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PositionUtils

The PositionUtils is a library contract that provides utility functions for position management across the Satoshi Perps protocol. It encapsulates common position-related logic for reuse across different contracts.

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Contract Overview

The PositionUtils handles:
  • Utility functions for fee calculations
  • Helper functions for position operations
  • Standardized implementations of common position logic
As a library, PositionUtils does not store state and is designed to be used by other contracts.

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Key Functions

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Fee Utilities

function shouldDeductFee(
    address _account,
    address _router,
    address[] memory _path,
    uint256 _amountIn,
    address _indexToken,
    bool _isLong
) external view returns (bool);
Determines whether a deposit fee should be charged to prevent zero-fee swaps.

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Position Operations

function increasePosition(
    address _account,
    address _collateralToken,
    address _indexToken,
    uint256 _sizeDelta,
    bool _isLong,
    uint256 _price
) external;
Standard implementation for increasing a position with validation.

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Usage in Other Contracts

The PositionUtils library is utilized by various contracts in the Satoshi Perps protocol:
  1. BasePositionManager: Uses utility functions for position operations
  2. PositionManager: Inherits position utility functions through BasePositionManager
  3. PositionRouter: Uses fee utility functions to determine fee application

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Implementation Details

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Fee Deduction Logic

The shouldDeductFee function implements the following logic:
  • If the path length is 1 (no swap), check if amountIn is greater than 0
  • If it’s a long position with collateral token same as index token, no fee
  • For all other cases, apply the fee
This logic helps prevent users from avoiding fees through complex transaction paths.

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Integration Example

Here’s how the PositionUtils library is typically used in other contracts: 
// In a position management contract
function increasePosition(/* parameters */) external {
    bool shouldChargeFee = PositionUtils.shouldDeductFee(
        msg.sender,
        router,
        path,
        amountIn,
        indexToken,
        isLong
    );
    
    if (shouldChargeFee) {
        // Apply fee logic
    }
    
    // Proceed with position increase
}

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Benefits of Library Approach

Using a library for position utilities offers several advantages:
  • Code Reusability: Common logic is defined once and reused across contracts
  • Gas Efficiency: Library code is deployed once and shared by all contracts
  • Consistency: Ensures uniform behavior across different contract implementations
  • Maintainability: Changes to the utility functions need to be made in only one place
Library contracts like PositionUtils help maintain consistent behavior across the protocol and make the codebase more maintainable.
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