106 lines
5.1 KiB
Solidity
106 lines
5.1 KiB
Solidity
// SPDX-License-Identifier: AGPL-3.0-or-later
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pragma solidity ^0.8.13;
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import "openzeppelin-contracts/contracts/interfaces/IERC20.sol";
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import "interfaces/IPairFunctionsTypes.sol";
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/// @title IPairFunctions
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/// @dev Implement this interface to support propeller routing through your pairs.
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/// @dev Before implementing the interface we need to introduce three function for a
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/// @dev given pair: The swap(x), gas(x) and price(x) functions:
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/// @dev The swap function accepts some specified token amount: x and returns the
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/// @dev amount y a user can get by swapping x through the venue.
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/// @dev The gas function simply returns the estimated gas cost given a specified
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/// @dev amount x.
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/// @dev Last but not least, the price function is the derivative of the swap
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/// @dev function. It represents the best possible price a user can get from a
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/// @dev pair after swapping x of the specified token.
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/// @dev During calls to price, swap and getLimits, the caller can be assumed to
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/// @dev have the required sell or buy token balance as well as unlimited approvals
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/// @dev to this contract.
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interface IPairFunctions is IPairFunctionTypes {
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/// @notice Calculates pair prices for specified amounts (optional).
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/// @dev The returned prices should include all dex fees, in case the fee
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/// @dev is dynamic, the returned price is expected to include the minimum fee.
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/// @dev Ideally this method should be implemented, although it is optional as
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/// @dev the price function can be numerically estimated from the swap function.
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/// @dev In case it is not available it should be flagged via capabilities and
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/// @dev calling it should revert using the `NotImplemented` error.
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/// @dev The method needs to be implemented as view as this is usually more efficient
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/// @dev and can be run in parallel.
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/// @dev all.
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/// @param pairId The ID of the trading pair.
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/// @param sellToken The token being sold.
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/// @param buyToken The token being bought.
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/// @param sellAmounts The specified amounts used for price calculation.
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/// @return prices array of prices as fractions corresponding to the provided amounts.
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function price(
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bytes32 pairId,
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IERC20 sellToken,
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IERC20 buyToken,
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uint256[] memory sellAmounts
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) external view returns (Fraction[] memory prices);
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/// @notice Simulates swapping tokens on a given pair.
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/// @dev This function should be state modifying meaning it should actually execute
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/// @dev the swap and change the state of the evm accordingly.
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/// @dev Please include a gas usage estimate for each amount. This can be achieved
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/// @dev e.g. by using the `gasleft()` function.
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/// @dev
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/// @param pairId The ID of the trading pair.
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/// @param sellToken The token being sold.
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/// @param buyToken The token being bought.
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/// @param side The side of the trade (Sell or Buy).
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/// @param specifiedAmount The amount to be traded.
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/// @return trade Trade struct representing the executed trade.
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function swap(
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bytes32 pairId,
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IERC20 sellToken,
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IERC20 buyToken,
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SwapSide side,
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uint256 specifiedAmount
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) external returns (Trade memory trade);
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/// @notice Retrieves the limits for each token.
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/// @dev Retrieve the maximum limits of a token that can be traded. The limit is reached
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/// @dev when the change in the received amounts is zero or close to zero. If in doubt
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/// @dev over estimate. The swap function should not error with `LimitExceeded` if
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/// @dev called with amounts below the limit.
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/// @param pairId The ID of the trading pair.
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/// @return An array of limits.
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function getLimits(bytes32 pairId, SwapSide side)
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external
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returns (uint256[] memory);
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/// @notice Retrieves the capabilities of the selected pair.
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/// @param pairId The ID of the trading pair.
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/// @return An array of Capabilities.
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function getCapabilities(bytes32 pairId, IERC20 sellToken, IERC20 buyToken)
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external
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returns (Capabilities[] memory);
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/// @notice Minimum gas usage of exchange logic excluding transfers.
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/// @return gasUsage the amount of gas used by the exchange logic
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function minGasUsage() external view returns (uint256);
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/// @notice Retrieves the tokens in the selected pair.
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/// @dev Mainly used for testing as this is redundant with the required substreams
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/// @dev implementation.
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/// @param pairId The ID of the trading pair.
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/// @return tokens array of IERC20 contracts.
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function getTokens(bytes32 pairId)
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external
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returns (IERC20[] memory tokens);
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/// @notice Retrieves a range of pool IDs.
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/// @dev Mainly used for testing it is alright to not return all available pools here.
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/// @dev Nevertheless this is useful to test against the substreams implementation. If
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/// @dev implemented it safes time writing custom tests.
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/// @param offset The starting index from which to retrieve pool IDs.
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/// @param limit The maximum number of pool IDs to retrieve.
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/// @return ids array of pool IDs.
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function getPoolIds(uint256 offset, uint256 limit)
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external
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returns (bytes32[] memory ids);
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}
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