EVM Opcodes 102

// SPDX-License-Identifier: MIT
// wtf.academy
pragma solidity ^0.8.4;

/**
 * @dev Proxy合约的所有调用都通过`delegatecall`操作码委托给另一个合约执行。后者被称为逻辑合约（Implementation）。
 *
 * 委托调用的返回值，会直接返回给Proxy的调用者
 */
contract Proxy {
    address public implementation; // 逻辑合约地址。implementation合约同一个位置的状态变量类型必须和Proxy合约的相同，不然会报错。

    /**
     * @dev 初始化逻辑合约地址
     */
    constructor(address implementation_){
        implementation = implementation_;
    }

    /**
     * @dev 回调函数，调用`_delegate()`函数将本合约的调用委托给 `implementation` 合约
     */
    fallback() external payable {
        _delegate();
    }

    /**
     * @dev 将调用委托给逻辑合约运行
     */
    function _delegate() internal {
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // 读取位置为0的storage，也就是implementation地址。
            let _implementation := sload(0)

            calldatacopy(0, 0, calldatasize())

            // 利用delegatecall调用implementation合约
            // delegatecall操作码的参数分别为：gas, 目标合约地址，input mem起始位置，input mem长度，output area mem起始位置，output area mem长度
            // output area起始位置和长度位置，所以设为0
            // delegatecall成功返回1，失败返回0
            let result := delegatecall(gas(), _implementation, 0, calldatasize(), 0, 0)

            // 将起始位置为0，长度为returndatasize()的returndata复制到mem位置0
            returndatacopy(0, 0, returndatasize())

            switch result
            // 如果delegate call失败，revert
            case 0 {
                revert(0, returndatasize())
            }
            // 如果delegate call成功，返回mem起始位置为0，长度为returndatasize()的数据（格式为bytes）
            default {
                return(0, returndatasize())
            }
        }
    }
}

363d3d373d3d3d363d73bebebebebebebebebebebebebebebebebebebebe5af43d82803e903d91602b57fd5bf3

365f5f375f5f365f73bebebebebebebebebebebebebebebebebebebebe5af43d5f5f3e5f3d91602a57fd5bf3

602c8060095f395ff3365f5f375f5f365f73bebebebebebebebebebebebebebebebebebebebe5af43d5f5f3e5f3d91602a57fd5bf3

602c8060095f395ff3

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.20;

// Note: this contract requires `PUSH0`, which is available in solidity > 0.8.20 and EVM version > Shanghai
contract Clone0Factory {
    error FailedCreateClone();

    receive() external payable {}

    /**
     * @dev Deploys and returns the address of a clone0 (Minimal Proxy Contract with `PUSH0`) that mimics the behaviour of `implementation`.
     *
     * This function uses the create opcode, which should never revert.
     */
    function clone0(address impl) public payable returns (address addr) {
        // first 18 bytes of the creation code 
        bytes memory data1 = hex"602c8060095f395ff3365f5f375f5f365f73";
        // last 15 bytes of the creation code
        bytes memory data2 = hex"5af43d5f5f3e5f3d91602a57fd5bf3";
        // complete the creation code of Clone0
        bytes memory _code = abi.encodePacked(data1, impl, data2);

        // deploy with create op
        assembly {
            // create(v, p, n)
            addr := create(callvalue(), add(_code, 0x20), mload(_code))
        }

        if (addr == address(0)) {
            revert FailedCreateClone();
        }
    }
}