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| 1 | +// SPDX-License-Identifier: MIT |
| 2 | +pragma solidity 0.8.18; |
| 3 | + |
| 4 | +import "hardhat/console.sol"; // used in testing chains |
| 5 | + |
| 6 | +/** |
| 7 | + * @title Simple Multisig Wallet Contract |
| 8 | + * @author Al-Qa'qa' |
| 9 | + * @notice This contract works like a sinple mutlisig wallet |
| 10 | + */ |
| 11 | +contract MultisigWallet { |
| 12 | + event Deposit(address indexed sender, uint256 amount); |
| 13 | + event Submit(uint256 indexed txId); |
| 14 | + event Approve(address indexed owner, uint256 indexed txId); |
| 15 | + event Revoke(address indexed owner, uint256 indexed txId); |
| 16 | + event Execute(uint256 indexed txId); |
| 17 | + |
| 18 | + struct Transaction { |
| 19 | + address to; |
| 20 | + uint256 value; |
| 21 | + bytes data; |
| 22 | + bool executed; |
| 23 | + } |
| 24 | + |
| 25 | + address[] public owners; // the owners of the contract |
| 26 | + mapping(address => bool) public isOwner; // if the address is owner |
| 27 | + uint256 public required; // how many requires needed |
| 28 | + |
| 29 | + Transaction[] public transactions; // all transactions occuars in our wallet |
| 30 | + |
| 31 | + mapping(uint256 => mapping(address => bool)) public approved; // store the tx approvals by owner |
| 32 | + |
| 33 | + modifier onlyOwner() { |
| 34 | + require(isOwner[msg.sender], "You are not owner"); |
| 35 | + _; |
| 36 | + } |
| 37 | + |
| 38 | + modifier txExists(uint256 _txId) { |
| 39 | + require(_txId < transactions.length, "tx does not existed"); |
| 40 | + _; |
| 41 | + } |
| 42 | + |
| 43 | + modifier notApproved(uint256 _txId) { |
| 44 | + require(!approved[_txId][msg.sender], "tx already approved"); |
| 45 | + _; |
| 46 | + } |
| 47 | + |
| 48 | + modifier notExecuted(uint256 _txId) { |
| 49 | + require(!transactions[_txId].executed, "tx already executed"); |
| 50 | + _; |
| 51 | + } |
| 52 | + |
| 53 | + /** |
| 54 | + * When making the our wallet we should provide an array of address that represent the owners of this contract |
| 55 | + * that have access to this wallet. |
| 56 | + * We should provide the minimun number of approvals of owners needed in order to execute a transaction. |
| 57 | + * |
| 58 | + * @param _owners Array of owners addresses of the contract |
| 59 | + * @param _required the number of addresses needed to approve for a transaction in order ro execute |
| 60 | + */ |
| 61 | + constructor(address[] memory _owners, uint256 _required) { |
| 62 | + require(_owners.length > 0, "Owners required"); |
| 63 | + require( |
| 64 | + _required > 0 && _required <= _owners.length, |
| 65 | + "Invalid required number of owners" |
| 66 | + ); |
| 67 | + |
| 68 | + console.log("Check passed successfully"); |
| 69 | + |
| 70 | + for (uint256 i; i < _owners.length; i++) { |
| 71 | + address owner = _owners[i]; |
| 72 | + |
| 73 | + require(owner != address(0), "Invalid owner"); // check the owner is not address zero |
| 74 | + require(!isOwner[owner], "owner is not unique"); // check the owner is not already existed |
| 75 | + isOwner[owner] = true; // active owner |
| 76 | + owners.push(owner); // add the owner address to owners array |
| 77 | + console.log("New owner added: ", owner); |
| 78 | + } |
| 79 | + |
| 80 | + required = _required; |
| 81 | + console.log("Finished constructor"); |
| 82 | + } |
| 83 | + |
| 84 | + /** |
| 85 | + * Handle receiving ETH from external wallets |
| 86 | + */ |
| 87 | + receive() external payable { |
| 88 | + emit Deposit(msg.sender, msg.value); |
| 89 | + } |
| 90 | + |
| 91 | + /** |
| 92 | + * Sumbit new tx into our multisig wallet |
| 93 | + * |
| 94 | + * @param _to address that will receive the transaction |
| 95 | + * @param _value the amount of ETH that will transfered to the receiver |
| 96 | + * @param _data data passed with the tx |
| 97 | + */ |
| 98 | + function submit( |
| 99 | + address _to, |
| 100 | + uint256 _value, |
| 101 | + bytes calldata _data |
| 102 | + ) external onlyOwner { |
| 103 | + transactions.push(Transaction(_to, _value, _data, false)); |
| 104 | + emit Submit(transactions.length - 1); // the index of the last element of transactions array |
| 105 | + |
| 106 | + // This logic is weak since you should approve the address that submited the tx |
| 107 | + // Its better to approve the address that sumbitted |
| 108 | + } |
| 109 | + |
| 110 | + /** |
| 111 | + * Approve the transaction already sumbitted, but it is waiting approvals to be executed |
| 112 | + * |
| 113 | + * @param _txId transaction index in transaction array |
| 114 | + */ |
| 115 | + function approve( |
| 116 | + uint256 _txId |
| 117 | + ) external onlyOwner txExists(_txId) notApproved(_txId) notExecuted(_txId) { |
| 118 | + approved[_txId][msg.sender] = true; |
| 119 | + emit Approve(msg.sender, _txId); |
| 120 | + } |
| 121 | + |
| 122 | + /** |
| 123 | + * execute the transaction and send ETH and data of the transaction to the receiver address |
| 124 | + * |
| 125 | + * @param _txId transaction index in transactions |
| 126 | + */ |
| 127 | + function execute(uint256 _txId) external txExists(_txId) notExecuted(_txId) { |
| 128 | + require(_getApprovalCount(_txId) >= required, "approvals < required"); |
| 129 | + Transaction storage transaction = transactions[_txId]; |
| 130 | + transaction.executed = true; |
| 131 | + |
| 132 | + (bool success, ) = transaction.to.call{value: transaction.value}( |
| 133 | + transaction.data |
| 134 | + ); |
| 135 | + require(success, "Transaction failed"); |
| 136 | + |
| 137 | + emit Execute(_txId); |
| 138 | + } |
| 139 | + |
| 140 | + /** |
| 141 | + * Revoke that approval of the owner address (remove the approval) |
| 142 | + * |
| 143 | + * @param _txId transaction index in transactions |
| 144 | + */ |
| 145 | + function revoke( |
| 146 | + uint256 _txId |
| 147 | + ) external onlyOwner txExists(_txId) notExecuted(_txId) { |
| 148 | + require(approved[_txId][msg.sender], "tx not approved"); |
| 149 | + approved[_txId][msg.sender] = false; |
| 150 | + emit Revoke(msg.sender, _txId); |
| 151 | + |
| 152 | + // You are not handle deleting the transaction which is not a good thing |
| 153 | + // storing in array has its drawbacks too |
| 154 | + } |
| 155 | + |
| 156 | + /** |
| 157 | + * Get the number of approvals if the transaction id |
| 158 | + * |
| 159 | + * @param _txId transaction index in transactions |
| 160 | + */ |
| 161 | + function _getApprovalCount(uint _txId) private view returns (uint256 count) { |
| 162 | + for (uint i; i < owners.length; i++) { |
| 163 | + if (approved[_txId][owners[i]]) { |
| 164 | + count++; |
| 165 | + } |
| 166 | + } |
| 167 | + } |
| 168 | +} |
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