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Position.sol
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Position.sol
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// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.20;
import {FullMath} from "./FullMath.sol";
import {FixedPoint128} from "./FixedPoint128.sol";
import {LiquidityMath} from "./LiquidityMath.sol";
import {CustomRevert} from "./CustomRevert.sol";
/// @title Position
/// @notice Positions represent an owner address' liquidity between a lower and upper tick boundary
/// @dev Positions store additional state for tracking fees owed to the position
library Position {
using CustomRevert for bytes4;
/// @notice Cannot update a position with no liquidity
error CannotUpdateEmptyPosition();
// info stored for each user's position
struct Info {
// the amount of liquidity owned by this position
uint128 liquidity;
// fee growth per unit of liquidity as of the last update to liquidity or fees owed
uint256 feeGrowthInside0LastX128;
uint256 feeGrowthInside1LastX128;
}
/// @notice Returns the Info struct of a position, given an owner and position boundaries
/// @param self The mapping containing all user positions
/// @param owner The address of the position owner
/// @param tickLower The lower tick boundary of the position
/// @param tickUpper The upper tick boundary of the position
/// @param salt A unique value to differentiate between multiple positions in the same range
/// @return position The position info struct of the given owners' position
function get(mapping(bytes32 => Info) storage self, address owner, int24 tickLower, int24 tickUpper, bytes32 salt)
internal
view
returns (Info storage position)
{
// positionKey = keccak256(abi.encodePacked(owner, tickLower, tickUpper, salt))
bytes32 positionKey;
assembly ("memory-safe") {
mstore(0x26, salt) // [0x26, 0x46)
mstore(0x06, tickUpper) // [0x23, 0x26)
mstore(0x03, tickLower) // [0x20, 0x23)
mstore(0, owner) // [0x0c, 0x20)
positionKey := keccak256(0x0c, 0x3a) // len is 58 bytes
mstore(0x26, 0) // rewrite 0x26 to 0
}
position = self[positionKey];
}
/// @notice Credits accumulated fees to a user's position
/// @param self The individual position to update
/// @param liquidityDelta The change in pool liquidity as a result of the position update
/// @param feeGrowthInside0X128 The all-time fee growth in currency0, per unit of liquidity, inside the position's tick boundaries
/// @param feeGrowthInside1X128 The all-time fee growth in currency1, per unit of liquidity, inside the position's tick boundaries
/// @return feesOwed0 The amount of currency0 owed to the position owner
/// @return feesOwed1 The amount of currency1 owed to the position owner
function update(
Info storage self,
int128 liquidityDelta,
uint256 feeGrowthInside0X128,
uint256 feeGrowthInside1X128
) internal returns (uint256 feesOwed0, uint256 feesOwed1) {
uint128 liquidity = self.liquidity;
if (liquidityDelta == 0) {
// disallow pokes for 0 liquidity positions
if (liquidity == 0) CannotUpdateEmptyPosition.selector.revertWith();
} else {
self.liquidity = LiquidityMath.addDelta(liquidity, liquidityDelta);
}
// calculate accumulated fees. overflow in the subtraction of fee growth is expected
unchecked {
feesOwed0 =
FullMath.mulDiv(feeGrowthInside0X128 - self.feeGrowthInside0LastX128, liquidity, FixedPoint128.Q128);
feesOwed1 =
FullMath.mulDiv(feeGrowthInside1X128 - self.feeGrowthInside1LastX128, liquidity, FixedPoint128.Q128);
}
// update the position
self.feeGrowthInside0LastX128 = feeGrowthInside0X128;
self.feeGrowthInside1LastX128 = feeGrowthInside1X128;
}
}