Struct FeeSponsorshipNote 

pub struct FeeSponsorshipNote { /* private fields */ }

A FEE_SPONSORSHIP note: carries the fee for exactly one feature note.

Under the sponsorship fee model, the feature note (BURN, CLAIM, B2AGG, …) stays entirely fee-unaware. The fee travels in this separate note as exactly one asset; the note names the feature note it pays for by carrying that note’s NoteId in its note storage. The note carries no attachments; its tag routes it to the network account the feature note targets.

Consumption

The note may only be consumed in a transaction that also consumes the bound feature note; it does not restrict who that consumer is. Consumption rights are thereby inherited from the feature note: whoever may consume the feature note may take its sponsorship in the same transaction. The script enforces the pairing itself, rather than relying on the account: the sponsor trusts neither the consuming account nor the transaction builder, but does choose the note’s script root.

The mirror-image check (that a feature note is not consumed without sponsorship) protects the consuming account rather than the sponsor, and so lives in the account’s auth procedure. That check binds sponsorships to feature notes by note ID, so the note can be at any position in the input notes. Several sponsorship notes may be bound to the same feature note to top up its fee between them.

Reclaim

Every consumption without the bound feature note is a reclaim: the note returns to its reclaimer once reclaim_height is reached. If the bound feature note is consumed by some other transaction, reclaim is the only way to recover the assets. A reclaim cannot happen in a transaction that also collects fees, which rejects a sponsorship whose feature note is absent.

Implementations

impl FeeSponsorshipNote

pub fn builder() -> FeeSponsorshipNoteBuilder

Builds a new FeeSponsorshipNote sponsoring feature_note_id, tagged for target.

Prefer the builder’s generate_serial_number over supplying a serial number by hand.

The fee is exactly one asset; the note script rejects notes carrying any other number of assets, which keeps fee collection simple.

The reclaimer, the account allowed to reclaim the note after reclaim_height, defaults to sender when left unset.

Errors

Returns an error if:

• the target account is not public. A network note’s tag must route to a public account.

impl FeeSponsorshipNote

pub const NUM_STORAGE_ITEMS: usize = FeeSponsorshipNoteStorage::NUM_ITEMS

Expected number of storage items of the FEE_SPONSORSHIP note.

pub fn script() -> NoteScript

Returns the script of the FEE_SPONSORSHIP note.

pub fn script_root() -> NoteScriptRoot

Returns the FEE_SPONSORSHIP note script root.

pub fn target_id(&self) -> AccountId

Returns the account ID of the network account the note’s tag routes to.

The tag is a discovery hint for the network transaction builder; the script itself does not restrict consumption to this account.

pub fn feature_note_id(&self) -> NoteId

Returns the ID of the bound feature note this note sponsors.

pub fn reclaimer(&self) -> AccountId

Returns the account ID allowed to reclaim the note after reclaim_height.

pub fn reclaim_height(&self) -> Option<BlockNumber>

Returns the block height at or after which the reclaimer may reclaim the note, if reclaim is enabled.

Trait Implementations

impl Clone for FeeSponsorshipNote

fn clone(&self) -> FeeSponsorshipNote

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FeeSponsorshipNote

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

Formats the value using the given formatter.

impl From<FeeSponsorshipNote> for Note

fn from(note: FeeSponsorshipNote) -> Note

Converts to this type from the input type.

impl NoteConsumptionCost for FeeSponsorshipNote

fn consumption_cycles() -> u32

Cycles of the canonical network-account transaction consuming this note (maximum across the benchmarked execution paths - an estimate, not a worst case).

fn created_notes() -> Vec<NoteScriptRoot>

Script roots of all the notes this note’s consumption is expected to create.