ProxyFactory.sol

pragma solidity ^0.5.3;

import "./InitializableAdminUpgradeabilityProxy.sol";
import "../cryptography/ECDSA.sol";

contract ProxyFactory {
  
  event ProxyCreated(address proxy);

  bytes32 private contractCodeHash;

  constructor() public {
    contractCodeHash = keccak256(
      type(InitializableAdminUpgradeabilityProxy).creationCode
    );
  }

  function deployMinimal(address _logic, bytes memory _data) public returns (address proxy) {
    // Adapted from https://github.com/optionality/clone-factory/blob/32782f82dfc5a00d103a7e61a17a5dedbd1e8e9d/contracts/CloneFactory.sol
    bytes20 targetBytes = bytes20(_logic);
    assembly {
      let clone := mload(0x40)
      mstore(clone, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
      mstore(add(clone, 0x14), targetBytes)
      mstore(add(clone, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
      proxy := create(0, clone, 0x37)
    }
    
    emit ProxyCreated(address(proxy));

    if(_data.length > 0) {
      (bool success,) = proxy.call(_data);
      require(success);
    }    
  }

  function deploy(uint256 _salt, address _logic, address _admin, bytes memory _data) public returns (address) {
    return _deployProxy(_salt, _logic, _admin, _data, msg.sender);
  }

  function deploySigned(uint256 _salt, address _logic, address _admin, bytes memory _data, bytes memory _signature) public returns (address) {
    address signer = getSigner(_salt, _logic, _admin, _data, _signature);
    require(signer != address(0), "Invalid signature");
    return _deployProxy(_salt, _logic, _admin, _data, signer);
  }

  function getDeploymentAddress(uint256 _salt, address _sender) public view returns (address) {
    // Adapted from https://github.com/archanova/solidity/blob/08f8f6bedc6e71c24758d20219b7d0749d75919d/contracts/contractCreator/ContractCreator.sol
    bytes32 salt = _getSalt(_salt, _sender);
    bytes32 rawAddress = keccak256(
      abi.encodePacked(
        bytes1(0xff),
        address(this),
        salt,
        contractCodeHash
      )
    );

    return address(bytes20(rawAddress << 96));
  }

  function getSigner(uint256 _salt, address _logic, address _admin, bytes memory _data, bytes memory _signature) public view returns (address) {
    bytes32 msgHash = OpenZeppelinUpgradesECDSA.toEthSignedMessageHash(
      keccak256(
        abi.encodePacked(
          _salt, _logic, _admin, _data, address(this)
        )
      )
    );

    return OpenZeppelinUpgradesECDSA.recover(msgHash, _signature);
  }

  function _deployProxy(uint256 _salt, address _logic, address _admin, bytes memory _data, address _sender) internal returns (address) {
    InitializableAdminUpgradeabilityProxy proxy = _createProxy(_salt, _sender);
    emit ProxyCreated(address(proxy));
    proxy.initialize(_logic, _admin, _data);
    return address(proxy);
  }

  function _createProxy(uint256 _salt, address _sender) internal returns (InitializableAdminUpgradeabilityProxy) {
    address payable addr;
    bytes memory code = type(InitializableAdminUpgradeabilityProxy).creationCode;
    bytes32 salt = _getSalt(_salt, _sender);

    assembly {
      addr := create2(0, add(code, 0x20), mload(code), salt)
      if iszero(extcodesize(addr)) {
        revert(0, 0)
      }
    }

    return InitializableAdminUpgradeabilityProxy(addr);
  }

  function _getSalt(uint256 _salt, address _sender) internal pure returns (bytes32) {
    return keccak256(abi.encodePacked(_salt, _sender)); 
  }
}