UniswapV2DirectToLiquidity

Git Source

Inherits: BaseDirectToLiquidity

This Callback contract deposits the proceeds from a batch auction into a Uniswap V2 pool in order to create liquidity immediately. The LP tokens are transferred to DTLConfiguration.recipient, or can optionally vest to the auction seller. An important risk to consider: if the auction's base token is available and liquid, a third-party could front-run the auction by creating the pool before the auction ends. This would allow them to manipulate the price of the pool and potentially profit from the eventual deposit of the auction proceeds.

As a general rule, this callback contract does not retain balances of tokens between calls.

Transfers are performed within the same function that requires the balance.

State Variables

uniV2Factory

The Uniswap V2 factory

This contract is used to create Uniswap V2 pools

IUniswapV2Factory public uniV2Factory;

uniV2Router

The Uniswap V2 router

This contract is used to add liquidity to Uniswap V2 pools

IUniswapV2Router02 public uniV2Router;

Functions

constructor

constructor(
    address auctionHouse_,
    address uniswapV2Factory_,
    address uniswapV2Router_
) BaseDirectToLiquidity(auctionHouse_);

__onCreate

Uniswap-specific implementation of the onCreate callback

This function implements the following:

• Validates the parameters

This function reverts if:

• The callback data is of the incorrect length
• UniswapV2OnCreateParams.maxSlippage is out of bounds

Note that this function does not check if the pool already exists. The reason for this is that it could be used as a DoS vector.

function __onCreate(
    uint96 lotId_,
    address,
    address,
    address,
    uint256,
    bool,
    bytes calldata
) internal virtual override;

Parameters

Name	Type	Description
lotId_	uint96	The lot ID
<none>	address
<none>	address
<none>	address
<none>	uint256
<none>	bool
<none>	bytes

_mintAndDeposit

Mint and deposit into the pool

This function implements the following:

• Creates the pool if necessary
• Detects and handles (if necessary) manipulation of pool reserves
• Deposits the tokens into the pool

function _mintAndDeposit(
    uint96 lotId_,
    address quoteToken_,
    uint256 quoteTokenAmount_,
    address baseToken_,
    uint256 baseTokenAmount_,
    bytes memory
) internal virtual override returns (ERC20 poolToken);

Parameters

Name	Type	Description
lotId_	uint96	The lot ID
quoteToken_	address	The quote token address
quoteTokenAmount_	uint256	The amount of quote tokens to deposit
baseToken_	address	The base token address
baseTokenAmount_	uint256	The amount of base tokens to deposit
<none>	bytes

Returns

Name	Type	Description
poolToken	ERC20	The ERC20 pool token

_decodeOnCreateParameters

Decodes the configuration parameters from the DTLConfiguration

The configuration parameters are stored in DTLConfiguration.implParams

function _decodeOnCreateParameters(
    uint96 lotId_
) internal view returns (UniswapV2OnCreateParams memory);

_mitigateDonation

This function mitigates the risk of a third-party having donated quote tokens to the pool causing the auction settlement to fail.

It performs the following:

• Checks if the pool has had quote tokens donated, or exits
• Swaps the quote tokens for base tokens to adjust the reserves to the correct price

function _mitigateDonation(
    address pairAddress_,
    uint256 auctionPrice_,
    address quoteToken_,
    address baseToken_
) internal returns (uint256 quoteTokensUsed, uint256 baseTokensUsed);

Parameters

Name	Type	Description
pairAddress_	address	The address of the Uniswap V2 pair
auctionPrice_	uint256	The price of the auction
quoteToken_	address	The quote token of the pair
baseToken_	address	The base token of the pair

Returns

Name	Type	Description
quoteTokensUsed	uint256	The amount of quote tokens used in the swap
baseTokensUsed	uint256	The amount of base tokens used in the swap

Structs

UniswapV2OnCreateParams

Parameters for the onCreate callback

This will be encoded in the callbackData_ parameter

struct UniswapV2OnCreateParams {
    uint24 maxSlippage;
}

Properties

Name	Type	Description
maxSlippage	uint24	The maximum slippage allowed when adding liquidity (in terms of basis points, where 1% = 1e2)