use EIP5805

contracts/governance/extensions/GovernorVotes.sol

@@ -4,17 +4,17 @@
 pragma solidity ^0.8.0;
 
 import "../Governor.sol";
-import "../utils/IVotes.sol";
+import "../utils/IEIP5805.sol";
 
 /**
  * @dev Extension of {Governor} for voting weight extraction from an {ERC20Votes} token, or since v4.5 an {ERC721Votes} token.
  *
  * _Available since v4.3._
  */
 abstract contract GovernorVotes is Governor {
-    IVotes public immutable token;
+    IEIP5805 public immutable token;
 
-    constructor(IVotes tokenAddress) {
+    constructor(IEIP5805 tokenAddress) {
         token = tokenAddress;
     }
 

contracts/governance/utils/Votes.sol → contracts/governance/utils/EIP5805.sol

@@ -1,16 +1,22 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (governance/utils/Votes.sol)
 pragma solidity ^0.8.0;
 
+<<<<<<< HEAD:contracts/governance/utils/Votes.sol
 import "./IVotes.sol";
 import "../../utils/cryptography/draft-EIP712.sol";
 import "../../utils/cryptography/ECDSA.sol";
+=======
+>>>>>>> 040f8132 (use EIP5805):contracts/governance/utils/EIP5805.sol
 import "../../utils/Context.sol";
-import "../../utils/Nonces.sol";
+import "../../utils/Counters.sol";
 import "../../utils/Checkpoints.sol";
+import "../../utils/cryptography/EIP712.sol";
+import "./IEIP5805.sol";
 
 /**
- * @dev This is a base abstract contract that tracks voting units, which are a measure of voting power that can be
+ * @dev Core implementation of EIP-5805
+ *
+ * This is a base abstract contract that tracks voting units, which are a measure of voting power that can be
  * transferred, and provides a system of vote delegation, where an account can delegate its voting units to a sort of
  * "representative" that will pool delegated voting units from different accounts and can then use it to vote in
  * decisions. In fact, voting units _must_ be delegated in order to count as actual votes, and an account has to
@@ -19,25 +25,32 @@ import "../../utils/Checkpoints.sol";
  * This contract is often combined with a token contract such that voting units correspond to token units. For an
  * example, see {ERC721Votes}.
  *
- * The full history of delegate votes is tracked on-chain so that governance protocols can consider votes as distributed
- * at a particular block number to protect against flash loans and double voting. The opt-in delegate system makes the
- * cost of this history tracking optional.
+ * The full history of delegate votes is tracked on-chain so that governance protocols can consider votes as
+ * distributed at a particular timestamp to protect against flash loans and double voting. The opt-in delegate system
+ * makes the cost of this history tracking optional.
  *
  * When using this module the derived contract must implement {_getVotingUnits} (for example, make it return
  * {ERC721-balanceOf}), and can use {_transferVotingUnits} to track a change in the distribution of those units (in the
  * previous example, it would be included in {ERC721-_beforeTokenTransfer}).
- *
- * _Available since v4.5._
  */
-abstract contract Votes is IVotes, Context, EIP712, Nonces {
-    using Checkpoints for Checkpoints.History;
+abstract contract EIP5805 is IEIP5805, Context, EIP712 {
+    using Checkpoints for Checkpoints.Trace224;
+    using Counters for Counters.Counter;
 
     bytes32 private constant _DELEGATION_TYPEHASH =
         keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
 
     mapping(address => address) private _delegation;
-    mapping(address => Checkpoints.History) private _delegateCheckpoints;
-    Checkpoints.History private _totalCheckpoints;
+    mapping(address => Checkpoints.Trace224) private _delegateCheckpoints;
+    Checkpoints.Trace224 private _totalCheckpoints;
+    mapping(address => Counters.Counter) private _nonces;
+
+    /**
+     * @dev Return the current timestamp, this can be overriden to use `block.timestamp` or any other mechanism
+     */
+    function clock() public view virtual override returns (uint256) {
+        return block.number;
+    }
 
     /**
      * @dev Returns the current amount of votes that `account` has.
@@ -47,29 +60,43 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     }
 
     /**
-     * @dev Returns the amount of votes that `account` had at the end of a past block (`blockNumber`).
+     * @dev Returns the amount of votes that `account` had at the end of a past timepoint (`timepoint`).
      *
      * Requirements:
      *
-     * - `blockNumber` must have been already mined
+     * - `timepoint` must have been already mined
      */
+<<<<<<< HEAD:contracts/governance/utils/Votes.sol
     function getPastVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
         return _delegateCheckpoints[account].getAtProbablyRecentBlock(blockNumber);
+=======
+    function getPastVotes(address account, uint256 timepoint) public view virtual override returns (uint256) {
+        require(timepoint < clock(), "Checkpoints: invalid past lookup");
+        // TODO: optimisitc lookup
+        return _delegateCheckpoints[account].upperLookup(SafeCast.toUint32(timepoint));
+>>>>>>> 040f8132 (use EIP5805):contracts/governance/utils/EIP5805.sol
     }
 
     /**
-     * @dev Returns the total supply of votes available at the end of a past block (`blockNumber`).
+     * @dev Returns the total supply of votes available at the end of a past timepoint (`timepoint`).
      *
      * NOTE: This value is the sum of all available votes, which is not necessarily the sum of all delegated votes.
      * Votes that have not been delegated are still part of total supply, even though they would not participate in a
      * vote.
      *
      * Requirements:
      *
-     * - `blockNumber` must have been already mined
+     * - `timepoint` must have been already mined
      */
+<<<<<<< HEAD:contracts/governance/utils/Votes.sol
     function getPastTotalSupply(uint256 blockNumber) public view virtual override returns (uint256) {
         return _totalCheckpoints.getAtBlock(blockNumber);
+=======
+    function getPastTotalSupply(uint256 timepoint) public view virtual override returns (uint256) {
+        require(timepoint < clock(), "Checkpoints: invalid past lookup");
+        // TODO: optimisitc lookup
+        return _totalCheckpoints.upperLookup(SafeCast.toUint32(timepoint));
+>>>>>>> 040f8132 (use EIP5805):contracts/governance/utils/EIP5805.sol
     }
 
     /**
@@ -139,10 +166,10 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
         uint256 amount
     ) internal virtual {
         if (from == address(0)) {
-            _totalCheckpoints.push(_add, amount);
+            _totalCheckpoints.push(SafeCast.toUint32(clock()), _add, amount);
         }
         if (to == address(0)) {
-            _totalCheckpoints.push(_subtract, amount);
+            _totalCheckpoints.push(SafeCast.toUint32(clock()), _subtract, amount);
         }
         _moveDelegateVotes(delegates(from), delegates(to), amount);
     }
@@ -157,22 +184,40 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     ) private {
         if (from != to && amount > 0) {
             if (from != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(_subtract, amount);
+                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(SafeCast.toUint32(clock()), _subtract, amount);
                 emit DelegateVotesChanged(from, oldValue, newValue);
             }
             if (to != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(_add, amount);
+                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(SafeCast.toUint32(clock()), _add, amount);
                 emit DelegateVotesChanged(to, oldValue, newValue);
             }
         }
     }
 
-    function _add(uint256 a, uint256 b) private pure returns (uint256) {
-        return a + b;
+    function _add(uint224 a, uint256 b) private pure returns (uint224) {
+        return SafeCast.toUint224(a + b);
+    }
+
+    function _subtract(uint224 a, uint256 b) private pure returns (uint224) {
+        return SafeCast.toUint224(a - b);
     }
 
-    function _subtract(uint256 a, uint256 b) private pure returns (uint256) {
-        return a - b;
+    /**
+     * @dev Consumes a nonce.
+     *
+     * Returns the current value and increments nonce.
+     */
+    function _useNonce(address owner) internal virtual returns (uint256 current) {
+        Counters.Counter storage nonce = _nonces[owner];
+        current = nonce.current();
+        nonce.increment();
+    }
+
+    /**
+     * @dev Returns an address nonce.
+     */
+    function nonces(address owner) public view virtual returns (uint256) {
+        return _nonces[owner].current();
     }
 
     /**

contracts/governance/utils/IVotes.sol → contracts/governance/utils/IEIP5805.sol

@@ -1,13 +1,10 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.5.0) (governance/utils/IVotes.sol)
 pragma solidity ^0.8.0;
 
 /**
- * @dev Common interface for {ERC20Votes}, {ERC721Votes}, and other {Votes}-enabled contracts.
- *
- * _Available since v4.5._
+ * @dev EIP-5805 interface: common interface for {ERC20Votes}, {ERC721Votes}, and other {Votes}-enabled contracts.
  */
-interface IVotes {
+interface IEIP5805 {
     /**
      * @dev Emitted when an account changes their delegate.
      */
@@ -18,6 +15,11 @@ interface IVotes {
      */
     event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance);
 
+    /**
+     * @dev Return the current timestamp, this can be overriden to use `block.timestamp` or any other mechanism
+     */
+    function clock() external view returns (uint256);
+
     /**
      * @dev Returns the current amount of votes that `account` has.
      */

contracts/mocks/VotesMock.sol → contracts/mocks/EIP5805Mock.sol

@@ -2,9 +2,9 @@
 
 pragma solidity ^0.8.0;
 
-import "../governance/utils/Votes.sol";
+import "../governance/utils/EIP5805.sol";
 
-contract VotesMock is Votes {
+contract EIP5805Mock is EIP5805 {
     mapping(address => uint256) private _balances;
     mapping(uint256 => address) private _owners;
 

contracts/mocks/GovernorMock.sol

@@ -15,7 +15,7 @@ contract GovernorMock is
 {
     constructor(
         string memory name_,
-        IVotes token_,
+        IEIP5805 token_,
         uint256 votingDelay_,
         uint256 votingPeriod_,
         uint256 quorumNumerator_

contracts/mocks/GovernorPreventLateQuorumMock.sol

@@ -17,7 +17,7 @@ contract GovernorPreventLateQuorumMock is
 
     constructor(
         string memory name_,
-        IVotes token_,
+        IEIP5805 token_,
         uint256 votingDelay_,
         uint256 votingPeriod_,
         uint256 quorum_,

contracts/mocks/GovernorTimelockCompoundMock.sol

@@ -15,7 +15,7 @@ contract GovernorTimelockCompoundMock is
 {
     constructor(
         string memory name_,
-        IVotes token_,
+        IEIP5805 token_,
         uint256 votingDelay_,
         uint256 votingPeriod_,
         ICompoundTimelock timelock_,

contracts/mocks/GovernorTimelockControlMock.sol

@@ -15,7 +15,7 @@ contract GovernorTimelockControlMock is
 {
     constructor(
         string memory name_,
-        IVotes token_,
+        IEIP5805 token_,
         uint256 votingDelay_,
         uint256 votingPeriod_,
         TimelockController timelock_,

contracts/mocks/GovernorVoteMock.sol

@@ -6,7 +6,7 @@ import "../governance/extensions/GovernorCountingSimple.sol";
 import "../governance/extensions/GovernorVotes.sol";
 
 contract GovernorVoteMocks is GovernorVotes, GovernorCountingSimple {
-    constructor(string memory name_, IVotes token_) Governor(name_) GovernorVotes(token_) {}
+    constructor(string memory name_, IEIP5805 token_) Governor(name_) GovernorVotes(token_) {}
 
     function quorum(uint256) public pure override returns (uint256) {
         return 0;

contracts/mocks/GovernorWithParamsMock.sol

@@ -8,7 +8,7 @@ import "../governance/extensions/GovernorVotes.sol";
 contract GovernorWithParamsMock is GovernorVotes, GovernorCountingSimple {
     event CountParams(uint256 uintParam, string strParam);
 
-    constructor(string memory name_, IVotes token_) Governor(name_) GovernorVotes(token_) {}
+    constructor(string memory name_, IEIP5805 token_) Governor(name_) GovernorVotes(token_) {}
 
     function quorum(uint256) public pure override returns (uint256) {
         return 0;

contracts/mocks/wizard/MyGovernor1.sol

@@ -14,7 +14,7 @@ contract MyGovernor1 is
     GovernorVotesQuorumFraction,
     GovernorCountingSimple
 {
-    constructor(IVotes _token, TimelockController _timelock)
+    constructor(IEIP5805 _token, TimelockController _timelock)
         Governor("MyGovernor")
         GovernorVotes(_token)
         GovernorVotesQuorumFraction(4)

contracts/mocks/wizard/MyGovernor2.sol

@@ -16,7 +16,7 @@ contract MyGovernor2 is
     GovernorVotesQuorumFraction,
     GovernorCountingSimple
 {
-    constructor(IVotes _token, TimelockController _timelock)
+    constructor(IEIP5805 _token, TimelockController _timelock)
         Governor("MyGovernor")
         GovernorVotes(_token)
         GovernorVotesQuorumFraction(4)

contracts/mocks/wizard/MyGovernor3.sol

@@ -14,7 +14,7 @@ contract MyGovernor is
     GovernorVotes,
     GovernorVotesQuorumFraction
 {
-    constructor(IVotes _token, TimelockController _timelock)
+    constructor(IEIP5805 _token, TimelockController _timelock)
         Governor("MyGovernor")
         GovernorVotes(_token)
         GovernorVotesQuorumFraction(4)

contracts/token/ERC721/extensions/ERC721Votes.sol

@@ -3,7 +3,7 @@
 pragma solidity ^0.8.0;
 
 import "../ERC721.sol";
-import "../../../governance/utils/Votes.sol";
+import "../../../governance/utils/EIP5805.sol";
 
 /**
  * @dev Extension of ERC721 to support voting and delegation as implemented by {Votes}, where each individual NFT counts
@@ -15,7 +15,7 @@ import "../../../governance/utils/Votes.sol";
  *
  * _Available since v4.5._
  */
-abstract contract ERC721Votes is ERC721, Votes {
+abstract contract ERC721Votes is ERC721, EIP5805 {
     /**
      * @dev See {ERC721-_afterTokenTransfer}. Adjusts votes when tokens are transferred.
      *

contracts/utils/Checkpoints.sol

@@ -234,6 +234,21 @@ library Checkpoints {
         return _insert(self._checkpoints, key, value);
     }
 
+    /**
+     * @dev Pushes a value onto a History, by updating the latest value using binary operation `op`. The new value will
+     * be set to `op(latest, delta)`.
+     *
+     * Returns previous value and new value.
+     */
+    function push(
+        Trace224 storage self,
+        uint32 key,
+        function(uint224, uint256) view returns (uint224) op,
+        uint256 delta
+    ) internal returns (uint256, uint256) {
+        return push(self, key, op(latest(self), delta));
+    }
+
     /**
      * @dev Returns the value in the oldest checkpoint with key greater or equal than the search key, or zero if there is none.
      */
@@ -399,6 +414,21 @@ library Checkpoints {
         return _insert(self._checkpoints, key, value);
     }
 
+    /**
+     * @dev Pushes a value onto a History, by updating the latest value using binary operation `op`. The new value will
+     * be set to `op(latest, delta)`.
+     *
+     * Returns previous value and new value.
+     */
+    function push(
+        Trace160 storage self,
+        uint96 key,
+        function(uint160, uint256) view returns (uint160) op,
+        uint256 delta
+    ) internal returns (uint256, uint256) {
+        return push(self, key, op(latest(self), delta));
+    }
+
     /**
      * @dev Returns the value in the oldest checkpoint with key greater or equal than the search key, or zero if there is none.
      */