从工厂模式到克隆工厂模式

Question

下面是一个坚固合同的例子，这是一种工厂模式的原生方法，它将船员添加到矩阵中的neb星舰中。

这个合同的克隆工厂版本是什么？

// SPDX-License-Identifier: MIT
pragma solidity >0.4.23 <0.9.0;

contract NebCrewFactory {

    //Creating an array of neb crew addresses
    NebCrew[] public NebCrewAddresses;

    function addNebCrew() public {

        //Creating a new crew object, you need to pay //for the deployment of this contract everytime - $$$$
        NebCrew nebCrewAddress = new NebCrew();

        //Adding the new crew to our list of crew addresses
        NebCrewAddresses.push(nebCrewAddress);
    }
}

contract NebCrew{

    address public crew;

    constructor() {
        crew = msg.sender;
    }

    function welcomeCrew() public pure returns (string memory _greeting) {
        return "Welcome to the truth...";
    }
}

Answer 1

我展示的克隆工厂版本使用了OpenZeppelin库这里。

// SPDX-License-Identifier: MIT
pragma solidity >0.4.23 <0.9.0;

import { Clones } from "@openzeppelin/contracts/proxy/Clones.sol";

contract NebCrewFactory {

    //Creating an array of neb crew addresses
    NebCrew[] public NebCrewAddresses;
    address public implementationAddress;
    function addNebCrew() public {

        //Creating a new crew object, you need to pay //for the deployment of this contract everytime - $$$$
        NebCrew nebCrewAddress = NewCrew(Clones.clone(implementationAddress));

        // since the clone create a proxy, the constructor is redundant and you have to use the initialize function
        nebCrewAddress.initialize(); 

        //Adding the new crew to our list of crew addresses
        NebCrewAddresses.push(nebCrewAddress);
    }
}

contract NebCrew{

    address public crew;

    initialize() {
        require(crew == address(0), "already initialized");
        crew = msg.sender;
    }

    function welcomeCrew() public pure returns (string memory _greeting) {
        return "Welcome to the truth...";
    }
}

也不相关，但我想提一下，如果可以的话，最好是在工厂中使用一个映射，而不是一个数组，因为它可能会在将来造成问题。