Quoter

Allows getting the expected amount out or amount in for a given swap without executing the swap

These functions are not gas efficient and should not be called on chain. Instead, optimistically execute the swap and check the amounts in the callback.

State Variables

amountOutCached

Transient storage variable used to check a safety condition in exact output swaps.

uint256 private amountOutCached;

Functions

constructor

constructor(address _factory, address _WSEI) PeripheryImmutableState(_factory, _WSEI);

getPool

function getPool(address tokenA, address tokenB, uint24 fee) private view returns (IDragonswapV2Pool);

dragonswapV2SwapCallback

Called to msg.sender after executing a swap via IDragonswapV2Pool#swap.

In the implementation you must pay the pool tokens owed for the swap. The caller of this method must be checked to be a DragonswapV2Pool deployed by the canonical DragonswapV2Factory. amount0Delta and amount1Delta can both be 0 if no tokens were swapped.

function dragonswapV2SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes memory path) external view override;

Parameters

Name	Type	Description
amount0Delta	int256	The amount of token0 that was sent (negative) or must be received (positive) by the pool by the end of the swap. If positive, the callback must send that amount of token0 to the pool.
amount1Delta	int256	The amount of token1 that was sent (negative) or must be received (positive) by the pool by the end of the swap. If positive, the callback must send that amount of token1 to the pool.
path	bytes

parseRevertReason

Parses a revert reason that should contain the numeric quote

function parseRevertReason(bytes memory reason) private pure returns (uint256);

quoteExactInputSingle

Returns the amount out received for a given exact input but for a swap of a single pool

function quoteExactInputSingle(
    address tokenIn,
    address tokenOut,
    uint24 fee,
    uint256 amountIn,
    uint160 sqrtPriceLimitX96
) public override returns (uint256 amountOut);

Parameters

Name	Type	Description
tokenIn	address	The token being swapped in
tokenOut	address	The token being swapped out
fee	uint24	The fee of the token pool to consider for the pair
amountIn	uint256	The desired input amount
sqrtPriceLimitX96	uint160	The price limit of the pool that cannot be exceeded by the swap

Returns

Name	Type	Description
amountOut	uint256	The amount of tokenOut that would be received

quoteExactInput

Returns the amount out received for a given exact input swap without executing the swap

function quoteExactInput(bytes memory path, uint256 amountIn) external override returns (uint256 amountOut);

Parameters

Name	Type	Description
path	bytes	The path of the swap, i.e. each token pair and the pool fee
amountIn	uint256	The amount of the first token to swap

Returns

Name	Type	Description
amountOut	uint256	The amount of the last token that would be received

quoteExactOutputSingle

Returns the amount in required to receive the given exact output amount but for a swap of a single pool

function quoteExactOutputSingle(
    address tokenIn,
    address tokenOut,
    uint24 fee,
    uint256 amountOut,
    uint160 sqrtPriceLimitX96
) public override returns (uint256 amountIn);

Parameters

Name	Type	Description
tokenIn	address	The token being swapped in
tokenOut	address	The token being swapped out
fee	uint24	The fee of the token pool to consider for the pair
amountOut	uint256	The desired output amount
sqrtPriceLimitX96	uint160	The price limit of the pool that cannot be exceeded by the swap

Returns

Name	Type	Description
amountIn	uint256	The amount required as the input for the swap in order to receive amountOut

quoteExactOutput

Returns the amount in required for a given exact output swap without executing the swap

function quoteExactOutput(bytes memory path, uint256 amountOut) external override returns (uint256 amountIn);

Parameters

Name	Type	Description
path	bytes	The path of the swap, i.e. each token pair and the pool fee. Path must be provided in reverse order
amountOut	uint256	The amount of the last token to receive

Returns

Name	Type	Description
amountIn	uint256	The amount of first token required to be paid