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Abstract
以下规范容许为代表单个底层 ERC-20 份额的保险库施行规范 API。该规范是 ERC-20 代币的扩大,它提供了存取代币和读取余额的基本功能。
Motivation
代币化保险库不足标准化,导致施行细节多样化。一些不同的例子包含借贷市场、聚合器和具备外在利息的代币。这使得须要合乎许多规范的协定在聚合器或插件层难以集成,并迫使每个协定实现本人的适配器,这些适配器容易出错并节约开发资源。代币化保险库的规范将升高收益保险库的集成工作量,同时创立更加统一和弱小的施行模式。
Code
Events
Deposit 事件:
event Deposit(address indexed caller, address indexed owner, uint256 assets, uint256 shares);
Withdraw 事件:
event Withdraw(
address indexed caller,
address indexed receiver,
address indexed owner,
uint256 assets,
uint256 shares
);
IMMUTABLES
ERC20 public immutable asset;
constructor(
ERC20 _asset,
string memory _name,
string memory _symbol
) ERC20(_name, _symbol, _asset.decimals()) {asset = _asset;}
Main Logic
Deposit 函数:function deposit(uint256 assets, address receiver) public virtual returns (uint256 shares) {
// Check for rounding error since we round down in previewDeposit.
require((shares = previewDeposit(assets)) != 0, "ZERO_SHARES");
// Need to transfer before minting or ERC777s could reenter.
asset.safeTransferFrom(msg.sender, address(this), assets);
_mint(receiver, shares);
emit Deposit(msg.sender, receiver, assets, shares);
afterDeposit(assets, shares);
}
Mint 函数:
function mint(uint256 shares, address receiver) public virtual returns (uint256 assets) {assets = previewMint(shares); // No need to check for rounding error, previewMint rounds up.
// Need to transfer before minting or ERC777s could reenter.
asset.safeTransferFrom(msg.sender, address(this), assets);
_mint(receiver, shares);
emit Deposit(msg.sender, receiver, assets, shares);
afterDeposit(assets, shares);
}
Withdraw 函数:
function withdraw(
uint256 assets,
address receiver,
address owner
) public virtual returns (uint256 shares) {shares = previewWithdraw(assets); // No need to check for rounding error, previewWithdraw rounds up.
if (msg.sender != owner) {uint256 allowed = allowance[owner][msg.sender]; // Saves gas for limited approvals.
if (allowed != type(uint256).max) allowance[owner][msg.sender] = allowed - shares;
}
beforeWithdraw(assets, shares);
_burn(owner, shares);
emit Withdraw(msg.sender, receiver, owner, assets, shares);
asset.safeTransfer(receiver, assets);
}
Redeem 函数:
function redeem(
uint256 shares,
address receiver,
address owner
) public virtual returns (uint256 assets) {if (msg.sender != owner) {uint256 allowed = allowance[owner][msg.sender]; // Saves gas for limited approvals.
if (allowed != type(uint256).max) allowance[owner][msg.sender] = allowed - shares;
}
// Check for rounding error since we round down in previewRedeem.
require((assets = previewRedeem(shares)) != 0, "ZERO_ASSETS");
beforeWithdraw(assets, shares);
_burn(owner, shares);
emit Withdraw(msg.sender, receiver, owner, assets, shares);
asset.safeTransfer(receiver, assets);
}
Account Logic
function totalAssets() public view virtual returns (uint256);
function convertToShares(uint256 assets) public view returns (uint256) {
uint256 supply = totalSupply; // Saves an extra SLOAD if totalSupply is non-zero.
return supply == 0 ? assets : assets.mulDivDown(supply, totalAssets());
}
function convertToAssets(uint256 shares) public view returns (uint256) {
uint256 supply = totalSupply; // Saves an extra SLOAD if totalSupply is non-zero.
return supply == 0 ? shares : shares.mulDivDown(totalAssets(), supply);
}
function previewDeposit(uint256 assets) public view virtual returns (uint256) {return convertToShares(assets);
}
function previewMint(uint256 shares) public view virtual returns (uint256) {
uint256 supply = totalSupply; // Saves an extra SLOAD if totalSupply is non-zero.
return supply == 0 ? shares : shares.mulDivUp(totalAssets(), supply);
}
function previewWithdraw(uint256 assets) public view virtual returns (uint256) {
uint256 supply = totalSupply; // Saves an extra SLOAD if totalSupply is non-zero.
return supply == 0 ? assets : assets.mulDivUp(supply, totalAssets());
}
function previewRedeem(uint256 shares) public view virtual returns (uint256) {return convertToAssets(shares);
}
/*///////////////////////////////////////////////////////////////
DEPOSIT/WITHDRAWAL LIMIT LOGIC
//////////////////////////////////////////////////////////////*/
function maxDeposit(address) public view virtual returns (uint256) {return type(uint256).max;
}
function maxMint(address) public view virtual returns (uint256) {return type(uint256).max;
}
function maxWithdraw(address owner) public view virtual returns (uint256) {return convertToAssets(balanceOf[owner]);
}
function maxRedeem(address owner) public view virtual returns (uint256) {return balanceOf[owner];
}
Hooks Logic
function beforeWithdraw(uint256 assets, uint256 shares) internal virtual {}
function afterDeposit(uint256 assets, uint256 shares) internal virtual {}
参考文章
https://ethereum-magicians.or…
https://github.com/Rari-Capit…
正文完