Dependency Injection Trait Locker for Uniques Pallet

bin/node/runtime/src/lib.rs

@@ -1352,6 +1352,7 @@ impl pallet_uniques::Config for Runtime {
  #[cfg(feature = "runtime-benchmarks")]
  type Helper = ();
  type CreateOrigin = AsEnsureOriginWithArg<EnsureSigned<AccountId>>;
+ type Locker = ();
 }
 
 impl pallet_transaction_storage::Config for Runtime {

frame/support/src/traits.rs

@@ -55,9 +55,9 @@ pub use misc::{
  Backing, ConstBool, ConstI128, ConstI16, ConstI32, ConstI64, ConstI8, ConstU128, ConstU16,
  ConstU32, ConstU64, ConstU8, DefensiveSaturating, EnsureInherentsAreFirst, EqualPrivilegeOnly,
  EstimateCallFee, ExecuteBlock, ExtrinsicCall, Get, GetBacking, GetDefault, HandleLifetime,
- IsSubType, IsType, Len, OffchainWorker, OnKilledAccount, OnNewAccount, PreimageProvider,
- PreimageRecipient, PrivilegeCmp, SameOrOther, Time, TryCollect, TryDrop, UnixTime,
- WrapperKeepOpaque, WrapperOpaque,
+ IsSubType, IsType, Len, Locker, OffchainWorker, OnKilledAccount, OnNewAccount,
+ PreimageProvider, PreimageRecipient, PrivilegeCmp, SameOrOther, Time, TryCollect, TryDrop,
+ UnixTime, WrapperKeepOpaque, WrapperOpaque,
 };
 #[doc(hidden)]
 pub use misc::{DEFENSIVE_OP_INTERNAL_ERROR, DEFENSIVE_OP_PUBLIC_ERROR};

frame/support/src/traits/misc.rs

@@ -950,6 +950,24 @@ impl<Hash> PreimageRecipient<Hash> for () {
  fn unnote_preimage(_: &Hash) {}
 }
 
+/// Trait to handle asset locking mechanism to ensure interactions with the asset can be implemented
+/// downstream to extend logic of Uniques current functionality
+pub trait Locker<ClassId, InstanceId> {
+ /// Check if the asset should be locked and prevent interactions with the asset from executing.
+ fn is_locked(class: ClassId, instance: InstanceId) -> bool;
+}
+
+impl<ClassId, InstanceId> Locker<ClassId, InstanceId> for () {
+ /// Check if the asset should be locked and prevent interactions with the asset from executing.
+ /// Default will be false if not implemented downstream
+ ///
+ /// Note: The logic check in this function must be constant time and consistent for benchmarks
+ /// to work
+ fn is_locked(_class: ClassId, _instance: InstanceId) -> bool {
+ false
+ }
+}
+
 #[cfg(test)]
 mod test {
  use super::*;

frame/uniques/src/functions.rs

@@ -33,6 +33,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
  ) -> DispatchResult {
  let class_details = Class::<T, I>::get(&class).ok_or(Error::<T, I>::UnknownClass)?;
  ensure!(!class_details.is_frozen, Error::<T, I>::Frozen);
+ ensure!(!T::Locker::is_locked(class, instance), Error::<T, I>::Locked);
 
  let mut details =
  Asset::<T, I>::get(&class, &instance).ok_or(Error::<T, I>::UnknownClass)?;

frame/uniques/src/lib.rs

@@ -43,7 +43,7 @@ pub mod weights;
 
 use codec::{Decode, Encode};
 use frame_support::traits::{
- BalanceStatus::Reserved, Currency, EnsureOriginWithArg, ReservableCurrency,
+ BalanceStatus::Reserved, Currency, EnsureOriginWithArg, Locker, ReservableCurrency,
 };
 use frame_system::Config as SystemConfig;
 use sp_runtime::{
@@ -108,6 +108,9 @@ pub mod pallet {
  Self::ClassId,
  >;
 
+ /// Locker trait to enable Locking mechanism downstream
+ type Locker: Locker<Self::ClassId, Self::InstanceId>;
+
  /// The basic amount of funds that must be reserved for an asset class.
  #[pallet::constant]
  type ClassDeposit: Get<DepositBalanceOf<Self, I>>;
@@ -352,6 +355,8 @@ pub mod pallet {
  Unapproved,
  /// The named owner has not signed ownership of the class is acceptable.
  Unaccepted,
+ /// The asset instance is locked.
+ Locked,
  }
 
  impl<T: Config<I>, I: 'static> Pallet<T, I> {

frame/uniques/src/mock.rs

@@ -91,6 +91,7 @@ impl Config for Test {
  type Currency = Balances;
  type CreateOrigin = AsEnsureOriginWithArg<frame_system::EnsureSigned<u64>>;
  type ForceOrigin = frame_system::EnsureRoot<u64>;
+ type Locker = ();
  type ClassDeposit = ConstU64<2>;
  type InstanceDeposit = ConstU64<1>;
  type MetadataDepositBase = ConstU64<1>;