Add Timelock

src/Timelock.sol

@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copied from https://github.com/compound-finance/compound-protocol/blob/master/contracts/Timelock.sol
+pragma solidity ^0.8.0;
+
+contract Timelock {
+    event NewAdmin(address indexed newAdmin);
+    event NewPendingAdmin(address indexed newPendingAdmin);
+    event NewDelay(uint indexed newDelay);
+    event CancelTransaction(bytes32 indexed txHash, address indexed target, uint value, string signature,  bytes data, uint eta);
+    event ExecuteTransaction(bytes32 indexed txHash, address indexed target, uint value, string signature,  bytes data, uint eta);
+    event QueueTransaction(bytes32 indexed txHash, address indexed target, uint value, string signature, bytes data, uint eta);
+
+    uint public constant GRACE_PERIOD = 14 days;
+    uint public constant MINIMUM_DELAY = 2 days;
+    uint public constant MAXIMUM_DELAY = 30 days;
+
+    address public admin;
+    address public pendingAdmin;
+    uint public delay;
+
+    mapping (bytes32 => bool) public queuedTransactions;
+
+    constructor(address admin_, uint delay_) {
+        require(delay_ >= MINIMUM_DELAY, "Timelock::constructor: Delay must exceed minimum delay.");
+        require(delay_ <= MAXIMUM_DELAY, "Timelock::setDelay: Delay must not exceed maximum delay.");
+
+        admin = admin_;
+        delay = delay_;
+    }
+
+    receive() external payable { }
+
+    function setDelay(uint delay_) public {
+        require(msg.sender == address(this), "Timelock::setDelay: Call must come from Timelock.");
+        require(delay_ >= MINIMUM_DELAY, "Timelock::setDelay: Delay must exceed minimum delay.");
+        require(delay_ <= MAXIMUM_DELAY, "Timelock::setDelay: Delay must not exceed maximum delay.");
+        delay = delay_;
+
+        emit NewDelay(delay);
+    }
+
+    function acceptAdmin() public {
+        require(msg.sender == pendingAdmin, "Timelock::acceptAdmin: Call must come from pendingAdmin.");
+        admin = msg.sender;
+        pendingAdmin = address(0);
+
+        emit NewAdmin(admin);
+    }
+
+    function setPendingAdmin(address pendingAdmin_) public {
+        require(msg.sender == address(this), "Timelock::setPendingAdmin: Call must come from Timelock.");
+        pendingAdmin = pendingAdmin_;
+
+        emit NewPendingAdmin(pendingAdmin);
+    }
+
+    function queueTransaction(address target, uint value, string memory signature, bytes memory data, uint eta) public returns (bytes32) {
+        require(msg.sender == admin, "Timelock::queueTransaction: Call must come from admin.");
+        require(eta >= getBlockTimestamp() + delay, "Timelock::queueTransaction: Estimated execution block must satisfy delay.");
+
+        bytes32 txHash = keccak256(abi.encode(target, value, signature, data, eta));
+        queuedTransactions[txHash] = true;
+
+        emit QueueTransaction(txHash, target, value, signature, data, eta);
+        return txHash;
+    }
+
+    function cancelTransaction(address target, uint value, string memory signature, bytes memory data, uint eta) public {
+        require(msg.sender == admin, "Timelock::cancelTransaction: Call must come from admin.");
+
+        bytes32 txHash = keccak256(abi.encode(target, value, signature, data, eta));
+        queuedTransactions[txHash] = false;
+
+        emit CancelTransaction(txHash, target, value, signature, data, eta);
+    }
+
+    function executeTransaction(address target, uint value, string memory signature, bytes memory data, uint eta) public payable returns (bytes memory) {
+        require(msg.sender == admin, "Timelock::executeTransaction: Call must come from admin.");
+
+        bytes32 txHash = keccak256(abi.encode(target, value, signature, data, eta));
+        require(queuedTransactions[txHash], "Timelock::executeTransaction: Transaction hasn't been queued.");
+        require(getBlockTimestamp() >= eta, "Timelock::executeTransaction: Transaction hasn't surpassed time lock.");
+        require(getBlockTimestamp() <= eta + GRACE_PERIOD, "Timelock::executeTransaction: Transaction is stale.");
+
+        queuedTransactions[txHash] = false;
+
+        bytes memory callData;
+
+        if (bytes(signature).length == 0) {
+            callData = data;
+        } else {
+            callData = abi.encodePacked(bytes4(keccak256(bytes(signature))), data);
+        }
+
+        // solium-disable-next-line security/no-call-value
+        (bool success, bytes memory returnData) = target.call{value: value}(callData);
+        require(success, "Timelock::executeTransaction: Transaction execution reverted.");
+
+        emit ExecuteTransaction(txHash, target, value, signature, data, eta);
+
+        return returnData;
+    }
+
+    function getBlockTimestamp() internal view returns (uint) {
+        // solium-disable-next-line security/no-block-members
+        return block.timestamp;
+    }
+}