You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

64 lines
2.2 KiB
Solidity

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/extensions/ERC20Wrapper.sol)
pragma solidity ^0.8.0;
import "../ERC20.sol";
import "../utils/SafeERC20.sol";
/**
* @dev Extension of the ERC20 token contract to support token wrapping.
*
* Users can deposit and withdraw "underlying tokens" and receive a matching number of "wrapped tokens". This is useful
* in conjunction with other modules. For example, combining this wrapping mechanism with {ERC20Votes} will allow the
* wrapping of an existing "basic" ERC20 into a governance token.
*
* _Available since v4.2._
*/
abstract contract ERC20Wrapper is ERC20 {
IERC20 public immutable underlying;
constructor(IERC20 underlyingToken) {
underlying = underlyingToken;
}
/**
* @dev See {ERC20-decimals}.
*/
function decimals() public view virtual override returns (uint8) {
try IERC20Metadata(address(underlying)).decimals() returns (uint8 value) {
return value;
} catch {
return super.decimals();
}
}
/**
* @dev Allow a user to deposit underlying tokens and mint the corresponding number of wrapped tokens.
*/
function depositFor(address account, uint256 amount) public virtual returns (bool) {
SafeERC20.safeTransferFrom(underlying, _msgSender(), address(this), amount);
_mint(account, amount);
return true;
}
/**
* @dev Allow a user to burn a number of wrapped tokens and withdraw the corresponding number of underlying tokens.
*/
function withdrawTo(address account, uint256 amount) public virtual returns (bool) {
_burn(_msgSender(), amount);
SafeERC20.safeTransfer(underlying, account, amount);
return true;
}
/**
* @dev Mint wrapped token to cover any underlyingTokens that would have been transferred by mistake. Internal
* function that can be exposed with access control if desired.
*/
function _recover(address account) internal virtual returns (uint256) {
uint256 value = underlying.balanceOf(address(this)) - totalSupply();
_mint(account, value);
return value;
}
}