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