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{
"language": "Solidity",
"sources": {
"contracts/Farm.sol": {
"content": "//SPDX-License-Identifier: Unlicense\npragma solidity ^0.6.8;\n\n//import \"@nomiclabs/buidler/console.sol\";\nimport \"@openzeppelin/contracts/access/Ownable.sol\";\nimport \"@openzeppelin/contracts/token/ERC20/SafeERC20.sol\";\nimport \"@openzeppelin/contracts/math/SafeMath.sol\";\nimport \"@openzeppelin/contracts/utils/ReentrancyGuard.sol\";\nimport \"@openzeppelin/contracts/utils/Pausable.sol\";\n\n\ncontract Farm is ReentrancyGuard, Pausable, Ownable {\n using SafeMath for uint256;\n using SafeERC20 for IERC20;\n\n /* ========== STATE VARIABLES ========== */\n\n IERC20 public rewardsToken;\n IERC20 public stakingToken;\n uint256 public periodFinish = 0;\n uint256 public rewardRate = 0;\n uint256 public rewardsDuration;\n uint256 public lastUpdateTime;\n uint256 public rewardPerTokenStored;\n uint256 public stakingTokensDecimalRate;\n bool private initialised;\n\n mapping(address => uint256) public userRewardPerTokenPaid;\n mapping(address => uint256) public rewards;\n\n uint256 private _totalSupply;\n mapping(address => uint256) private _balances;\n\n /* ========== CONSTRUCTOR ========== */\n\n constructor (\n address _rewardsToken,\n address _stakingToken,\n uint _rewardsDuration,\n uint _stakingTokensDecimal\n ) public {\n stakingTokensDecimalRate = pow(10, _stakingTokensDecimal);\n rewardsToken = IERC20(_rewardsToken);\n stakingToken = IERC20(_stakingToken);\n rewardsDuration = _rewardsDuration;\n }\n\n\n\n /* ========== VIEWS ========== */\n\n function totalSupply() external view returns (uint256) {\n return _totalSupply;\n }\n\n function pow(uint n, uint e) public pure returns (uint) {\n\n if (e == 0) {\n return 1;\n } else if (e == 1) {\n return n;\n } else {\n uint p = pow(n, e.div(2));\n p = p.mul(p);\n if (e.mod(2) == 1) {\n p = p.mul(n);\n }\n return p;\n }\n }\n\n function balanceOf(address account) external view returns (uint256) {\n return _balances[account];\n }\n\n function lastTimeRewardApplicable() public view returns (uint256) {\n return min(block.timestamp, periodFinish);\n }\n\n function rewardPerToken() public view returns (uint256) {\n if (_totalSupply == 0) {\n return rewardPerTokenStored;\n }\n return\n rewardPerTokenStored.add(\n lastTimeRewardApplicable()\n .sub(lastUpdateTime)\n .mul(rewardRate)\n .mul(stakingTokensDecimalRate)\n .div(_totalSupply)\n );\n }\n\n function earned(address account) public view returns (uint256) {\n return\n _balances[account]\n .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))\n .div(stakingTokensDecimalRate)\n .add(rewards[account]);\n }\n\n function getRewardForDuration() external view returns (uint256) {\n return rewardRate.mul(rewardsDuration);\n }\n\n function min(uint256 a, uint256 b) public pure returns (uint256) {\n return a < b ? a : b;\n }\n\n /* ========== MUTATIVE FUNCTIONS ========== */\n\n function stake(uint256 amount)\n external\n nonReentrant\n whenNotPaused\n updateReward(msg.sender)\n {\n require(amount > 0, \"Cannot stake 0\");\n _totalSupply = _totalSupply.add(amount);\n _balances[msg.sender] = _balances[msg.sender].add(amount);\n stakingToken.safeTransferFrom(msg.sender, address(this), amount);\n emit Staked(msg.sender, amount);\n }\n\n function withdraw(uint256 amount)\n public\n nonReentrant\n updateReward(msg.sender)\n {\n require(amount > 0, \"Cannot withdraw 0\");\n\n _totalSupply = _totalSupply.sub(amount);\n _balances[msg.sender] = _balances[msg.sender].sub(amount);\n stakingToken.safeTransfer(msg.sender, amount);\n emit Withdrawn(msg.sender, amount);\n }\n\n function getReward() public nonReentrant updateReward(msg.sender) {\n uint256 reward = rewards[msg.sender];\n if (reward > 0) {\n rewards[msg.sender] = 0;\n rewardsToken.safeTransfer(msg.sender, reward);\n emit RewardPaid(msg.sender, reward);\n }\n }\n\n function exit() external {\n withdraw(_balances[msg.sender]);\n getReward();\n }\n\n /* ========== RESTRICTED FUNCTIONS ========== */\n\n function notifyRewardAmount(uint256 reward)\n external\n onlyOwner\n updateReward(address(0))\n {\n if (block.timestamp >= periodFinish) {\n rewardRate = reward.div(rewardsDuration);\n } else {\n uint256 remaining = periodFinish.sub(block.timestamp);\n uint256 leftover = remaining.mul(rewardRate);\n rewardRate = reward.add(leftover).div(rewardsDuration);\n }\n\n // Ensure the provided reward amount is not more than the balance in the contract.\n // This keeps the reward rate in the right range, preventing overflows due to\n // very high values of rewardRate in the earned and rewardsPerToken functions;\n // Reward + leftover must be less than 2^256 / 10^18 to avoid overflow.\n uint256 balance = rewardsToken.balanceOf(address(this));\n require(\n rewardRate <= balance.div(rewardsDuration),\n \"Provided reward too high\"\n );\n\n lastUpdateTime = block.timestamp;\n periodFinish = block.timestamp.add(rewardsDuration);\n emit RewardAdded(reward);\n }\n\n // Added to support recovering LP Rewards from other systems such as BAL to be distributed to holders\n function recoverERC20(address tokenAddress, uint256 tokenAmount)\n external\n onlyOwner\n {\n // Cannot recover the staking token or the rewards token\n require(\n tokenAddress != address(rewardsToken),\n \"Cannot withdraw the rewards tokens\"\n );\n if (_totalSupply != 0) {\n require(\n tokenAddress != address(stakingToken),\n \"Cannot withdraw the staking tokens\"\n );\n }\n IERC20(tokenAddress).safeTransfer(msg.sender, tokenAmount);\n emit Recovered(tokenAddress, tokenAmount);\n }\n\n function setRewardsDuration(uint256 _rewardsDuration) external onlyOwner {\n require(\n block.timestamp > periodFinish,\n \"Previous rewards period must be complete before changing the duration for the new period\"\n );\n rewardsDuration = _rewardsDuration;\n emit RewardsDurationUpdated(rewardsDuration);\n }\n\n /* ========== MODIFIERS ========== */\n\n modifier updateReward(address account) {\n rewardPerTokenStored = rewardPerToken();\n lastUpdateTime = lastTimeRewardApplicable();\n if (account != address(0)) {\n rewards[account] = earned(account);\n userRewardPerTokenPaid[account] = rewardPerTokenStored;\n }\n _;\n }\n\n /* ========== EVENTS ========== */\n\n event RewardAdded(uint256 reward);\n event Staked(address indexed user, uint256 amount);\n event Withdrawn(address indexed user, uint256 amount);\n event RewardPaid(address indexed user, uint256 reward);\n event RewardsDurationUpdated(uint256 newDuration);\n event Recovered(address token, uint256 amount);\n}"
},
"@openzeppelin/contracts/access/Ownable.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"../GSN/Context.sol\";\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n address private _owner;\n\n event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n /**\n * @dev Initializes the contract setting the deployer as the initial owner.\n */\n constructor () internal {\n address msgSender = _msgSender();\n _owner = msgSender;\n emit OwnershipTransferred(address(0), msgSender);\n }\n\n /**\n * @dev Returns the address of the current owner.\n */\n function owner() public view returns (address) {\n return _owner;\n }\n\n /**\n * @dev Throws if called by any account other than the owner.\n */\n modifier onlyOwner() {\n require(_owner == _msgSender(), \"Ownable: caller is not the owner\");\n _;\n }\n\n /**\n * @dev Leaves the contract without owner. It will not be possible to call\n * `onlyOwner` functions anymore. Can only be called by the current owner.\n *\n * NOTE: Renouncing ownership will leave the contract without an owner,\n * thereby removing any functionality that is only available to the owner.\n */\n function renounceOwnership() public virtual onlyOwner {\n emit OwnershipTransferred(_owner, address(0));\n _owner = address(0);\n }\n\n /**\n * @dev Transfers ownership of the contract to a new account (`newOwner`).\n * Can only be called by the current owner.\n */\n function transferOwnership(address newOwner) public virtual onlyOwner {\n require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n emit OwnershipTransferred(_owner, newOwner);\n _owner = newOwner;\n }\n}\n"
},
"@openzeppelin/contracts/token/ERC20/SafeERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"./IERC20.sol\";\nimport \"../../math/SafeMath.sol\";\nimport \"../../utils/Address.sol\";\n\n/**\n * @title SafeERC20\n * @dev Wrappers around ERC20 operations that throw on failure (when the token\n * contract returns false). Tokens that return no value (and instead revert or\n * throw on failure) are also supported, non-reverting calls are assumed to be\n * successful.\n * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,\n * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.\n */\nlibrary SafeERC20 {\n using SafeMath for uint256;\n using Address for address;\n\n function safeTransfer(IERC20 token, address to, uint256 value) internal {\n _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));\n }\n\n function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {\n _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));\n }\n\n /**\n * @dev Deprecated. This function has issues similar to the ones found in\n * {IERC20-approve}, and its usage is discouraged.\n *\n * Whenever possible, use {safeIncreaseAllowance} and\n * {safeDecreaseAllowance} instead.\n */\n function safeApprove(IERC20 token, address spender, uint256 value) internal {\n // safeApprove should only be called when setting an initial allowance,\n // or when resetting it to zero. To increase and decrease it, use\n // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'\n // solhint-disable-next-line max-line-length\n require((value == 0) || (token.allowance(address(this), spender) == 0),\n \"SafeERC20: approve from non-zero to non-zero allowance\"\n );\n _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));\n }\n\n function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {\n uint256 newAllowance = token.allowance(address(this), spender).add(value);\n _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));\n }\n\n function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {\n uint256 newAllowance = token.allowance(address(this), spender).sub(value, \"SafeERC20: decreased allowance below zero\");\n _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));\n }\n\n /**\n * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement\n * on the return value: the return value is optional (but if data is returned, it must not be false).\n * @param token The token targeted by the call.\n * @param data The call data (encoded using abi.encode or one of its variants).\n */\n function _callOptionalReturn(IERC20 token, bytes memory data) private {\n // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since\n // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that\n // the target address contains contract code and also asserts for success in the low-level call.\n\n bytes memory returndata = address(token).functionCall(data, \"SafeERC20: low-level call failed\");\n if (returndata.length > 0) { // Return data is optional\n // solhint-disable-next-line max-line-length\n require(abi.decode(returndata, (bool)), \"SafeERC20: ERC20 operation did not succeed\");\n }\n }\n}\n"
},
"@openzeppelin/contracts/math/SafeMath.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Wrappers over Solidity's arithmetic operations with added overflow\n * checks.\n *\n * Arithmetic operations in Solidity wrap on overflow. This can easily result\n * in bugs, because programmers usually assume that an overflow raises an\n * error, which is the standard behavior in high level programming languages.\n * `SafeMath` restores this intuition by reverting the transaction when an\n * operation overflows.\n *\n * Using this library instead of the unchecked operations eliminates an entire\n * class of bugs, so it's recommended to use it always.\n */\nlibrary SafeMath {\n /**\n * @dev Returns the addition of two unsigned integers, reverting on\n * overflow.\n *\n * Counterpart to Solidity's `+` operator.\n *\n * Requirements:\n *\n * - Addition cannot overflow.\n */\n function add(uint256 a, uint256 b) internal pure returns (uint256) {\n uint256 c = a + b;\n require(c >= a, \"SafeMath: addition overflow\");\n\n return c;\n }\n\n /**\n * @dev Returns the subtraction of two unsigned integers, reverting on\n * overflow (when the result is negative).\n *\n * Counterpart to Solidity's `-` operator.\n *\n * Requirements:\n *\n * - Subtraction cannot overflow.\n */\n function sub(uint256 a, uint256 b) internal pure returns (uint256) {\n return sub(a, b, \"SafeMath: subtraction overflow\");\n }\n\n /**\n * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\n * overflow (when the result is negative).\n *\n * Counterpart to Solidity's `-` operator.\n *\n * Requirements:\n *\n * - Subtraction cannot overflow.\n */\n function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b <= a, errorMessage);\n uint256 c = a - b;\n\n return c;\n }\n\n /**\n * @dev Returns the multiplication of two unsigned integers, reverting on\n * overflow.\n *\n * Counterpart to Solidity's `*` operator.\n *\n * Requirements:\n *\n * - Multiplication cannot overflow.\n */\n function mul(uint256 a, uint256 b) internal pure returns (uint256) {\n // Gas optimization: this is cheaper than requiring 'a' not being zero, but the\n // benefit is lost if 'b' is also tested.\n // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\n if (a == 0) {\n return 0;\n }\n\n uint256 c = a * b;\n require(c / a == b, \"SafeMath: multiplication overflow\");\n\n return c;\n }\n\n /**\n * @dev Returns the integer division of two unsigned integers. Reverts on\n * division by zero. The result is rounded towards zero.\n *\n * Counterpart to Solidity's `/` operator. Note: this function uses a\n * `revert` opcode (which leaves remaining gas untouched) while Solidity\n * uses an invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function div(uint256 a, uint256 b) internal pure returns (uint256) {\n return div(a, b, \"SafeMath: division by zero\");\n }\n\n /**\n * @dev Returns the integer division of two unsigned integers. Reverts with custom message on\n * division by zero. The result is rounded towards zero.\n *\n * Counterpart to Solidity's `/` operator. Note: this function uses a\n * `revert` opcode (which leaves remaining gas untouched) while Solidity\n * uses an invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b > 0, errorMessage);\n uint256 c = a / b;\n // assert(a == b * c + a % b); // There is no case in which this doesn't hold\n\n return c;\n }\n\n /**\n * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n * Reverts when dividing by zero.\n *\n * Counterpart to Solidity's `%` operator. This function uses a `revert`\n * opcode (which leaves remaining gas untouched) while Solidity uses an\n * invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function mod(uint256 a, uint256 b) internal pure returns (uint256) {\n return mod(a, b, \"SafeMath: modulo by zero\");\n }\n\n /**\n * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n * Reverts with custom message when dividing by zero.\n *\n * Counterpart to Solidity's `%` operator. This function uses a `revert`\n * opcode (which leaves remaining gas untouched) while Solidity uses an\n * invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b != 0, errorMessage);\n return a % b;\n }\n}\n"
},
"@openzeppelin/contracts/utils/ReentrancyGuard.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Contract module that helps prevent reentrant calls to a function.\n *\n * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier\n * available, which can be applied to functions to make sure there are no nested\n * (reentrant) calls to them.\n *\n * Note that because there is a single `nonReentrant` guard, functions marked as\n * `nonReentrant` may not call one another. This can be worked around by making\n * those functions `private`, and then adding `external` `nonReentrant` entry\n * points to them.\n *\n * TIP: If you would like to learn more about reentrancy and alternative ways\n * to protect against it, check out our blog post\n * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].\n */\nabstract contract ReentrancyGuard {\n // Booleans are more expensive than uint256 or any type that takes up a full\n // word because each write operation emits an extra SLOAD to first read the\n // slot's contents, replace the bits taken up by the boolean, and then write\n // back. This is the compiler's defense against contract upgrades and\n // pointer aliasing, and it cannot be disabled.\n\n // The values being non-zero value makes deployment a bit more expensive,\n // but in exchange the refund on every call to nonReentrant will be lower in\n // amount. Since refunds are capped to a percentage of the total\n // transaction's gas, it is best to keep them low in cases like this one, to\n // increase the likelihood of the full refund coming into effect.\n uint256 private constant _NOT_ENTERED = 1;\n uint256 private constant _ENTERED = 2;\n\n uint256 private _status;\n\n constructor () internal {\n _status = _NOT_ENTERED;\n }\n\n /**\n * @dev Prevents a contract from calling itself, directly or indirectly.\n * Calling a `nonReentrant` function from another `nonReentrant`\n * function is not supported. It is possible to prevent this from happening\n * by making the `nonReentrant` function external, and make it call a\n * `private` function that does the actual work.\n */\n modifier nonReentrant() {\n // On the first call to nonReentrant, _notEntered will be true\n require(_status != _ENTERED, \"ReentrancyGuard: reentrant call\");\n\n // Any calls to nonReentrant after this point will fail\n _status = _ENTERED;\n\n _;\n\n // By storing the original value once again, a refund is triggered (see\n // https://eips.ethereum.org/EIPS/eip-2200)\n _status = _NOT_ENTERED;\n }\n}\n"
},
"@openzeppelin/contracts/utils/Pausable.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"../GSN/Context.sol\";\n\n/**\n * @dev Contract module which allows children to implement an emergency stop\n * mechanism that can be triggered by an authorized account.\n *\n * This module is used through inheritance. It will make available the\n * modifiers `whenNotPaused` and `whenPaused`, which can be applied to\n * the functions of your contract. Note that they will not be pausable by\n * simply including this module, only once the modifiers are put in place.\n */\nabstract contract Pausable is Context {\n /**\n * @dev Emitted when the pause is triggered by `account`.\n */\n event Paused(address account);\n\n /**\n * @dev Emitted when the pause is lifted by `account`.\n */\n event Unpaused(address account);\n\n bool private _paused;\n\n /**\n * @dev Initializes the contract in unpaused state.\n */\n constructor () internal {\n _paused = false;\n }\n\n /**\n * @dev Returns true if the contract is paused, and false otherwise.\n */\n function paused() public view returns (bool) {\n return _paused;\n }\n\n /**\n * @dev Modifier to make a function callable only when the contract is not paused.\n *\n * Requirements:\n *\n * - The contract must not be paused.\n */\n modifier whenNotPaused() {\n require(!_paused, \"Pausable: paused\");\n _;\n }\n\n /**\n * @dev Modifier to make a function callable only when the contract is paused.\n *\n * Requirements:\n *\n * - The contract must be paused.\n */\n modifier whenPaused() {\n require(_paused, \"Pausable: not paused\");\n _;\n }\n\n /**\n * @dev Triggers stopped state.\n *\n * Requirements:\n *\n * - The contract must not be paused.\n */\n function _pause() internal virtual whenNotPaused {\n _paused = true;\n emit Paused(_msgSender());\n }\n\n /**\n * @dev Returns to normal state.\n *\n * Requirements:\n *\n * - The contract must be paused.\n */\n function _unpause() internal virtual whenPaused {\n _paused = false;\n emit Unpaused(_msgSender());\n }\n}\n"
},
"@openzeppelin/contracts/GSN/Context.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/*\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with GSN meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n function _msgSender() internal view virtual returns (address payable) {\n return msg.sender;\n }\n\n function _msgData() internal view virtual returns (bytes memory) {\n this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691\n return msg.data;\n }\n}\n"
},
"@openzeppelin/contracts/token/ERC20/IERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n /**\n * @dev Returns the amount of tokens in existence.\n */\n function totalSupply() external view returns (uint256);\n\n /**\n * @dev Returns the amount of tokens owned by `account`.\n */\n function balanceOf(address account) external view returns (uint256);\n\n /**\n * @dev Moves `amount` tokens from the caller's account to `recipient`.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transfer(address recipient, uint256 amount) external returns (bool);\n\n /**\n * @dev Returns the remaining number of tokens that `spender` will be\n * allowed to spend on behalf of `owner` through {transferFrom}. This is\n * zero by default.\n *\n * This value changes when {approve} or {transferFrom} are called.\n */\n function allowance(address owner, address spender) external view returns (uint256);\n\n /**\n * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * IMPORTANT: Beware that changing an allowance with this method brings the risk\n * that someone may use both the old and the new allowance by unfortunate\n * transaction ordering. One possible solution to mitigate this race\n * condition is to first reduce the spender's allowance to 0 and set the\n * desired value afterwards:\n * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n *\n * Emits an {Approval} event.\n */\n function approve(address spender, uint256 amount) external returns (bool);\n\n /**\n * @dev Moves `amount` tokens from `sender` to `recipient` using the\n * allowance mechanism. `amount` is then deducted from the caller's\n * allowance.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);\n\n /**\n * @dev Emitted when `value` tokens are moved from one account (`from`) to\n * another (`to`).\n *\n * Note that `value` may be zero.\n */\n event Transfer(address indexed from, address indexed to, uint256 value);\n\n /**\n * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n * a call to {approve}. `value` is the new allowance.\n */\n event Approval(address indexed owner, address indexed spender, uint256 value);\n}\n"
},
"@openzeppelin/contracts/utils/Address.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.2 <0.8.0;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n /**\n * @dev Returns true if `account` is a contract.\n *\n * [IMPORTANT]\n * ====\n * It is unsafe to assume that an address for which this function returns\n * false is an externally-owned account (EOA) and not a contract.\n *\n * Among others, `isContract` will return false for the following\n * types of addresses:\n *\n * - an externally-owned account\n * - a contract in construction\n * - an address where a contract will be created\n * - an address where a contract lived, but was destroyed\n * ====\n */\n function isContract(address account) internal view returns (bool) {\n // This method relies on extcodesize, which returns 0 for contracts in\n // construction, since the code is only stored at the end of the\n // constructor execution.\n\n uint256 size;\n // solhint-disable-next-line no-inline-assembly\n assembly { size := extcodesize(account) }\n return size > 0;\n }\n\n /**\n * @dev Replacement for Solidity's `transfer`: sends `amount` wei to\n * `recipient`, forwarding all available gas and reverting on errors.\n *\n * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n * of certain opcodes, possibly making contracts go over the 2300 gas limit\n * imposed by `transfer`, making them unable to receive funds via\n * `transfer`. {sendValue} removes this limitation.\n *\n * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n *\n * IMPORTANT: because control is transferred to `recipient`, care must be\n * taken to not create reentrancy vulnerabilities. Consider using\n * {ReentrancyGuard} or the\n * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n */\n function sendValue(address payable recipient, uint256 amount) internal {\n require(address(this).balance >= amount, \"Address: insufficient balance\");\n\n // solhint-disable-next-line avoid-low-level-calls, avoid-call-value\n (bool success, ) = recipient.call{ value: amount }(\"\");\n require(success, \"Address: unable to send value, recipient may have reverted\");\n }\n\n /**\n * @dev Performs a Solidity function call using a low level `call`. A\n * plain`call` is an unsafe replacement for a function call: use this\n * function instead.\n *\n * If `target` reverts with a revert reason, it is bubbled up by this\n * function (like regular Solidity function calls).\n *\n * Returns the raw returned data. To convert to the expected return value,\n * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n *\n * Requirements:\n *\n * - `target` must be a contract.\n * - calling `target` with `data` must not revert.\n *\n * _Available since v3.1._\n */\n function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n return functionCall(target, data, \"Address: low-level call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n * `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {\n return functionCallWithValue(target, data, 0, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but also transferring `value` wei to `target`.\n *\n * Requirements:\n *\n * - the calling contract must have an ETH balance of at least `value`.\n * - the called Solidity function must be `payable`.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {\n return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n * with `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {\n require(address(this).balance >= value, \"Address: insufficient balance for call\");\n require(isContract(target), \"Address: call to non-contract\");\n\n // solhint-disable-next-line avoid-low-level-calls\n (bool success, bytes memory returndata) = target.call{ value: value }(data);\n return _verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\n return functionStaticCall(target, data, \"Address: low-level static call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {\n require(isContract(target), \"Address: static call to non-contract\");\n\n // solhint-disable-next-line avoid-low-level-calls\n (bool success, bytes memory returndata) = target.staticcall(data);\n return _verifyCallResult(success, returndata, errorMessage);\n }\n\n function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {\n if (success) {\n return returndata;\n } else {\n // Look for revert reason and bubble it up if present\n if (returndata.length > 0) {\n // The easiest way to bubble the revert reason is using memory via assembly\n\n // solhint-disable-next-line no-inline-assembly\n assembly {\n let returndata_size := mload(returndata)\n revert(add(32, returndata), returndata_size)\n }\n } else {\n revert(errorMessage);\n }\n }\n }\n}\n"
}
},
"settings": {
"optimizer": {
"enabled": false,
"runs": 200
},
"outputSelection": {
"*": {
"*": [
"evm.bytecode",
"evm.deployedBytecode",
"abi"
]
}
},
"libraries": {}
}
} |