Merge pull request #58 from coinbase/wilson/bytes4

Optimize getting function selector

.gas-snapshot

@@ -23,7 +23,7 @@ CoinbaseSmartWalletFactoryTest:test_implementation_returnsExpectedAddress() (gas
 CoinbaseSmartWalletFactoryTest:test_initCodeHash() (gas: 7912)
 CoinbaseSmartWalletFactoryTest:test_revertsIfNoOwners() (gas: 29232)
 ERC1271Test:test_returnsExpectedDomainHashWhenProxy() (gas: 29198)
-ERC1271Test:test_static() (gas: 3249331)
+ERC1271Test:test_static() (gas: 3229650)
 MultiOwnableInitializeTest:testRevertsIfLength32ButLargerThanAddress() (gas: 81111)
 MultiOwnableInitializeTest:testRevertsIfLength32NotAddress() (gas: 81092)
 MultiOwnableInitializeTest:testRevertsIfLengthNot32Or64() (gas: 103395)
@@ -45,29 +45,29 @@ TestCanSkipChainIdValidation:test_approvedSelectorsReturnTrue() (gas: 17781)
 TestCanSkipChainIdValidation:test_otherSelectorsReturnFalse() (gas: 12579)
 TestExecuteWithoutChainIdValidation:testExecute() (gas: 424837)
 TestExecuteWithoutChainIdValidation:testExecuteBatch() (gas: 728897)
-TestExecuteWithoutChainIdValidation:testExecuteBatch(uint256) (runs: 256, μ: 3631749, ~: 3655292)
-TestExecuteWithoutChainIdValidation:test__codesize() (gas: 49987)
-TestExecuteWithoutChainIdValidation:test__codesize() (gas: 50222)
-TestExecuteWithoutChainIdValidation:test_revertsWithReservedNonce() (gas: 82347)
+TestExecuteWithoutChainIdValidation:testExecuteBatch(uint256) (runs: 256, μ: 3597261, ~: 3458766)
+TestExecuteWithoutChainIdValidation:test__codesize() (gas: 49890)
+TestExecuteWithoutChainIdValidation:test__codesize() (gas: 50125)
+TestExecuteWithoutChainIdValidation:test_revertsWithReservedNonce() (gas: 81983)
 TestExecuteWithoutChainIdValidation:test_reverts_whenCallerNotEntryPoint() (gas: 11053)
-TestExecuteWithoutChainIdValidation:test_reverts_whenOneCallReverts() (gas: 467957)
-TestExecuteWithoutChainIdValidation:test_reverts_whenOneSelectorNotApproved() (gas: 179805)
-TestExecuteWithoutChainIdValidation:test_reverts_whenSelectorNotApproved() (gas: 106879)
-TestExecuteWithoutChainIdValidation:test_succeeds_whenSelectorAllowed() (gas: 424401)
+TestExecuteWithoutChainIdValidation:test_reverts_whenOneCallReverts() (gas: 467715)
+TestExecuteWithoutChainIdValidation:test_reverts_whenOneSelectorNotApproved() (gas: 179684)
+TestExecuteWithoutChainIdValidation:test_reverts_whenSelectorNotApproved() (gas: 106758)
+TestExecuteWithoutChainIdValidation:test_succeeds_whenSelectorAllowed() (gas: 423916)
 TestImplementation:testImplementation() (gas: 12623)
 TestInitialize:testInitialize() (gas: 21034)
-TestInitialize:test_cannotInitImplementation() (gas: 2904513)
+TestInitialize:test_cannotInitImplementation() (gas: 2885066)
 TestIsValidSignature:testReturnsInvalidIfPasskeySigButWrongOwnerLength() (gas: 40187)
 TestIsValidSignature:testRevertsIfEthereumSignatureButWrongOwnerLength() (gas: 24040)
 TestIsValidSignature:testRevertsIfOwnerIsInvalidEthereumAddress() (gas: 22021)
-TestIsValidSignature:testSmartWalletSigner() (gas: 3180147)
+TestIsValidSignature:testSmartWalletSigner() (gas: 3160701)
 TestIsValidSignature:testValidateSignatureWithEOASigner() (gas: 24922)
 TestIsValidSignature:testValidateSignatureWithEOASignerFailsWithWrongSigner() (gas: 23877)
 TestIsValidSignature:testValidateSignatureWithPasskeySigner() (gas: 423238)
 TestIsValidSignature:testValidateSignatureWithPasskeySignerFailsBadOwnerIndex() (gas: 35664)
 TestIsValidSignature:testValidateSignatureWithPasskeySignerFailsWithWrongBadSignature() (gas: 430704)
 TestUpgradeToAndCall:testUpgradeToAndCall() (gas: 25477)
-TestValidateUserOp:test_reverts_whenReplayableNonceKeyInvalidForSelector() (gas: 14551)
-TestValidateUserOp:test_reverts_whenSelectorInvalidForReplayableNonceKey() (gas: 14816)
-TestValidateUserOp:test_succeedsWithEOASigner() (gas: 447664)
-TestValidateUserOp:test_succeedsWithPasskeySigner() (gas: 785032)
+TestValidateUserOp:test_reverts_whenReplayableNonceKeyInvalidForSelector() (gas: 14187)
+TestValidateUserOp:test_reverts_whenSelectorInvalidForReplayableNonceKey() (gas: 14452)
+TestValidateUserOp:test_succeedsWithEOASigner() (gas: 447938)
+TestValidateUserOp:test_succeedsWithPasskeySigner() (gas: 785169)

src/CoinbaseSmartWallet.sol

@@ -144,9 +144,7 @@ contract CoinbaseSmartWallet is MultiOwnable, UUPSUpgradeable, Receiver, ERC1271
     {
         uint256 key = userOp.nonce >> 64;
 
-        if (
-            userOp.callData.length >= 4 && bytes4(userOp.callData[0:4]) == this.executeWithoutChainIdValidation.selector
-        ) {
+        if (bytes4(userOp.callData) == this.executeWithoutChainIdValidation.selector) {
             userOpHash = getUserOpHashWithoutChainId(userOp);
             if (key != REPLAYABLE_NONCE_KEY) {
                 revert InvalidNonceKey(key);
@@ -181,7 +179,7 @@ contract CoinbaseSmartWallet is MultiOwnable, UUPSUpgradeable, Receiver, ERC1271
     function executeWithoutChainIdValidation(bytes[] calldata calls) public payable virtual onlyEntryPoint {
         for (uint256 i; i < calls.length; i++) {
             bytes calldata call = calls[i];
-            bytes4 selector = bytes4(call[0:4]);
+            bytes4 selector = bytes4(call);
             if (!canSkipChainIdValidation(selector)) {
                 revert SelectorNotAllowed(selector);
             }