/
BaseAaveToken.sol
177 lines (149 loc) · 5.03 KB
/
BaseAaveToken.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Context} from 'openzeppelin-contracts/contracts/utils/Context.sol';
import {IERC20} from 'openzeppelin-contracts/contracts/token/ERC20/IERC20.sol';
import {IERC20Metadata} from 'openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol';
import {DelegationMode} from './DelegationAwareBalance.sol';
// Inspired by OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/ERC20.sol)
abstract contract BaseAaveToken is Context, IERC20Metadata {
struct DelegationAwareBalance {
uint104 balance;
uint72 delegatedPropositionBalance;
uint72 delegatedVotingBalance;
DelegationMode delegationMode;
}
mapping(address => DelegationAwareBalance) internal _balances;
mapping(address => mapping(address => uint256)) internal _allowances;
uint256 internal _totalSupply;
string internal _name;
string internal _symbol;
// @dev DEPRECATED
// kept for backwards compatibility with old storage layout
uint8 private ______DEPRECATED_OLD_ERC20_DECIMALS;
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
function decimals() public view virtual override returns (uint8) {
return 18;
}
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account].balance;
}
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, amount);
return true;
}
function allowance(address owner, address spender)
public
view
virtual
override
returns (uint256)
{
return _allowances[owner][spender];
}
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, spender, amount);
return true;
}
function transferFrom(
address from,
address to,
uint256 amount
) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
address owner = _msgSender();
_approve(owner, spender, _allowances[owner][spender] + addedValue);
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue)
public
virtual
returns (bool)
{
address owner = _msgSender();
uint256 currentAllowance = _allowances[owner][spender];
require(currentAllowance >= subtractedValue, 'ERC20: decreased allowance below zero');
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
function _transfer(
address from,
address to,
uint256 amount
) internal virtual {
require(from != address(0), 'ERC20: transfer from the zero address');
require(to != address(0), 'ERC20: transfer to the zero address');
if (from != to) {
uint104 fromBalanceBefore = _balances[from].balance;
uint104 toBalanceBefore = _balances[to].balance;
require(fromBalanceBefore >= amount, 'ERC20: transfer amount exceeds balance');
unchecked {
_balances[from].balance = fromBalanceBefore - uint104(amount);
}
_balances[to].balance = toBalanceBefore + uint104(amount);
_afterTokenTransfer(from, to, fromBalanceBefore, toBalanceBefore, amount);
}
emit Transfer(from, to, amount);
}
function _approve(
address owner,
address spender,
uint256 amount
) internal virtual {
require(owner != address(0), 'ERC20: approve from the zero address');
require(spender != address(0), 'ERC20: approve to the zero address');
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
function _spendAllowance(
address owner,
address spender,
uint256 amount
) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, 'ERC20: insufficient allowance');
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
/**
* @dev after token transfer hook, added for delegation system
* @param from token sender
* @param to token recipient
* @param fromBalanceBefore balance of the sender before transfer
* @param toBalanceBefore balance of the recipient before transfer
* @param amount amount of tokens sent
**/
function _afterTokenTransfer(
address from,
address to,
uint256 fromBalanceBefore,
uint256 toBalanceBefore,
uint256 amount
) internal virtual {}
}