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pragma solidity ^0.4.24;
import './UpgradeabilityProxy.sol';
/**
* @title AdminUpgradeabilityProxy
* @dev This contract combines an upgradeability proxy with an authorization
* mechanism for administrative tasks.
* All external functions in this contract must be guarded by the
* `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
* feature proposal that would enable this to be done automatically.
*/
contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
/**
* @dev Emitted when the administration has been transferred.
* @param previousAdmin Address of the previous admin.
* @param newAdmin Address of the new admin.
*/
event AdminChanged(address previousAdmin, address newAdmin);
/**
* @dev Storage slot with the admin of the contract.
* This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
* validated in the constructor.
*/
bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
/**
* @dev Modifier to check whether the `msg.sender` is the admin.
* If it is, it will run the function. Otherwise, it will delegate the call
* to the implementation.
*/
modifier ifAdmin() {
if (msg.sender == _admin()) {
_;
} else {
_fallback();
}
}
/**
* Contract constructor.
* It sets the `msg.sender` as the proxy administrator.
* @param _implementation address of the initial implementation.
* @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
* It should include the signature and the parameters of the function to be called, as described in
* https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
* This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
*/
constructor(address _implementation, bytes _data) UpgradeabilityProxy(_implementation, _data) public payable {
assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
_setAdmin(msg.sender);
}
/**
* @return The address of the proxy admin.
*/
function admin() external view ifAdmin returns (address) {
return _admin();
}
/**
* @return The address of the implementation.
*/
function implementation() external view ifAdmin returns (address) {
return _implementation();
}
/**
* @dev Changes the admin of the proxy.
* Only the current admin can call this function.
* @param newAdmin Address to transfer proxy administration to.
*/
function changeAdmin(address newAdmin) external ifAdmin {
require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
emit AdminChanged(_admin(), newAdmin);
_setAdmin(newAdmin);
}
/**
* @dev Upgrade the backing implementation of the proxy.
* Only the admin can call this function.
* @param newImplementation Address of the new implementation.
*/
function upgradeTo(address newImplementation) external ifAdmin {
_upgradeTo(newImplementation);
}
/**
* @dev Upgrade the backing implementation of the proxy and call a function
* on the new implementation.
* This is useful to initialize the proxied contract.
* @param newImplementation Address of the new implementation.
* @param data Data to send as msg.data in the low level call.
* It should include the signature and the parameters of the function to be called, as described in
* https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
*/
function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
_upgradeTo(newImplementation);
require(newImplementation.delegatecall(data));
}
/**
* @return The admin slot.
*/
function _admin() internal view returns (address adm) {
bytes32 slot = ADMIN_SLOT;
assembly {
adm := sload(slot)
}
}
/**
* @dev Sets the address of the proxy admin.
* @param newAdmin Address of the new proxy admin.
*/
function _setAdmin(address newAdmin) internal {
bytes32 slot = ADMIN_SLOT;
assembly {
sstore(slot, newAdmin)
}
}
/**
* @dev Only fall back when the sender is not the admin.
*/
function _willFallback() internal {
require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
super._willFallback();
}
}