Add SetMaintainer trait and implement for signature bridge

pallets/signature-bridge/src/lib.rs

@@ -61,6 +61,7 @@ use codec::{self, Decode, Encode, EncodeLike, MaxEncodedLen};
 use frame_support::{
 	pallet_prelude::{ensure, DispatchResultWithPostInfo},
 	traits::{EnsureOrigin, Get},
+	BoundedVec,
 };
 use frame_system::{self as system, ensure_root};
 pub use pallet::*;
@@ -71,7 +72,8 @@ use sp_runtime::{
 };
 use sp_std::{convert::TryInto, prelude::*};
 use webb_primitives::{
-	signing::SigningSystem, utils::compute_chain_id_type, webb_proposals::ResourceId,
+	signature_bridge::SetMaintainer, signing::SigningSystem, utils::compute_chain_id_type,
+	webb_proposals::ResourceId,
 };
 pub use weights::WeightInfo;
 
@@ -86,6 +88,7 @@ pub mod pallet {
 	};
 	use frame_system::pallet_prelude::*;
 	use sp_runtime::traits::AtLeast32Bit;
+	use webb_primitives::signature_bridge::SetMaintainer;
 
 	#[pallet::pallet]
 	#[pallet::generate_store(pub(super) trait Store)]
@@ -138,6 +141,7 @@ pub mod pallet {
 
 		/// Signature verification utility over public key infrastructure
 		type SignatureVerifier: SigningSystem;
+
 		/// The identifier for this chain.
 		/// This must be unique and must not collide with existing IDs within a
 		/// set of bridged chains.
@@ -589,6 +593,29 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	}
 }
 
+/// Implements the SetMaintainer post-processing hook for the pallet
+impl<T: Config<I>, I: 'static> SetMaintainer<T::MaintainerNonce, T::MaxStringLength>
+	for Pallet<T, I>
+{
+	fn set_maintainer(
+		nonce: T::MaintainerNonce,
+		new_maintainer: BoundedVec<u8, T::MaxStringLength>,
+	) -> Result<(), DispatchError> {
+		let next_maintainer_nonce = MaintainerNonce::<T, I>::get() + 1u32.into();
+		// Nonce should increment by 1
+		ensure!(next_maintainer_nonce == nonce, Error::<T, I>::InvalidNonce);
+		// set the new maintainer nonce
+		MaintainerNonce::<T, I>::put(nonce);
+		// set the new maintainer
+		Maintainer::<T, I>::try_mutate(|maintainer| {
+			let old_maintainer = maintainer.clone();
+			*maintainer = new_maintainer.clone();
+			Self::deposit_event(Event::MaintainerSet { old_maintainer, new_maintainer });
+			Ok(().into())
+		})
+	}
+}
+
 /// Simple ensure origin for the bridge account
 #[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo, RuntimeDebug)]
 pub struct EnsureBridge<T, I>(sp_std::marker::PhantomData<(T, I)>);

primitives/src/traits/mod.rs

@@ -3,4 +3,5 @@ pub mod key_storage;
 pub mod linkable_tree;
 pub mod merkle_tree;
 pub mod mixer;
+pub mod signature_bridge;
 pub mod vanchor;

primitives/src/traits/signature_bridge.rs

@@ -0,0 +1,12 @@
+//! All the traits exposed to be used in other custom pallets
+use frame_support::{dispatch, BoundedVec};
+
+/// Post-processing hook for setting a maintainer after a maintainer is selected
+/// in some external process.
+pub trait SetMaintainer<N, M> {
+	/// Set the maintainer of the pallet.
+	fn set_maintainer(
+		nonce: N,
+		maintainer: BoundedVec<u8, M>,
+	) -> Result<(), dispatch::DispatchError>;
+}