Rename functions and variables for clarity

contracts/staking/contracts/src/fees/MixinExchangeFees.sol

@@ -129,7 +129,7 @@ contract MixinExchangeFees is
     /// @dev Returns the total balance of this contract, including WETH,
     ///      minus any WETH that has been reserved for rewards.
     /// @return totalBalance Total balance.
-    function getAvailableBalance()
+    function getAvailableRewardsBalance()
         external
         view
         returns (uint256 totalBalance)

contracts/staking/contracts/src/immutable/MixinStorage.sol

@@ -83,7 +83,7 @@ contract MixinStorage is
     mapping (bytes32 => IStructs.Pool) internal _poolById;
 
     // mapping from PoolId to balance of members
-    mapping (bytes32 => uint256) public balanceByPoolId;
+    mapping (bytes32 => uint256) public rewardsByPoolId;
 
     // current epoch
     uint256 public currentEpoch = INITIAL_EPOCH;
@@ -147,7 +147,7 @@ contract MixinStorage is
     IStructs.UnfinalizedState public unfinalizedState;
 
     /// @dev The WETH balance of this contract that is reserved for pool reward payouts.
-    uint256 _reservedWethBalance;
+    uint256 _wethReservedForPoolRewards;
 
     /// @dev Adds owner as an authorized address.
     constructor()

contracts/staking/contracts/src/staking_pools/MixinStakingPoolRewards.sol

@@ -203,8 +203,7 @@ contract MixinStakingPoolRewards is
 
         if (membersReward > 0) {
             // Increment the balance of the pool
-            balanceByPoolId[poolId] = balanceByPoolId[poolId].safeAdd(membersReward);
+            _incrementPoolRewards(poolId, membersReward);
-            _reservedWethBalance = _reservedWethBalance.safeAdd(membersReward);
 
             // Fetch the last epoch at which we stored an entry for this pool;
             // this is the most up-to-date cumulative rewards for this pool.
@@ -297,8 +296,7 @@ contract MixinStakingPoolRewards is
         }
 
         // Decrement the balance of the pool
-        balanceByPoolId[poolId] = balanceByPoolId[poolId].safeSub(balance);
+        _decrementPoolRewards(poolId, balance);
-        _reservedWethBalance = _reservedWethBalance.safeSub(balance);
 
         // Withdraw the member's WETH balance
         _getWethContract().transfer(member, balance);
@@ -432,4 +430,24 @@ contract MixinStakingPoolRewards is
             );
         }
     }
+
+    /// @dev Increments rewards for a pool.
+    /// @param poolId Unique id of pool.
+    /// @param amount Amount to increment rewards by.
+    function _incrementPoolRewards(bytes32 poolId, uint256 amount)
+        private
+    {
+        rewardsByPoolId[poolId] = rewardsByPoolId[poolId].safeAdd(amount);
+        _wethReservedForPoolRewards = _wethReservedForPoolRewards.safeAdd(amount);
+    }
+
+    /// @dev Decrements rewards for a pool.
+    /// @param poolId Unique id of pool.
+    /// @param amount Amount to decrement rewards by.
+    function _decrementPoolRewards(bytes32 poolId, uint256 amount)
+        private
+    {
+        rewardsByPoolId[poolId] = rewardsByPoolId[poolId].safeSub(amount);
+        _wethReservedForPoolRewards = _wethReservedForPoolRewards.safeSub(amount);
+    }
 }

contracts/staking/contracts/src/sys/MixinFinalizer.sol

@@ -257,7 +257,7 @@ contract MixinFinalizer is
         returns (uint256 wethBalance)
     {
         wethBalance = _getWethContract().balanceOf(address(this))
-            .safeSub(_reservedWethBalance);
+            .safeSub(_wethReservedForPoolRewards);
 
         return wethBalance;
     }

contracts/staking/test/actors/finalizer_actor.ts

@@ -230,7 +230,7 @@ export class FinalizerActor extends BaseActor {
         for (const poolId of poolIds) {
             rewardVaultBalanceByPoolId[
                 poolId
-            ] = await this._stakingApiWrapper.stakingContract.balanceByPoolId.callAsync(poolId);
+            ] = await this._stakingApiWrapper.stakingContract.rewardsByPoolId.callAsync(poolId);
         }
         return rewardVaultBalanceByPoolId;
     }
@@ -241,7 +241,7 @@ export class FinalizerActor extends BaseActor {
                 this._stakingApiWrapper.stakingContract.getActiveStakingPoolThisEpoch.callAsync(poolId),
             ),
         );
-        const totalRewards = await this._stakingApiWrapper.stakingContract.getAvailableBalance.callAsync();
+        const totalRewards = await this._stakingApiWrapper.stakingContract.getAvailableRewardsBalance.callAsync();
         const totalFeesCollected = BigNumber.sum(...activePools.map(p => p.feesCollected));
         const totalWeightedStake = BigNumber.sum(...activePools.map(p => p.weightedStake));
         if (totalRewards.eq(0) || totalFeesCollected.eq(0) || totalWeightedStake.eq(0)) {

contracts/staking/test/rewards_test.ts

@@ -131,7 +131,7 @@ blockchainTests.resets('Testing Rewards', env => {
                 // operator
                 stakingApiWrapper.wethContract.balanceOf.callAsync(poolOperator.getOwner()),
                 // undivided balance in reward pool
-                stakingApiWrapper.stakingContract.balanceByPoolId.callAsync(poolId),
+                stakingApiWrapper.stakingContract.rewardsByPoolId.callAsync(poolId),
             ]);
             expect(finalEndBalancesAsArray[0], 'stakerRewardBalance_1').to.be.bignumber.equal(
                 expectedEndBalances.stakerRewardBalance_1,