Struct StorageLock

pub struct StorageLock<'a, L = Time> { /* private fields */ }

Storage based lock.

A lock that is persisted in the DB and provides the ability to guard against concurrent access in an off-chain worker, with a defined expiry deadline based on the concrete Lockable implementation.

Implementations

impl<'a, L: Lockable + Default> StorageLock<'a, L>

pub fn new(key: &'a [u8]) -> Self

Create a new storage lock with a default() instance of type L.

impl<'a, L: Lockable> StorageLock<'a, L>

pub fn with_lockable(key: &'a [u8], lockable: L) -> Self

Create a new storage lock with an explicit instance of a lockable L.

pub fn try_lock( &mut self, ) -> Result<StorageLockGuard<'a, '_, L>, <L as Lockable>::Deadline>

A single attempt to lock using the storage entry.

Returns a lock guard on success, otherwise an error containing the <Self::Lockable>::Deadline in for the currently active lock by another task Err(<L as Lockable>::Deadline).

pub fn lock(&mut self) -> StorageLockGuard<'a, '_, L>

Repeated lock attempts until the lock is successfully acquired.

If one uses fn forget(..), it is highly likely fn try_lock(..) is the correct API to use instead of fn lock(..), since that might never unlock in the anticipated span i.e. when used with BlockAndTime during a certain block number span.

impl<'a> StorageLock<'a, Time>

pub fn with_deadline(key: &'a [u8], expiration_duration: Duration) -> Self

Explicitly create a time based storage lock with a non-default expiration timeout.

impl<'a, B> StorageLock<'a, BlockAndTime<B>>

where B: BlockNumberProvider,

pub fn with_block_and_time_deadline( key: &'a [u8], expiration_block_number_offset: u32, expiration_duration: Duration, ) -> Self

Explicitly create a time and block number based storage lock with a non-default expiration duration and block number offset.

pub fn with_block_deadline( key: &'a [u8], expiration_block_number_offset: u32, ) -> Self

Explicitly create a time and block number based storage lock with the default expiration duration and a non-default block number offset.