pallet_assets_freezer/lib.rs
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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: MIT-0
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
// of the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//! # Assets Freezer Pallet
//!
//! A pallet capable of freezing fungibles from `pallet-assets`. This is an extension of
//! `pallet-assets`, wrapping [`fungibles::Inspect`](`Inspect`).
//! It implements both
//! [`fungibles::freeze::Inspect`](InspectFreeze) and
//! [`fungibles::freeze::Mutate`](MutateFreeze). The complexity
//! of the operations is `O(n)`. where `n` is the variant count of `RuntimeFreezeReason`.
//!
//! ## Pallet API
//!
//! See the [`pallet`] module for more information about the interfaces this pallet exposes,
//! including its configuration trait, dispatchables, storage items, events and errors.
//!
//! ## Overview
//!
//! This pallet provides the following functionality:
//!
//! - Pallet hooks allowing [`pallet-assets`] to know the frozen balance for an account on a given
//! asset (see [`pallet_assets::FrozenBalance`]).
//! - An implementation of [`fungibles::freeze::Inspect`](InspectFreeze) and
//! [`fungibles::freeze::Mutate`](MutateFreeze), allowing other pallets to manage freezes for the
//! `pallet-assets` assets.
#![cfg_attr(not(feature = "std"), no_std)]
use frame::{
prelude::*,
traits::{
fungibles::{Inspect, InspectFreeze, MutateFreeze},
tokens::{
DepositConsequence, Fortitude, IdAmount, Preservation, Provenance, WithdrawConsequence,
},
},
};
pub use pallet::*;
#[cfg(feature = "try-runtime")]
use frame::try_runtime::TryRuntimeError;
#[cfg(test)]
mod mock;
#[cfg(test)]
mod tests;
mod impls;
#[frame::pallet]
pub mod pallet {
use super::*;
#[pallet::config(with_default)]
pub trait Config<I: 'static = ()>: frame_system::Config + pallet_assets::Config<I> {
/// The overarching freeze reason.
#[pallet::no_default_bounds]
type RuntimeFreezeReason: Parameter + Member + MaxEncodedLen + Copy + VariantCount;
/// The overarching event type.
#[pallet::no_default_bounds]
type RuntimeEvent: From<Event<Self, I>>
+ IsType<<Self as frame_system::Config>::RuntimeEvent>;
}
#[pallet::error]
pub enum Error<T, I = ()> {
/// Number of freezes on an account would exceed `MaxFreezes`.
TooManyFreezes,
}
#[pallet::pallet]
pub struct Pallet<T, I = ()>(_);
#[pallet::event]
#[pallet::generate_deposit(pub(super) fn deposit_event)]
pub enum Event<T: Config<I>, I: 'static = ()> {
// `who`s frozen balance was increased by `amount`.
Frozen { who: T::AccountId, asset_id: T::AssetId, amount: T::Balance },
// `who`s frozen balance was decreased by `amount`.
Thawed { who: T::AccountId, asset_id: T::AssetId, amount: T::Balance },
}
/// A map that stores freezes applied on an account for a given AssetId.
#[pallet::storage]
pub type Freezes<T: Config<I>, I: 'static = ()> = StorageDoubleMap<
_,
Blake2_128Concat,
T::AssetId,
Blake2_128Concat,
T::AccountId,
BoundedVec<
IdAmount<T::RuntimeFreezeReason, T::Balance>,
VariantCountOf<T::RuntimeFreezeReason>,
>,
ValueQuery,
>;
/// A map that stores the current total frozen balance for every account on a given AssetId.
#[pallet::storage]
pub type FrozenBalances<T: Config<I>, I: 'static = ()> = StorageDoubleMap<
_,
Blake2_128Concat,
T::AssetId,
Blake2_128Concat,
T::AccountId,
T::Balance,
>;
#[pallet::hooks]
impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Pallet<T, I> {
#[cfg(feature = "try-runtime")]
fn try_state(_: BlockNumberFor<T>) -> Result<(), TryRuntimeError> {
Self::do_try_state()
}
}
}
impl<T: Config<I>, I: 'static> Pallet<T, I> {
fn update_freezes(
asset: T::AssetId,
who: &T::AccountId,
freezes: BoundedSlice<
IdAmount<T::RuntimeFreezeReason, T::Balance>,
VariantCountOf<T::RuntimeFreezeReason>,
>,
) -> DispatchResult {
let prev_frozen = FrozenBalances::<T, I>::get(asset.clone(), who).unwrap_or_default();
let after_frozen = freezes.into_iter().map(|f| f.amount).max().unwrap_or_else(Zero::zero);
FrozenBalances::<T, I>::set(asset.clone(), who, Some(after_frozen));
if freezes.is_empty() {
Freezes::<T, I>::remove(asset.clone(), who);
FrozenBalances::<T, I>::remove(asset.clone(), who);
} else {
Freezes::<T, I>::insert(asset.clone(), who, freezes);
}
if prev_frozen > after_frozen {
let amount = prev_frozen.saturating_sub(after_frozen);
Self::deposit_event(Event::Thawed { asset_id: asset, who: who.clone(), amount });
} else if after_frozen > prev_frozen {
let amount = after_frozen.saturating_sub(prev_frozen);
Self::deposit_event(Event::Frozen { asset_id: asset, who: who.clone(), amount });
}
Ok(())
}
#[cfg(feature = "try-runtime")]
fn do_try_state() -> Result<(), TryRuntimeError> {
for (asset, who, _) in FrozenBalances::<T, I>::iter() {
let max_frozen_amount =
Freezes::<T, I>::get(asset.clone(), who.clone()).iter().map(|l| l.amount).max();
ensure!(
FrozenBalances::<T, I>::get(asset, who) == max_frozen_amount,
"The `FrozenAmount` is not equal to the maximum amount in `Freezes` for (`asset`, `who`)"
);
}
Ok(())
}
}