Add RecordedBalanceChanged and RecordedVestingBalanceChanged events (#219)

Author: zpoken

solana/programs/staking/src/contexts/claim_vesting.rs

@@ -101,12 +101,15 @@ impl<'info> ClaimVesting<'info> {
                     VestingError::InvalidStakeAccountOwner
                 );
 
-                // Update the recorded vesting balance
-                stake_account_metadata.recorded_vesting_balance = stake_account_metadata
+                let new_recorded_vesting_balance = stake_account_metadata
                     .recorded_vesting_balance
                     .checked_sub(self.vest.amount)
                     .ok_or(VestingError::Underflow)?;
 
+                // Update the recorded vesting balance
+                stake_account_metadata
+                    .update_recorded_vesting_balance(new_recorded_vesting_balance);
+
                 // Update checkpoints
                 let current_delegate_checkpoints_account_info =
                     stake_account_checkpoints.to_account_info();

solana/programs/staking/src/contexts/transfer_vesting.rs

@@ -144,11 +144,14 @@ impl<'info> crate::contexts::TransferVesting<'info> {
                     VestingError::InvalidStakeAccountMetadataPDA
                 );
 
-                stake_account_metadata.recorded_vesting_balance = stake_account_metadata
+                let new_recorded_vesting_balance = stake_account_metadata
                     .recorded_vesting_balance
                     .checked_sub(self.vest.amount)
                     .ok_or(VestingError::Underflow)?;
 
+                stake_account_metadata
+                    .update_recorded_vesting_balance(new_recorded_vesting_balance);
+
                 // Update checkpoints
                 let current_delegate_checkpoints_account_info =
                     stake_account_checkpoints.to_account_info();
@@ -226,11 +229,14 @@ impl<'info> crate::contexts::TransferVesting<'info> {
                     VestingError::InvalidStakeAccountMetadataPDA
                 );
 
-                new_stake_account_metadata.recorded_vesting_balance = new_stake_account_metadata
+                let new_recorded_vesting_balance = new_stake_account_metadata
                     .recorded_vesting_balance
                     .checked_add(self.vest.amount)
                     .ok_or(VestingError::Overflow)?;
 
+                new_stake_account_metadata
+                    .update_recorded_vesting_balance(new_recorded_vesting_balance);
+
                 let current_delegate_checkpoints_account_info =
                     new_stake_account_checkpoints.to_account_info();
 

solana/programs/staking/src/lib.rs

@@ -202,8 +202,8 @@ pub mod staking {
                     );
 
                     vesting_balance.stake_account_metadata = stake_account_metadata.key();
-                    stake_account_metadata.recorded_vesting_balance =
-                        vesting_balance.total_vesting_balance;
+                    stake_account_metadata
+                        .update_recorded_vesting_balance(vesting_balance.total_vesting_balance);
                 }
             }
         }
@@ -292,7 +292,7 @@ pub mod staking {
         }
 
         if current_stake_balance != stake_account_metadata.recorded_balance {
-            stake_account_metadata.recorded_balance = current_stake_balance;
+            stake_account_metadata.update_recorded_balance(current_stake_balance);
         }
 
         let delegatee_stake_account_checkpoints =
@@ -466,7 +466,9 @@ pub mod staking {
             drop(loaded_checkpoints);
         }
 
-        ctx.accounts.stake_account_metadata.recorded_balance = *current_stake_balance;
+        ctx.accounts
+            .stake_account_metadata
+            .update_recorded_balance(*current_stake_balance);
 
         Ok(())
     }

solana/programs/staking/src/state/stake_account.rs

@@ -20,6 +20,20 @@ pub struct StakeAccountMetadata {
     pub stake_account_checkpoints_last_index: u8,
 }
 
+#[event]
+pub struct RecordedBalanceChanged {
+    pub owner: Pubkey,
+    pub previous_balance: u64,
+    pub new_balance: u64,
+}
+
+#[event]
+pub struct RecordedVestingBalanceChanged {
+    pub owner: Pubkey,
+    pub previous_balance: u64,
+    pub new_balance: u64,
+}
+
 impl StakeAccountMetadata {
     pub const LEN: usize =
         StakeAccountMetadata::DISCRIMINATOR.len() + size_of::<StakeAccountMetadata>();
@@ -40,6 +54,26 @@ impl StakeAccountMetadata {
         self.delegate = *delegate;
         self.stake_account_checkpoints_last_index = stake_account_checkpoints_last;
     }
+
+    pub fn update_recorded_balance(&mut self, new_recorded_balance: u64) {
+        emit!(RecordedBalanceChanged {
+            owner: self.owner,
+            previous_balance: self.recorded_balance,
+            new_balance: new_recorded_balance,
+        });
+
+        self.recorded_balance = new_recorded_balance;
+    }
+
+    pub fn update_recorded_vesting_balance(&mut self, new_recorded_vesting_balance: u64) {
+        emit!(RecordedVestingBalanceChanged {
+            owner: self.owner,
+            previous_balance: self.recorded_vesting_balance,
+            new_balance: new_recorded_vesting_balance,
+        });
+
+        self.recorded_vesting_balance = new_recorded_vesting_balance;
+    }
 }
 
 #[cfg(test)]