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* UniswapV2Library.sol -> UniswapV2Periphery.sol, and make the library a real library

* Call the library directly wherever possible

* Remove periphery inheritance and just use the V2 library

* Remove duplicate library

* Remove some unnecessary lines from periphery

* Drop the periphery contract and interface

* Address comments
3 contributors

Users who have contributed to this file

@NoahZinsmeister @moodysalem @k06a
pragma solidity =0.6.6;
import '@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol';
import '@uniswap/lib/contracts/libraries/TransferHelper.sol';
import './libraries/UniswapV2Library.sol';
import './interfaces/IUniswapV2Router01.sol';
import './interfaces/IERC20.sol';
import './interfaces/IWETH.sol';
contract UniswapV2Router01 is IUniswapV2Router01 {
address public immutable override factory;
address public immutable override WETH;
modifier ensure(uint deadline) {
require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
_;
}
constructor(address _factory, address _WETH) public {
factory = _factory;
WETH = _WETH;
}
receive() external payable {
assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
}
// **** ADD LIQUIDITY ****
function _addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin
) private returns (uint amountA, uint amountB) {
// create the pair if it doesn't exist yet
if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
IUniswapV2Factory(factory).createPair(tokenA, tokenB);
}
(uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
if (reserveA == 0 && reserveB == 0) {
(amountA, amountB) = (amountADesired, amountBDesired);
} else {
uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
if (amountBOptimal <= amountBDesired) {
require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
(amountA, amountB) = (amountADesired, amountBOptimal);
} else {
uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
assert(amountAOptimal <= amountADesired);
require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
(amountA, amountB) = (amountAOptimal, amountBDesired);
}
}
}
function addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
(amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
liquidity = IUniswapV2Pair(pair).mint(to);
}
function addLiquidityETH(
address token,
uint amountTokenDesired,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
(amountToken, amountETH) = _addLiquidity(
token,
WETH,
amountTokenDesired,
msg.value,
amountTokenMin,
amountETHMin
);
address pair = UniswapV2Library.pairFor(factory, token, WETH);
TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
IWETH(WETH).deposit{value: amountETH}();
assert(IWETH(WETH).transfer(pair, amountETH));
liquidity = IUniswapV2Pair(pair).mint(to);
if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH); // refund dust eth, if any
}
// **** REMOVE LIQUIDITY ****
function removeLiquidity(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) public override ensure(deadline) returns (uint amountA, uint amountB) {
address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
(uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
(address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
(amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
}
function removeLiquidityETH(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) public override ensure(deadline) returns (uint amountToken, uint amountETH) {
(amountToken, amountETH) = removeLiquidity(
token,
WETH,
liquidity,
amountTokenMin,
amountETHMin,
address(this),
deadline
);
TransferHelper.safeTransfer(token, to, amountToken);
IWETH(WETH).withdraw(amountETH);
TransferHelper.safeTransferETH(to, amountETH);
}
function removeLiquidityWithPermit(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external override returns (uint amountA, uint amountB) {
address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
uint value = approveMax ? uint(-1) : liquidity;
IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
(amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
}
function removeLiquidityETHWithPermit(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external override returns (uint amountToken, uint amountETH) {
address pair = UniswapV2Library.pairFor(factory, token, WETH);
uint value = approveMax ? uint(-1) : liquidity;
IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
(amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);
}
// **** SWAP ****
// requires the initial amount to have already been sent to the first pair
function _swap(uint[] memory amounts, address[] memory path, address _to) private {
for (uint i; i < path.length - 1; i++) {
(address input, address output) = (path[i], path[i + 1]);
(address token0,) = UniswapV2Library.sortTokens(input, output);
uint amountOut = amounts[i + 1];
(uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(amount0Out, amount1Out, to, new bytes(0));
}
}
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external override ensure(deadline) returns (uint[] memory amounts) {
amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
_swap(amounts, path, to);
}
function swapTokensForExactTokens(
uint amountOut,
uint amountInMax,
address[] calldata path,
address to,
uint deadline
) external override ensure(deadline) returns (uint[] memory amounts) {
amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
_swap(amounts, path, to);
}
function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
external
override
payable
ensure(deadline)
returns (uint[] memory amounts)
{
require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
IWETH(WETH).deposit{value: amounts[0]}();
assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
_swap(amounts, path, to);
}
function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
external
override
ensure(deadline)
returns (uint[] memory amounts)
{
require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
_swap(amounts, path, address(this));
IWETH(WETH).withdraw(amounts[amounts.length - 1]);
TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
}
function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
external
override
ensure(deadline)
returns (uint[] memory amounts)
{
require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
_swap(amounts, path, address(this));
IWETH(WETH).withdraw(amounts[amounts.length - 1]);
TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
}
function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
external
override
payable
ensure(deadline)
returns (uint[] memory amounts)
{
require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
IWETH(WETH).deposit{value: amounts[0]}();
assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
_swap(amounts, path, to);
if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]); // refund dust eth, if any
}
function quote(uint amountA, uint reserveA, uint reserveB) public pure override returns (uint amountB) {
return UniswapV2Library.quote(amountA, reserveA, reserveB);
}
function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) public pure override returns (uint amountOut) {
return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
}
function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) public pure override returns (uint amountIn) {
return UniswapV2Library.getAmountOut(amountOut, reserveIn, reserveOut);
}
function getAmountsOut(uint amountIn, address[] memory path) public view override returns (uint[] memory amounts) {
return UniswapV2Library.getAmountsOut(factory, amountIn, path);
}
function getAmountsIn(uint amountOut, address[] memory path) public view override returns (uint[] memory amounts) {
return UniswapV2Library.getAmountsIn(factory, amountOut, path);
}
}