♻️ SkipNFTDefault (#148)

Author: Vectorized

src/DN404.sol

@@ -33,6 +33,21 @@ pragma solidity ^0.8.4;
 /// - The ERC20 token allowances and ERC721 token / operator approvals are separate.
 /// - For MEV safety, users should NOT have concurrently open orders for the ERC20 and ERC721.
 abstract contract DN404 {
+    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
+    /*                           ENUMS                            */
+    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
+
+    /// @dev Denotes the default skip NFT status.
+    /// Override `_skipNFTDefault` to return a preferred value (defaults to `HasCode`).
+    enum SkipNFTDefault {
+        // `On` if the ERC20 owner has code, else `Off`.
+        HasCode,
+        // Skip NFT (ERC20 transfers will NOT trigger NFT minting / burning / transferring).
+        On,
+        // NOT skip NFT (ERC20 transfers will trigger NFT minting / burning / transferring).
+        Off
+    }
+
     /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
     /*                           EVENTS                           */
     /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
@@ -309,6 +324,11 @@ abstract contract DN404 {
     /*                       CONFIGURABLES                        */
     /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
 
+    /// @dev Returns the default mode for the skip NFT status.
+    function _skipNFTDefault() internal view virtual returns (SkipNFTDefault) {
+        return SkipNFTDefault.HasCode;
+    }
+
     /// @dev Returns whether the tokens IDs are from `[1..n]` instead of `[0..n-1]`.
     function _useOneIndexed() internal pure virtual returns (bool) {
         return true;
@@ -1033,12 +1053,16 @@ abstract contract DN404 {
     /// Returns false otherwise.
     function getSkipNFT(address owner) public view virtual returns (bool result) {
         uint8 flags = _getDN404Storage().addressData[owner].flags;
-        /// @solidity memory-safe-assembly
-        assembly {
-            result := iszero(iszero(and(flags, _ADDRESS_DATA_SKIP_NFT_FLAG)))
-            if iszero(and(flags, _ADDRESS_DATA_SKIP_NFT_INITIALIZED_FLAG)) {
-                result := iszero(iszero(extcodesize(owner)))
+        result = flags & _ADDRESS_DATA_SKIP_NFT_FLAG != 0;
+        if (flags & _ADDRESS_DATA_SKIP_NFT_INITIALIZED_FLAG == uint256(0)) {
+            if (_skipNFTDefault() == SkipNFTDefault.HasCode) {
+                /// @solidity memory-safe-assembly
+                assembly {
+                    result := iszero(iszero(extcodesize(owner)))
+                }
             }
+            if (_skipNFTDefault() == SkipNFTDefault.On) result = true;
+            if (_skipNFTDefault() == SkipNFTDefault.Off) result = false;
         }
     }
 

src/DN420.sol

@@ -42,6 +42,21 @@ pragma solidity ^0.8.4;
 /// - The ERC20 token allowances and ERC1155 token / operator approvals are separate.
 /// - For MEV safety, users should NOT have concurrently open orders for the ERC20 and ERC1155.
 abstract contract DN420 {
+    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
+    /*                           ENUMS                            */
+    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
+
+    /// @dev Denotes the default skip NFT status.
+    /// Override `_skipNFTDefault` to return a preferred value (defaults to `HasCode`).
+    enum SkipNFTDefault {
+        // `On` if the ERC20 owner has code, else `Off`.
+        HasCode,
+        // Skip NFT (ERC20 transfers will NOT trigger NFT minting / burning / transferring).
+        On,
+        // NOT skip NFT (ERC20 transfers will trigger NFT minting / burning / transferring).
+        Off
+    }
+
     /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
     /*                           EVENTS                           */
     /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
@@ -321,6 +336,11 @@ abstract contract DN420 {
     /*                       CONFIGURABLES                        */
     /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/
 
+    /// @dev Returns the default mode for the skip NFT status.
+    function _skipNFTDefault() internal view virtual returns (SkipNFTDefault) {
+        return SkipNFTDefault.HasCode;
+    }
+
     /// @dev Returns if direct NFT transfers should be used during ERC20 transfers
     /// whenever possible, instead of burning and re-minting.
     function _useDirectTransfersIfPossible() internal view virtual returns (bool) {
@@ -986,12 +1006,16 @@ abstract contract DN420 {
     /// Returns false otherwise.
     function getSkipNFT(address owner) public view virtual returns (bool result) {
         uint8 flags = _getDN420Storage().addressData[owner].flags;
-        /// @solidity memory-safe-assembly
-        assembly {
-            result := iszero(iszero(and(flags, _ADDRESS_DATA_SKIP_NFT_FLAG)))
-            if iszero(and(flags, _ADDRESS_DATA_SKIP_NFT_INITIALIZED_FLAG)) {
-                result := iszero(iszero(extcodesize(owner)))
+        result = flags & _ADDRESS_DATA_SKIP_NFT_FLAG != 0;
+        if (flags & _ADDRESS_DATA_SKIP_NFT_INITIALIZED_FLAG == uint256(0)) {
+            if (_skipNFTDefault() == SkipNFTDefault.HasCode) {
+                /// @solidity memory-safe-assembly
+                assembly {
+                    result := iszero(iszero(extcodesize(owner)))
+                }
             }
+            if (_skipNFTDefault() == SkipNFTDefault.On) result = true;
+            if (_skipNFTDefault() == SkipNFTDefault.Off) result = false;
         }
     }