ZrxAdapter.sol

// Copyright (C) 2020 Zerion Inc. <https://zerion.io>
//
// 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 <https://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: LGPL-3.0-only

pragma solidity 0.7.3;
pragma experimental ABIEncoderV2;

import { ERC20 } from "../../shared/ERC20.sol";
import { ProtocolAdapter } from "../ProtocolAdapter.sol";

/**
 * @dev Staking contract interface.
 * Only the functions required for ZrxAdapter contract are added.
 * The Staking contract is available here
 * github.com/0xProject/0x-monorepo/blob/development/contracts/staking/contracts/src/Staking.sol.
 */
interface Staking {
    function getTotalStake(address) external view returns (uint256);
}

/**
 * @title Adapter for 0x protocol.
 * @dev Implementation of ProtocolAdapter abstract contract.
 * @author Igor Sobolev <sobolev@zerion.io>
 */
contract ZrxAdapter is ProtocolAdapter {
    address internal constant STAKING = 0xa26e80e7Dea86279c6d778D702Cc413E6CFfA777;

    /**
     * @return Amount of ZRX locked on the protocol by the given account.
     * @dev Implementation of ProtocolAdapter abstract contract function.
     */
    function getBalance(address, address account) public override returns (int256) {
        return int256(Staking(STAKING).getTotalStake(account));
    }
}