Trait JournalStore 

pub trait JournalStore: Send + Sync {
    // Required methods
    fn capabilities(&self) -> JournalCapabilities;
    fn append(
        &self,
        actor: &NamedNode,
        expected: Position,
        entries: &[Entry],
        meta: &AppendMeta,
    ) -> Result<Position, AppendError>;
    fn read(
        &self,
        actor: &NamedNode,
        from: Position,
    ) -> Result<Vec<JournalRecord>, StoreError>;
    fn head(&self, actor: &NamedNode) -> Result<Position, StoreError>;
    fn actors(&self) -> Result<Vec<NamedNode>, StoreError>;

    // Provided method
    fn supports_fencing(&self) -> bool { ... }
}

A journal store: per actor address, a linearizable, all-or-nothing append at an expected position, and reads from a position.

Required Methods

fn capabilities(&self) -> JournalCapabilities

What the store supports beyond compare-and-set.

fn append( &self, actor: &NamedNode, expected: Position, entries: &[Entry], meta: &AppendMeta, ) -> Result<Position, AppendError>

Appends entries to actor’s journal if, and only if, its last entry is at expected.

On success the entries are at expected + 1 ..= expected + entries.len() and the new head is returned. On any error nothing is written: no entry, no state change and no fencing epoch. Appends for one actor are linearizable.

Errors

AppendError::Conflict when the journal is elsewhere, AppendError::Fenced for a stale fencing epoch, AppendError::Unsupported for metadata the store does not support, AppendError::Invalid for malformed entries, AppendError::Storage when the store fails.

fn read( &self, actor: &NamedNode, from: Position, ) -> Result<Vec<JournalRecord>, StoreError>

The entries of actor’s journal from position from (inclusive; 0 reads from the start) to the head, in order.

Errors

StoreError when the store fails.

fn head(&self, actor: &NamedNode) -> Result<Position, StoreError>

The position of actor’s last entry, 0 for an empty journal.

Errors

StoreError when the store fails.

fn actors(&self) -> Result<Vec<NamedNode>, StoreError>

Every actor with at least one entry.

Errors

StoreError when the store fails.

Provided Methods

fn supports_fencing(&self) -> bool

True when the store enforces fencing tokens.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<J: JournalStore + ?Sized> JournalStore for Arc<J>

fn capabilities(&self) -> JournalCapabilities

fn append( &self, actor: &NamedNode, expected: Position, entries: &[Entry], meta: &AppendMeta, ) -> Result<Position, AppendError>

fn read( &self, actor: &NamedNode, from: Position, ) -> Result<Vec<JournalRecord>, StoreError>

fn head(&self, actor: &NamedNode) -> Result<Position, StoreError>

fn actors(&self) -> Result<Vec<NamedNode>, StoreError>

Implementors

impl JournalStore for MemoryStore