feat: add listResourceConstraints view

Author: MishkaRogachev

ArbOwner.sol

@@ -4,6 +4,8 @@
 
 pragma solidity >=0.4.21 <0.9.0;
 
+import {ArbResourceConstraintsTypes} from "./ArbResourceConstraintsTypes.sol";
+
 /**
  * @title Provides owners with tools for managing the rollup.
  * @notice Calls by non-owners will always revert.
@@ -256,21 +258,13 @@ interface ArbOwner {
         bool enable
     ) external;
 
-    /// @notice A pair representing a resource kind and its weight in constraint calculations.
-    /// @param resource the resource kind (see Nitro documentation for list of resources)
-    /// @param weight the relative weight of this resource in the constraint
-    struct ResourceWeight {
-        uint8 resource;
-        uint64 weight;
-    }
-
     /// @notice Adds or updates a resource constraint
     /// @notice Available on ArbOS version 50 and above
     /// @param resources an array of (resource, weight) pairs
     /// @param periodSecs the time window for the constraint
     /// @param targetPerSec allowed usage per second across weighted resources
     function setResourceConstraint(
-        ResourceWeight[] calldata resources,
+        ArbResourceConstraintsTypes.ResourceWeight[] calldata resources,
         uint32 periodSecs,
         uint64 targetPerSec
     ) external;

ArbOwnerPublic.sol

@@ -4,6 +4,8 @@
 
 pragma solidity >=0.4.21 <0.9.0;
 
+import {ArbResourceConstraintsTypes} from "./ArbResourceConstraintsTypes.sol";
+
 /// @title Provides non-owners with info about the current chain owners.
 /// @notice Precompiled contract that exists in every Arbitrum chain at 0x000000000000000000000000000000000000006b.
 interface ArbOwnerPublic {
@@ -55,4 +57,11 @@ interface ArbOwnerPublic {
     function isCalldataPriceIncreaseEnabled() external view returns (bool);
 
     event ChainOwnerRectified(address rectifiedOwner);
+
+    /// @notice Lists all resource constraints currently configured in ArbOS.
+    /// @notice Available on ArbOS version 50 and above
+    function listResourceConstraints()
+        external
+        view
+        returns (ArbResourceConstraintsTypes.ResourceConstraint[] memory constraints);
 }

ArbResourceConstraintsTypes.sol

@@ -0,0 +1,23 @@
+// Copyright 2025, Offchain Labs, Inc.
+// For license information, see https://github.com/OffchainLabs/nitro-contracts/blob/main/LICENSE
+// SPDX-License-Identifier: BUSL-1.1
+
+pragma solidity >=0.4.21 <0.9.0;
+
+/// @title ArbResourceConstraintsTypes
+/// @notice Resource constraints type definitions used by ArbOwner and ArbOwnerPublic precompiles.
+library ArbResourceConstraintsTypes {
+    /// @notice A pair representing a resource kind and its weight in constraint calculations.
+    struct ResourceWeight {
+        uint8 resource;
+        uint64 weight;
+    }
+
+    /// @notice A constraint describing limits for a set of weighted resources.
+    struct ResourceConstraint {
+        ResourceWeight[] resources;
+        uint32 periodSecs;
+        uint64 targetPerSec;
+        uint64 backlog;
+    }
+}