Merge pull request #19 for FF exhibition v4 release

Feralfile Exhibition V4

.github/workflows/prettier.yaml

@@ -0,0 +1,17 @@
+name: prettier
+on:
+    push:
+    pull_request:
+
+jobs:
+    prettier:
+        name: prettier
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout Code
+              uses: actions/checkout@v3
+            - name: Prettify code
+              uses: creyD/[email protected]
+              with:
+                  # This part is also where you can pass other options, for example:
+                  prettier_options: --check contracts/FeralfileArtworkV4.sol

.gitignore

@@ -2,4 +2,4 @@
 build
 node_modules
 coverage/*
-coverage.json
+coverage.json

contracts/ECDSASigner.sol

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.13;
+
+import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+contract ECDSASigner is Ownable {
+    address private _signer;
+
+    constructor(address signer_) {
+        require(signer_ != address(0), "ECDSASign: signer_ is zero address");
+        _signer = signer_;
+    }
+
+    /// @notice isValidSignature validates a message by ecrecover to ensure
+    //          it is signed by signer.
+    /// @param message_ - the raw message for signing
+    /// @param r_ - part of signature for validating parameters integrity
+    /// @param s_ - part of signature for validating parameters integrity
+    /// @param v_ - part of signature for validating parameters integrity
+    function isValidSignature(
+        bytes32 message_,
+        bytes32 r_,
+        bytes32 s_,
+        uint8 v_
+    ) internal view returns (bool) {
+        address reqSigner = ECDSA.recover(
+            ECDSA.toEthSignedMessageHash(message_),
+            v_,
+            r_,
+            s_
+        );
+        return reqSigner == _signer;
+    }
+
+    /// @notice set the signer
+    /// @param signer_ - the address of signer
+    function setSigner(address signer_) external onlyOwner {
+        require(signer_ != address(0), "ECDSASign: signer_ is zero address");
+        _signer = signer_;
+    }
+
+    function signer() external view returns (address) {
+        return _signer;
+    }
+}