pragma solidity ^0.6.0; import "./ERC20.sol"; import "../../Initializable.sol"; /** * @dev Extension of {ERC20} that adds a cap to the supply of tokens. */ abstract contract ERC20CappedUpgradeSafe is Initializable, ERC20UpgradeSafe { uint256 private _cap; /** * @dev Sets the value of the `cap`. This value is immutable, it can only be * set once during construction. */ function __ERC20Capped_init(uint256 cap) internal initializer { __Context_init_unchained(); __ERC20Capped_init_unchained(cap); } function __ERC20Capped_init_unchained(uint256 cap) internal initializer { require(cap > 0, "ERC20Capped: cap is 0"); _cap = cap; } /** * @dev Returns the cap on the token's total supply. */ function cap() public view returns (uint256) { return _cap; } /** * @dev See {ERC20-_beforeTokenTransfer}. * * Requirements: * * - minted tokens must not cause the total supply to go over the cap. */ function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override { super._beforeTokenTransfer(from, to, amount); if (from == address(0)) { // When minting tokens require(totalSupply().add(amount) <= _cap, "ERC20Capped: cap exceeded"); } } uint256[49] private __gap; }