Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.23;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
*
* Implementation of a diamond.
/******************************************************************************/
import { LibDiamond } from "./libraries/LibDiamond.sol";
import { IDiamondCut } from "./interfaces/IDiamondCut.sol";
contract Diamond {
constructor(address _contractOwner, address _diamondCutFacet) payable {
LibDiamond.setContractOwner(_contractOwner);
// Add the diamondCut external function from the diamondCutFacet
IDiamondCut.FacetCut[] memory cut = new IDiamondCut.FacetCut[](1);
bytes4[] memory functionSelectors = new bytes4[](1);
functionSelectors[0] = IDiamondCut.diamondCut.selector;
cut[0] = IDiamondCut.FacetCut({ facetAddress: _diamondCutFacet, action: IDiamondCut.FacetCutAction.Add, functionSelectors: functionSelectors });
LibDiamond.diamondCut(cut, address(0), "");
}
// Find facet for function that is called and execute the
// function if a facet is found and return any value.
// solhint-disable-next-line no-complex-fallback
fallback() external payable {
LibDiamond.DiamondStorage storage ds;
bytes32 position = LibDiamond.DIAMOND_STORAGE_POSITION;
// get diamond storage
assembly {
ds.slot := position
}
// get facet from function selector
address facet = ds.selectorToFacetAndPosition[msg.sig].facetAddress;
require(facet != address(0), "Diamond: Function does not exist");
// Execute external function from facet using delegatecall and return any value.
assembly {
// copy function selector and any arguments
calldatacopy(0, 0, calldatasize())
// execute function call using the facet
let result := delegatecall(gas(), facet, 0, calldatasize(), 0, 0)
// get any return value
returndatacopy(0, 0, returndatasize())
// return any return value or error back to the caller
switch result
case 0 {
revert(0, returndatasize())
}
default {
return(0, returndatasize())
}
}
}
receive() external payable {}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.23;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
interface IDiamondCut {
enum FacetCutAction {
Add,
Replace,
Remove
}
// Add=0, Replace=1, Remove=2
struct FacetCut {
address facetAddress;
FacetCutAction action;
bytes4[] functionSelectors;
}
/// @notice Add/replace/remove any number of functions and optionally execute
/// a function with delegatecall
/// @param _diamondCut Contains the facet addresses and function selectors
/// @param _init The address of the contract or facet to execute _calldata
/// @param _calldata A function call, including function selector and arguments
/// _calldata is executed with delegatecall on _init
function diamondCut(FacetCut[] calldata _diamondCut, address _init, bytes calldata _calldata) external;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.23;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
import { IDiamondCut } from "../interfaces/IDiamondCut.sol";
// Remember to add the loupe functions from DiamondLoupeFacet to the diamond.
// The loupe functions are required by the EIP2535 Diamonds standard
error InitializationFunctionReverted(address _initializationContractAddress, bytes _calldata);
library LibDiamond {
bytes32 public constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");
struct FacetAddressAndPosition {
address facetAddress;
uint96 functionSelectorPosition; // position in facetFunctionSelectors.functionSelectors array
}
struct FacetFunctionSelectors {
bytes4[] functionSelectors;
uint256 facetAddressPosition; // position of facetAddress in facetAddresses array
}
struct DiamondStorage {
// maps function selector to the facet address and
// the position of the selector in the facetFunctionSelectors.selectors array
mapping(bytes4 => FacetAddressAndPosition) selectorToFacetAndPosition;
// maps facet addresses to function selectors
mapping(address => FacetFunctionSelectors) facetFunctionSelectors;
// facet addresses
address[] facetAddresses;
// Used to query if a contract implements an interface.
// Used to implement ERC-165.
mapping(bytes4 => bool) supportedInterfaces;
// owner of the contract
address contractOwner;
}
function diamondStorage() internal pure returns (DiamondStorage storage ds) {
bytes32 position = DIAMOND_STORAGE_POSITION;
// solhint-disable-next-line no-inline-assembly
assembly {
ds.slot := position
}
}
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
function setContractOwner(address _newOwner) internal {
DiamondStorage storage ds = diamondStorage();
address previousOwner = ds.contractOwner;
ds.contractOwner = _newOwner;
emit OwnershipTransferred(previousOwner, _newOwner);
}
function contractOwner() internal view returns (address contractOwner_) {
contractOwner_ = diamondStorage().contractOwner;
}
function enforceIsContractOwner() internal view {
require(msg.sender == diamondStorage().contractOwner, "LibDiamond: Must be contract owner");
}
event DiamondCut(IDiamondCut.FacetCut[] _diamondCut, address _init, bytes _calldata);
// Internal function version of diamondCut
function diamondCut(IDiamondCut.FacetCut[] memory _diamondCut, address _init, bytes memory _calldata) internal {
for (uint256 facetIndex; facetIndex < _diamondCut.length; facetIndex++) {
IDiamondCut.FacetCutAction action = _diamondCut[facetIndex].action;
if (action == IDiamondCut.FacetCutAction.Add) {
addFunctions(_diamondCut[facetIndex].facetAddress, _diamondCut[facetIndex].functionSelectors);
} else if (action == IDiamondCut.FacetCutAction.Replace) {
replaceFunctions(_diamondCut[facetIndex].facetAddress, _diamondCut[facetIndex].functionSelectors);
} else if (action == IDiamondCut.FacetCutAction.Remove) {
removeFunctions(_diamondCut[facetIndex].facetAddress, _diamondCut[facetIndex].functionSelectors);
} else {
revert("LibDiamondCut: Incorrect FacetCutAction");
}
}
emit DiamondCut(_diamondCut, _init, _calldata);
initializeDiamondCut(_init, _calldata);
}
function addFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {
require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut");
DiamondStorage storage ds = diamondStorage();
require(_facetAddress != address(0), "LibDiamondCut: Add facet can't be address(0)");
uint96 selectorPosition = uint96(ds.facetFunctionSelectors[_facetAddress].functionSelectors.length);
// add new facet address if it does not exist
if (selectorPosition == 0) {
addFacet(ds, _facetAddress);
}
for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
bytes4 selector = _functionSelectors[selectorIndex];
address oldFacetAddress = ds.selectorToFacetAndPosition[selector].facetAddress;
require(oldFacetAddress == address(0), "LibDiamondCut: Can't add function that already exists");
addFunction(ds, selector, selectorPosition, _facetAddress);
selectorPosition++;
}
}
function replaceFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {
require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut");
DiamondStorage storage ds = diamondStorage();
require(_facetAddress != address(0), "LibDiamondCut: Add facet can't be address(0)");
uint96 selectorPosition = uint96(ds.facetFunctionSelectors[_facetAddress].functionSelectors.length);
// add new facet address if it does not exist
if (selectorPosition == 0) {
addFacet(ds, _facetAddress);
}
for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
bytes4 selector = _functionSelectors[selectorIndex];
address oldFacetAddress = ds.selectorToFacetAndPosition[selector].facetAddress;
require(oldFacetAddress != _facetAddress, "LibDiamondCut: Can't replace function with same function");
removeFunction(ds, oldFacetAddress, selector);
addFunction(ds, selector, selectorPosition, _facetAddress);
selectorPosition++;
}
}
function removeFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {
require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut");
DiamondStorage storage ds = diamondStorage();
// if function does not exist then do nothing and return
require(_facetAddress == address(0), "LibDiamondCut: Remove facet address must be address(0)");
for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
bytes4 selector = _functionSelectors[selectorIndex];
address oldFacetAddress = ds.selectorToFacetAndPosition[selector].facetAddress;
removeFunction(ds, oldFacetAddress, selector);
}
}
function addFacet(DiamondStorage storage ds, address _facetAddress) internal {
enforceHasContractCode(_facetAddress, "LibDiamondCut: New facet has no code");
ds.facetFunctionSelectors[_facetAddress].facetAddressPosition = ds.facetAddresses.length;
ds.facetAddresses.push(_facetAddress);
}
function addFunction(DiamondStorage storage ds, bytes4 _selector, uint96 _selectorPosition, address _facetAddress) internal {
ds.selectorToFacetAndPosition[_selector].functionSelectorPosition = _selectorPosition;
ds.facetFunctionSelectors[_facetAddress].functionSelectors.push(_selector);
ds.selectorToFacetAndPosition[_selector].facetAddress = _facetAddress;
}
function removeFunction(DiamondStorage storage ds, address _facetAddress, bytes4 _selector) internal {
require(_facetAddress != address(0), "LibDiamondCut: Can't remove function that doesn't exist");
// an immutable function is a function defined directly in a diamond
require(_facetAddress != address(this), "LibDiamondCut: Can't remove immutable function");
// replace selector with last selector, then delete last selector
uint256 selectorPosition = ds.selectorToFacetAndPosition[_selector].functionSelectorPosition;
uint256 lastSelectorPosition = ds.facetFunctionSelectors[_facetAddress].functionSelectors.length - 1;
// if not the same then replace _selector with lastSelector
if (selectorPosition != lastSelectorPosition) {
bytes4 lastSelector = ds.facetFunctionSelectors[_facetAddress].functionSelectors[lastSelectorPosition];
ds.facetFunctionSelectors[_facetAddress].functionSelectors[selectorPosition] = lastSelector;
ds.selectorToFacetAndPosition[lastSelector].functionSelectorPosition = uint96(selectorPosition);
}
// delete the last selector
ds.facetFunctionSelectors[_facetAddress].functionSelectors.pop();
delete ds.selectorToFacetAndPosition[_selector];
// if no more selectors for facet address then delete the facet address
if (lastSelectorPosition == 0) {
// replace facet address with last facet address and delete last facet address
uint256 lastFacetAddressPosition = ds.facetAddresses.length - 1;
uint256 facetAddressPosition = ds.facetFunctionSelectors[_facetAddress].facetAddressPosition;
if (facetAddressPosition != lastFacetAddressPosition) {
address lastFacetAddress = ds.facetAddresses[lastFacetAddressPosition];
ds.facetAddresses[facetAddressPosition] = lastFacetAddress;
ds.facetFunctionSelectors[lastFacetAddress].facetAddressPosition = facetAddressPosition;
}
ds.facetAddresses.pop();
delete ds.facetFunctionSelectors[_facetAddress].facetAddressPosition;
}
}
function initializeDiamondCut(address _init, bytes memory _calldata) internal {
if (_init == address(0)) {
return;
}
enforceHasContractCode(_init, "LibDiamondCut: _init address has no code");
(bool success, bytes memory error) = _init.delegatecall(_calldata);
if (!success) {
if (error.length > 0) {
// bubble up error
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(error)
revert(add(32, error), returndata_size)
}
} else {
revert InitializationFunctionReverted(_init, _calldata);
}
}
}
function enforceHasContractCode(address _contract, string memory _errorMessage) internal view {
uint256 contractSize;
assembly {
contractSize := extcodesize(_contract)
}
require(contractSize > 0, _errorMessage);
}
}
