Trait sp_database::Database

pub trait Database<H: Clone + AsRef<[u8]>>: Send + Sync {
    // Required methods
    fn commit(&self, transaction: Transaction<H>) -> Result<()>;
    fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>>;

    // Provided methods
    fn contains(&self, col: ColumnId, key: &[u8]) -> bool { ... }
    fn value_size(&self, col: ColumnId, key: &[u8]) -> Option<usize> { ... }
    fn with_get(&self, col: ColumnId, key: &[u8], f: &mut dyn FnMut(&[u8])) { ... }
    fn supports_ref_counting(&self) -> bool { ... }
    fn sanitize_key(&self, _key: &mut Vec<u8>) { ... }
}

Required Methods

fn commit(&self, transaction: Transaction<H>) -> Result<()>

Commit the transaction to the database atomically. Any further calls to get or lookup will reflect the new state.

fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>>

Retrieve the value previously stored against key or None if key is not currently in the database.

Provided Methods

fn contains(&self, col: ColumnId, key: &[u8]) -> bool

Check if the value exists in the database without retrieving it.

fn value_size(&self, col: ColumnId, key: &[u8]) -> Option<usize>

Check value size in the database possibly without retrieving it.

fn with_get(&self, col: ColumnId, key: &[u8], f: &mut dyn FnMut(&[u8]))

Call f with the value previously stored against key.

This may be faster than get since it doesn’t allocate. Use with_get helper function if you need f to return a value from f

fn supports_ref_counting(&self) -> bool

Check if database supports internal ref counting for state data.

For backwards compatibility returns false by default.

fn sanitize_key(&self, _key: &mut Vec<u8>)

Remove a possible path-prefix from the key.

Not all database implementations use a prefix for keys, so this function may be a noop.

Trait Implementations

impl<H> Debug for dyn Database<H>

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

Formats the value using the given formatter.

Implementors

impl<H> Database<H> for MemDbwhere H: Clone + AsRef<[u8]>,