Trait polkadot_runtime_common::traits::Leaser

pub trait Leaser<BlockNumber> {
    type AccountId;
    type LeasePeriod;
    type Currency: ReservableCurrency<Self::AccountId>;

    fn lease_out(
        para: ParaId,
        leaser: &Self::AccountId,
        amount: <Self::Currency as Currency<Self::AccountId>>::Balance,
        period_begin: Self::LeasePeriod,
        period_count: Self::LeasePeriod
    ) -> Result<(), LeaseError>;
    fn deposit_held(
        para: ParaId,
        leaser: &Self::AccountId
    ) -> <Self::Currency as Currency<Self::AccountId>>::Balance;
    fn lease_period_length() -> (BlockNumber, BlockNumber);
    fn lease_period_index(
        block: BlockNumber
    ) -> Option<(Self::LeasePeriod, bool)>;
    fn already_leased(
        para_id: ParaId,
        first_period: Self::LeasePeriod,
        last_period: Self::LeasePeriod
    ) -> bool;
}

Lease manager. Used by the auction module to handle parachain slot leases.

Required Associated Types

type AccountId

An account identifier for a leaser.

type LeasePeriod

The measurement type for counting lease periods (generally just a BlockNumber).

type Currency: ReservableCurrency<Self::AccountId>

The currency type in which the lease is taken.

Required Methods

fn lease_out(
    para: ParaId,
    leaser: &Self::AccountId,
    amount: <Self::Currency as Currency<Self::AccountId>>::Balance,
    period_begin: Self::LeasePeriod,
    period_count: Self::LeasePeriod
) -> Result<(), LeaseError>

Lease a new parachain slot for para.

leaser shall have a total of amount balance reserved by the implementer of this trait.

Note: The implementer of the trait (the leasing system) is expected to do all reserve/unreserve calls. The caller of this trait SHOULD NOT pre-reserve the deposit (though should ensure that it is reservable).

The lease will last from period_begin for period_count lease periods. It is undefined if the para already has a slot leased during those periods.

Returns Err in the case of an error, and in which case nothing is changed.

fn deposit_held(
    para: ParaId,
    leaser: &Self::AccountId
) -> <Self::Currency as Currency<Self::AccountId>>::Balance

Return the amount of balance currently held in reserve on leaser’s account for leasing para. This won’t go down outside a lease period.

fn lease_period_length() -> (BlockNumber, BlockNumber)

The length of a lease period, and any offset which may be introduced. This is only used in benchmarking to automate certain calls.

fn lease_period_index(block: BlockNumber) -> Option<(Self::LeasePeriod, bool)>

Returns the lease period at block, and if this is the first block of a new lease period.

Will return None if the first lease period has not started yet, for example when an offset is placed.

fn already_leased(
    para_id: ParaId,
    first_period: Self::LeasePeriod,
    last_period: Self::LeasePeriod
) -> bool

Returns true if the parachain already has a lease in any of lease periods in the inclusive range [first_period, last_period], intersected with the unbounded range [current_lease_period..] .

Implementors

impl<T: Config> Leaser<<T as Config>::BlockNumber> for Pallet<T>

type AccountId = <T as Config>::AccountId

type LeasePeriod = <T as Config>::BlockNumber

type Currency = <T as Config>::Currency