feat(tokens): OnDeposit, OnTransfer, OnSlash hooks

Author: daniel-savu

asset-registry/src/mock/para.rs

@@ -93,6 +93,9 @@ impl orml_tokens::Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = ();
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type ReserveIdentifier = [u8; 8];
 	type MaxReserves = ();
 	type MaxLocks = ConstU32<50>;

currencies/src/mock.rs

@@ -81,6 +81,9 @@ impl orml_tokens::Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = orml_tokens::TransferDust<Runtime, DustAccount>;
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type MaxLocks = ConstU32<100_000>;
 	type MaxReserves = ConstU32<100_000>;
 	type ReserveIdentifier = ReserveIdentifier;

payments/src/mock.rs

@@ -99,6 +99,9 @@ impl orml_tokens::Config for Test {
 	type Event = Event;
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = ();
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type WeightInfo = ();
 	type MaxLocks = MaxLocks;
 	type DustRemovalWhitelist = MockDustRemovalWhitelist;

tokens/src/lib.rs

@@ -66,7 +66,7 @@ use sp_std::{cmp, convert::Infallible, marker, prelude::*, vec::Vec};
 
 use orml_traits::{
 	arithmetic::{self, Signed},
-	currency::TransferAll,
+	currency::{OnDeposit, OnSlash, OnTransfer, TransferAll},
 	BalanceStatus, GetByKey, Happened, LockIdentifier, MultiCurrency, MultiCurrencyExtended, MultiLockableCurrency,
 	MultiReservableCurrency, NamedMultiReservableCurrency, OnDust,
 };
@@ -173,6 +173,8 @@ pub use module::*;
 
 #[frame_support::pallet]
 pub mod module {
+	use orml_traits::currency::{OnDeposit, OnSlash, OnTransfer};
+
 	use super::*;
 
 	#[pallet::config]
@@ -216,6 +218,15 @@ pub mod module {
 		/// Handler to burn or transfer account's dust
 		type OnDust: OnDust<Self::AccountId, Self::CurrencyId, Self::Balance>;
 
+		/// Hook to run before slashing an account.
+		type OnSlash: OnSlash<Self::AccountId, Self::CurrencyId, Self::Balance>;
+
+		/// Hook to run before depositing into an account.
+		type OnDeposit: OnDeposit<Self::AccountId, Self::CurrencyId, Self::Balance>;
+
+		/// Hook to run before transferring from an account to another.
+		type OnTransfer: OnTransfer<Self::AccountId, Self::CurrencyId, Self::Balance>;
+
 		/// Handler for when an account was created
 		type OnNewTokenAccount: Happened<(Self::AccountId, Self::CurrencyId)>;
 
@@ -890,6 +901,7 @@ impl<T: Config> Pallet<T> {
 		amount: T::Balance,
 		existence_requirement: ExistenceRequirement,
 	) -> DispatchResult {
+		T::OnTransfer::on_transfer(currency_id, from, to, amount)?;
 		if amount.is_zero() || from == to {
 			return Ok(());
 		}
@@ -1015,6 +1027,7 @@ impl<T: Config> Pallet<T> {
 		require_existed: bool,
 		change_total_issuance: bool,
 	) -> DispatchResult {
+		T::OnDeposit::on_deposit(currency_id, who, amount)?;
 		if amount.is_zero() {
 			return Ok(());
 		}
@@ -1110,6 +1123,7 @@ impl<T: Config> MultiCurrency<T::AccountId> for Pallet<T> {
 	/// reserved funds, however we err on the side of punishment if things
 	/// are inconsistent or `can_slash` wasn't used appropriately.
 	fn slash(currency_id: Self::CurrencyId, who: &T::AccountId, amount: Self::Balance) -> Self::Balance {
+		T::OnSlash::on_slash(currency_id, who, amount);
 		if amount.is_zero() {
 			return amount;
 		}
@@ -1276,6 +1290,7 @@ impl<T: Config> MultiReservableCurrency<T::AccountId> for Pallet<T> {
 	///
 	/// Is a no-op if the value to be slashed is zero.
 	fn slash_reserved(currency_id: Self::CurrencyId, who: &T::AccountId, value: Self::Balance) -> Self::Balance {
+		T::OnSlash::on_slash(currency_id, who, value);
 		if value.is_zero() {
 			return value;
 		}

tokens/src/mock.rs

@@ -280,6 +280,9 @@ impl Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = TransferDust<Runtime, DustReceiver>;
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type OnNewTokenAccount = TrackCreatedAccounts;
 	type OnKilledTokenAccount = TrackKilledAccounts;
 	type MaxLocks = ConstU32<2>;

traits/src/currency.rs

@@ -657,3 +657,34 @@ impl<AccountId> TransferAll<AccountId> for Tuple {
 		Ok(())
 	}
 }
+
+/// Hook to run before slashing an account.
+pub trait OnSlash<AccountId, CurrencyId, Balance> {
+	fn on_slash(currency_id: CurrencyId, who: &AccountId, amount: Balance);
+}
+
+impl<AccountId, CurrencyId, Balance> OnSlash<AccountId, CurrencyId, Balance> for () {
+	fn on_slash(_: CurrencyId, _: &AccountId, _: Balance) {}
+}
+
+/// Hook to run before depositing into an account.
+pub trait OnDeposit<AccountId, CurrencyId, Balance> {
+	fn on_deposit(currency_id: CurrencyId, who: &AccountId, amount: Balance) -> DispatchResult;
+}
+
+impl<AccountId, CurrencyId, Balance> OnDeposit<AccountId, CurrencyId, Balance> for () {
+	fn on_deposit(_: CurrencyId, _: &AccountId, _: Balance) -> DispatchResult {
+		Ok(())
+	}
+}
+
+/// Hook to run before transferring from an account to another.
+pub trait OnTransfer<AccountId, CurrencyId, Balance> {
+	fn on_transfer(currency_id: CurrencyId, from: &AccountId, to: &AccountId, amount: Balance) -> DispatchResult;
+}
+
+impl<AccountId, CurrencyId, Balance> OnTransfer<AccountId, CurrencyId, Balance> for () {
+	fn on_transfer(_: CurrencyId, _: &AccountId, _: &AccountId, _: Balance) -> DispatchResult {
+		Ok(())
+	}
+}

xtokens/src/mock/para.rs

@@ -84,6 +84,9 @@ impl orml_tokens::Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = ();
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type MaxLocks = ConstU32<50>;
 	type MaxReserves = ConstU32<50>;
 	type ReserveIdentifier = [u8; 8];

xtokens/src/mock/para_relative_view.rs

@@ -87,6 +87,9 @@ impl orml_tokens::Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = ();
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type MaxLocks = ConstU32<50>;
 	type MaxReserves = ConstU32<50>;
 	type ReserveIdentifier = [u8; 8];

xtokens/src/mock/para_teleport.rs

@@ -85,6 +85,9 @@ impl orml_tokens::Config for Runtime {
 	type WeightInfo = ();
 	type ExistentialDeposits = ExistentialDeposits;
 	type OnDust = ();
+	type OnSlash = ();
+	type OnDeposit = ();
+	type OnTransfer = ();
 	type MaxLocks = ConstU32<50>;
 	type MaxReserves = ConstU32<50>;
 	type ReserveIdentifier = [u8; 8];