Solidity8.0-03

对应崔棉大师 41-50课程
https://www.bilibili.com/video/BV1yS4y1N7yu/?spm_id_from=333.788&vd_source=c81b130b6f8bb3082bdb42226729d69c

调用其他合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

contract Callee {
    uint public x;
    uint public value;

    function setX(uint _x) public returns (uint) {
        x = _x;
        return x;
    }

    function setXandSendEther(uint _x) public payable returns (uint, uint) {
        x = _x;
        value = msg.value;

        return (x, value);
    }
}

contract Caller {
    function setX(Callee _callee, uint _x) public {
        uint x = _callee.setX(_x);
    }

    function setXFromAddress(address _addr, uint _x) public {
        Callee callee = Callee(_addr);
        callee.setX(_x);
    }

    function setXandSendEther(Callee _callee, uint _x) public payable {
        (uint x, uint value) = _callee.setXandSendEther{value: msg.value}(_x);
    }
}

 

接口合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

contract Counter {
    uint public count;

    function increment() external {
        count += 1;
    }
}

interface ICounter {
    function count() external view returns (uint);

    function increment() external;
}

contract MyContract {
    function incrementCounter(address _counter) external {
        ICounter(_counter).increment();
    }

    function getCount(address _counter) external view returns (uint) {
        return ICounter(_counter).count();
    }
}

// Uniswap example
interface UniswapV2Factory {
    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);
}

interface UniswapV2Pair {
    function getReserves()
        external
        view
        returns (
            uint112 reserve0,
            uint112 reserve1,
            uint32 blockTimestampLast
        );
}

contract UniswapExample {
    address private factory = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f;
    address private dai = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    address private weth = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;

    function getTokenReserves() external view returns (uint, uint) {
        address pair = UniswapV2Factory(factory).getPair(dai, weth);
        (uint reserve0, uint reserve1, ) = UniswapV2Pair(pair).getReserves();
        return (reserve0, reserve1);
    }
}

低级call

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

contract Receiver {
    event Received(address caller, uint amount, string message);

    fallback() external payable {
        emit Received(msg.sender, msg.value, "Fallback was called");
    }

    function foo(string memory _message, uint _x) public payable returns (uint) {
        emit Received(msg.sender, msg.value, _message);

        return _x + 1;
    }
}

contract Caller {
    event Response(bool success, bytes data);

    // Let's imagine that contract B does not have the source code for
    // contract A, but we do know the address of A and the function to call.
    function testCallFoo(address payable _addr) public payable {
        // You can send ether and specify a custom gas amount 
　　　　　//uint要写成uint256 特殊 ,不指定gas 会带全部gas发送交易
        (bool success, bytes memory data) = _addr.call{value: msg.value, gas: 5000}(
            abi.encodeWithSignature("foo(string,uint256)", "call foo", 123)
        );

        emit Response(success, data);
    }

    // Calling a function that does not exist triggers the fallback function.
    function testCallDoesNotExist(address _addr) public {
        (bool success, bytes memory data) = _addr.call(
            abi.encodeWithSignature("doesNotExist()")
        );

        emit Response(success, data);
    }
}

委托调用
http://www.theblockbeats.info/en/news/31694
https://learnblockchain.cn/article/4125
工厂合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;
contract Account{
    address public bank;
    address public owner;

    constructor(address _owner) payable{
            bank = msg.sender;
            owner = _owner;
    }

}

contract Factory{

    Account[] public Accounts;

    function createAccount(address _owner) external payable{
        Account acc = new Account{value:111}(_owner);
        Accounts.push(acc);
    }

}

库合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint) {
        uint z = x + y;
        require(z >= x, "uint overflow");

        return z;
    }
}

library Math {
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
        // else z = 0 (default value)
    }
}

contract TestSafeMath {
    using SafeMath for uint;

    uint public MAX_UINT = 2**256 - 1;

    function testAdd(uint x, uint y) public pure returns (uint) {
        return x.add(y);
    }

    function testSquareRoot(uint x) public pure returns (uint) {
        return Math.sqrt(x);
    }
}

// Array function to delete element at index and re-organize the array
// so that their are no gaps between the elements.
library Array {
    function remove(uint[] storage arr, uint index) public {
        // Move the last element into the place to delete
        require(arr.length > 0, "Can't remove from empty array");
        arr[index] = arr[arr.length - 1];
        arr.pop();
    }
}

contract TestArray {
    using Array for uint[];

    uint[] public arr;

    function testArrayRemove() public {
        for (uint i = 0; i < 3; i++) {
            arr.push(i);
        }

        arr.remove(1);

        assert(arr.length == 2);
        assert(arr[0] == 0);
        assert(arr[1] == 2);
    }
}

哈希运算

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

contract HashFunction {
    function hash(string memory _text,uint _num,address _addr) public pure returns (bytes32) {
        return keccak256(abi.encodePacked(_text, _num, _addr));
    }

 
    function encode_keccak256(string memory _text, string memory _text2) public pure returns (bytes32){
        {
            return keccak256(abi.encode(_text, _text2));
        }
    }
    function encode(string memory _text, string memory _text2) public pure returns (bytes memory){
        {
            return abi.encode(_text, _text2);
        }
    }
        /*
            encode 将数据转为16进制并补0到长度64
            encodePacked将数据转为16进制拼接
            当两个字符串使用encodePacked "AAA","BBB" 和 "AA","ABBB"结果相同 特别注意
            当返回非定长数组时 返回类型为  bytes
        */
     function encodePacked(string memory _text,string memory _text2) public pure returns (bytes32) {
        return keccak256(abi.encodePacked(_text, _text2));
    }

    function collision(string memory _text,uint _num,string memory _text2) public pure returns (bytes32) {
        return keccak256(abi.encodePacked(_text, _num, _text2));
    }
}

验证签名
 

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

/* Signature Verification

How to Sign and Verify
# Signing
1. Create message to sign 创建签名
2. Hash the message 对签名hash
3. Sign the hash (off chain, keep your private key secret) 线下对签名hash用私钥加密

# Verify
1. Recreate hash from the original message  取椭圆加密 r s v
2. Recover signer from signature and hash   ecrocver('签名hash',r,s,v) 解密签名的钱包地址
3. Compare recovered signer to claimed signer 比较解密后的地址和加密的钱包地址是否一致
*/

contract VerifySignature {
    /* 1. Unlock MetaMask account
    ethereum.enable()
    */

    /* 2. Get message hash to sign
    getMessageHash(
        0x14723A09ACff6D2A60DcdF7aA4AFf308FDDC160C,
        123,
        "coffee and donuts",
        1
    )

    hash = "0xcf36ac4f97dc10d91fc2cbb20d718e94a8cbfe0f82eaedc6a4aa38946fb797cd"
    */
    function getMessageHash(
        address _to,
        uint _amount,
        string memory _message,
        uint _nonce
    ) public pure returns (bytes32) {
        return keccak256(abi.encodePacked(_to, _amount, _message, _nonce));
    }

    /* 3. Sign message hash
    # using browser
    account = "copy paste account of signer here"
    ethereum.request({ method: "personal_sign", params: [account, hash]}).then(console.log)

    # using web3
    web3.personal.sign(hash, web3.eth.defaultAccount, console.log)

    Signature will be different for different accounts
    0x993dab3dd91f5c6dc28e17439be475478f5635c92a56e17e82349d3fb2f166196f466c0b4e0c146f285204f0dcb13e5ae67bc33f4b888ec32dfe0a063e8f3f781b
    */
    function getEthSignedMessageHash(bytes32 _messageHash)
        public
        pure
        returns (bytes32)
    {
        /*
        Signature is produced by signing a keccak256 hash with the following format:
        "\x19Ethereum Signed Message\n" + len(msg) + msg
        */
        return
            keccak256(
                abi.encodePacked("\x19Ethereum Signed Message:\n32", _messageHash)
            );
    }

    /* 4. Verify signature
    signer = 0xB273216C05A8c0D4F0a4Dd0d7Bae1D2EfFE636dd
    to = 0x14723A09ACff6D2A60DcdF7aA4AFf308FDDC160C
    amount = 123
    message = "coffee and donuts"
    nonce = 1
    signature =
        0x993dab3dd91f5c6dc28e17439be475478f5635c92a56e17e82349d3fb2f166196f466c0b4e0c146f285204f0dcb13e5ae67bc33f4b888ec32dfe0a063e8f3f781b
    */
    function verify(
        address _signer,
        address _to,
        uint _amount,
        string memory _message,
        uint _nonce,
        bytes memory signature
    ) public pure returns (bool) {
        bytes32 messageHash = getMessageHash(_to, _amount, _message, _nonce);
        bytes32 ethSignedMessageHash = getEthSignedMessageHash(messageHash);

        return recoverSigner(ethSignedMessageHash, signature) == _signer;
    }

    function recoverSigner(bytes32 _ethSignedMessageHash, bytes memory _signature)
        public
        pure
        returns (address)
    {
        (bytes32 r, bytes32 s, uint8 v) = splitSignature(_signature);

        return ecrecover(_ethSignedMessageHash, v, r, s);
    }

    function splitSignature(bytes memory sig)
        public
        pure
        returns (
            bytes32 r,
            bytes32 s,
            uint8 v
        )
    {
        require(sig.length == 65, "invalid signature length");

        assembly {
            /*
            First 32 bytes stores the length of the signature

            add(sig, 32) = pointer of sig + 32
            effectively, skips first 32 bytes of signature

            mload(p) loads next 32 bytes starting at the memory address p into memory
            */

            // first 32 bytes, after the length prefix
            r := mload(add(sig, 32))
            // second 32 bytes
            s := mload(add(sig, 64))
            // final byte (first byte of the next 32 bytes)
            v := byte(0, mload(add(sig, 96)))
        }

        // implicitly return (r, s, v)
    }
}

权限控制合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;
contract AccessControl{
    event GrantRole(bytes32 indexed role,address indexed account);
    event RevokeRole(bytes32 indexed role,address indexed account);
   
    constructor(){
        _grantRole(ADMIN,msg.sender);
    }

    mapping(bytes32 => mapping(address => bool)) public roles;

    bytes32 public constant ADMIN = keccak256(abi.encodePacked("ADMIN"));
    bytes32 public constant USER = keccak256(abi.encodePacked("USER"));

     modifier onlyAdmin(bytes32 _role){
         require(roles[_role][msg.sender],"not admin");
         _;
     }

    function _grantRole(bytes32 _role,address _account) internal {
        roles[_role][_account] = true;
        emit GrantRole(_role,_account);
    }
    function grantRole(bytes32 _role,address _account) external onlyAdmin(ADMIN){
            _grantRole(_role,_account);
    }
    function revokeRole(bytes32 _role,address _account) external onlyAdmin(ADMIN){
        roles[_role][_account] = false;
        emit RevokeRole(_role,_account);
    }

}

自毁合约

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;
contract Kill{
    constructor() payable {
       
    }
    /*
    1.删除合约
    2.强制发送主币 目标是合约地址没有fallback也可以发送主币
    */
    function kill() external{
        selfdestruct(payable(msg.sender));
    }
    function testCall() external pure returns(uint){
        return 123;
    }
}

contract Helper{
 
    function getBalance() external view returns  (uint){
        return address(this).balance;
    }

    function Killer(Kill _kill) external {
        _kill.kill();
    }
 
}