// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev The contract has an owner address, and provides basic authorization control whitch
* simplifies the implementation of user permissions. This contract is based on the source code at:
* https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/ownership/Ownable.sol
*/
contract Ownable
{
/**
* @dev Error constants.
*/
string public constant NOT_CURRENT_OWNER = "018001";
string public constant CANNOT_TRANSFER_TO_ZERO_ADDRESS = "018002";
/**
* @dev Current owner address.
*/
address public owner;
/**
* @dev An event which is triggered when the owner is changed.
* @param previousOwner The address of the previous owner.
* @param newOwner The address of the new owner.
*/
event OwnershipTransferred(
address indexed previousOwner,
address indexed newOwner
);
/**
* @dev The constructor sets the original `owner` of the contract to the sender account.
*/
constructor()
{
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner()
{
Erequire(msg.sender == owner, NOT_CURRENT_OWNER);
_;
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param _newOwner The address to transfer ownership to.
*/
function transferOwnership(
address _newOwner
)
public
onlyOwner
{
require(_newOwner != address(0), CANNOT_TRANSFER_TO_ZERO_ADDRESS);
emit OwnershipTransferred(owner, _newOwner);
owner = _newOwner;
}
}
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