pragma solidity ^0.7.0; pragma experimental ABIEncoderV2; import { TokenDelegatorStorage, TokenEvents } from "./TokenInterfaces.sol"; contract TokenDelegator is TokenDelegatorStorage, TokenEvents { constructor( address account, address minter_, address implementation_, uint mintingAllowedAfter_, uint changeImplementationAfter_, bool transferPaused_ ) { // Admin set to msg.sender for initialization minter = msg.sender; delegateTo( implementation_, abi.encodeWithSignature( "initialize(address,address,uint256,bool)", account, minter_, mintingAllowedAfter_, transferPaused_ ) ); changeImplementationAfter = changeImplementationAfter_; _setImplementation(implementation_); minter = minter_; } /** * @notice Called by the admin to update the implementation of the delegator * @param implementation_ The address of the new implementation for delegation */ function _setImplementation(address implementation_) public { require(msg.sender == minter, "TokenDelegator::_setImplementation: admin only"); require(implementation_ != address(0), "TokenDelegator::_setImplementation: invalid implementation address"); require(changeImplementationAfter >= block.timestamp, "TokenDelegator::_setImplementation: can change implementation changeImplementationAfter time only"); address oldImplementation = implementation; implementation = implementation_; emit NewImplementation(oldImplementation, implementation); } /** * @notice Internal method to delegate execution to another contract * @dev It returns to the external caller whatever the implementation returns or forwards reverts * @param callee The contract to delegatecall * @param data The raw data to delegatecall */ function delegateTo(address callee, bytes memory data) internal { (bool success, bytes memory returnData) = callee.delegatecall(data); assembly { if eq(success, 0) { revert(add(returnData, 0x20), returndatasize()) } } } /** * @dev Delegates execution to an implementation contract. * It returns to the external caller whatever the implementation returns * or forwards reverts. */ fallback () external payable { // delegate all other functions to current implementation (bool success, ) = implementation.delegatecall(msg.data); assembly { let free_mem_ptr := mload(0x40) returndatacopy(free_mem_ptr, 0, returndatasize()) switch success case 0 { revert(free_mem_ptr, returndatasize()) } default { return(free_mem_ptr, returndatasize()) } } } }