meta-txs: optimize nonce tracking costs

contracts/apps/AppStorage.sol

@@ -11,15 +11,17 @@ import "../kernel/IKernel.sol";
 contract AppStorage {
     using UnstructuredStorage for bytes32;
 
-    /* Hardcoded constants to save gas
-    bytes32 internal constant KERNEL_POSITION = keccak256("aragonOS.appStorage.kernel");
-    bytes32 internal constant APP_ID_POSITION = keccak256("aragonOS.appStorage.appId");
+    /*
+    * Hardcoded constants to save gas
+    * bytes32 internal constant KERNEL_POSITION = keccak256("aragonOS.appStorage.kernel");
+    * bytes32 internal constant APP_ID_POSITION = keccak256("aragonOS.appStorage.appId");
+    * bytes32 internal constant LAST_NONCE_POSITION_BASE = keccak256("aragonOS.appStorage.lastNonce");
+    * bytes32 internal constant VOLATILE_SENDER_POSITION = keccak256("aragonOS.appStorage.volatile.sender");
     */
     bytes32 internal constant KERNEL_POSITION = 0x4172f0f7d2289153072b0a6ca36959e0cbe2efc3afe50fc81636caa96338137b;
     bytes32 internal constant APP_ID_POSITION = 0xd625496217aa6a3453eecb9c3489dc5a53e6c67b444329ea2b2cbc9ff547639b;
-
-    bytes32 internal constant USED_NONCE_POSITION_BASE = keccak256("aragonOS.appStorage.usedNonce");
-    bytes32 internal constant VOLATILE_SENDER_POSITION = keccak256("aragonOS.appStorage.volatile.sender");
+    bytes32 internal constant LAST_NONCE_POSITION_BASE = 0x66c8c1e117f8d5835231a971a56ce0c7b70f9291340698a4263ada738d9269bd;
+    bytes32 internal constant VOLATILE_SENDER_POSITION = 0xd6486d5aa3dac4242db35dd7559408452252cf8050988dbc66956eaa315379ce;
 
     function kernel() public view returns (IKernel) {
         return IKernel(KERNEL_POSITION.getStorageAddress());
@@ -33,8 +35,8 @@ contract AppStorage {
         return VOLATILE_SENDER_POSITION.getStorageAddress();
     }
 
-    function usedNonce(address _account, uint256 _nonce) public view returns (bool) {
-        return usedNoncePosition(_account, _nonce).getStorageBool();
+    function lastNonce(address _account) public view returns (uint256) {
+        return lastNoncePosition(_account).getStorageUint256();
     }
 
     function setKernel(IKernel _kernel) internal {
@@ -49,11 +51,11 @@ contract AppStorage {
         VOLATILE_SENDER_POSITION.setStorageAddress(_sender);
     }
 
-    function setUsedNonce(address _account, uint256 _nonce, bool _used) internal {
-        return usedNoncePosition(_account, _nonce).setStorageBool(_used);
+    function setLastNonce(address _account, uint256 _lastNonce) internal {
+        return lastNoncePosition(_account).setStorageUint256(_lastNonce);
     }
 
-    function usedNoncePosition(address _account, uint256 _nonce) internal returns (bytes32) {
-        return keccak256(abi.encodePacked(USED_NONCE_POSITION_BASE, _account, _nonce));
+    function lastNoncePosition(address _account) internal returns (bytes32) {
+        return keccak256(abi.encodePacked(LAST_NONCE_POSITION_BASE, _account));
     }
 }

contracts/relayer/RelayerAragonAppWithParameterizedSender.sol

@@ -17,13 +17,13 @@ contract RelayerAragonAppWithParameterizedSender is BaseRelayer {
     function exec(address from, uint256 nonce, bytes calldata, bytes signature) external refundGas auth(OFF_CHAIN_RELAYER_SERVICE_ROLE) {
         assertValidTransaction(from, nonce, calldata, signature);
 
-        setUsedNonce(from, nonce, true);
+        setLastNonce(from, nonce);
         bool success = address(this).call(calldata);
         if (!success) revertForwardingError();
         emit TransactionRelayed(from, address(this), nonce, calldata);
     }
 
     function isNonceUsed(address _account, uint256 _nonce) public view returns (bool) {
-        return usedNonce(_account, _nonce);
+        return lastNonce(_account) >= _nonce;
     }
 }

contracts/relayer/RelayerAragonAppWithVolatileSender.sol

@@ -8,7 +8,7 @@ contract RelayerAragonAppWithVolatileSender is BaseRelayer {
         assertValidTransaction(from, nonce, calldata, signature);
 
         setVolatileStorageSender(from);
-        setUsedNonce(from, nonce, true);
+        setLastNonce(from, nonce);
 
         bool success = address(this).call(calldata);
         if (!success) revertForwardingError();
@@ -18,7 +18,7 @@ contract RelayerAragonAppWithVolatileSender is BaseRelayer {
     }
 
     function isNonceUsed(address _account, uint256 _nonce) public view returns (bool) {
-        return usedNonce(_account, _nonce);
+        return lastNonce(_account) >= _nonce;
     }
 
     function sender() internal view returns (address) {

contracts/relayer/StandAloneRelayer.sol

@@ -4,18 +4,18 @@ import "./BaseRelayer.sol";
 
 
 contract StandAloneRelayer is BaseRelayer {
-    mapping (address => mapping (uint256 => bool)) internal usedNonces;
+    mapping (address => uint256) internal lastUsedNonce;
 
     function relay(address from, address to, uint256 nonce, bytes calldata, bytes signature) external refundGas auth(OFF_CHAIN_RELAYER_SERVICE_ROLE) {
         assertValidTransaction(from, nonce, calldata, signature);
 
-        usedNonces[from][nonce] = true;
+        lastUsedNonce[from] = nonce;
         bool success = to.call(calldata);
         if (!success) revertForwardingError();
         emit TransactionRelayed(from, to, nonce, calldata);
     }
 
     function isNonceUsed(address sender, uint256 nonce) public view returns (bool) {
-        return usedNonces[sender][nonce];
+        return lastUsedNonce[sender] >= nonce;
     }
 }

test/contracts/relayer/parameterized_relayed_app.js

@@ -9,7 +9,7 @@ const SampleApp = artifacts.require('RelayedAragonAppWithParameterizedSenderMock
 const getEventArgument = (receipt, event, arg) => receipt.logs.filter(l => l.event === event)[0].args[arg]
 
 contract('ParameterizedRelayedApp', ([_, root, sender, vault, offChainRelayerService]) => {
-  let daoFactory, dao, acl, app, relayer, relayedTx, nonce = 0
+  let daoFactory, dao, acl, app, relayer, relayedTx, nonce = 1
   let kernelBase, aclBase, sampleAppBase, relayerBase
   let WRITING_ROLE, APP_MANAGER_ROLE, RELAYER_ROLE, OFF_CHAIN_RELAYER_SERVICE_ROLE
 
@@ -67,7 +67,7 @@ contract('ParameterizedRelayedApp', ([_, root, sender, vault, offChainRelayerSer
     assert.equal((await app.read()).toString(), 10, 'app value does not match')
   })
 
-  it('overloads a transaction with ~94k of gas', async () => {
+  it('overloads a transaction with ~78k of gas', async () => {
     const { receipt: { cumulativeGasUsed: relayedGasUsed } } = relayedTx
     const { receipt: { cumulativeGasUsed: nonRelayerGasUsed } } = await app.write(10, { from: sender })
 
@@ -76,6 +76,6 @@ contract('ParameterizedRelayedApp', ([_, root, sender, vault, offChainRelayerSer
     console.log('nonRelayerGasUsed:', nonRelayerGasUsed)
     console.log('gasOverload:', gasOverload)
 
-    assert.isBelow(gasOverload, 94000, 'relayed txs gas overload is higher than 94k')
+    assert.isBelow(gasOverload, 78000, 'relayed txs gas overload is higher than 78k')
   })
 })

test/contracts/relayer/parameterized_relayer_app.js

@@ -8,7 +8,7 @@ const SampleApp = artifacts.require('RelayerAragonAppWithParameterizedSenderMock
 const getEventArgument = (receipt, event, arg) => receipt.logs.filter(l => l.event === event)[0].args[arg]
 
 contract('ParameterizedRelayerApp', ([_, root, sender, vault, offChainRelayerService]) => {
-  let daoFactory, dao, acl, app, relayedTx, nonce = 0
+  let daoFactory, dao, acl, app, relayedTx, nonce = 1
   let kernelBase, aclBase, sampleAppBase
   let WRITING_ROLE, APP_MANAGER_ROLE, OFF_CHAIN_RELAYER_SERVICE_ROLE
 

test/contracts/relayer/volatile_relayed_app.js

@@ -9,7 +9,7 @@ const SampleApp = artifacts.require('RelayedAragonAppWithVolatileSenderMock')
 const getEventArgument = (receipt, event, arg) => receipt.logs.filter(l => l.event === event)[0].args[arg]
 
 contract('VolatileRelayedApp', ([_, root, sender, vault, offChainRelayerService]) => {
-  let daoFactory, dao, acl, app, relayer, relayedTx, nonce = 0
+  let daoFactory, dao, acl, app, relayer, relayedTx, nonce = 1
   let kernelBase, aclBase, sampleAppBase, relayerBase
   let WRITING_ROLE, APP_MANAGER_ROLE, RELAYER_ROLE, OFF_CHAIN_RELAYER_SERVICE_ROLE
 
@@ -68,7 +68,7 @@ contract('VolatileRelayedApp', ([_, root, sender, vault, offChainRelayerService]
     assert.equal((await app.read()).toString(), 10, 'app value does not match')
   })
 
-  it('overloads a transaction with ~115k of gas', async () => {
+  it('overloads a transaction with ~99k of gas', async () => {
     const { receipt: { cumulativeGasUsed: relayedGasUsed } } = relayedTx
     const { receipt: { cumulativeGasUsed: nonRelayerGasUsed } } = await app.write(10, { from: sender })
 
@@ -77,6 +77,6 @@ contract('VolatileRelayedApp', ([_, root, sender, vault, offChainRelayerService]
     console.log('nonRelayerGasUsed:', nonRelayerGasUsed)
     console.log('gasOverload:', gasOverload)
 
-    assert.isBelow(gasOverload, 115000, 'relayed txs gas overload is higher than 115k')
+    assert.isBelow(gasOverload, 99000, 'relayed txs gas overload is higher than 99k')
   })
 })

test/contracts/relayer/volatile_relayer_app.js

@@ -8,7 +8,7 @@ const SampleApp = artifacts.require('RelayerAragonAppWithVolatileSenderMock')
 const getEventArgument = (receipt, event, arg) => receipt.logs.filter(l => l.event === event)[0].args[arg]
 
 contract('VolatileRelayerApp', ([_, root, sender, vault, offChainRelayerService]) => {
-  let daoFactory, dao, acl, app, relayedTx, nonce = 0
+  let daoFactory, dao, acl, app, relayedTx, nonce = 1
   let kernelBase, aclBase, sampleAppBase
   let WRITING_ROLE, APP_MANAGER_ROLE, OFF_CHAIN_RELAYER_SERVICE_ROLE
 
@@ -56,7 +56,7 @@ contract('VolatileRelayerApp', ([_, root, sender, vault, offChainRelayerService]
     assert.equal((await app.read()).toString(), 10, 'app value does not match')
   })
 
-  it('overloads a transaction with ~84k of gas', async () => {
+  it('overloads a transaction with ~83k of gas', async () => {
     const { receipt: { cumulativeGasUsed: relayedGasUsed } } = relayedTx
     const { receipt: { cumulativeGasUsed: nonRelayerGasUsed } } = await app.write(10, { from: sender })
 
@@ -65,6 +65,6 @@ contract('VolatileRelayerApp', ([_, root, sender, vault, offChainRelayerService]
     console.log('nonRelayerGasUsed:', nonRelayerGasUsed)
     console.log('gasOverload:', gasOverload)
 
-    assert.isBelow(gasOverload, 84000, 'relayed txs gas overload is higher than 84k')
+    assert.isBelow(gasOverload, 83000, 'relayed txs gas overload is higher than 83k')
   })
 })