feture: refactored ERC6909

src/token/ERC6909/ERC6909/Approve/ERC6909ApproveFacet.sol

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+contract ERC6909ApproveFacet {
+    /**
+     * @notice Thrown when the spender address is invalid.
+     */
+    error ERC6909InvalidSpender(address _spender);
+
+    /**
+     * @notice Emitted when an approval occurs.
+     */
+    event Approval(address indexed _owner, address indexed _spender, uint256 indexed _id, uint256 _amount);
+    /**
+     * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+     */
+    bytes32 constant STORAGE_POSITION = keccak256("erc6909");
+
+    /**
+     * @custom:storage-location erc8042:erc6909
+     */
+    struct ERC6909Storage {
+        mapping(address owner => mapping(uint256 id => uint256 amount)) balanceOf;
+        mapping(address owner => mapping(address spender => mapping(uint256 id => uint256 amount))) allowance;
+        mapping(address owner => mapping(address spender => bool)) isOperator;
+    }
+
+    /**
+     * @notice Returns a pointer to the ERC-6909 storage struct.
+     * @dev Uses inline assembly to access the storage slot defined by STORAGE_POSITION.
+     * @return s The ERC6909Storage struct in storage.
+     */
+    function getStorage() internal pure returns (ERC6909Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+        assembly {
+            s.slot := position
+        }
+    }
+
+    /**
+     * @notice Approves an amount of an id to a spender.
+     * @param _spender The address of the spender.
+     * @param _id The id of the token.
+     * @param _amount The amount of the token.
+     * @return Whether the approval succeeded.
+     */
+    function approve(address _spender, uint256 _id, uint256 _amount) external returns (bool) {
+        if (_spender == address(0)) {
+            revert ERC6909InvalidSpender(address(0));
+        }
+
+        ERC6909Storage storage s = getStorage();
+
+        s.allowance[msg.sender][_spender][_id] = _amount;
+
+        emit Approval(msg.sender, _spender, _id, _amount);
+
+        return true;
+    }
+
+    /**
+     * @notice Exports the function selectors of the ERC6909ApproveFacet
+     * @dev This function is use as a selector discovery mechanism for diamonds
+     * @return selectors The exported function selectors of the ERC6909ApproveFacet
+     */
+    function exportSelectors() external pure returns (bytes memory) {
+        return bytes.concat(this.approve.selector);
+    }
+}

src/token/ERC6909/ERC6909/Approve/ERC6909ApproveMod.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.
+ */
+error ERC6909InvalidSpender(address _spender);
+
+/**
+ * @notice Emitted when an approval occurs.
+ */
+event Approval(address indexed _owner, address indexed _spender, uint256 indexed _id, uint256 _amount);
+/**
+ * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+ */
+bytes32 constant STORAGE_POSITION = keccak256("erc6909");
+
+/**
+ * @custom:storage-location erc8042:erc6909
+ */
+struct ERC6909Storage {
+    mapping(address owner => mapping(uint256 id => uint256 amount)) balanceOf;
+    mapping(address owner => mapping(address spender => mapping(uint256 id => uint256 amount))) allowance;
+    mapping(address owner => mapping(address spender => bool)) isOperator;
+}
+
+/**
+ * @notice Returns a pointer to the ERC-6909 storage struct.
+ * @dev Uses inline assembly to access the storage slot defined by STORAGE_POSITION.
+ * @return s The ERC6909Storage struct in storage.
+ */
+function getStorage() pure returns (ERC6909Storage storage s) {
+    bytes32 position = STORAGE_POSITION;
+    assembly {
+        s.slot := position
+    }
+}
+
+/**
+ * @notice Approves an amount of an id to a spender.
+ * @param _spender The address of the spender.
+ * @param _id The id of the token.
+ * @param _amount The amount of the token.
+ * @return Whether the approval succeeded.
+ */
+function approve(address _spender, uint256 _id, uint256 _amount) returns (bool) {
+    if (_spender == address(0)) {
+        revert ERC6909InvalidSpender(address(0));
+    }
+
+    ERC6909Storage storage s = getStorage();
+
+    s.allowance[msg.sender][_spender][_id] = _amount;
+
+    emit Approval(msg.sender, _spender, _id, _amount);
+
+    return true;
+}

src/token/ERC6909/ERC6909/Burn/ERC6909BurnFacet.sol

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+contract ERC6909BurnFacet {
+    /**
+     * @notice Thrown when the sender has insufficient balance.
+     */
+    error ERC6909InsufficientBalance(address _sender, uint256 _balance, uint256 _needed, uint256 _id);
+
+    /**
+     * @notice Thrown when the spender has insufficient allowance.
+     */
+    error ERC6909InsufficientAllowance(address _spender, uint256 _allowance, uint256 _needed, uint256 _id);
+
+    /**
+     * @notice Thrown when the sender address is invalid.
+     */
+    error ERC6909InvalidSender(address _sender);
+
+    /**
+     * @notice Emitted when a transfer occurs.
+     */
+
+    event Transfer(
+        address _caller, address indexed _sender, address indexed _receiver, uint256 indexed _id, uint256 _amount
+    );
+
+    /**
+     * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+     */
+    bytes32 constant STORAGE_POSITION = keccak256("erc6909");
+
+    /**
+     * @custom:storage-location erc8042:erc6909
+     */
+    struct ERC6909Storage {
+        mapping(address owner => mapping(uint256 id => uint256 amount)) balanceOf;
+        mapping(address owner => mapping(address spender => mapping(uint256 id => uint256 amount))) allowance;
+        mapping(address owner => mapping(address spender => bool)) isOperator;
+    }
+
+    /**
+     * @notice Returns a pointer to the ERC-6909 storage struct.
+     * @dev Uses inline assembly to access the storage slot defined by STORAGE_POSITION.
+     * @return s The ERC6909Storage struct in storage.
+     */
+    function getStorage() internal pure returns (ERC6909Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+        assembly {
+            s.slot := position
+        }
+    }
+
+    /**
+     * @notice Burns (destroys) a specific amount of tokens from the caller's balance.
+     * @dev Emits a {Transfer} event to the zero address.
+     * @param _amount The amount of tokens to burn.
+     */
+    function burn(uint256 _id, uint256 _amount) external {
+        ERC6909Storage storage s = getStorage();
+
+        uint256 fromBalance = s.balanceOf[msg.sender][_id];
+
+        if (fromBalance < _amount) {
+            revert ERC6909InsufficientBalance(msg.sender, fromBalance, _amount, _id);
+        }
+
+        unchecked {
+            s.balanceOf[msg.sender][_id] = fromBalance - _amount;
+        }
+
+        emit Transfer(msg.sender, msg.sender, address(0), _id, _amount);
+    }
+
+    /**
+     * @notice Burns tokens from another account, deducting from the caller's allowance.
+     * @dev Emits a {Transfer} event to the zero address.
+     * @param _from The address whose tokens will be burned.
+     * @param _amount The amount of tokens to burn.
+     */
+    function burnFrom(address _from, uint256 _id, uint256 _amount) external {
+        if (_from == address(0)) {
+            revert ERC6909InvalidSender(_from);
+        }
+
+        ERC6909Storage storage s = getStorage();
+
+        uint256 currentAllowance = s.allowance[_from][msg.sender][_id];
+
+        if (currentAllowance < type(uint256).max) {
+            if (currentAllowance < _amount) {
+                revert ERC6909InsufficientAllowance(msg.sender, currentAllowance, _amount, _id);
+            }
+            unchecked {
+                s.allowance[_from][msg.sender][_id] = currentAllowance - _amount;
+            }
+
+            uint256 fromBalance = s.balanceOf[_from][_id];
+
+            unchecked {
+                s.balanceOf[_from][_id] = fromBalance - _amount;
+            }
+        }
+        emit Transfer(msg.sender, _from, address(0), _id, _amount);
+    }
+
+    /**
+     * @notice Exports the function selectors of the ERC6909BurnFacet
+     * @dev This function is use as a selector discovery mechanism for diamonds
+     * @return selectors The exported function selectors of the ERC6909BurnFacet
+     */
+    function exportSelectors() external pure returns (bytes memory) {
+        return bytes.concat(this.burn.selector, this.burnFrom.selector);
+    }
+}

src/token/ERC6909/ERC6909/Burn/ERC6909BurnMod.sol

@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+/**
+ * @notice Thrown when the sender has insufficient balance.
+ */
+error ERC6909InsufficientBalance(address _sender, uint256 _balance, uint256 _needed, uint256 _id);
+
+/**
+ * @notice Thrown when the spender has insufficient allowance.
+ */
+error ERC6909InsufficientAllowance(address _spender, uint256 _allowance, uint256 _needed, uint256 _id);
+
+/**
+ * @notice Emitted when a transfer occurs.
+ */
+event Transfer(
+    address _caller, address indexed _sender, address indexed _receiver, uint256 indexed _id, uint256 _amount
+);
+
+/**
+ * @dev Storage position determined by the keccak256 hash of the diamond storage identifier.
+ */
+bytes32 constant STORAGE_POSITION = keccak256("erc6909");
+
+/**
+ * @custom:storage-location erc8042:erc6909
+ */
+struct ERC6909Storage {
+    mapping(address owner => mapping(uint256 id => uint256 amount)) balanceOf;
+    mapping(address owner => mapping(address spender => mapping(uint256 id => uint256 amount))) allowance;
+    mapping(address owner => mapping(address spender => bool)) isOperator;
+}
+
+/**
+ * @notice Returns a pointer to the ERC-6909 storage struct.
+ * @dev Uses inline assembly to access the storage slot defined by STORAGE_POSITION.
+ * @return s The ERC6909Storage struct in storage.
+ */
+function getStorage() pure returns (ERC6909Storage storage s) {
+    bytes32 position = STORAGE_POSITION;
+    assembly {
+        s.slot := position
+    }
+}
+
+/**
+ * @notice Burns (destroys) a specific amount of tokens from the caller's balance.
+ * @dev Emits a {Transfer} event to the zero address.
+ * @param _amount The amount of tokens to burn.
+ */
+function burn(uint256 _id, uint256 _amount) external {
+    ERC6909Storage storage s = getStorage();
+
+    uint256 fromBalance = s.balanceOf[msg.sender][_id];
+
+    if (fromBalance < _amount) {
+        revert ERC6909InsufficientBalance(msg.sender, fromBalance, _amount, _id);
+    }
+
+    unchecked {
+        s.balanceOf[msg.sender][_id] = fromBalance - _amount;
+    }
+
+    emit Transfer(msg.sender, msg.sender, address(0), _id, _amount);
+}
+
+/**
+ * @notice Burns tokens from another account, deducting from the caller's allowance.
+ * @dev Emits a {Transfer} event to the zero address.
+ * @param _from The address whose tokens will be burned.
+ * @param _amount The amount of tokens to burn.
+ */
+function burnFrom(address _from, uint256 _id, uint256 _amount) external {
+    if (_from == address(0)) {
+        revert ERC6909InvalidSender(_from);
+    }
+
+    ERC6909Storage storage s = getStorage();
+
+    uint256 currentAllowance = s.allowance[_from][msg.sender][_id];
+
+    if (currentAllowance < type(uint256).max) {
+        if (currentAllowance < _amount) {
+            revert ERC6909InsufficientAllowance(msg.sender, currentAllowance, _amount, _id);
+        }
+        unchecked {
+            s.allowance[_from][msg.sender][_id] = currentAllowance - _amount;
+        }
+
+        uint256 fromBalance = s.balanceOf[_from][_id];
+
+        unchecked {
+            s.balanceOf[_from][_id] = fromBalance - _amount;
+        }
+    }
+    emit Transfer(msg.sender, _from, address(0), _id, _amount);
+}