abstract contract Proxy {
/**
* @dev Delegates the current call to `implementation`.
*
* This function does not return to its internall call site, it will return directly to the external caller.
*/
function _delegate(address implementation) internal {
// solhint-disable-next-line no-inline-assembly
assembly {
// Copy msg.data. We take full control of memory in this inline assembly
// block because it will not return to Solidity code. We overwrite the
// Solidity scratch pad at memory position 0.
calldatacopy(0, 0, calldatasize())
// Call the implementation.
// out and outsize are 0 because we don't know the size yet.
let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
// Copy the returned data.
returndatacopy(0, 0, returndatasize())
switch result
// delegatecall returns 0 on error.
case 0 { revert(0, returndatasize()) }
default { return(0, returndatasize()) }
}
}
/**
* @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
* and {_fallback} should delegate.
*/
function _implementation() internal virtual view returns (address);
/**
* @dev Delegates the current call to the address returned by `_implementation()`.
*
* This function does not return to its internall call site, it will return directly to the external caller.
*/
function _fallback() internal {
_beforeFallback();
_delegate(_implementation());
}
/**
* @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
* function in the contract matches the call data.
*/
fallback () payable external {
_fallback();
}
/**
* @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
* is empty.
*/
receive () payable external {
_fallback();
}
/**
* @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
* call, or as part of the Solidity `fallback` or `receive` functions.
*
* If overriden should call `super._beforeFallback()`.
*/
function _beforeFallback() internal virtual {
}
}
contract UpgradeableProxy is Proxy {
/**
* @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
*
* If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
* function call, and allows initializating the storage of the proxy like a Solidity constructor.
*/
constructor(address _logic, bytes memory _data) public payable {
assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
_setImplementation(_logic);
if(_data.length > 0) {
// solhint-disable-next-line avoid-low-level-calls
(bool success,) = _logic.delegatecall(_data);
require(success);
}
}
/**
* @dev Emitted when the implementation is upgraded.
*/
event Upgraded(address indexed implementation);
/**
* @dev Storage slot with the address of the current implementation.
* This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
* validated in the constructor.
*/
bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
/**
* @dev Returns the current implementation address.
*/
function _implementation() internal override view returns (address impl) {
bytes32 slot = _IMPLEMENTATION_SLOT;
// solhint-disable-next-line no-inline-assembly
assembly {
impl := sload(slot)
}
}
/**
* @dev Upgrades the proxy to a new implementation.
*
* Emits an {Upgraded} event.
*/
function _upgradeTo(address newImplementation) internal {
_setImplementation(newImplementation);
emit Upgraded(newImplementation);
}
/**
* @dev Stores a new address in the EIP1967 implementation slot.
*/
function _setImplementation(address newImplementation) private {
require(isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");
bytes32 slot = _IMPLEMENTATION_SLOT;
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(slot, newImplementation)
}
}
function isContract(address account) internal view returns (bool) {
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
}
contract TransparentUpgradeableProxy is UpgradeableProxy {
/**
* @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
* optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
*/
constructor(address _logic, address _admin, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
_setAdmin(_admin);
}
/**
* @dev Emitted when the admin account has changed.
*/
event AdminChanged(address previousAdmin, address newAdmin);
/**
* @dev Storage slot with the admin of the contract.
* This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
* validated in the constructor.
*/
bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
/**
* @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
*/
modifier ifAdmin() {
if (msg.sender == _admin()) {
_;
} else {
_fallback();
}
}
/**
* @dev Returns the current admin.
*
* NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
*
* TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
* https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
* `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
*/
function admin() external ifAdmin returns (address) {
return _admin();
}
/**
* @dev Returns the current implementation.
*
* NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
*
* TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
* https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
* `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
*/
function implementation() external ifAdmin returns (address) {
return _implementation();
}
/**
* @dev Changes the admin of the proxy.
*
* Emits an {AdminChanged} event.
*
* NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
*/
function changeAdmin(address newAdmin) external ifAdmin {
require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
emit AdminChanged(_admin(), newAdmin);
_setAdmin(newAdmin);
}
/**
* @dev Upgrade the implementation of the proxy.
*
* NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
*/
function upgradeTo(address newImplementation) external ifAdmin {
_upgradeTo(newImplementation);
}
/**
* @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
* by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
* proxied contract.
*
* NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
*/
function upgradeToAndCall(address newImplementation, bytes calldata data) external payable ifAdmin {
_upgradeTo(newImplementation);
// solhint-disable-next-line avoid-low-level-calls
(bool success,) = newImplementation.delegatecall(data);
require(success);
}
/**
* @dev Returns the current admin.
*/
function _admin() internal view returns (address adm) {
bytes32 slot = _ADMIN_SLOT;
// solhint-disable-next-line no-inline-assembly
assembly {
adm := sload(slot)
}
}
/**
* @dev Stores a new address in the EIP1967 admin slot.
*/
function _setAdmin(address newAdmin) private {
bytes32 slot = _ADMIN_SLOT;
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(slot, newAdmin)
}
}
/**
* @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
*/
function _beforeFallback() internal override virtual {
require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
super._beforeFallback();
}
}
contract MoMoProxy is TransparentUpgradeableProxy {
constructor(address _implementation, address _admin, bytes memory _data) public TransparentUpgradeableProxy(_implementation, _admin, _data) {
}
}
