From 2ed1eacc4db50d009f90b818f362d6c6bbcd5e87 Mon Sep 17 00:00:00 2001
From: Thrilok Kumar <thrilok2000@gmail.com>
Date: Thu, 24 Sep 2020 16:23:42 +0530
Subject: [PATCH] Updated flusher.sol to fallback function

---
 contracts/flusher/flusher.sol | 57 +++++++++++++++--------------------
 1 file changed, 25 insertions(+), 32 deletions(-)

diff --git a/contracts/flusher/flusher.sol b/contracts/flusher/flusher.sol
index 3535b8a..648b539 100644
--- a/contracts/flusher/flusher.sol
+++ b/contracts/flusher/flusher.sol
@@ -1,42 +1,35 @@
 // SPDX-License-Identifier: MIT
-
 pragma solidity ^0.6.8;
 pragma experimental ABIEncoderV2;
 
-interface DeployerInterface {
-  function signer(address) external view returns (bool); 
-  function isConnector(address[] calldata) external view returns (bool);
-}
+import "@openzeppelin/contracts/proxy/Proxy.sol";
 
-contract Flusher {
-  event LogCast(address indexed sender, uint value);
+contract Flusher is Proxy {
+    /**
+     * @dev Storage slot with the address of the current implementation.
+     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1
+     */
+    bytes32 private constant _IMPLEMENTATION_SLOT = bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1); // 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc
 
-  string constant public name = "Flusher-v1";
-
-  DeployerInterface public constant deployer = DeployerInterface(address(0)); // TODO - Change while deploying
-
-  function spell(address _target, bytes memory _data) internal {
-    require(_target != address(0), "target-invalid");
-    assembly {
-      let succeeded := delegatecall(gas(), _target, add(_data, 0x20), mload(_data), 0, 0)
-      switch iszero(succeeded)
-        case 1 {
-            let size := returndatasize()
-            returndatacopy(0x00, 0x00, size)
-            revert(0x00, size)
+    /**
+     * @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)
         }
     }
-  }
 
-  function cast(address[] calldata _targets, bytes[] calldata _datas) external payable {
-    require(deployer.signer(msg.sender), "not-signer");
-    require(_targets.length == _datas.length , "invalid-array-length");
-    require(deployer.isConnector(_targets), "not-connector");
-    for (uint i = 0; i < _targets.length; i++) {
-        spell(_targets[i], _datas[i]);
+    function setBasic(address newImplementation) public {
+        require(_implementation() == address(0), "_implementation-logic-already-set");
+        require(newImplementation == address(0), "newImplementation-not-vaild");
+        bytes32 slot = _IMPLEMENTATION_SLOT;
+
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            sstore(slot, newImplementation)
+        }
     }
-    emit LogCast(msg.sender, msg.value);
-  }
-
-  receive() external payable {}
-}
\ No newline at end of file
+}