StorageError>

Serialises value and stages it beside path.

fn commit(self) -> Result<(), StorageError>

Renames the scratch file over its final path, and makes that durable.

Trait Implementations

impl Drop for Staged

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.