feat: [Foundry] Fetch HIP-719 remote state for fungible tokens

@hts-forking/test/data/MFCT/getTokenRelationship_0xa3612a87022a4706fc9452c50abd2703ac4fd7d9.json

@@ -0,0 +1,16 @@
+{
+    "tokens": [
+        {
+            "automatic_association": false,
+            "balance": 5000,
+            "created_timestamp": "1724382479.562855337",
+            "decimals": 0,
+            "token_id": "0.0.4730999",
+            "freeze_status": "NOT_APPLICABLE",
+            "kyc_status": "NOT_APPLICABLE"
+        }
+    ],
+    "links": {
+        "next": null
+    }
+}

@hts-forking/test/data/USDC/getTokenRelationship_0x0000000000000000000000000000000000001438.json

@@ -0,0 +1,16 @@
+{
+    "tokens": [
+        {
+            "automatic_association": false,
+            "balance": 5000000,
+            "created_timestamp": "1706825561.156945003",
+            "decimals": 6,
+            "token_id": "0.0.429274",
+            "freeze_status": "UNFROZEN",
+            "kyc_status": "NOT_APPLICABLE"
+        }
+    ],
+    "links": {
+        "next": null
+    }
+}

scripts/curl

@@ -84,6 +84,21 @@ for (const [re, fn] of /** @type {const} */([
             return undefined;
         }
     }],
+    [/^accounts\/((0x[0-9a-fA-F]{40})|(0\.0\.\d+))\/tokens/, idOrAliasOrEvmAddress => {
+        assert(typeof idOrAliasOrEvmAddress === 'string');
+        const tokenId = searchParams.get('token.id');
+        assert(tokenId !== null);
+
+        const token = tokens[tokenId];
+        if (token === undefined)
+            return { tokens: [], links: { next: null } };
+
+        try {
+            return require(`../@hts-forking/test/data/${token.symbol}/getTokenRelationship_${idOrAliasOrEvmAddress.toLowerCase()}.json`);
+        } catch {
+            return undefined;
+        }
+    }],
 ])) {
     const match = endpoint.match(re);
     if (match !== null) {

src/HtsSystemContract.sol

@@ -213,14 +213,17 @@ contract HtsSystemContract is IHederaTokenService, IERC20Events {
             emit Approval(owner, spender, amount);
             return abi.encode(true);
         } else if (selector == IHRC719.associate.selector) {
+            _initTokenRelationships(msg.sender);
             bytes32 slot = _isAssociatedSlot(msg.sender);
             assembly { sstore(slot, true) }
             return abi.encode(true);
         } else if (selector == IHRC719.dissociate.selector) {
+            _initTokenRelationships(msg.sender);
             bytes32 slot = _isAssociatedSlot(msg.sender);
             assembly { sstore(slot, false) }
             return abi.encode(true);
         } else if (selector == IHRC719.isAssociated.selector) {
+            _initTokenRelationships(msg.sender);
             bytes32 slot = _isAssociatedSlot(msg.sender);
             bool res;
             assembly { res := sload(slot) }
@@ -246,6 +249,9 @@ contract HtsSystemContract is IHederaTokenService, IERC20Events {
     function _initTokenData() internal virtual {
     }
 
+    function _initTokenRelationships(address account) internal virtual {
+    }
+
     function _balanceOfSlot(address account) internal virtual returns (bytes32) {
         bytes4 selector = IERC20.balanceOf.selector;
         uint192 pad = 0x0;

src/HtsSystemContractJson.sol

@@ -14,6 +14,7 @@ contract HtsSystemContractJson is HtsSystemContract {
     MirrorNode private _mirrorNode;
 
     bool private initialized;
+    mapping (address => bool) private relationshipsInitialized;
 
     function setMirrorNodeProvider(MirrorNode mirrorNode_) htsCall external {
         _mirrorNode = mirrorNode_;
@@ -81,6 +82,35 @@ contract HtsSystemContractJson is HtsSystemContract {
         _initTokenInfo(json);
     }
 
+    function _initTokenRelationships(address account) internal override {
+        if (relationshipsInitialized[account]) {
+            // Already initialized
+            return;
+        }
+
+        bytes32 slot = _isAssociatedSlot(account);
+        try mirrorNode().fetchTokenRelationshipOfAccount(vm.toString(account), address(this)) returns (string memory json) {
+            string memory notFoundError = "{\"_status\":{\"messages\":[{\"message\":\"Not found\"}]}}";
+            if (keccak256(bytes(json)) == keccak256(bytes(notFoundError))) {
+                storeBool(address(this), uint256(slot), false);
+            } else {
+                bytes memory tokens = vm.parseJson(json, ".tokens");
+                IMirrorNodeResponses.TokenRelationship[] memory relationships = abi.decode(tokens, (IMirrorNodeResponses.TokenRelationship[]));
+                storeBool(address(this), uint256(slot), relationships.length > 0);
+            }
+        } catch {
+            storeBool(address(this), uint256(slot), false);
+        }
+
+        // The value corresponding to a mapping key k is located at keccak256(h(k).p),
+        // where . is concatenation, p is the base slot and h is a function applied to the key depending on its type:
+        // - for value types, h pads the value to 32 bytes in the same way as when storing the value in memory.
+        // - for strings and byte arrays, h(k) is just the non-padded data.
+        assembly { slot := relationshipsInitialized.slot }
+        slot = keccak256(abi.encodePacked(bytes32(uint256(uint160(account))), slot));
+        storeBool(address(this), uint256(slot), true);
+    }
+
     function _initTokenInfo(string memory json) internal {
         TokenInfo memory tokenInfo = _getTokenInfo(json);
 

src/IMirrorNodeResponses.sol

@@ -39,4 +39,14 @@ interface IMirrorNodeResponses {
         int64 amount;
         string denominating_token_id;
     }
+
+    struct TokenRelationship {
+        bool automatic_association;
+        uint256 balance;
+        string created_timestamp;
+        uint256 decimals;
+        string token_id;
+        string freeze_status;
+        string kyc_status;
+    }
 }

src/MirrorNode.sol

@@ -25,6 +25,8 @@ abstract contract MirrorNode {
 
     function fetchAccount(string memory account) external virtual returns (string memory json);
 
+    function fetchTokenRelationshipOfAccount(string memory account, address token) external virtual returns (string memory json);
+
     function getBalance(address token, address account) external returns (uint256) {
         uint32 accountNum = _getAccountNum(account);
         if (accountNum == 0) return 0;

src/MirrorNodeFFI.sol

@@ -60,6 +60,15 @@ contract MirrorNodeFFI is MirrorNode {
         ));
     }
 
+    function fetchTokenRelationshipOfAccount(string memory idOrAliasOrEvmAddress, address token) external override returns (string memory) {
+        return _get(string.concat(
+            "accounts/",
+            idOrAliasOrEvmAddress,
+            "/tokens?token.id=0.0.",
+            vm.toString(uint160(token))
+        ));
+    }
+
     /**
      * @dev Returns the block information by given number.
      *

test/IHRC719.t.sol

@@ -65,4 +65,19 @@ contract IHRC719TokenAssociationTest is Test, TestSetup {
 
         vm.stopPrank();
     }
+
+    function test_IHRC719_with_real_accounts() external {
+        vm.startPrank(USDC_TREASURY);
+        assertEq(IHRC719(USDC).isAssociated(), true);
+        assertEq(IHRC719(USDC).dissociate(), 1);
+        assertEq(IHRC719(USDC).isAssociated(), false);
+
+
+        vm.startPrank(MFCT_TREASURY);
+        assertEq(IHRC719(MFCT).isAssociated(), true);
+        assertEq(IHRC719(MFCT).dissociate(), 1);
+        assertEq(IHRC719(MFCT).isAssociated(), false);
+
+        vm.stopPrank();
+    }
 }

test/lib/MirrorNodeMock.sol

@@ -43,4 +43,10 @@ contract MirrorNodeMock is MirrorNode {
         string memory path = string.concat("./@hts-forking/test/data/getAccount_", vm.toLowercase(account), ".json");
         return vm.readFile(path);
     }
+
+    function fetchTokenRelationshipOfAccount(string memory idOrAliasOrEvmAddress, address token) external override view returns (string memory) {
+        string memory symbol = _symbolOf[token];
+        string memory path = string.concat("./@hts-forking/test/data/", symbol, "/getTokenRelationship_", vm.toLowercase(idOrAliasOrEvmAddress), ".json");
+        return vm.readFile(path);
+    }
 }