简单的提供流动性可能是参与 DeFi 最流行的方法，也就是向一个 DeFi 协议的流动性资金池中提供数字资产对，供其他人交换这些资产。现在，在许多 DeFi 协议中都存在这种流动性挖矿活动，也包括去中心化交易所 DEX 或自动做市商 AMM。
在这些 DeFi 协议中，SushiSwap 和 UniSwap 控制着大多数用户和交易额，因此 DeFi 领域所获取的大量流动性都存在于这两个协议中，也就不足为奇了。PlasmaFinance DeFi 控制中心使您可以查看现有的每个流动性资金池，可以按代币或协议进行搜索，帮助您寻找最佳利率、最佳流动性和最佳的可能收益率估算。
代码语言：javascript复制
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.6.2;
// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
function safeApprove(address token, address to, uint value) internal {
// bytes4(keccak256(bytes('approve(address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
}
function safeTransfer(address token, address to, uint value) internal {
// bytes4(keccak256(bytes('transfer(address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
}
function safeTransferFrom(address token, address from, address to, uint value) internal {
// bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
(bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
}
function safeTransferETH(address to, uint value) internal {
(bool success,) = to.call{value:value}(new bytes(0));
require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
}
}
interface IUniswapV2Pair {
event Approval(address indexed owner, address indexed spender, uint value);
event Transfer(address indexed from, address indexed to, uint value);
function name() external pure returns (string memory);
function symbol() external pure returns (string memory);
function decimals() external pure returns (uint8);
function totalSupply() external view returns (uint);
function balanceOf(address owner) external view returns (uint);
function allowance(address owner, address spender) external view returns (uint);
function approve(address spender, uint value) external returns (bool);
function transfer(address to, uint value) external returns (bool);
function transferFrom(address from, address to, uint value) external returns (bool);
function DOMAIN_SEPARATOR() external view returns (bytes32);
function PERMIT_TYPEHASH() external pure returns (bytes32);
function nonces(address owner) external view returns (uint);
function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
event Mint(address indexed sender, uint amount0, uint amount1);
event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
event Swap(
address indexed sender,
uint amount0In,
uint amount1In,
uint amount0Out,
uint amount1Out,
address indexed to
);
event Sync(uint112 reserve0, uint112 reserve1);
function MINIMUM_LIQUIDITY() external pure returns (uint);
function factory() external view returns (address);
function token0() external view returns (address);
function token1() external view returns (address);
function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
function price0CumulativeLast() external view returns (uint);
function price1CumulativeLast() external view returns (uint);
function kLast() external view returns (uint);
function mint(address to) external returns (uint liquidity);
function burn(address to) external returns (uint amount0, uint amount1);
function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
function skim(address to) external;
function sync() external;
function initialize(address, address) external;
}
library SafeMath {
function add(uint x, uint y) internal pure returns (uint z) {
require((z = x y) >= x, 'ds-math-add-overflow');
}
function sub(uint x, uint y) internal pure returns (uint z) {
require((z = x - y) <= x, 'ds-math-sub-underflow');
}
function mul(uint x, uint y) internal pure returns (uint z) {
require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
}
}
// given an output amount of an asset and pair reserves, returns a required input amount of the other asset
function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
uint numerator = reserveIn.mul(amountOut).mul(1000);
uint denominator = reserveOut.sub(amountOut).mul(997);
amountIn = (numerator / denominator).add(1);
}
// performs chained getAmountOut calculations on any number of pairs
function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
amounts = new uint[](path.length);
amounts[0] = amountIn;
for (uint i; i < path.length - 1; i ) {
(uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i 1]);
amounts[i 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
}
}
// performs chained getAmountIn calculations on any number of pairs
function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
amounts = new uint[](path.length);
amounts[amounts.length - 1] = amountOut;
for (uint i = path.length - 1; i > 0; i--) {
(uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
}
}
}
interface uniSwap{
// 1、用指定的代币交唤代币
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
// 2、用代币交唤指定的代币
function swapTokensForExactTokens(
uint amountOut,
uint amountInMax,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
// 3、用指定的 ETH 币交唤代币
function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
// 4、用代币交换指定的 ETH 币
function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
// 5、用指定的代币交换 ETH 币
function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
// 6、用 ETH 币交换指定的代币
function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
