Scribe LST extension (#33)

Co-authored-by: jar-o <jar@example.com>

src/extensions/IScribeLST.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.16;
+
+import {IScribe} from "../IScribe.sol";
+
+import {IRateSource} from "./external_/interfaces/IRateSource.sol";
+
+interface IScribeLST is IScribe, IRateSource {}

src/extensions/IScribeOptimisticLST.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.16;
+
+import {IScribeOptimistic} from "../IScribeOptimistic.sol";
+
+import {IRateSource} from "./external_/interfaces/IRateSource.sol";
+
+interface IScribeOptimisticLST is IScribeOptimistic, IRateSource {}

src/extensions/ScribeLST.sol

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.16;
+
+import {IScribeLST} from "./IScribeLST.sol";
+import {IRateSource} from "./external_/interfaces/IRateSource.sol";
+
+import {Scribe} from "../Scribe.sol";
+
+/**
+ * @title ScribeLST
+ *
+ * @notice Schnorr based Oracle with onchain fault resolution for Liquid
+ *         Staking Token APRs.
+ */
+contract ScribeLST is IScribeLST, Scribe {
+    constructor(address initialAuthed_, bytes32 wat_)
+        Scribe(initialAuthed_, wat_)
+    {}
+
+    /// @inheritdoc IRateSource
+    /// @dev Only callable by toll'ed address.
+    function getAPR() external view toll returns (uint) {
+        // Note that function does not revert if val is zero.
+        return _pokeData.val;
+    }
+}
+
+/**
+ * @dev Contract overwrite to deploy contract instances with specific naming.
+ *
+ *      For more info, see docs/Deployment.md.
+ */
+contract Chronicle_BASE_QUOTE_COUNTER is ScribeLST {
+    // @todo       ^^^^ ^^^^^ ^^^^^^^ Adjust name of Scribe instance.
+    constructor(address initialAuthed, bytes32 wat_)
+        ScribeLST(initialAuthed, wat_)
+    {}
+}

src/extensions/ScribeOptimisticLST.sol

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.16;
+
+import {IScribeOptimisticLST} from "./IScribeOptimisticLST.sol";
+import {IRateSource} from "./external_/interfaces/IRateSource.sol";
+
+import {ScribeOptimistic} from "../ScribeOptimistic.sol";
+
+/**
+ * @title ScribeOptimisticLST
+ *
+ * @notice Schnorr based optimistic Oracle with onchain fault resolution for
+ *         Liquid Staking Token APRs.
+ */
+contract ScribeOptimisticLST is IScribeOptimisticLST, ScribeOptimistic {
+    constructor(address initialAuthed_, bytes32 wat_)
+        ScribeOptimistic(initialAuthed_, wat_)
+    {}
+
+    /// @inheritdoc IRateSource
+    /// @dev Only callable by toll'ed address.
+    function getAPR() external view toll returns (uint) {
+        // Note that function does not revert if val is zero.
+        return _currentPokeData().val;
+    }
+}
+
+/**
+ * @dev Contract overwrite to deploy contract instances with specific naming.
+ *
+ *      For more info, see docs/Deployment.md.
+ */
+contract Chronicle_BASE_QUOTE_COUNTER is ScribeOptimisticLST {
+    // @todo       ^^^^ ^^^^^ ^^^^^^^ Adjust name of Scribe instance.
+    constructor(address initialAuthed, bytes32 wat_)
+        ScribeOptimisticLST(initialAuthed, wat_)
+    {}
+}

src/extensions/external_/interfaces/IRateSource.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: AGPL-3.0
+pragma solidity >=0.8.0;
+
+/**
+ * @dev Interest rate oracle interface from [Spark](https://spark.fi/).
+ *
+ *      Copied from https://github.com/marsfoundation/sparklend-advanced/blob/277ea9d9ad7faf330b88198c9c6de979a2fad561/src/interfaces/IRateSource.sol.
+ */
+interface IRateSource {
+    /// @notice Returns the oracle's current APR value.
+    /// @return The oracle's current APR value.
+    function getAPR() external view returns (uint);
+}

test/IScribeOptimisticTest.sol

@@ -51,7 +51,7 @@ abstract contract IScribeOptimisticTest is IScribeTest {
         uint newMaxChallengeReward
     );
 
-    function setUp(address scribe_) internal override(IScribeTest) {
+    function setUp(address scribe_) internal virtual override(IScribeTest) {
         super.setUp(scribe_);
 
         opScribe = IScribeOptimistic(scribe_);

test/Runner.t.sol

@@ -26,6 +26,17 @@ contract ScribeInvariantTest is IScribeInvariantTest {
     }
 }
 
+// -- Extensions
+
+import {ScribeLST} from "src/extensions/ScribeLST.sol";
+import {IScribeLSTTest} from "./extensions/IScribeLSTTest.sol";
+
+contract ScribeLSTest is IScribeLSTTest {
+    function setUp() public {
+        setUp(address(new ScribeLST(address(this), "ETH/USD")));
+    }
+}
+
 // -- Test: Optimistic Scribe --
 
 import {ScribeOptimistic} from "src/ScribeOptimistic.sol";
@@ -39,6 +50,20 @@ contract ScribeOptimisticTest is IScribeOptimisticTest {
     }
 }
 
+// -- Extensions
+
+import {ScribeOptimisticLST} from "src/extensions/ScribeOptimisticLST.sol";
+import {IScribeOptimisticLSTTest} from
+    "./extensions/IScribeOptimisticLSTTest.sol";
+
+contract ScribeOptimisticLSTTest is IScribeOptimisticLSTTest {
+    function setUp() public {
+        setUp(
+            payable(address(new ScribeOptimisticLST(address(this), "ETH/USD")))
+        );
+    }
+}
+
 // -- Test: Libraries --
 
 import {LibSecp256k1Test as LibSecp256k1Test_} from "./LibSecp256k1Test.sol";

test/extensions/IScribeLSTTest.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.16;
+
+import {IToll} from "chronicle-std/toll/IToll.sol";
+
+import {IScribeLST} from "src/extensions/IScribeLST.sol";
+
+import {IScribeTest} from "../IScribeTest.sol";
+
+abstract contract IScribeLSTTest is IScribeTest {
+    IScribeLST private scribeLST;
+
+    function setUp(address scribe_) internal override(IScribeTest) {
+        super.setUp(scribe_);
+
+        scribeLST = IScribeLST(scribe_);
+    }
+
+    function test_getAPR_DoesNotRevertIf_ValIsZero() public {
+        uint val = scribeLST.getAPR();
+        assertEq(val, 0);
+    }
+
+    // -- Test: Toll Protected Functions --
+
+    function test_getAPR_isTollProtected() public {
+        vm.prank(address(0xbeef));
+        vm.expectRevert(
+            abi.encodeWithSelector(IToll.NotTolled.selector, address(0xbeef))
+        );
+        scribeLST.getAPR();
+    }
+}

test/extensions/IScribeOptimisticLSTTest.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.16;
+
+import {IToll} from "chronicle-std/toll/IToll.sol";
+
+import {IScribeOptimisticLST} from "src/extensions/IScribeOptimisticLST.sol";
+
+import {IScribeOptimisticTest} from "../IScribeOptimisticTest.sol";
+
+abstract contract IScribeOptimisticLSTTest is IScribeOptimisticTest {
+    IScribeOptimisticLST private opScribeLST;
+
+    function setUp(address scribe_) internal override(IScribeOptimisticTest) {
+        super.setUp(scribe_);
+
+        opScribeLST = IScribeOptimisticLST(scribe_);
+    }
+
+    function test_getAPR_DoesNotRevertIf_ValIsZero() public {
+        uint val = opScribeLST.getAPR();
+        assertEq(val, 0);
+    }
+
+    // -- Test: Toll Protected Functions --
+
+    function test_getAPR_isTollProtected() public {
+        vm.prank(address(0xbeef));
+        vm.expectRevert(
+            abi.encodeWithSelector(IToll.NotTolled.selector, address(0xbeef))
+        );
+        opScribeLST.getAPR();
+    }
+}