034_升级合约模式详解：从透明代理到2025年钻石模式，构建可持续发展的智能合约系统

// 简化的透明代理合约示例
contract TransparentUpgradeableProxy {
    address private _implementation;
    address private _admin;
    
    constructor(address implementation, address admin) {
        _implementation = implementation;
        _admin = admin;
    }
    
    // 管理员函数，用于升级实现合约
    function upgradeTo(address newImplementation) external {
        require(msg.sender == _admin, "Not authorized");
        _implementation = newImplementation;
    }
    
    // 回退函数，将调用委托给实现合约
    fallback() external payable {
        address _impl = _implementation;
        assembly {
            calldatacopy(0, 0, calldatasize())
            let result := delegatecall(gas(), _impl, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())
            switch result
            case 0 {
                revert(0, returndatasize())
            }
            default {
                return(0, returndatasize())
            }
        }
    }
}

// 简化的UUPS代理合约示例
contract UUPSProxy {
    address private _implementation;
    
    constructor(address implementation, bytes memory initData) {
        _implementation = implementation;
        // 初始化实现合约
        (bool success,) = implementation.delegatecall(initData);
        require(success, "Initialization failed");
    }
    
    // 回退函数，将所有调用委托给实现合约
    fallback() external payable {
        address _impl = _implementation;
        assembly {
            calldatacopy(0, 0, calldatasize())
            let result := delegatecall(gas(), _impl, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())
            switch result
            case 0 {
                revert(0, returndatasize())
            }
            default {
                return(0, returndatasize())
            }
        }
    }
}

// 实现合约需包含的升级逻辑
contract MyImplementation {
    address private _admin;
    address private _implementation;
    
    modifier onlyAdmin() {
        require(msg.sender == _admin, "Not authorized");
        _;
    }
    
    // 初始化函数
    function initialize(address admin) external {
        require(_admin == address(0), "Already initialized");
        _admin = admin;
    }
    
    // 升级函数 - 符合UUPS标准
    function upgradeTo(address newImplementation) external onlyAdmin {
        // 调用存储在代理合约中的_implementation变量
        assembly {
            sstore(0, newImplementation) // 假设_implementation存储在插槽0
        }
    }
    
    // 业务逻辑函数
    function businessLogic() external {
        // 实现具体功能
    }
}

// 钻石存储模式示例
library LibA {
    bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.storage.libA");
    
    struct DiamondStorage {
        uint256 valueA;
        mapping(address => bool) authorized;
        // 其他存储变量
    }
    
    function diamondStorage() internal pure returns (DiamondStorage storage ds) {
        bytes32 position = DIAMOND_STORAGE_POSITION;
        assembly {
            ds.slot := position
        }
    }
}

// 存储冲突示例
// 原始合约
contract OriginalContract {
    uint256 public totalSupply;     // 存储槽0
    mapping(address => uint256) public balanceOf; // 映射使用哈希计算的存储槽
}

// 不安全的升级合约 - 变量顺序改变导致冲突
contract InsecureUpgrade {
    address public owner;           // 错误：这会覆盖存储槽0的totalSupply
    uint256 public totalSupply;     // 现在存储在新位置
    mapping(address => uint256) public balanceOf;
}

// 代理合约保留特定存储槽
contract SafeProxy {
    // 保留前几个存储槽用于代理管理
    address private _implementation; // 槽0
    address private _admin;         // 槽1
    uint256 private _upgradeCount;  // 槽2
    
    // 回退函数和升级逻辑
    // ...
}

// 实现合约从特定槽开始使用存储
contract SafeImplementation {
    // 确保实现合约不使用代理保留的槽
    // 使用_ gap变量为未来扩展预留空间
    uint256[50] private _gap;
    
    // 实现合约的状态变量从槽53开始
    uint256 public totalSupply;
    mapping(address => uint256) public balanceOf;
}

// 渐进式迁移示例
contract MigratedImplementation {
    // 旧存储结构
    mapping(address => uint256) private oldBalances;
    
    // 新存储结构
    struct BalanceInfo {
        uint256 amount;
        uint256 lastUpdated;
    }
    mapping(address => BalanceInfo) private newBalances;
    mapping(address => bool) private migrated;
    
    // 获取余额，按需迁移
    function balanceOf(address user) public view returns (uint256) {
        if (!migrated[user]) {
            // 虚拟迁移，不修改存储
            return oldBalances[user];
        }
        return newBalances[user].amount;
    }
    
    // 触发迁移的函数
    function migrateIfNeeded() internal {
        if (!migrated[msg.sender]) {
            // 执行实际迁移
            newBalances[msg.sender] = BalanceInfo({
                amount: oldBalances[msg.sender],
                lastUpdated: block.timestamp
            });
            migrated[msg.sender] = true;
            // 可选：清除旧存储以节省gas
            // delete oldBalances[msg.sender];
        }
    }
    
    // 所有修改余额的函数都调用迁移
    function transfer(address to, uint256 amount) external {
        migrateIfNeeded();
        // 转账逻辑，使用新存储结构
        // ...
    }
}

contract TimelockController {
    uint256 public constant MINIMUM_DELAY = 2 days;
    uint256 public constant MAXIMUM_DELAY = 30 days;
    uint256 public constant GRACE_PERIOD = 14 days;
    
    struct Delay {
        uint256 value;
        uint256 changeDeadline;
        address pendingAdmin;
    }
    
    mapping(bytes32 => bool) public queuedTransactions;
    uint256 public delay;
    address public admin;
    address public pendingAdmin;
    
    event CallScheduled(bytes32 indexed id, uint256 indexed index, address target, uint256 value, string signature, bytes data, uint256 predecessor, uint256 delay);
    event CallExecuted(bytes32 indexed id, uint256 indexed index, address target, uint256 value, string signature, bytes data);
    event CallCanceled(bytes32 indexed id, uint256 indexed index);
    
    modifier onlyAdmin() {
        require(msg.sender == admin, "Not authorized");
        _;
    }
    
    function schedule(address target, uint256 value, string calldata signature, bytes calldata data, uint256 predecessor, uint256 delay) public onlyAdmin returns (bytes32) {
        require(delay >= MINIMUM_DELAY, "Delay must exceed minimum delay");
        require(delay <= MAXIMUM_DELAY, "Delay must not exceed maximum delay");
        
        bytes32 id = keccak256(abi.encode(target, value, signature, data, predecessor, delay));
        
        if (predecessor != bytes32(0)) {
            require(queuedTransactions[predecessor], "Predecessor not queued");
        }
        
        queuedTransactions[id] = true;
        
        uint256 eta = block.timestamp + delay;
        emit CallScheduled(id, 0, target, value, signature, data, predecessor, delay);
        
        return id;
    }
    
    function execute(address target, uint256 value, string calldata signature, bytes calldata data, uint256 predecessor, uint256 delay) public payable returns (bytes memory) {
        bytes32 id = keccak256(abi.encode(target, value, signature, data, predecessor, delay));
        
        require(queuedTransactions[id], "Transaction hasn't been queued");
        
        uint256 eta = block.timestamp - delay;
        require(block.timestamp >= eta, "Transaction hasn't surpassed time lock");
        require(block.timestamp <= eta + GRACE_PERIOD, "Transaction is stale");
        
        queuedTransactions[id] = false;
        
        bytes memory callData;
        if (bytes(signature).length == 0) {
            callData = data;
        } else {
            callData = abi.encodePacked(bytes4(keccak256(bytes(signature))), data);
        }
        
        (bool success, bytes memory returnData) = target.call{value: value}(callData);
        require(success, "Transaction execution reverted");
        
        emit CallExecuted(id, 0, target, value, signature, data);
        
        return returnData;
    }
    
    function cancel(bytes32 id) public onlyAdmin {
        require(queuedTransactions[id], "Transaction hasn't been queued");
        
        queuedTransactions[id] = false;
        
        emit CallCanceled(id, 0);
    }
}

// 简化的自动化升级触发示例
contract AutoUpgradeMonitor {
    address public upgradeController;
    uint256 public threshold;
    uint256 public anomalyCount;
    mapping(uint256 => bool) public detectedAnomalies;
    
    event AnomalyDetected(uint256 indexed id, string description);
    event UpgradeTriggered(uint256 anomalyCount);
    
    modifier onlyUpgradeController() {
        require(msg.sender == upgradeController, "Not authorized");
        _;
    }
    
    constructor(address _upgradeController, uint256 _threshold) {
        upgradeController = _upgradeController;
        threshold = _threshold;
    }
    
    function reportAnomaly(string calldata description) external {
        uint256 anomalyId = uint256(keccak256(abi.encodePacked(block.timestamp, msg.sender, description)));
        require(!detectedAnomalies[anomalyId], "Anomaly already reported");
        
        detectedAnomalies[anomalyId] = true;
        anomalyCount++;
        
        emit AnomalyDetected(anomalyId, description);
        
        // 检查是否达到触发升级的阈值
        if (anomalyCount >= threshold) {
            triggerUpgrade();
        }
    }
    
    function triggerUpgrade() internal {
        // 调用升级控制器执行升级
        (bool success,) = upgradeController.call(abi.encodeWithSignature("triggerEmergencyUpgrade()"));
        require(success, "Upgrade failed");
        
        emit UpgradeTriggered(anomalyCount);
        
        // 重置异常计数
        anomalyCount = 0;
    }
    
    function setThreshold(uint256 newThreshold) external onlyUpgradeController {
        threshold = newThreshold;
    }
}

// 安全初始化示例
bool private _initialized;
bool private _initializing;

modifier initializer() {
    require(_initializing || !_initialized, "Initializable: contract is already initialized");
    
    bool isTopLevelCall = !_initializing;
    if (isTopLevelCall) {
        _initializing = true;
    }
    
    _;
    
    if (isTopLevelCall) {
        _initializing = false;
        _initialized = true;
    }
}

function initialize() public initializer {
    // 初始化代码
}