Move Context from GSN to utils directory (#2453)

Co-authored-by: Hadrien Croubois <hadrien@openzeppelin.com>
Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

CHANGELOG.md

@@ -7,6 +7,7 @@
  * `ERC20Permit`: added an implementation of the ERC20 permit extension for gasless token approvals. ([#2237](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237))
  * Presets: added token presets with preminted fixed supply `ERC20PresetFixedSupply` and `ERC777PresetFixedSupply`. ([#2399](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2399))
  * `Address`: added `functionDelegateCall`, similar to the existing `functionCall`. ([#2333](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2333))
+ * `Context`: moved from `contracts/GSN` to `contracts/utils`. ([#2453](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2453)) 
  * `PaymentSplitter`: replace usage of `.transfer()` with `Address.sendValue` for improved compatibility with smart wallets. ([#2455](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2455))
  * `UpgradeableProxy`: bubble revert reasons from initialization calls. ([#2454](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2454)) 
 

contracts/GSN/Context.sol

@@ -2,23 +2,4 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-/*
- * @dev Provides information about the current execution context, including the
- * sender of the transaction and its data. While these are generally available
- * via msg.sender and msg.data, they should not be accessed in such a direct
- * manner, since when dealing with GSN meta-transactions the account sending and
- * paying for execution may not be the actual sender (as far as an application
- * is concerned).
- *
- * This contract is only required for intermediate, library-like contracts.
- */
-abstract contract Context {
-    function _msgSender() internal view virtual returns (address payable) {
-        return msg.sender;
-    }
-
-    function _msgData() internal view virtual returns (bytes memory) {
-        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
-        return msg.data;
-    }
-}
+import "../utils/Context.sol";

contracts/GSN/GSNRecipient.sol

@@ -2,9 +2,9 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
+import "../utils/Context.sol";
 import "./IRelayRecipient.sol";
 import "./IRelayHub.sol";
-import "./Context.sol";
 
 /**
  * @dev Base GSN recipient contract: includes the {IRelayRecipient} interface

contracts/access/AccessControl.sol

@@ -4,7 +4,7 @@ pragma solidity >=0.6.0 <0.8.0;
 
 import "../utils/EnumerableSet.sol";
 import "../utils/Address.sol";
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 
 /**
  * @dev Contract module that allows children to implement role-based access

contracts/access/Ownable.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 /**
  * @dev Contract module which provides a basic access control mechanism, where
  * there is an account (an owner) that can be granted exclusive access to

contracts/mocks/ContextMock.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 
 contract ContextMock is Context {
     event Sender(address sender);

contracts/mocks/ERC777Mock.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../token/ERC777/ERC777.sol";
 
 contract ERC777Mock is Context, ERC777 {

contracts/mocks/ERC777SenderRecipientMock.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../token/ERC777/IERC777.sol";
 import "../token/ERC777/IERC777Sender.sol";
 import "../token/ERC777/IERC777Recipient.sol";

contracts/mocks/ReentrancyAttack.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 contract ReentrancyAttack is Context {
     function callSender(bytes4 data) public {
         // solhint-disable-next-line avoid-low-level-calls

contracts/mocks/SafeERC20Helper.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../token/ERC20/IERC20.sol";
 import "../token/ERC20/SafeERC20.sol";
 

contracts/payment/PaymentSplitter.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../math/SafeMath.sol";
 import "../utils/Address.sol";
 

contracts/presets/ERC1155PresetMinterPauser.sol

@@ -3,7 +3,7 @@
 pragma solidity >=0.6.0 <0.8.0;
 
 import "../access/AccessControl.sol";
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../token/ERC1155/ERC1155.sol";
 import "../token/ERC1155/ERC1155Burnable.sol";
 import "../token/ERC1155/ERC1155Pausable.sol";

contracts/presets/ERC20PresetMinterPauser.sol

@@ -3,7 +3,7 @@
 pragma solidity >=0.6.0 <0.8.0;
 
 import "../access/AccessControl.sol";
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../token/ERC20/ERC20.sol";
 import "../token/ERC20/ERC20Burnable.sol";
 import "../token/ERC20/ERC20Pausable.sol";

contracts/presets/ERC721PresetMinterPauserAutoId.sol

@@ -3,7 +3,7 @@
 pragma solidity >=0.6.0 <0.8.0;
 
 import "../access/AccessControl.sol";
-import "../GSN/Context.sol";
+import "../utils/Context.sol";
 import "../utils/Counters.sol";
 import "../token/ERC721/ERC721.sol";
 import "../token/ERC721/ERC721Burnable.sol";

contracts/token/ERC1155/ERC1155.sol

@@ -5,7 +5,7 @@ pragma solidity >=0.6.0 <0.8.0;
 import "./IERC1155.sol";
 import "./IERC1155MetadataURI.sol";
 import "./IERC1155Receiver.sol";
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "../../introspection/ERC165.sol";
 import "../../math/SafeMath.sol";
 import "../../utils/Address.sol";

contracts/token/ERC20/ERC20.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "./IERC20.sol";
 import "../../math/SafeMath.sol";
 

contracts/token/ERC20/ERC20Burnable.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "./ERC20.sol";
 
 /**

contracts/token/ERC721/ERC721.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "./IERC721.sol";
 import "./IERC721Metadata.sol";
 import "./IERC721Enumerable.sol";

contracts/token/ERC721/ERC721Burnable.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "./ERC721.sol";
 
 /**

contracts/token/ERC777/ERC777.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../../GSN/Context.sol";
+import "../../utils/Context.sol";
 import "./IERC777.sol";
 import "./IERC777Recipient.sol";
 import "./IERC777Sender.sol";

contracts/utils/Context.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.6.0 <0.8.0;
+
+/*
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they should not be accessed in such a direct
+ * manner, since when dealing with GSN meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+abstract contract Context {
+    function _msgSender() internal view virtual returns (address payable) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view virtual returns (bytes memory) {
+        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
+        return msg.data;
+    }
+}

contracts/utils/Pausable.sol

@@ -2,7 +2,7 @@
 
 pragma solidity >=0.6.0 <0.8.0;
 
-import "../GSN/Context.sol";
+import "./Context.sol";
 
 /**
  * @dev Contract module which allows children to implement an emergency stop