110 lines
5.3 KiB
Solidity
110 lines
5.3 KiB
Solidity
// SPDX-License-Identifier: AGPL-3.0-or-later
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pragma solidity ^0.8.13;
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import {IERC20} from "openzeppelin-contracts/contracts/interfaces/IERC20.sol";
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import {ISwapAdapterTypes} from "src/interfaces/ISwapAdapterTypes.sol";
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/// @title ISwapAdapter
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/// @dev Implement this interface to support Propeller routing through your
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/// pools. Before implementing the interface we need to introduce some function
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/// for a given pool. The main one, the swap(x) function, implements a sell
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/// order of a specified token.
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/// The gas function simply
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/// returns the estimated gas cost given a specified amount x. Last but not
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/// least, the price function is the derivative of the swap function. It
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/// represents the best possible price a user can get from a pool after swapping
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/// x of the specified token. During calls to swap and getLimits, the caller can
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/// be assumed to have the required sell or buy token balance as well as
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/// unlimited approvals to this contract.
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interface ISwapAdapter is ISwapAdapterTypes {
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/// @notice Calculates pool prices for specified amounts (optional).
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/// @dev The returned prices should include all dex fees. In case the fee is
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/// dynamic, the returned price is expected to include the minimum fee.
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/// Ideally this method should be implemented, although it is optional as
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/// the price function can be numerically estimated from the swap function.
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/// In case it is not available, it should be flagged via capabilities and
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/// calling it should revert using the `NotImplemented` error. The method
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/// needs to be implemented as view as this is usually more efficient and
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/// can be run in parallel.
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/// @param poolId The ID of the trading pool.
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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 specifiedAmounts The specified amounts used for price
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/// calculation.
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/// @return prices array of prices as fractions corresponding to the
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/// provided amounts.
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function price(
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bytes32 poolId,
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IERC20 sellToken,
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IERC20 buyToken,
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uint256[] memory specifiedAmounts
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) external view returns (Fraction[] memory prices);
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/**
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* @notice Simulates swapping tokens on a given pool.
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* @dev This function should be state modifying, meaning it should actually
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* execute the swap and change the state of the EVM accordingly. Please
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* include a gas usage estimate for each amount. This can be achieved e.g. by
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* using the `gasleft()` function. The return type `Trade` has an attribute
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* called price which should contain the value of `price(specifiedAmount)`.
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* As this is optional, defined via `Capability.PriceFunction`, it is valid
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* to return a Fraction(0, 0) value for this price. In that case the price
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* will be estimated numerically.
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* @param poolId The ID of the trading pool.
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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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*/
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function swap(
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bytes32 poolId,
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IERC20 sellToken,
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IERC20 buyToken,
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OrderSide 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
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/// limit is reached when the change in the received amounts is zero or
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/// close to zero or when the swap fails because of the pools restrictions.
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/// Overestimate if in doubt rather than underestimate. The
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/// swap function should not error with `LimitExceeded` if called with
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/// amounts below the limit.
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/// @param poolId The ID of the trading pool.
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/// @param sellToken The token being sold.
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/// @param buyToken The token being bought.
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/// @return limits An array of limits.
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function getLimits(bytes32 poolId, IERC20 sellToken, IERC20 buyToken)
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external
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returns (uint256[] memory limits);
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/// @notice Retrieves the capabilities of the selected pool.
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/// @param poolId The ID of the trading pool.
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/// @return capabilities An array of Capability.
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function getCapabilities(bytes32 poolId, IERC20 sellToken, IERC20 buyToken)
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external
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returns (Capability[] memory capabilities);
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/// @notice Retrieves the tokens in the selected pool.
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/// @dev Mainly used for testing as this is redundant with the required
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/// substreams implementation.
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/// @param poolId The ID of the trading pool.
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/// @return tokens An array of IERC20 contracts.
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function getTokens(bytes32 poolId)
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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
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/// pools here. Nevertheless, this is useful to test against the substreams
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/// implementation. If implemented, it saves 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 An 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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