Add Governor contracts (#2672)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

contracts/mocks/compound/CompTimelock.sol

@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// solhint-disable private-vars-leading-underscore
+/**
+ * Copyright 2020 Compound Labs, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
+ * following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+ *    disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+ *    following disclaimer in the documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
+ *    products derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+pragma solidity ^0.8.0;
+
+contract CompTimelock {
+    event NewAdmin(address indexed newAdmin);
+    event NewPendingAdmin(address indexed newPendingAdmin);
+    event NewDelay(uint256 indexed newDelay);
+    event CancelTransaction(
+        bytes32 indexed txHash,
+        address indexed target,
+        uint256 value,
+        string signature,
+        bytes data,
+        uint256 eta
+    );
+    event ExecuteTransaction(
+        bytes32 indexed txHash,
+        address indexed target,
+        uint256 value,
+        string signature,
+        bytes data,
+        uint256 eta
+    );
+    event QueueTransaction(
+        bytes32 indexed txHash,
+        address indexed target,
+        uint256 value,
+        string signature,
+        bytes data,
+        uint256 eta
+    );
+
+    uint256 public constant GRACE_PERIOD = 14 days;
+    uint256 public constant MINIMUM_DELAY = 2 days;
+    uint256 public constant MAXIMUM_DELAY = 30 days;
+
+    address public admin;
+    address public pendingAdmin;
+    uint256 public delay;
+
+    mapping(bytes32 => bool) public queuedTransactions;
+
+    constructor(address admin_, uint256 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(uint256 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,
+        uint256 value,
+        string memory signature,
+        bytes memory data,
+        uint256 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,
+        uint256 value,
+        string memory signature,
+        bytes memory data,
+        uint256 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,
+        uint256 value,
+        string memory signature,
+        bytes memory data,
+        uint256 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 (uint256) {
+        // solium-disable-next-line security/no-block-members
+        return block.timestamp;
+    }
+}