Rorganized ERC20 functionality

Author: mudgen

src/token/ERC20/ERC20Approve/ERC20ApproveFacet.sol

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+contract ERC20ApproveFacet {
+    /**
+     * @notice Thrown when the spender address is invalid (e.g., zero address).
+     * @param _spender Invalid spender address.
+     */
+    error ERC20InvalidSpender(address _spender);
+
+    /**
+     * @notice Emitted when an approval is made for a spender by an owner.
+     * @param _owner The address granting the allowance.
+     * @param _spender The address receiving the allowance.
+     * @param _value The amount approved.
+     */
+    event Approval(address indexed _owner, address indexed _spender, uint256 _value);  
+
+    /**
+     * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+     */
+    bytes32 constant STORAGE_POSITION = keccak256("erc20");
+
+    /**
+     * @dev ERC-8042 compliant storage struct for ERC20 token data.
+     * @custom:storage-location erc8042:erc20
+     */
+    struct ERC20Storage {
+        mapping(address owner => uint256 balance) balanceOf;
+        uint256 totalSupply;
+        mapping(address owner => mapping(address spender => uint256 allowance)) allowance;
+    }
+
+    /**
+     * @notice Returns the ERC20 storage struct from the predefined diamond storage slot.
+     * @dev Uses inline assembly to set the storage slot reference.
+     * @return s The ERC20 storage struct reference.
+     */
+    function getStorage() internal pure returns (ERC20Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+        assembly {
+            s.slot := position
+        }
+    }
+    
+    /**
+     * @notice Approves a spender to transfer up to a certain amount of tokens on behalf of the caller.
+     * @dev Emits an {Approval} event.
+     * @param _spender The address approved to spend tokens.
+     * @param _value The number of tokens to approve.
+     * @return True if the approval was successful.
+     */
+    function approve(address _spender, uint256 _value) external returns (bool) {
+        ERC20Storage storage s = getStorage();
+        if (_spender == address(0)) {
+            revert ERC20InvalidSpender(address(0));
+        }
+        s.allowance[msg.sender][_spender] = _value;
+        emit Approval(msg.sender, _spender, _value);
+        return true;
+    }
+}

src/token/ERC20/ERC20Approve/ERC20ApproveMod.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+/**
+* @notice Thrown when the spender address is invalid (e.g., zero address).
+* @param _spender Invalid spender address.
+*/
+error ERC20InvalidSpender(address _spender);
+
+/**
+* @notice Emitted when an approval is made for a spender by an owner.
+* @param _owner The address granting the allowance.
+* @param _spender The address receiving the allowance.
+* @param _value The amount approved.
+*/
+event Approval(address indexed _owner, address indexed _spender, uint256 _value);  
+
+/**
+* @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+*/
+bytes32 constant STORAGE_POSITION = keccak256("erc20");
+
+/**
+* @dev ERC-8042 compliant storage struct for ERC20 token data.
+* @custom:storage-location erc8042:erc20
+*/
+struct ERC20Storage {
+    mapping(address owner => uint256 balance) balanceOf;
+    uint256 totalSupply;
+    mapping(address owner => mapping(address spender => uint256 allowance)) allowance;
+}
+
+/**
+* @notice Returns the ERC20 storage struct from the predefined diamond storage slot.
+* @dev Uses inline assembly to set the storage slot reference.
+* @return s The ERC20 storage struct reference.
+*/
+function getStorage() pure returns (ERC20Storage storage s) {
+    bytes32 position = STORAGE_POSITION;
+    assembly {
+        s.slot := position
+    }
+}
+
+/**
+ * @notice Approves a spender to transfer tokens on behalf of the caller.
+ * @dev Sets the allowance for the spender.
+ * @param _spender The address to approve for spending.
+ * @param _value The amount of tokens to approve.
+ */
+function approve(address _spender, uint256 _value) {
+    if (_spender == address(0)) {
+        revert ERC20InvalidSpender(address(0));
+    }
+    ERC20Storage storage s = getStorage();
+    s.allowance[msg.sender][_spender] = _value;
+    emit Approval(msg.sender, _spender, _value);
+}

src/token/ERC20/ERC20Bridgeable/ERC20BridgeableFacet.sol

@@ -80,13 +80,13 @@ contract ERC20BridgeableFacet {
      * @notice Storage slot for ERC-20 token using ERC8042 for storage location standardization
      * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
      */
-    bytes32 constant ERC20_TRANSFER_STORAGE_POSITION = keccak256("erc20.transfer");
+    bytes32 constant ERC20_STORAGE_POSITION = keccak256("erc20");
 
     /**
      * @dev ERC-8042 compliant storage struct for ERC20 token data.
-     * @custom:storage-location erc8042:erc20.transfer
+     * @custom:storage-location erc8042:erc20
      */
-    struct ERC20TransferStorage {
+    struct ERC20Storage {
         mapping(address owner => uint256 balance) balanceOf;
         uint256 totalSupply;
     }
@@ -96,8 +96,8 @@ contract ERC20BridgeableFacet {
      * @return s The ERC20 storage struct reference.
      */
 
-    function getERC20TransferStorage() internal pure returns (ERC20TransferStorage storage s) {
-        bytes32 position = ERC20_TRANSFER_STORAGE_POSITION;
+    function getERC20Storage() internal pure returns (ERC20Storage storage s) {
+        bytes32 position = ERC20_STORAGE_POSITION;
         assembly {
             s.slot := position
         }
@@ -137,7 +137,7 @@ contract ERC20BridgeableFacet {
      * @param _value The amount to mint.
      */
     function crosschainMint(address _account, uint256 _value) external {
-        ERC20TransferStorage storage erc20Transfer = getERC20TransferStorage();
+        ERC20Storage storage erc20Storage = getERC20Storage();
 
         AccessControlStorage storage acs = getAccessControlStorage();
 
@@ -153,8 +153,8 @@ contract ERC20BridgeableFacet {
         }
 
         unchecked {
-            erc20Transfer.totalSupply += _value;
-            erc20Transfer.balanceOf[_account] += _value;
+            erc20Storage.totalSupply += _value;
+            erc20Storage.balanceOf[_account] += _value;
         }
         emit Transfer(address(0), _account, _value);
         emit CrosschainMint(_account, _value, msg.sender);
@@ -166,7 +166,7 @@ contract ERC20BridgeableFacet {
      * @param _value The amount to burn.
      */
     function crosschainBurn(address _from, uint256 _value) external {
-        ERC20TransferStorage storage erc20Transfer = getERC20TransferStorage();
+        ERC20Storage storage erc20Storage = getERC20Storage();
 
         AccessControlStorage storage acs = getAccessControlStorage();
 
@@ -180,15 +180,15 @@ contract ERC20BridgeableFacet {
             revert ERC20InvalidReceiver(address(0));
         }
 
-        uint256 accountBalance = erc20Transfer.balanceOf[_from];
+        uint256 accountBalance = erc20Storage.balanceOf[_from];
 
         if (accountBalance < _value) {
             revert ERC20InsufficientBalance(_from, accountBalance, _value);
         }
 
         unchecked {
-            erc20Transfer.totalSupply -= _value;
-            erc20Transfer.balanceOf[_from] -= _value;
+            erc20Storage.totalSupply -= _value;
+            erc20Storage.balanceOf[_from] -= _value;
         }
 
         emit Transfer(_from, address(0), _value);

src/token/ERC20/ERC20Bridgeable/ERC20BridgeableMod.sol

@@ -80,13 +80,13 @@ event Transfer(address indexed _from, address indexed _to, uint256 _value);
  * @notice Storage slot for ERC-20 token using ERC8042 for storage location standardization
  * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
  */
-bytes32 constant ERC20_TRANSFER_STORAGE_POSITION = keccak256("erc20.transfer");
+bytes32 constant ERC20_STORAGE_POSITION = keccak256("erc20");
 
 /**
  * @dev ERC-8042 compliant storage struct for ERC20 token data.
- * @custom:storage-location erc8042:erc20.transfer
+ * @custom:storage-location erc8042:erc20
  */
-struct ERC20TransferStorage {
+struct ERC20Storage {
     mapping(address owner => uint256 balance) balanceOf;
     uint256 totalSupply;
 }
@@ -96,8 +96,8 @@ struct ERC20TransferStorage {
  * @return s The ERC20 storage struct reference.
  */
 
-function getERC20TransferStorage() pure returns (ERC20TransferStorage storage s) {
-    bytes32 position = ERC20_TRANSFER_STORAGE_POSITION;
+function getERC20Storage() pure returns (ERC20Storage storage s) {
+    bytes32 position = ERC20_STORAGE_POSITION;
     assembly {
         s.slot := position
     }
@@ -137,7 +137,7 @@ function getAccessControlStorage() pure returns (AccessControlStorage storage s)
  * @param _value The amount to mint.
  */
 function crosschainMint(address _account, uint256 _value) {
-    ERC20TransferStorage storage erc20Transfer = getERC20TransferStorage();
+    ERC20Storage storage erc20Storage = getERC20Storage();
 
     AccessControlStorage storage acs = getAccessControlStorage();
 
@@ -153,8 +153,8 @@ function crosschainMint(address _account, uint256 _value) {
     }
 
     unchecked {
-        erc20Transfer.totalSupply += _value;
-        erc20Transfer.balanceOf[_account] += _value;
+        erc20Storage.totalSupply += _value;
+        erc20Storage.balanceOf[_account] += _value;
     }
 
     emit Transfer(address(0), _account, _value);
@@ -167,7 +167,7 @@ function crosschainMint(address _account, uint256 _value) {
  * @param _value The amount to burn.
  */
 function crosschainBurn(address _from, uint256 _value) {
-    ERC20TransferStorage storage erc20Transfer = getERC20TransferStorage();
+    ERC20Storage storage erc20Storage = getERC20Storage();
 
     AccessControlStorage storage acs = getAccessControlStorage();
 
@@ -182,15 +182,15 @@ function crosschainBurn(address _from, uint256 _value) {
         revert ERC20InvalidReceiver(address(0));
     }
 
-    uint256 accountBalance = erc20Transfer.balanceOf[_from];
+    uint256 accountBalance = erc20Storage.balanceOf[_from];
 
     if (accountBalance < _value) {
         revert ERC20InsufficientBalance(_from, accountBalance, _value);
     }
 
     unchecked {
-        erc20Transfer.totalSupply -= _value;
-        erc20Transfer.balanceOf[_from] -= _value;
+        erc20Storage.totalSupply -= _value;
+        erc20Storage.balanceOf[_from] -= _value;
     }
     emit Transfer(_from, address(0), _value);
     emit CrosschainBurn(_from, _value, msg.sender);

src/token/ERC20/ERC20Data/ERC20DataFacet.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+contract ERC20DataFacet {  
+    /**
+     * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+     */
+    bytes32 constant STORAGE_POSITION = keccak256("erc20");
+
+    /**
+     * @dev ERC-8042 compliant storage struct for ERC20 token data.
+     * @custom:storage-location erc8042:erc20.transfer
+     */
+    struct ERC20Storage {
+        mapping(address owner => uint256 balance) balanceOf;
+        uint256 totalSupply;
+        mapping(address owner => mapping(address spender => uint256 allowance)) allowance;
+    }
+
+    /**
+     * @notice Returns the ERC20 storage struct from the predefined diamond storage slot.
+     * @dev Uses inline assembly to set the storage slot reference.
+     * @return s The ERC20 storage struct reference.
+     */
+    function getStorage() internal pure returns (ERC20Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+        assembly {
+            s.slot := position
+        }
+    }
+
+    /**
+     * @notice Returns the total supply of tokens.
+     * @return The total token supply.
+     */
+    function totalSupply() external view returns (uint256) {
+        return getStorage().totalSupply;
+    }
+
+    /**
+     * @notice Returns the balance of a specific account.
+     * @param _account The address of the account.
+     * @return The account balance.
+     */
+    function balanceOf(address _account) external view returns (uint256) {
+        return getStorage().balanceOf[_account];
+    }
+
+    /**
+     * @notice Returns the remaining number of tokens that a spender is allowed to spend on behalf of an owner.
+     * @param _owner The address of the token owner.
+     * @param _spender The address of the spender.
+     * @return The remaining allowance.
+     */
+    function allowance(address _owner, address _spender) external view returns (uint256) {
+        return getStorage().allowance[_owner][_spender];
+    }
+}

src/token/ERC20/ERC20Permit/ERC20PermitFacet.sol

@@ -50,19 +50,19 @@ contract ERC20PermitFacet {
         }
     }
 
-    bytes32 constant ERC20_TRANSFER_STORAGE_POSITION = keccak256("erc20.transfer");
+    bytes32 constant ERC20_STORAGE_POSITION = keccak256("erc20");
 
     /**
-     * @custom:storage-location erc8042:erc20.transfer
+     * @custom:storage-location erc8042:erc20
      */
-    struct ERC20TransferStorage {
+    struct ERC20Storage {
         mapping(address owner => uint256 balance) balanceOf;
         uint256 totalSupply;
         mapping(address owner => mapping(address spender => uint256 allowance)) allowance;
     }
 
-    function getERC20TransferStorage() internal pure returns (ERC20TransferStorage storage s) {
-        bytes32 position = ERC20_TRANSFER_STORAGE_POSITION;
+    function getERC20Storage() internal pure returns (ERC20Storage storage s) {
+        bytes32 position = ERC20_STORAGE_POSITION;
         assembly {
             s.slot := position
         }
@@ -139,7 +139,7 @@ contract ERC20PermitFacet {
         }
 
         NoncesStorage storage s = getStorage();
-        ERC20TransferStorage storage erc20Transfer = getERC20TransferStorage();
+        ERC20Storage storage erc20Storage = getERC20Storage();
         uint256 currentNonce = s.nonces[_owner];
         bytes32 structHash = keccak256(
             abi.encode(
@@ -173,7 +173,7 @@ contract ERC20PermitFacet {
             revert ERC2612InvalidSignature(_owner, _spender, _value, _deadline, _v, _r, _s);
         }
 
-        erc20Transfer.allowance[_owner][_spender] = _value;
+        erc20Storage.allowance[_owner][_spender] = _value;
         s.nonces[_owner] = currentNonce + 1;
         emit Approval(_owner, _spender, _value);
     }