583 lines
18 KiB
Solidity
583 lines
18 KiB
Solidity
/**
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*Submitted for verification at Etherscan.io on 2021-12-08
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*/
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// SPDX-License-Identifier: MIT
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// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
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// OpenZeppelin Contracts v4.4.0 (token/ERC20/IERC20.sol)
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pragma solidity ^0.8.0;
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/**
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* @dev Interface of the ERC20 standard as defined in the EIP.
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*/
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interface IERC20 {
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/**
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* @dev Returns the amount of tokens in existence.
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*/
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function totalSupply() external view returns (uint256);
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/**
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* @dev Returns the amount of tokens owned by `account`.
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*/
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function balanceOf(address account) external view returns (uint256);
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/**
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* @dev Moves `amount` tokens from the caller's account to `recipient`.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transfer(address recipient, uint256 amount) external returns (bool);
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/**
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* @dev Returns the remaining number of tokens that `spender` will be
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* allowed to spend on behalf of `owner` through {transferFrom}. This is
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* zero by default.
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*
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* This value changes when {approve} or {transferFrom} are called.
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*/
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function allowance(address owner, address spender) external view returns (uint256);
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/**
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* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* IMPORTANT: Beware that changing an allowance with this method brings the risk
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* that someone may use both the old and the new allowance by unfortunate
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* transaction ordering. One possible solution to mitigate this race
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* condition is to first reduce the spender's allowance to 0 and set the
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* desired value afterwards:
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* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
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*
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* Emits an {Approval} event.
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*/
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function approve(address spender, uint256 amount) external returns (bool);
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/**
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* @dev Moves `amount` tokens from `sender` to `recipient` using the
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* allowance mechanism. `amount` is then deducted from the caller's
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* allowance.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transferFrom(
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address sender,
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address recipient,
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uint256 amount
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) external returns (bool);
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/**
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* @dev Emitted when `value` tokens are moved from one account (`from`) to
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* another (`to`).
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*
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* Note that `value` may be zero.
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*/
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event Transfer(address indexed from, address indexed to, uint256 value);
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/**
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* @dev Emitted when the allowance of a `spender` for an `owner` is set by
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* a call to {approve}. `value` is the new allowance.
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*/
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event Approval(address indexed owner, address indexed spender, uint256 value);
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}
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// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol
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// OpenZeppelin Contracts v4.4.0 (token/ERC20/extensions/IERC20Metadata.sol)
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pragma solidity ^0.8.0;
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/**
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* @dev Interface for the optional metadata functions from the ERC20 standard.
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*
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* _Available since v4.1._
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*/
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interface IERC20Metadata is IERC20 {
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/**
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* @dev Returns the name of the token.
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*/
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function name() external view returns (string memory);
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/**
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* @dev Returns the symbol of the token.
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*/
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function symbol() external view returns (string memory);
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/**
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* @dev Returns the decimals places of the token.
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*/
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function decimals() external view returns (uint8);
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}
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// File: @openzeppelin/contracts/utils/Context.sol
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// OpenZeppelin Contracts v4.4.0 (utils/Context.sol)
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pragma solidity ^0.8.0;
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/**
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* @dev Provides information about the current execution context, including the
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* sender of the transaction and its data. While these are generally available
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* via msg.sender and msg.data, they should not be accessed in such a direct
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* manner, since when dealing with meta-transactions the account sending and
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* paying for execution may not be the actual sender (as far as an application
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* is concerned).
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*
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* This contract is only required for intermediate, library-like contracts.
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*/
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abstract contract Context {
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function _msgSender() internal view virtual returns (address) {
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return msg.sender;
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}
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function _msgData() internal view virtual returns (bytes calldata) {
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return msg.data;
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}
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}
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// File: @openzeppelin/contracts/token/ERC20/ERC20.sol
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// OpenZeppelin Contracts v4.4.0 (token/ERC20/ERC20.sol)
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pragma solidity ^0.8.0;
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/**
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* @dev Implementation of the {IERC20} interface.
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*
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* This implementation is agnostic to the way tokens are created. This means
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* that a supply mechanism has to be added in a derived contract using {_mint}.
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* For a generic mechanism see {ERC20PresetMinterPauser}.
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*
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* TIP: For a detailed writeup see our guide
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* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
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* to implement supply mechanisms].
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*
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* We have followed general OpenZeppelin Contracts guidelines: functions revert
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* instead returning `false` on failure. This behavior is nonetheless
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* conventional and does not conflict with the expectations of ERC20
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* applications.
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*
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* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
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* This allows applications to reconstruct the allowance for all accounts just
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* by listening to said events. Other implementations of the EIP may not emit
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* these events, as it isn't required by the specification.
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*
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* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
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* functions have been added to mitigate the well-known issues around setting
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* allowances. See {IERC20-approve}.
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*/
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contract ERC20 is Context, IERC20, IERC20Metadata {
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mapping(address => uint256) private _balances;
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mapping(address => mapping(address => uint256)) private _allowances;
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uint256 private _totalSupply;
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string private _name;
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string private _symbol;
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/**
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* @dev Sets the values for {name} and {symbol}.
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*
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* The default value of {decimals} is 18. To select a different value for
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* {decimals} you should overload it.
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*
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* All two of these values are immutable: they can only be set once during
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* construction.
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*/
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constructor(string memory name_, string memory symbol_) {
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_name = name_;
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_symbol = symbol_;
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}
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/**
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* @dev Returns the name of the token.
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*/
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function name() public view virtual override returns (string memory) {
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return _name;
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}
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/**
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* @dev Returns the symbol of the token, usually a shorter version of the
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* name.
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*/
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function symbol() public view virtual override returns (string memory) {
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return _symbol;
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}
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/**
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* @dev Returns the number of decimals used to get its user representation.
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* For example, if `decimals` equals `2`, a balance of `505` tokens should
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* be displayed to a user as `5.05` (`505 / 10 ** 2`).
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*
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* Tokens usually opt for a value of 18, imitating the relationship between
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* Ether and Wei. This is the value {ERC20} uses, unless this function is
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* overridden;
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*
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* NOTE: This information is only used for _display_ purposes: it in
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* no way affects any of the arithmetic of the contract, including
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* {IERC20-balanceOf} and {IERC20-transfer}.
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*/
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function decimals() public view virtual override returns (uint8) {
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return 18;
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}
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/**
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* @dev See {IERC20-totalSupply}.
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*/
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function totalSupply() public view virtual override returns (uint256) {
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return _totalSupply;
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}
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/**
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* @dev See {IERC20-balanceOf}.
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*/
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function balanceOf(address account) public view virtual override returns (uint256) {
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return _balances[account];
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}
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/**
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* @dev See {IERC20-transfer}.
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*
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* Requirements:
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*
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* - `recipient` cannot be the zero address.
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* - the caller must have a balance of at least `amount`.
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*/
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function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
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_transfer(_msgSender(), recipient, amount);
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return true;
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}
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/**
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* @dev See {IERC20-allowance}.
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*/
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function allowance(address owner, address spender) public view virtual override returns (uint256) {
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return _allowances[owner][spender];
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}
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/**
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* @dev See {IERC20-approve}.
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*
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* Requirements:
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*
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* - `spender` cannot be the zero address.
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*/
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function approve(address spender, uint256 amount) public virtual override returns (bool) {
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_approve(_msgSender(), spender, amount);
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return true;
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}
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/**
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* @dev See {IERC20-transferFrom}.
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*
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* Emits an {Approval} event indicating the updated allowance. This is not
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* required by the EIP. See the note at the beginning of {ERC20}.
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*
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* Requirements:
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*
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* - `sender` and `recipient` cannot be the zero address.
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* - `sender` must have a balance of at least `amount`.
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* - the caller must have allowance for ``sender``'s tokens of at least
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* `amount`.
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*/
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function transferFrom(
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address sender,
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address recipient,
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uint256 amount
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) public virtual override returns (bool) {
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_transfer(sender, recipient, amount);
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uint256 currentAllowance = _allowances[sender][_msgSender()];
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require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
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unchecked {
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_approve(sender, _msgSender(), currentAllowance - amount);
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}
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return true;
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}
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/**
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* @dev Atomically increases the allowance granted to `spender` by the caller.
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*
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* This is an alternative to {approve} that can be used as a mitigation for
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* problems described in {IERC20-approve}.
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*
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* Emits an {Approval} event indicating the updated allowance.
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*
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* Requirements:
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*
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* - `spender` cannot be the zero address.
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*/
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function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
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_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
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return true;
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}
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/**
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* @dev Atomically decreases the allowance granted to `spender` by the caller.
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*
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* This is an alternative to {approve} that can be used as a mitigation for
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* problems described in {IERC20-approve}.
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*
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* Emits an {Approval} event indicating the updated allowance.
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*
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* Requirements:
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*
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* - `spender` cannot be the zero address.
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* - `spender` must have allowance for the caller of at least
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* `subtractedValue`.
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*/
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function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
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uint256 currentAllowance = _allowances[_msgSender()][spender];
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require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
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unchecked {
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_approve(_msgSender(), spender, currentAllowance - subtractedValue);
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}
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return true;
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}
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/**
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* @dev Moves `amount` of tokens from `sender` to `recipient`.
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*
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* This internal function is equivalent to {transfer}, and can be used to
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* e.g. implement automatic token fees, slashing mechanisms, etc.
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*
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* Emits a {Transfer} event.
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*
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* Requirements:
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*
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* - `sender` cannot be the zero address.
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* - `recipient` cannot be the zero address.
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* - `sender` must have a balance of at least `amount`.
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*/
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function _transfer(
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address sender,
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address recipient,
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uint256 amount
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) internal virtual {
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require(sender != address(0), "ERC20: transfer from the zero address");
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require(recipient != address(0), "ERC20: transfer to the zero address");
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_beforeTokenTransfer(sender, recipient, amount);
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uint256 senderBalance = _balances[sender];
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require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
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unchecked {
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_balances[sender] = senderBalance - amount;
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}
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_balances[recipient] += amount;
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emit Transfer(sender, recipient, amount);
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_afterTokenTransfer(sender, recipient, amount);
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}
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/** @dev Creates `amount` tokens and assigns them to `account`, increasing
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* the total supply.
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*
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* Emits a {Transfer} event with `from` set to the zero address.
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*
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* Requirements:
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*
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* - `account` cannot be the zero address.
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*/
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function _mint(address account, uint256 amount) internal virtual {
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require(account != address(0), "ERC20: mint to the zero address");
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_beforeTokenTransfer(address(0), account, amount);
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_totalSupply += amount;
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_balances[account] += amount;
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emit Transfer(address(0), account, amount);
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_afterTokenTransfer(address(0), account, amount);
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}
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/**
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* @dev Destroys `amount` tokens from `account`, reducing the
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* total supply.
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*
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* Emits a {Transfer} event with `to` set to the zero address.
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*
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* Requirements:
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*
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* - `account` cannot be the zero address.
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* - `account` must have at least `amount` tokens.
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*/
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function _burn(address account, uint256 amount) internal virtual {
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require(account != address(0), "ERC20: burn from the zero address");
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_beforeTokenTransfer(account, address(0), amount);
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uint256 accountBalance = _balances[account];
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require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
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unchecked {
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_balances[account] = accountBalance - amount;
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}
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_totalSupply -= amount;
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emit Transfer(account, address(0), amount);
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_afterTokenTransfer(account, address(0), amount);
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}
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/**
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* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
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*
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* This internal function is equivalent to `approve`, and can be used to
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* e.g. set automatic allowances for certain subsystems, etc.
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*
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* Emits an {Approval} event.
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*
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* Requirements:
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*
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* - `owner` cannot be the zero address.
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* - `spender` cannot be the zero address.
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*/
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function _approve(
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address owner,
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address spender,
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uint256 amount
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) internal virtual {
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require(owner != address(0), "ERC20: approve from the zero address");
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require(spender != address(0), "ERC20: approve to the zero address");
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_allowances[owner][spender] = amount;
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emit Approval(owner, spender, amount);
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}
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/**
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* @dev Hook that is called before any transfer of tokens. This includes
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* minting and burning.
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*
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* Calling conditions:
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*
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* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
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* will be transferred to `to`.
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* - when `from` is zero, `amount` tokens will be minted for `to`.
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* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
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* - `from` and `to` are never both zero.
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*
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* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
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*/
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function _beforeTokenTransfer(
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address from,
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address to,
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uint256 amount
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) internal virtual {}
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/**
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* @dev Hook that is called after any transfer of tokens. This includes
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* minting and burning.
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*
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* Calling conditions:
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*
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* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
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* has been transferred to `to`.
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* - when `from` is zero, `amount` tokens have been minted for `to`.
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* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
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* - `from` and `to` are never both zero.
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*
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* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
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*/
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function _afterTokenTransfer(
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address from,
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address to,
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uint256 amount
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) internal virtual {}
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}
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// File: contracts/token/ERC20/behaviours/ERC20Decimals.sol
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pragma solidity ^0.8.0;
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/**
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* @title ERC20Decimals
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* @dev Implementation of the ERC20Decimals. Extension of {ERC20} that adds decimals storage slot.
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*/
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abstract contract ERC20Decimals is ERC20 {
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uint8 private immutable _decimals;
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/**
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* @dev Sets the value of the `decimals`. This value is immutable, it can only be
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* set once during construction.
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*/
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constructor(uint8 decimals_) {
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_decimals = decimals_;
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}
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function decimals() public view virtual override returns (uint8) {
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return _decimals;
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}
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}
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// File: contracts/service/ServicePayer.sol
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pragma solidity ^0.8.0;
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interface IPayable {
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function pay(string memory serviceName) external payable;
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}
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/**
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* @title ServicePayer
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* @dev Implementation of the ServicePayer
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*/
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abstract contract ServicePayer {
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constructor(address payable receiver, string memory serviceName) payable {
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IPayable(receiver).pay{value: msg.value}(serviceName);
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}
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}
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// File: contracts/token/ERC20/StandardERC20.sol
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pragma solidity ^0.8.0;
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/**
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* @title StandardERC20
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* @dev Implementation of the StandardERC20
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*/
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contract StandardERC20 is ERC20Decimals, ServicePayer {
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constructor(
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string memory name_,
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string memory symbol_,
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uint8 decimals_,
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uint256 initialBalance_,
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address payable feeReceiver_
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) payable ERC20(name_, symbol_) ERC20Decimals(decimals_) ServicePayer(feeReceiver_, "StandardERC20") {
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require(initialBalance_ > 0, "StandardERC20: supply cannot be zero");
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_mint(_msgSender(), initialBalance_);
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}
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function decimals() public view virtual override returns (uint8) {
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return super.decimals();
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}
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}
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