Add FeeDistributorBALClaimer contract

pkg/liquidity-mining/contracts/fee-distribution/FeeDistributorBALClaimer.sol

@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+pragma solidity ^0.7.0;
+pragma experimental ABIEncoderV2;
+
+import "@balancer-labs/v2-standalone-utils/contracts/interfaces/IBALTokenHolder.sol";
+
+import "../interfaces/IFeeDistributor.sol";
+import "../interfaces/ISingleRecipientGauge.sol";
+
+/**
+ * @title FeeDistributorBALClaimer
+ * @notice Atomically mints any outstanding BAL from a SingleRecipientGauge and transfers it to the FeeDistributor
+ * in order for it to be distributed among veBAL holders.
+ */
+contract FeeDistributorBALClaimer {
+    IERC20 private immutable _balToken;
+    IAuthorizerAdaptor private immutable _authorizerAdaptor;
+    IFeeDistributor private immutable _feeDistributor;
+    ISingleRecipientGauge private immutable _gauge;
+    IBALTokenHolder private immutable _balTokenHolder;
+
+    constructor(
+        IFeeDistributor feeDistributor,
+        ISingleRecipientGauge gauge,
+        IAuthorizerAdaptor authorizerAdaptor
+    ) {
+        IBALTokenHolder balTokenHolder = IBALTokenHolder(gauge.getRecipient());
+
+        _balToken = balTokenHolder.getBalancerToken();
+        _authorizerAdaptor = authorizerAdaptor;
+        _feeDistributor = feeDistributor;
+        _gauge = gauge;
+        _balTokenHolder = balTokenHolder;
+    }
+
+    /**
+     * @notice Returns the address of the Balancer token contract.
+     */
+    function getBalancerToken() external view returns (IERC20) {
+        return _balToken;
+    }
+
+    /**
+     * @notice Returns the address of the AuthorizerAdaptor contract.
+     */
+    function getAuthorizerAdaptor() external view returns (IAuthorizerAdaptor) {
+        return _authorizerAdaptor;
+    }
+
+    /**
+     * @notice Returns the address of the FeeDistributor contract.
+     */
+    function getFeeDistributor() external view returns (IFeeDistributor) {
+        return _feeDistributor;
+    }
+
+    /**
+     * @notice Returns the address of the associated SingleRecipientGauge contract.
+     */
+    function getGauge() external view returns (ISingleRecipientGauge) {
+        return _gauge;
+    }
+
+    /**
+     * @notice Returns the address of the associated BALTokenHolder contract.
+     */
+    function getBALTokenHolder() external view returns (IBALTokenHolder) {
+        return _balTokenHolder;
+    }
+
+    /**
+     * @notice Mint any outstanding BAL emissions and send them to the FeeDistributor
+     * @dev In order to call this function the `FeeDistributorBALClaimer` must be authorized to:
+     * - Withdraw BAL from the linked BALTokenHolder
+     * - Checkpoint the associated SingleRecipientGauge in order to mint BAL.
+     */
+    function distributeBAL() external {
+        _checkpointGauge(_gauge);
+        _balTokenHolder.withdrawFunds(address(_feeDistributor), _balToken.balanceOf(address(_balTokenHolder)));
+        _feeDistributor.checkpointToken(_balToken);
+    }
+
+    function _checkpointGauge(IStakelessGauge gauge) private {
+        _authorizerAdaptor.performAction(address(gauge), abi.encodeWithSelector(IStakelessGauge.checkpoint.selector));
+    }
+}

pkg/liquidity-mining/contracts/gauges/StakelessGauge.sol

@@ -20,9 +20,9 @@ import "@balancer-labs/v2-solidity-utils/contracts/openzeppelin/ReentrancyGuard.
 import "../interfaces/IBalancerMinter.sol";
 import "../interfaces/IBalancerTokenAdmin.sol";
 import "../interfaces/IGaugeController.sol";
-import "../interfaces/ILiquidityGauge.sol";
+import "../interfaces/IStakelessGauge.sol";
 
-abstract contract StakelessGauge is ILiquidityGauge, ReentrancyGuard {
+abstract contract StakelessGauge is IStakelessGauge, ReentrancyGuard {
     IERC20 internal immutable _balToken;
     IBalancerTokenAdmin private immutable _tokenAdmin;
     IBalancerMinter private immutable _minter;
@@ -78,7 +78,7 @@ abstract contract StakelessGauge is ILiquidityGauge, ReentrancyGuard {
         _startEpochTime = _tokenAdmin.startEpochTimeWrite();
     }
 
-    function checkpoint() external payable nonReentrant returns (bool) {
+    function checkpoint() external payable override nonReentrant returns (bool) {
         require(msg.sender == address(_authorizerAdaptor), "SENDER_NOT_ALLOWED");
         uint256 lastPeriod = _period;
         uint256 currentPeriod = _currentPeriod();

pkg/liquidity-mining/contracts/interfaces/ISingleRecipientGauge.sol

@@ -14,9 +14,9 @@
 
 pragma solidity ^0.7.0;
 
-import "./ILiquidityGauge.sol";
+import "./IStakelessGauge.sol";
 
-interface ISingleRecipientGauge is ILiquidityGauge {
+interface ISingleRecipientGauge is IStakelessGauge {
     function initialize(address recipient) external;
 
     function getRecipient() external view returns (address);

pkg/liquidity-mining/contracts/interfaces/IStakelessGauge.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+pragma solidity ^0.7.0;
+
+import "./ILiquidityGauge.sol";
+
+interface IStakelessGauge is ILiquidityGauge {
+    function checkpoint() external payable returns (bool);
+}

pkg/standalone-utils/contracts/BALTokenHolder.sol

@@ -18,7 +18,6 @@ import "@balancer-labs/v2-solidity-utils/contracts/helpers/Authentication.sol";
 import "@balancer-labs/v2-solidity-utils/contracts/openzeppelin/SafeERC20.sol";
 
 import "@balancer-labs/v2-vault/contracts/interfaces/IVault.sol";
-import "@balancer-labs/v2-liquidity-mining/contracts/interfaces/IBalancerToken.sol";
 
 import "./interfaces/IBALTokenHolder.sol";
 
@@ -51,7 +50,7 @@ contract BALTokenHolder is IBALTokenHolder, Authentication {
         _name = name;
     }
 
-    function getBalancerToken() external view returns (IBalancerToken) {
+    function getBalancerToken() external view override returns (IBalancerToken) {
         return _balancerToken;
     }
 

pkg/standalone-utils/contracts/interfaces/IBALTokenHolder.sol

@@ -16,8 +16,11 @@ pragma solidity ^0.7.0;
 
 import "@balancer-labs/v2-solidity-utils/contracts/helpers/IAuthentication.sol";
 import "@balancer-labs/v2-solidity-utils/contracts/openzeppelin/IERC20.sol";
+import "@balancer-labs/v2-liquidity-mining/contracts/interfaces/IBalancerToken.sol";
 
 interface IBALTokenHolder is IAuthentication {
+    function getBalancerToken() external view returns (IBalancerToken);
+
     function withdrawFunds(address recipient, uint256 amount) external;
 
     function sweepTokens(

pkg/standalone-utils/contracts/test/MockUnbuttonERC20.sol

@@ -36,11 +36,7 @@ contract MockUnbuttonERC20 is ERC20, IButtonWrapper {
 
     function initialize(uint256 initialRate) public {
         uint256 mintAmount = INITIAL_DEPOSIT * initialRate;
-        IERC20(_underlying).safeTransferFrom(
-            msg.sender,
-            address(this),
-            INITIAL_DEPOSIT
-        );
+        IERC20(_underlying).safeTransferFrom(msg.sender, address(this), INITIAL_DEPOSIT);
         _mint(address(this), mintAmount);
     }