Substrate的transaction-payment模块分析

transaction-payment模块提供了转账包括的最小数量的手续费收取逻辑。

• weight fee:根据一个交易所消耗重量成比例的手续费。
• length fee:根据一个交易编码后长度成比例的手续费。
• tip:加速小费，更高小费，更快进入交易队列。

额外，还可以允许去配置如下：

• [WeightToFee] : 一个单位的重点对应到的费用设置mapping。
• [FeeMultiplierUpdate] : 基于之前一个区块的重量，乘以一个multiplier，用来更新下一个区块的费用。

Trait

/// The currency type in which fees will be paid.
type Currency: Currency<Self::AccountId>;

/// Handler for the unbalanced reduction when taking transaction fees.
type OnTransactionPayment: OnUnbalanced<NegativeImbalanceOf<Self>>;

/// The fee to be paid for making a transaction; the base.
type TransactionBaseFee: Get<BalanceOf<Self>>;

/// The fee to be paid for making a transaction; the per-byte portion.
type TransactionByteFee: Get<BalanceOf<Self>>;

/// Convert a weight value into a deductible fee based on the currency type.
type WeightToFee: Convert<Weight, BalanceOf<Self>>;

/// Update the multiplier of the next block, based on the previous block's weight.
type FeeMultiplierUpdate: Convert<Multiplier, Multiplier>;

Store

NextFeeMultiplier get(fn next_fee_multiplier): Multiplier = Multiplier::from_parts(0);

Module

fn on_finalize() {
    NextFeeMultiplier::mutate(|fm| {
        *fm = T::FeeMultiplierUpdate::convert(*fm)
    });
}

• pub fn query_info<Extrinsic: GetDispatchInfo>(unchecked_extrinsic: Extrinsic,len: u32,) -> RuntimeDispatchInfo<BalanceOf<T>>
  • 询问指定调用的数据相应的费用

ChargeTransactionPayment

pub struct ChargeTransactionPayment<T: Trait + Send + Sync>(#[codec(compact)] BalanceOf<T>);

• fn compute_fee(len: u32,info: DispatchInfo, tip: BalanceOf<T>) -> BalanceOf<T>