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();
}
}
