Equivalent tokens

celo-org · Jan 17, 2024 · 17aae0f · 17aae0f
1 parent 5d67d3e
commit 17aae0f
Show file tree

Hide file tree

Showing 2 changed files with 74 additions and 2 deletions.
diff --git a/packages/protocol/contracts/stability/SortedOracles.sol b/packages/protocol/contracts/stability/SortedOracles.sol
@@ -61,6 +61,10 @@ contract SortedOracles is ISortedOracles, ICeloVersionedContract, Ownable, Initi
   mapping(address => uint256) public tokenReportExpirySeconds;
 
   IBreakerBox public breakerBox;
+  // Maps a token address to its equivalent token address.
+  // For example, maps the USDC token address to the cUSD token address.
+  // Original token will return the median value as equivalent token.
+  mapping(address => address) public equivalentTokens;
 
   event OracleAdded(address indexed token, address indexed oracleAddress);
   event OracleRemoved(address indexed token, address indexed oracleAddress);
@@ -75,6 +79,7 @@ contract SortedOracles is ISortedOracles, ICeloVersionedContract, Ownable, Initi
   event ReportExpirySet(uint256 reportExpiry);
   event TokenReportExpirySet(address token, uint256 reportExpiry);
   event BreakerBoxUpdated(address indexed newBreakerBox);
+  event EquivalentTokenSet(address indexed token, address indexed equivalentToken);
 
   modifier onlyOracle(address token) {
     require(isOracle[token][msg.sender], "sender was not an oracle for token addr");
@@ -221,6 +226,17 @@ contract SortedOracles is ISortedOracles, ICeloVersionedContract, Ownable, Initi
     return (false, oldest);
   }
 
+  /**
+   * @notice Sets the equivalent token for a token.
+   * @param token The address of the token.
+   * @param equivalentToken The address of the equivalent token.
+   */
+  function setEquivalentToken(address token, address equivalentToken) external onlyOwner {
+    require(token != address(0), "token address cannot be 0");
+    equivalentTokens[token] = equivalentToken;
+    emit EquivalentTokenSet(token, equivalentToken);
+  }
+
   /**
    * @notice Updates an oracle value and the median.
    * @param token The rateFeedId for the rate that is being reported.
@@ -285,8 +301,17 @@ contract SortedOracles is ISortedOracles, ICeloVersionedContract, Ownable, Initi
    * @return uint256 The median exchange rate for rateFeedId.
    * @return fixidity
    */
-  function medianRate(address token) external view returns (uint256, uint256) {
-    return (rates[token].getMedianValue(), numRates(token) == 0 ? 0 : FIXED1_UINT);
+  function medianRate(address token) external view returns (uint256 rate, uint256 numRates) {
+    address equivalentToken = equivalentTokens[token];
+    if (equivalentToken != address(0)) {
+      rate = rates[equivalentToken].getMedianValue();
+      numRates = rates[equivalentToken].getNumElements();
+    } else {
+      rate = rates[token].getMedianValue();
+      numRates = rates[token].getNumElements();
+    }
+
+    numRates = numRates == 0 ? 0 : FIXED1_UINT;
   }
 
   /**

diff --git a/packages/protocol/test-sol/stability/SortedOracles.t.sol b/packages/protocol/test-sol/stability/SortedOracles.t.sol
@@ -8,6 +8,7 @@ import "../../contracts/common/FixidityLib.sol";
 import "../../contracts/common/linkedlists/AddressSortedLinkedListWithMedian.sol";
 import "../../contracts/common/linkedlists/SortedLinkedListWithMedian.sol";
 import { Constants } from "../constants.sol";
+import "forge-std/console.sol";
 
 contract SortedOraclesTest is Test, Constants {
   using FixidityLib for FixidityLib.Fraction;
@@ -31,6 +32,7 @@ contract SortedOraclesTest is Test, Constants {
   event MedianUpdated(address indexed token, uint256 value);
   event ReportExpirySet(uint256 reportExpiry);
   event TokenReportExpirySet(address token, uint256 reportExpiry);
+  event EquivalentTokenSet(address indexed token, address indexed equivalentToken);
 
   function setUp() public {
     warp(0);
@@ -80,6 +82,38 @@ contract SetReportExpiry is SortedOraclesTest {
   }
 }
 
+contract SetEquivalentToken is SortedOraclesTest {
+  address bToken = actor("bToken");
+
+  function test_ShouldSetReportExpiry() public {
+    sortedOracle.setEquivalentToken(aToken, bToken);
+    assertEq(sortedOracle.equivalentTokens(aToken), bToken);
+  }
+
+  function test_ShouldRevert_WhenEquivalentToken0() public {
+    vm.expectRevert("token address cannot be 0");
+    sortedOracle.setEquivalentToken(address(0), bToken);
+  }
+
+  function test_ShouldEmitEquivalentTokenSet() public {
+    vm.expectEmit(true, true, true, true);
+    emit EquivalentTokenSet(aToken, bToken);
+    sortedOracle.setEquivalentToken(aToken, bToken);
+  }
+
+  function test_ShouldRemoveEquivalentToken_WhenAlreadySet() public {
+    sortedOracle.setEquivalentToken(aToken, bToken);
+    sortedOracle.setEquivalentToken(aToken, address(0));
+    assertEq(sortedOracle.equivalentTokens(aToken), address(0));
+  }
+
+  function test_ShouldRevertWhenNotOwner() public {
+    vm.expectRevert("Ownable: caller is not the owner");
+    vm.prank(oracleAccount);
+    sortedOracle.setEquivalentToken(aToken, bToken);
+  }
+}
+
 contract SetTokenReportExpiry is SortedOraclesTest {
   function test_ShouldSetTokenReportExpiry() public {
     uint256 newReportExpiry = reportExpiry * 2;
@@ -479,6 +513,8 @@ contract Report is SortedOraclesTest {
   uint256 oracleValue2 = FixidityLib.newFixedFraction(3, 1).unwrap();
   uint256 anotherOracleValue = FIXED1;
 
+  address bToken = actor("bToken");
+
   function setUp() public {
     super.setUp();
     sortedOracle.addOracle(aToken, oracleAccount);
@@ -498,6 +534,17 @@ contract Report is SortedOraclesTest {
     assertEq(denominator, FIXED1);
   }
 
+  function test_ShouldSetTheMedianRate_WhenEquivalentTokenIsSet() public {
+    vm.prank(oracleAccount);
+    sortedOracle.report(aToken, value, address(0), address(0));
+    sortedOracle.setEquivalentToken(bToken, aToken);
+    (uint256 medianRate, uint256 denominator) = sortedOracle.medianRate(bToken);
+    console.log("medianRate", medianRate);
+    console.log("denominator", denominator);
+    assertEq(medianRate, value);
+    assertEq(denominator, FIXED1);
+  }
+
   function test_ShouldIncreaseTheNumberOfTimestamps() public {
     vm.prank(oracleAccount);
     sortedOracle.report(aToken, value, address(0), address(0));