perf(crosschain): parse the gateway chain from calldata in CrosschainLinked

.changeset/crosschain-linked-calldata-parse.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-tron-solidity': patch
+---
+
+`CrosschainLinked`: Parse the counterpart chain from calldata in `_isAuthorizedGateway`, avoiding an unnecessary memory copy of `sender`.

contracts/crosschain/CrosschainLinked.sol

@@ -98,12 +98,17 @@ abstract contract CrosschainLinked is TRC7786Recipient {
         address instance,
         bytes calldata sender
     ) internal view virtual override returns (bool) {
-        (address gateway, bytes memory router) = getLink(_extractChain(sender));
+        (address gateway, bytes memory router) = getLink(_extractChainCalldata(sender));
         return instance == gateway && sender.equal(router);
     }
 
     function _extractChain(bytes memory self) private pure returns (bytes memory) {
         (bytes2 chainType, bytes memory chainReference, ) = self.parseV1();
         return InteroperableAddress.formatV1(chainType, chainReference, hex"");
     }
+
+    function _extractChainCalldata(bytes calldata self) private pure returns (bytes memory) {
+        (bytes2 chainType, bytes calldata chainReference, ) = self.parseV1Calldata();
+        return InteroperableAddress.formatV1(chainType, chainReference, hex"");
+    }
 }

test/crosschain/CrosschainLinked.test.js

@@ -0,0 +1,48 @@
+const { ethers } = require('hardhat');
+const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
+const { getLocalChain } = require('../helpers/chains');
+
+async function fixture() {
+  const chain = await getLocalChain();
+  const [counterpart, other] = await ethers.getSigners();
+
+  const gateway = await ethers.deployContract('$TRC7786GatewayMock');
+  const token = await ethers.deployContract('$TRC20', ['Token', 'T']);
+  // `$BridgeTRC20` is a concrete `CrosschainLinked`. Register a link to `counterpart` on the local chain.
+  const linked = await ethers.deployContract('$BridgeTRC20', [[], token]);
+  await linked.$_setLink(gateway, chain.toErc7930(counterpart), false);
+
+  return { chain, gateway, counterpart, other, linked };
+}
+
+describe('CrosschainLinked', function () {
+  beforeEach(async function () {
+    Object.assign(this, await loadFixture(fixture));
+  });
+
+  describe('_isAuthorizedGateway', function () {
+    it('authorizes the registered gateway and counterpart', async function () {
+      const sender = this.chain.toErc7930(this.counterpart);
+      await expect(this.linked.$_isAuthorizedGateway(this.gateway, sender)).to.eventually.be.true;
+    });
+
+    it('rejects an instance that is not the registered gateway', async function () {
+      const sender = this.chain.toErc7930(this.counterpart);
+      await expect(this.linked.$_isAuthorizedGateway(this.other, sender)).to.eventually.be.false;
+    });
+
+    it('rejects a sender that is not the registered counterpart', async function () {
+      const sender = this.chain.toErc7930(this.other);
+      await expect(this.linked.$_isAuthorizedGateway(this.gateway, sender)).to.eventually.be.false;
+    });
+
+    it('reverts on a malformed sender', async function () {
+      await expect(this.linked.$_isAuthorizedGateway(this.gateway, '0x00010042')).to.be.revertedWithCustomError(
+        this.linked,
+        'InteroperableAddressParsingError',
+      );
+    });
+  });
+});