feat: add getNumberOfInputsBeforeCurrentBlock

cartesi · Jan 10, 2025 · 92da65b · 92da65b
1 parent f9c97d5
commit 92da65b
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Showing 3 changed files with 52 additions and 1 deletion.
diff --git a/contracts/inputs/IInputBox.sol b/contracts/inputs/IInputBox.sol
@@ -45,6 +45,14 @@ interface IInputBox {
         address appContract
     ) external view returns (uint256);
 
+    /// @notice Get the number of inputs sent to an application
+    /// before the current block. This can be useful for deriving
+    /// input ranges from block ranges.
+    /// @param appContract The application contract address
+    function getNumberOfInputsBeforeCurrentBlock(
+        address appContract
+    ) external view returns (uint256);
+
     /// @notice Get the hash of an input in an application's input box.
     /// @param appContract The application contract address
     /// @param index The input index

diff --git a/contracts/inputs/InputBox.sol b/contracts/inputs/InputBox.sol
@@ -11,6 +11,15 @@ contract InputBox is IInputBox {
     /// @notice Mapping of application contract addresses to arrays of input hashes.
     mapping(address => bytes32[]) private _inputBoxes;
 
+    /// @notice Snapshot of number of inputs
+    struct Snapshot {
+        uint256 blockNumber;
+        uint256 numberOfInputsBeforeBlock;
+    }
+
+    /// @notice Mapping of application contract addresses to snapshot.
+    mapping(address => Snapshot) private _snapshots;
+
     /// @inheritdoc IInputBox
     function addInput(
         address appContract,
@@ -20,6 +29,13 @@ contract InputBox is IInputBox {
 
         uint256 index = inputBox.length;
 
+        // take snapshot if first input of block
+        Snapshot storage snapshot = _snapshots[appContract];
+        if (snapshot.blockNumber < block.number) {
+            snapshot.blockNumber = block.number;
+            snapshot.numberOfInputsBeforeBlock = index;
+        }
+
         bytes memory input = abi.encodeCall(
             Inputs.EvmAdvance,
             (
@@ -54,10 +70,23 @@ contract InputBox is IInputBox {
     /// @inheritdoc IInputBox
     function getNumberOfInputs(
         address appContract
-    ) external view override returns (uint256) {
+    ) public view override returns (uint256) {
         return _inputBoxes[appContract].length;
     }
 
+    /// @inheritdoc IInputBox
+    function getNumberOfInputsBeforeCurrentBlock(
+        address appContract
+    ) external view returns (uint256) {
+        Snapshot storage snapshot = _snapshots[appContract];
+        if (snapshot.blockNumber == block.number) {
+            return snapshot.numberOfInputsBeforeBlock;
+        } else {
+            // snapshot.blockNumber < block.number
+            return getNumberOfInputs(appContract);
+        }
+    }
+
     /// @inheritdoc IInputBox
     function getInputHash(
         address appContract,

diff --git a/test/inputs/InputBox.t.sol b/test/inputs/InputBox.t.sol
@@ -20,6 +20,7 @@ contract InputBoxTest is Test {
 
     function testNoInputs(address appContract) public view {
         assertEq(_inputBox.getNumberOfInputs(appContract), 0);
+        assertEq(_inputBox.getNumberOfInputsBeforeCurrentBlock(appContract), 0);
     }
 
     function testAddLargeInput() public {
@@ -105,6 +106,19 @@ contract InputBoxTest is Test {
         }
     }
 
+    function testNumberOfInputsBeforeCurrentBlock() external {
+        address appContract = vm.addr(1);
+        for (uint256 j; j < 3; ++j) {
+            uint256 n = _inputBox.getNumberOfInputs(appContract);
+            for (uint256 i; i < 2; ++i) {
+                _inputBox.addInput(appContract, new bytes(0));
+                // prettier-ignore
+                assertEq(_inputBox.getNumberOfInputsBeforeCurrentBlock(appContract), n);
+            }
+            vm.roll(vm.getBlockNumber() + 1);
+        }
+    }
+
     function _prevrandao(uint256 blockNumber) internal pure returns (uint256) {
         return uint256(keccak256(abi.encode("prevrandao", blockNumber)));
     }