Handling ssc cost via stakes.

Author: mijovic

contracts/core/EntryPoint.sol

@@ -7,6 +7,7 @@ import "../interfaces/IAccount.sol";
 import "../interfaces/IAccountExecute.sol";
 import "../interfaces/IPaymaster.sol";
 import "../interfaces/IEntryPoint.sol";
+import "../interfaces/ISscOpcodes.sol";
 
 import "../utils/Exec.sol";
 import "./StakeManager.sol";
@@ -28,8 +29,18 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
 
     using UserOperationLib for PackedUserOperation;
 
+    int256 constant public SSC_STORAGE_SLOT_COST = 12800000000000000;
+    int256 constant public SSC_STORAGE_SLOT_REFUND = 12672000000000000;
+
+    int256 constant public SSC_ACCOUNT_COST = 12800000000000000;
+    int256 constant public SSC_ACCOUNT_REFUND = 12672000000000000;
+
+    int256 constant public SSC_CODE_CREATED_COST = 12800000000000000;
+
     SenderCreator private immutable _senderCreator = new SenderCreator();
 
+    ISscOpcodes private immutable _ssc = ISscOpcodes(address(0x665e930982A9a03c844641d453a2C3462ED7Ff41));
+
     function senderCreator() internal view virtual returns (SenderCreator) {
         return _senderCreator;
     }
@@ -82,6 +93,7 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
     returns
     (uint256 collected) {
         uint256 preGas = gasleft();
+        int256 preSSC = _netSSC();
         bytes memory context = getMemoryBytesFromOffset(opInfo.contextOffset);
         bool success;
         {
@@ -110,6 +122,13 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
                 collected := mload(0)
                 mstore(0x40, saveFreePtr)
             }
+            int256 netSSC = _netSSC() - preSSC;
+            if (netSSC < 0) {
+                // increment deposit for the user's account
+                _incrementDeposit(userOp.sender, uint256(-netSSC));
+            } else {
+                _decrementDeposit(userOp.sender, uint256(netSSC));
+            }
         }
         if (!success) {
             bytes32 innerRevertCode;
@@ -178,6 +197,8 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
         uint256 opslen = ops.length;
         UserOpInfo[] memory opInfos = new UserOpInfo[](opslen);
 
+        int256 preSSC = _netSSC();
+
         unchecked {
             for (uint256 i = 0; i < opslen; i++) {
                 UserOpInfo memory opInfo = opInfos[i];
@@ -200,6 +221,15 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
                 collected += _executeUserOp(i, ops[i], opInfos[i]);
             }
 
+            // this can be negative in cases of refunds
+            int256 netSSC = _netSSC() - preSSC;
+            if (netSSC < 0) {
+                _decrementDeposit(beneficiary, uint256(netSSC));
+            } else {
+                // increment deposit for the user's account
+                _incrementDeposit(beneficiary, uint256(-netSSC));
+            }
+
             _compensate(beneficiary, collected);
         }
     }
@@ -413,6 +443,15 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
         }
     }
 
+    /**
+     * Calculates total ssc cost / refund
+     */
+    function _netSSC() internal view returns (int256) {
+        return int256(_ssc.accountsCreated()) * SSC_ACCOUNT_COST - int256(_ssc.accountsCleared()) * SSC_ACCOUNT_REFUND
+            + int256(_ssc.slotsCreated()) * SSC_STORAGE_SLOT_COST - int256(_ssc.slotsCleared()) * SSC_STORAGE_SLOT_REFUND
+            + int256(_ssc.codeCreated()) * SSC_CODE_CREATED_COST;
+    }
+
     /**
      * Create sender smart contract account if init code is provided.
      * @param opIndex  - The operation index.

contracts/core/StakeManager.sol

@@ -56,6 +56,22 @@ abstract contract StakeManager is IStakeManager {
         return newAmount;
     }
 
+    /**
+     * Increments an account's deposit.
+     * @param account - The account to increment.
+     * @param amount  - The amount to increment by.
+     * @return the updated deposit of this account
+     */
+    function _decrementDeposit(address account, uint256 amount) internal returns (uint256) {
+        unchecked {
+            DepositInfo storage info = deposits[account];
+            require(info.deposit >= amount, "cannot decrement stake");
+            uint256 newAmount = info.deposit - amount;
+            info.deposit = newAmount;
+            return newAmount;
+        }
+    }
+
     /**
      * Add to the deposit of the given account.
      * @param account - The account to add to.

contracts/interfaces/ISscOpcodes.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.23;
+
+interface ISscOpcodes {
+    function accountsCreated() external view returns (uint256); // D0
+    function accountsCleared() external view returns (uint256); // D1
+    function slotsCreated() external view returns (uint256); // D2
+    function slotsCleared() external view returns (uint256); // D3
+    function codeCreated() external view returns (uint256); // D4
+}