A speed bump is used to slow down critical operations such as the withdrawal of assets, authorization of significant actions, etc. It imposes a temporal barrier that gives enough time to a monitoring system to detect a problematic activity and mitigate it. This pattern is a specialized form of time constraint pattern where the participating user can only execute an action after a predefined time period has passed (after the point the action request is registered). The wait time is modeled using a delay on a condition arrow from the activity requesting the specified action to the actual action.
The activities and relations DCR model of this pattern is reflecting the following Solidity contract:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract SpeedBump {
address public owner;
uint256 public withdrawalRequestedAt;
uint256 public withdrawalAmount;
uint256 public constant WAIT_PERIOD = 1 weeks; // 1 week delay
event WithdrawalRequested(address indexed requester, uint256 amount);
event WithdrawalExecuted(address indexed requester, uint256 amount);
constructor() {
owner = msg.sender;
}
modifier onlyOwner() {
require(msg.sender == owner, "Not authorized");
_;
}
function requestWithdrawal(uint256 amount) public onlyOwner {
require(amount <= address(this).balance, "Insufficient funds");
withdrawalRequestedAt = block.timestamp;
withdrawalAmount = amount;
emit WithdrawalRequested(msg.sender, amount);
}
function executeWithdrawal() public onlyOwner {
require(block.timestamp >= withdrawalRequestedAt + WAIT_PERIOD, "Wait period not met");
uint256 amount = withdrawalAmount;
withdrawalAmount = 0; // Reset withdrawal amount
payable(owner).transfer(amount);
emit WithdrawalExecuted(msg.sender, amount);
}
// Function to deposit ether into the contract
function deposit() public payable onlyOwner {}
}
The actual withdrawal can only be executed after a predefined delay the speed bump. This delay ensures that there's enough time for any monitoring system or other checks to detect and potentially prevent problematic activity.
