Struct MemoryStore 

pub struct MemoryStore(/* private fields */);

A session kept in memory, such as for tests or where there is no file system. Cloning shares the contents.

Trait Implementations

impl Clone for MemoryStore

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for MemoryStore

fn default() -> Self

Returns the “default value” for a type.

impl Files for MemoryStore

fn write_file(&self, name: &str, bytes: &[u8]) -> Result<()>

Replaces the file name with bytes, atomically: a reader sees the old content or the new.

fn append_file(&self, name: &str, bytes: &[u8]) -> Result<()>

Adds bytes at the end of the file name, which it creates when there is none.

fn read_file(&self, name: &str) -> Result<Vec<u8>>

The file name; io::ErrorKind::NotFound when there is none.

fn remove_file(&self, name: &str) -> Result<()>

Removes the file name; removing one that is not there succeeds.

fn files(&self) -> Result<Vec<String>>

The names of the files, in no particular order.

impl Store for MemoryStore

fn logs(&self) -> Result<Vec<String>>

The names of the logs, in no particular order.

fn read_log(&self, name: &str) -> Result<Vec<u8>>

The whole log name; io::ErrorKind::NotFound when there is none.

fn append_log( &self, name: &str, len: u64, bytes: &[u8], ) -> Result<(), LogWriteError>

Appends bytes to the log name if it is len bytes long now (0 when there is none, which it then starts); else LogWriteError::Changed, writing nothing. The check and the append are one step for every writer of the store, other processes included, so of two writers that read the log at the same length one appends and the other is refused. A log that shrank and grew back to exactly len bytes since it was read is not told apart; rig shrinks a log only by setting a torn last line aside, or by rewrite and Self::destroy, which are for a stopped session.

fn replace_log( &self, name: &str, len: u64, bytes: &[u8], ) -> Result<(), LogWriteError>

Replaces the log name with bytes, under the condition Self::append_log has, atomically and durably: a reader, and a crash or power loss, leave the old log or the new, never a part of either or an empty file; an append after it goes after the new bytes. Starts the log when there is none.

fn destroy(&self) -> Result<()>

Removes everything the store holds: logs and files. Idempotent: calling it again after a crash midway finishes the job.