From 51c721d33df37b277a5f733f726a2450046e2e3c Mon Sep 17 00:00:00 2001
From: Michael Eberhardt <github@michael-eberhardt.de>
Date: Fri, 8 Mar 2024 14:37:07 +0100
Subject: [PATCH] feat: unique usage of balance type in interfaces

---
 pallet/src/balance.rs | 20 +++----------
 pallet/src/lib.rs     | 33 +++++++++++++++-------
 pallet/src/mock.rs    |  1 +
 pallet/src/signer.rs  | 65 ++++++++++++++++++-------------------------
 4 files changed, 55 insertions(+), 64 deletions(-)

diff --git a/pallet/src/balance.rs b/pallet/src/balance.rs
index 2d2916a..5d33114 100644
--- a/pallet/src/balance.rs
+++ b/pallet/src/balance.rs
@@ -51,10 +51,7 @@ impl<T: Config> From<Error<T>> for StatusCode {
 
 /// Balance adapter for providing basic access to balance cheques within the MoveVM.
 #[derive(Clone)]
-pub struct BalanceAdapter<T: Config + SysConfig>
-where
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+pub struct BalanceAdapter<T: Config + SysConfig> {
     _pd_config: PhantomData<T>,
     /// Virtual cheques record of involved users.
     cheques: Rc<RefCell<HashMap<EncodedAccount, BalanceOf<T>>>>,
@@ -62,10 +59,7 @@ where
     initial_state: HashMap<EncodedAccount, BalanceOf<T>>,
 }
 
-impl<T: Config + SysConfig> BalanceAdapter<T>
-where
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+impl<T: Config + SysConfig> BalanceAdapter<T> {
     /// Create a new [`BalanceAdapter`].
     pub fn new() -> Self {
         BalanceAdapter {
@@ -180,19 +174,13 @@ where
     }
 }
 
-impl<T: Config> Default for BalanceAdapter<T>
-where
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+impl<T: Config> Default for BalanceAdapter<T> {
     fn default() -> Self {
         Self::new()
     }
 }
 
-impl<T: Config> BalanceHandler for BalanceAdapter<T>
-where
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+impl<T: Config> BalanceHandler for BalanceAdapter<T> {
     type Error = StatusCode;
 
     fn transfer(
diff --git a/pallet/src/lib.rs b/pallet/src/lib.rs
index 622a90a..d4697d3 100644
--- a/pallet/src/lib.rs
+++ b/pallet/src/lib.rs
@@ -93,9 +93,22 @@ pub mod pallet {
     #[pallet::config]
     pub trait Config: frame_system::Config {
         /// The currency mechanism.
-        type Currency: Currency<Self::AccountId>
-            + ReservableCurrency<Self::AccountId>
-            + LockableCurrency<Self::AccountId>;
+        type Currency: Currency<Self::AccountId, Balance = Self::CurrencyBalance>
+            + ReservableCurrency<Self::AccountId, Balance = Self::CurrencyBalance>
+            + LockableCurrency<Self::AccountId, Balance = Self::CurrencyBalance>;
+
+        /// Just the `Currency::Balance` type; we have this item to allow us to
+        /// constrain it to `From<u128>` and `Into<u128>`.
+        type CurrencyBalance: sp_runtime::traits::AtLeast32BitUnsigned
+            + FullCodec
+            + Copy
+            + MaybeSerializeDeserialize
+            + core::fmt::Debug
+            + Default
+            + From<u128>
+            + Into<u128>
+            + TypeInfo
+            + MaxEncodedLen;
 
         /// Maximum life time for requests.
         #[pallet::constant]
@@ -171,8 +184,8 @@ pub mod pallet {
 
     #[pallet::hooks]
     impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T>
-    where
-        BalanceOf<T>: From<u128> + Into<u128>,
+    // where
+    //     BalanceOf<T>: From<u128> + Into<u128> + Default,
     {
         fn on_idle(block_height: BlockNumberFor<T>, mut remaining_weight: Weight) -> Weight {
             let len = MultisigStorage::<T>::iter_keys().count() as u64;
@@ -235,8 +248,8 @@ pub mod pallet {
     // Dispatchable functions must be annotated with a weight and must return a DispatchResult.
     #[pallet::call]
     impl<T: Config> Pallet<T>
-    where
-        BalanceOf<T>: From<u128> + Into<u128>,
+    // where
+    //     BalanceOf<T>: From<u128> + Into<u128> + Default,
     {
         /// Execute Move script transaction sent by the user.
         // TODO(eiger) in M3: ensure the weight depends on basic extrinsic cost + gas_limit + size of the
@@ -288,7 +301,7 @@ pub mod pallet {
             };
             if signer_count > 0 {
                 let lock_id = Self::multi_signer_lock_id(&who, &transaction_bc[..], &cheque_limit);
-                signature_handler.sign_script(&who, cheque_limit.into(), lock_id)?;
+                signature_handler.sign_script(&who, &cheque_limit, lock_id)?;
             }
 
             // If the script is signed correctly, we can execute it in MoveVM and update the
@@ -413,8 +426,8 @@ pub mod pallet {
     }
 
     impl<T: Config> Pallet<T>
-    where
-        BalanceOf<T>: From<u128> + Into<u128>,
+    // where
+    //     BalanceOf<T>: From<u128> + Into<u128> + Default,
     {
         // Internal helper for creating new MoveVM instance with StorageAdapter.
         fn move_vm() -> MvmResult<T> {
diff --git a/pallet/src/mock.rs b/pallet/src/mock.rs
index 478e516..c7d92b0 100644
--- a/pallet/src/mock.rs
+++ b/pallet/src/mock.rs
@@ -92,6 +92,7 @@ parameter_types! {
 
 impl pallet_move::Config for Test {
     type Currency = Balances;
+    type CurrencyBalance = Balance;
     type MaxLifetimeRequests = MaxLifetimeRequests;
     type MaxScriptSigners = MaxScriptSigners;
     type RuntimeEvent = RuntimeEvent;
diff --git a/pallet/src/signer.rs b/pallet/src/signer.rs
index 121964a..2ba4d42 100644
--- a/pallet/src/signer.rs
+++ b/pallet/src/signer.rs
@@ -24,7 +24,7 @@ use crate::{
 
 // Some alias definition to make life easier.
 pub type MaxSignersOf<T> = <T as Config>::MaxScriptSigners;
-pub type MultisigOf<T> = Multisig<AccountIdOf<T>, BlockNumberFor<T>, MaxSignersOf<T>>;
+pub type MultisigOf<T> = Multisig<AccountIdOf<T>, BalanceOf<T>, BlockNumberFor<T>, MaxSignersOf<T>>;
 
 /// This definition stores the hash value of a script transaction.
 pub type CallHash = [u8; 32];
@@ -59,11 +59,11 @@ impl<T> From<MultisigError> for Error<T> {
 }
 
 #[derive(Clone, Eq, PartialEq, Encode, Decode, Default, RuntimeDebug, TypeInfo, MaxEncodedLen)]
-pub struct SignerData {
+pub struct SignerData<Balance> {
     /// State of the user's signature.
     pub signature: Signature,
     /// Individual cheque-limit.
-    pub cheque_limit: u128,
+    pub cheque_limit: Balance,
     /// Lock ID for locked currency.
     pub lock_id: LockIdentifier,
 }
@@ -71,21 +71,23 @@ pub struct SignerData {
 /// Storage struct definition for a multi-signer request.
 #[derive(Clone, Eq, PartialEq, Encode, Decode, RuntimeDebug, TypeInfo, MaxEncodedLen)]
 #[scale_info(skip_type_params(Size))]
-pub struct Multisig<AccountId, BlockNumber, Size>
+pub struct Multisig<AccountId, Balance, BlockNumber, Size>
 where
     AccountId: Parameter + Ord + MaybeSerializeDeserialize,
+    Balance: From<u128> + Into<u128> + Default,
     BlockNumber: Parameter + Ord + MaybeSerializeDeserialize + Default,
     Size: Get<u32>,
 {
     /// The signers of a script transaction.
-    signers: BoundedBTreeMap<AccountId, SignerData, Size>,
+    signers: BoundedBTreeMap<AccountId, SignerData<Balance>, Size>,
     /// The block number when this `Multisig` was created and stored.
     block_height: BlockNumber,
 }
 
-impl<AccountId, BlockNumber, Size> Multisig<AccountId, BlockNumber, Size>
+impl<AccountId, Balance, BlockNumber, Size> Multisig<AccountId, Balance, BlockNumber, Size>
 where
     AccountId: Parameter + Ord + MaybeSerializeDeserialize,
+    Balance: From<u128> + Into<u128> + Default,
     BlockNumber: Parameter + Ord + MaybeSerializeDeserialize + Default,
     Size: Get<u32>,
 {
@@ -95,7 +97,7 @@ where
             return Err(MultisigError::MaxSignersExceeded);
         }
 
-        let mut multisig_info = Multisig::<AccountId, BlockNumber, Size> {
+        let mut multisig_info = Multisig::<AccountId, Balance, BlockNumber, Size> {
             block_height,
             ..Default::default()
         };
@@ -113,22 +115,26 @@ where
     }
 }
 
-impl<AccountId, BlockNumber, Size> core::ops::Deref for Multisig<AccountId, BlockNumber, Size>
+impl<AccountId, Balance, BlockNumber, Size> core::ops::Deref
+    for Multisig<AccountId, Balance, BlockNumber, Size>
 where
     AccountId: Parameter + Ord + MaybeSerializeDeserialize,
+    Balance: From<u128> + Into<u128> + Default,
     BlockNumber: Parameter + Ord + MaybeSerializeDeserialize + Default,
     Size: Get<u32>,
 {
-    type Target = BoundedBTreeMap<AccountId, SignerData, Size>;
+    type Target = BoundedBTreeMap<AccountId, SignerData<Balance>, Size>;
 
     fn deref(&self) -> &Self::Target {
         &self.signers
     }
 }
 
-impl<AccountId, BlockNumber, Size> core::ops::DerefMut for Multisig<AccountId, BlockNumber, Size>
+impl<AccountId, Balance, BlockNumber, Size> core::ops::DerefMut
+    for Multisig<AccountId, Balance, BlockNumber, Size>
 where
     AccountId: Parameter + Ord + MaybeSerializeDeserialize,
+    Balance: From<u128> + Into<u128> + Default,
     BlockNumber: Parameter + Ord + MaybeSerializeDeserialize + Default,
     Size: Get<u32>,
 {
@@ -138,40 +144,30 @@ where
 }
 
 // Because in substrate_move::AccountAddress Default impl is missing.
-impl<AccountId, BlockNumber, Size> Default for Multisig<AccountId, BlockNumber, Size>
+impl<AccountId, Balance, BlockNumber, Size> Default
+    for Multisig<AccountId, Balance, BlockNumber, Size>
 where
     AccountId: Parameter + Ord + MaybeSerializeDeserialize,
+    Balance: From<u128> + Into<u128> + Default,
     BlockNumber: Parameter + Ord + MaybeSerializeDeserialize + Default,
     Size: Get<u32>,
 {
     fn default() -> Self {
         Multisig {
-            signers: BoundedBTreeMap::<AccountId, SignerData, Size>::new(),
+            signers: BoundedBTreeMap::<AccountId, SignerData<Balance>, Size>::new(),
             block_height: BlockNumber::default(),
         }
     }
 }
 
 /// Script signature handler tracks required signatures for the provided script.
-pub(crate) struct ScriptSignatureHandler<T>
-where
-    T: Config + SysConfig,
-    T::AccountId: Parameter + Ord + MaybeSerializeDeserialize,
-    BlockNumberFor<T>: Parameter + Ord + MaybeSerializeDeserialize,
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+pub(crate) struct ScriptSignatureHandler<T: Config + SysConfig> {
     _pd_config: PhantomData<T>,
     /// All required multisig_info.
     multisig_info: MultisigOf<T>,
 }
 
-impl<T> ScriptSignatureHandler<T>
-where
-    T: Config + SysConfig,
-    T::AccountId: Parameter + Ord + MaybeSerializeDeserialize,
-    BlockNumberFor<T>: Parameter + Ord + MaybeSerializeDeserialize,
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+impl<T: Config + SysConfig> ScriptSignatureHandler<T> {
     /// Creates a new [`ScriptSignatureHandler`] with all blank signatures for the provided script.
     pub(crate) fn new(
         accounts: Vec<T::AccountId>,
@@ -194,7 +190,7 @@ where
     pub(crate) fn sign_script(
         &mut self,
         account: &T::AccountId,
-        cheque_limit: u128,
+        cheque_limit: &BalanceOf<T>,
         lock_id: LockIdentifier,
     ) -> Result<(), Error<T>> {
         if let Some(ms_data) = self.multisig_info.get_mut(account) {
@@ -202,10 +198,9 @@ where
                 Err(Error::<T>::UserHasAlreadySigned)
             } else {
                 ms_data.signature = Signature::Approved;
-                ms_data.cheque_limit = cheque_limit;
+                ms_data.cheque_limit = *cheque_limit;
                 ms_data.lock_id = lock_id;
-                let amount = BalanceOf::<T>::from(cheque_limit);
-                T::Currency::set_lock(lock_id, account, amount, WithdrawReasons::all());
+                T::Currency::set_lock(lock_id, account, *cheque_limit, WithdrawReasons::all());
                 Ok(())
             }
         } else {
@@ -227,7 +222,7 @@ where
         for (account, ms_data) in self.multisig_info.iter() {
             T::Currency::remove_lock(ms_data.lock_id, account);
             balances
-                .write_cheque(account, &BalanceOf::<T>::from(ms_data.cheque_limit))
+                .write_cheque(account, &ms_data.cheque_limit)
                 .map_err(|_| Error::<T>::InsufficientBalance)?;
         }
 
@@ -246,13 +241,7 @@ where
     }
 }
 
-impl<T> From<MultisigOf<T>> for ScriptSignatureHandler<T>
-where
-    T: Config + SysConfig,
-    T::AccountId: Parameter + Ord + MaybeSerializeDeserialize,
-    BlockNumberFor<T>: Parameter + Ord + MaybeSerializeDeserialize,
-    BalanceOf<T>: From<u128> + Into<u128>,
-{
+impl<T: Config + SysConfig> From<MultisigOf<T>> for ScriptSignatureHandler<T> {
     fn from(multisig_info: MultisigOf<T>) -> Self {
         Self {
             _pd_config: PhantomData,