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Module sui_system::stake_subsidy

use std::address;
use std::ascii;
use std::bcs;
use std::option;
use std::string;
use std::type_name;
use std::u64;
use std::vector;
use sui::address;
use sui::bag;
use sui::balance;
use sui::coin;
use sui::config;
use sui::deny_list;
use sui::dynamic_field;
use sui::dynamic_object_field;
use sui::event;
use sui::hex;
use sui::object;
use sui::sui;
use sui::table;
use sui::transfer;
use sui::tx_context;
use sui::types;
use sui::url;
use sui::vec_set;

Struct StakeSubsidy​

public struct StakeSubsidy has store
Click to open
Fields
balance: sui::balance::Balance<sui::sui::SUI>
Balance of SUI set aside for stake subsidies that will be drawn down over time.
distribution_counter: u64
Count of the number of times stake subsidies have been distributed.
current_distribution_amount: u64
The amount of stake subsidy to be drawn down per distribution. This amount decays and decreases over time.
stake_subsidy_period_length: u64
Number of distributions to occur before the distribution amount decays.
stake_subsidy_decrease_rate: u16
The rate at which the distribution amount decays at the end of each period. Expressed in basis points.
extra_fields: sui::bag::Bag
Any extra fields that's not defined statically.

Constants​

const BASIS_POINT_DENOMINATOR: u128 = 10000;


const ESubsidyDecreaseRateTooLarge: u64 = 0;

Function create​

public(package) fun create(balance: sui::balance::Balance<sui::sui::SUI>, initial_distribution_amount: u64, stake_subsidy_period_length: u64, stake_subsidy_decrease_rate: u16, ctx: &mut sui::tx_context::TxContext): sui_system::stake_subsidy::StakeSubsidy
Click to open
Implementation
public(package) fun create(
    balance: Balance<SUI>,
    initial_distribution_amount: u64,
    stake_subsidy_period_length: u64,
    stake_subsidy_decrease_rate: u16,
    ctx: &mut TxContext,
): StakeSubsidy {
    // Rate can't be higher than 100%.
    assert!(
        stake_subsidy_decrease_rate <= BASIS_POINT_DENOMINATOR as u16,
        ESubsidyDecreaseRateTooLarge,
    );
    StakeSubsidy {
        balance,
        distribution_counter: 0,
        current_distribution_amount: initial_distribution_amount,
        stake_subsidy_period_length,
        stake_subsidy_decrease_rate,
        extra_fields: bag::new(ctx),
    }
}

Function advance_epoch​

Advance the epoch counter and draw down the subsidy for the epoch.

public(package) fun advance_epoch(self: &mut sui_system::stake_subsidy::StakeSubsidy): sui::balance::Balance<sui::sui::SUI>
Click to open
Implementation
public(package) fun advance_epoch(self: &mut StakeSubsidy): Balance<SUI> {
    // Take the minimum of the reward amount and the remaining balance in
    // order to ensure we don't overdraft the remaining stake subsidy
    // balance
    let to_withdraw = self.current_distribution_amount.min(self.balance.value());
    // Drawn down the subsidy for this epoch.
    let stake_subsidy = self.balance.split(to_withdraw);
    self.distribution_counter = self.distribution_counter + 1;
    // Decrease the subsidy amount only when the current period ends.
    if (self.distribution_counter % self.stake_subsidy_period_length == 0) {
        let decrease_amount = self.current_distribution_amount as u128
            * (self.stake_subsidy_decrease_rate as u128) / BASIS_POINT_DENOMINATOR;
        self.current_distribution_amount = self.current_distribution_amount - (decrease_amount as u64)
    };
    stake_subsidy
}

Function current_epoch_subsidy_amount​

Returns the amount of stake subsidy to be added at the end of the current epoch.

public fun current_epoch_subsidy_amount(self: &sui_system::stake_subsidy::StakeSubsidy): u64
Click to open
Implementation
public fun current_epoch_subsidy_amount(self: &StakeSubsidy): u64 {
    self.current_distribution_amount.min(self.balance.value())
}

Function get_distribution_counter​

Returns the number of distributions that have occurred.

public(package) fun get_distribution_counter(self: &sui_system::stake_subsidy::StakeSubsidy): u64
Click to open
Implementation
public(package) fun get_distribution_counter(self: &StakeSubsidy): u64 {
    self.distribution_counter
}