From e95828b7ddf79a7bf03256fde77e8cc93118e549 Mon Sep 17 00:00:00 2001
From: hueso <hueso@torguen.com.ar>
Date: Tue, 5 Sep 2023 00:40:18 -0300
Subject: [PATCH] ERC2771 compatibility

---
 contracts/core/OwnerSettings.sol        |  2 +-
 contracts/lib/metatx/ERC2771Context.sol | 17 +++++------------
 contracts/p2pix.sol                     | 15 +++++----------
 3 files changed, 11 insertions(+), 23 deletions(-)

diff --git a/contracts/core/OwnerSettings.sol b/contracts/core/OwnerSettings.sol
index 6bd9f82..4691811 100644
--- a/contracts/core/OwnerSettings.sol
+++ b/contracts/core/OwnerSettings.sol
@@ -67,7 +67,7 @@ abstract contract OwnerSettings is
                 sLoc := add(sLoc, 0x20)
             } {
                 // cache hashmap entry in scratch space
-                mstore(0x20, isTrustedForwarder.slot)
+                mstore(0x20, trustedForwarders.slot)
                 mstore(0x00, mload(fLoc))
                 //  let mapSlot := keccak256(0x00, 0x40)
                 sstore(keccak256(0x00, 0x40), mload(sLoc))
diff --git a/contracts/lib/metatx/ERC2771Context.sol b/contracts/lib/metatx/ERC2771Context.sol
index 04c75c7..82d8734 100644
--- a/contracts/lib/metatx/ERC2771Context.sol
+++ b/contracts/lib/metatx/ERC2771Context.sol
@@ -39,7 +39,7 @@ abstract contract Context {
 /// @dev Context variant with ERC2771 support.
 abstract contract ERC2771Context is Context {
     // address private immutable _trustedForwarder;
-    mapping(address => bool) public isTrustedForwarder;
+    mapping(address => bool) public trustedForwarders;
 
     /// @custom:oz-upgrades-unsafe-allow constructor
     // constructor(address trustedForwarder) {
@@ -53,7 +53,7 @@ abstract contract ERC2771Context is Context {
         override
         returns (address sender)
     {
-        if (isTrustedForwarder[msg.sender]) {
+        if (trustedForwarders[msg.sender]) {
             // The assembly code is more direct than the Solidity version using `abi.decode`.
             /// @solidity memory-safe-assembly
             assembly {
@@ -67,15 +67,8 @@ abstract contract ERC2771Context is Context {
         }
     }
 
-    function _isTrustedForwarder()
-        internal
-        view
-        returns (address _sender, uint256 _forwarder)
-    {
-        _sender = _msgSender();
-        _forwarder = (_sender != msg.sender)
-            ? uint256(1)
-            : uint256(0);
+    function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
+      return trustedForwarders[forwarder];
     }
 
     function _msgData()
@@ -85,7 +78,7 @@ abstract contract ERC2771Context is Context {
         override
         returns (bytes calldata)
     {
-        if (isTrustedForwarder[msg.sender]) {
+        if (isTrustedForwarder(msg.sender)) {
             return msg.data[:msg.data.length - 20];
         } else {
             return super._msgData();
diff --git a/contracts/p2pix.sol b/contracts/p2pix.sol
index 28fe041..8890f67 100644
--- a/contracts/p2pix.sol
+++ b/contracts/p2pix.sol
@@ -158,20 +158,18 @@ contract P2PIX is BaseUtils {
             mapLocks[lockID].expirationBlock >= block.number
         ) revert NotExpired();
 
-        address sender; uint256 forwarder;
-        (sender, forwarder) = _isTrustedForwarder();
         bytes32 _pixTarget = getPixTarget(args.seller, args.token);
 
         // transaction forwarding must leave `merkleProof` empty;
         // otherwise, the trustedForwarder must be previously added 
         // to a seller whitelist.
         if (args.merkleProof.length != 0) {
-            _merkleVerify( args.merkleProof, sellerAllowList(args.seller), sender);
+            _merkleVerify( args.merkleProof, sellerAllowList(args.seller), _msgSender());
 
-        } else if (args.amount > REPUTATION_LOWERBOUND && forwarder == 0) {
+        } else if ( args.amount > REPUTATION_LOWERBOUND && msg.sender == _msgSender() ) {
             
             uint256 spendLimit; uint256 userCredit = 
-            userRecord[_castAddrToKey(msg.sender)];
+            userRecord[_castAddrToKey(_msgSender())];
             (spendLimit) = _limiter(userCredit / WAD);
             if ( 
                 args.amount > (spendLimit * WAD) || 
@@ -185,7 +183,7 @@ contract P2PIX is BaseUtils {
             _pixTarget,
             args.amount,
             args.token,
-            sender,
+            _msgSender(),
             args.seller
         );
 
@@ -231,11 +229,8 @@ contract P2PIX is BaseUtils {
         l.amount = 0;
         l.expirationBlock = 0;
         _setUsedTransactions(message);
-
-        address sender; uint256 forwarder;
-        (sender, forwarder) = _isTrustedForwarder();
         
-        if (forwarder == 0) { 
+        if (_msgSender() == msg.sender) { 
         if (msg.sender != l.buyerAddress) {
             userRecord[_castAddrToKey(msg.sender)] += (lockAmount >> 1);
             userRecord[_castAddrToKey(l.buyerAddress)] += (lockAmount >> 1);