01-Solidity8.0新特性

Solidity8.0

01-Solidity8.0新特性

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前言

区块链越来越吃香了，开始做笔记

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一、Solidity是什么？

在区块链上运行的一种脚本语言！

二、新特性

1.安全数学

代码如下（示例）：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8;

contract SafeMath{
    function Underflow() public pure returns (uint){
        uint x =0;
        x--;
        return x;
    }
    function uncheckedUnderflow() public pure returns (uint){
        uint x =0;
        unchecked{x--;}
        return x;
    }
}

2.自定义错误

代码如下（示例）：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8;

error Unauthorized(address caller);

contract customer {
   address payable owner = payable(msg.sender);

   function withdraw() public {
       if (msg.sender != owner){
           revert Unauthorized(msg.sender);
       }
       owner.transfer(address(this).balance);
   }
}

3.函数在合约之外使用

代码如下（示例）：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8;

function add(uint256 a) pure returns (uint256) {
    return a + 7;
}

contract customer {
   function test() external view returns(uint256){
       return add(8);
   }
}

4.引入文件更改别名

代码如下（示例）：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8;

import {test, helper as help} from "./Common.sol";

5.Create2

代码如下（示例）：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8;

contract TestContract {
    address public owner;
    uint public foo;

    constructor(address _owner, uint _foo) payable {
        owner = _owner;
        foo = _foo;
    }

    function getBalance() public view returns (uint) {
        return address(this).balance;
    }
}
contract Factory {
    function deploy2(address _owner,uint _foo,bytes32 _salt) public payable returns (address) {
        return address(new TestContract{salt: _salt}(_owner, _foo));
    }
    
	event Deployed(address addr, uint salt);
    function getBytecode(address _owner, uint _foo) public pure returns (bytes memory) {
        bytes memory bytecode = type(TestContract).creationCode;
        return abi.encodePacked(bytecode, abi.encode(_owner, _foo));
    }
    
    function getAddress(bytes memory bytecode, uint _salt) public view returns (address) {
        bytes32 hash = keccak256(
            abi.encodePacked(bytes1(0xff), address(this), _salt, keccak256(bytecode))
        );
        return address(uint160(uint(hash)));
    }
    
    function deploy(bytes memory bytecode, uint _salt) public payable {
        address addr;
        assembly {
            addr := create2( callvalue(), add(bytecode, 0x20), mload(bytecode), _salt )
            if iszero(extcodesize(addr)) {
                revert(0, 0)
            }
        }
        emit Deployed(addr, _salt);
    }
}

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总结

日拱一卒。