Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamond Standard: https://eips.ethereum.org/EIPS/eip-2535
*
* Implementation of a diamond.
/******************************************************************************/
import "./libraries/LibDiamond.sol";
import "./interfaces/IDiamondLoupe.sol";
import "./interfaces/IDiamondCut.sol";
import "./interfaces/IERC173.sol";
import "./interfaces/IERC165.sol";
contract Diamond {
// more arguments are added to this struct
// this avoids stack too deep errors
struct DiamondArgs {
address owner;
}
constructor(IDiamondCut.FacetCut[] memory _diamondCut, DiamondArgs memory _args) payable {
LibDiamond.diamondCut(_diamondCut, address(0), new bytes(0));
LibDiamond.setContractOwner(_args.owner);
LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
// adding ERC165 data
ds.supportedInterfaces[type(IERC165).interfaceId] = true;
ds.supportedInterfaces[type(IDiamondCut).interfaceId] = true;
ds.supportedInterfaces[type(IDiamondLoupe).interfaceId] = true;
ds.supportedInterfaces[type(IERC173).interfaceId] = true;
}
// Find facet for function that is called and execute the
// function if a facet is found and return any value.
fallback() external payable {
LibDiamond.DiamondStorage storage ds;
bytes32 position = LibDiamond.DIAMOND_STORAGE_POSITION;
assembly {
ds.slot := position
}
address facet = ds.selectorToFacetAndPosition[msg.sig].facetAddress;
require(facet != address(0), "Diamond: Function does not exist");
assembly {
calldatacopy(0, 0, calldatasize())
let result := delegatecall(gas(), facet, 0, calldatasize(), 0, 0)
returndatacopy(0, 0, returndatasize())
switch result
case 0 {
revert(0, returndatasize())
}
default {
return(0, returndatasize())
}
}
}
receive() external payable {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamond Standard: 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;
event DiamondCut(FacetCut[] _diamondCut, address _init, bytes _calldata);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamond Standard: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
// A loupe is a small magnifying glass used to look at diamonds.
// These functions look at diamonds
interface IDiamondLoupe {
/// These functions are expected to be called frequently
/// by tools.
struct Facet {
address facetAddress;
bytes4[] functionSelectors;
}
/// @notice Gets all facet addresses and their four byte function selectors.
/// @return facets_ Facet
function facets() external view returns (Facet[] memory facets_);
/// @notice Gets all the function selectors supported by a specific facet.
/// @param _facet The facet address.
/// @return facetFunctionSelectors_
function facetFunctionSelectors(address _facet) external view returns (bytes4[] memory facetFunctionSelectors_);
/// @notice Get all the facet addresses used by a diamond.
/// @return facetAddresses_
function facetAddresses() external view returns (address[] memory facetAddresses_);
/// @notice Gets the facet that supports the given selector.
/// @dev If facet is not found return address(0).
/// @param _functionSelector The function selector.
/// @return facetAddress_ The facet address.
function facetAddress(bytes4 _functionSelector) external view returns (address facetAddress_);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
interface IERC165 {
/// @notice Query if a contract implements an interface
/// @param interfaceId The interface identifier, as specified in ERC-165
/// @dev Interface identification is specified in ERC-165. This function
/// uses less than 30,000 gas.
/// @return `true` if the contract implements `interfaceID` and
/// `interfaceID` is not 0xffffffff, `false` otherwise
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
/// @title ERC-173 Contract Ownership Standard
/// Note: the ERC-165 identifier for this interface is 0x7f5828d0
/* is ERC165 */
interface IERC173 {
/// @dev This emits when ownership of a contract changes.
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/// @notice Get the address of the owner
/// @return owner_ The address of the owner.
function owner() external view returns (address owner_);
/// @notice Set the address of the new owner of the contract
/// @dev Set _newOwner to address(0) to renounce any ownership.
/// @param _newOwner The address of the new owner of the contract
function transferOwnership(address _newOwner) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
/******************************************************************************\
* Author: Nick Mudge <[email protected]> (https://twitter.com/mudgen)
* EIP-2535 Diamond Standard: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
import "../interfaces/IDiamondCut.sol";
library LibDiamond {
bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");
struct FacetAddressAndPosition {
address facetAddress;
uint16 functionSelectorPosition; // position in facetFunctionSelectors.functionSelectors array
}
struct FacetFunctionSelectors {
bytes4[] functionSelectors;
uint16 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;
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();
// uint16 selectorCount = uint16(diamondStorage().selectors.length);
require(_facetAddress != address(0), "LibDiamondCut: Add facet can't be address(0)");
uint16 selectorPosition = uint16(ds.facetFunctionSelectors[_facetAddress].functionSelectors.length);
// add new facet address if it does not exist
if (selectorPosition == 0) {
enforceHasContractCode(_facetAddress, "LibDiamondCut: New facet has no code");
ds.facetFunctionSelectors[_facetAddress].facetAddressPosition = uint16(ds.facetAddresses.length);
ds.facetAddresses.push(_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");
ds.facetFunctionSelectors[_facetAddress].functionSelectors.push(selector);
ds.selectorToFacetAndPosition[selector].facetAddress = _facetAddress;
ds.selectorToFacetAndPosition[selector].functionSelectorPosition = selectorPosition;
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)");
uint16 selectorPosition = uint16(ds.facetFunctionSelectors[_facetAddress].functionSelectors.length);
// add new facet address if it does not exist
if (selectorPosition == 0) {
enforceHasContractCode(_facetAddress, "LibDiamondCut: New facet has no code");
ds.facetFunctionSelectors[_facetAddress].facetAddressPosition = uint16(ds.facetAddresses.length);
ds.facetAddresses.push(_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(oldFacetAddress, selector);
// add function
ds.selectorToFacetAndPosition[selector].functionSelectorPosition = selectorPosition;
ds.facetFunctionSelectors[_facetAddress].functionSelectors.push(selector);
ds.selectorToFacetAndPosition[selector].facetAddress = _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(oldFacetAddress, selector);
}
}
function removeFunction(address _facetAddress, bytes4 _selector) internal {
DiamondStorage storage ds = diamondStorage();
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 = uint16(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 = uint16(facetAddressPosition);
}
ds.facetAddresses.pop();
delete ds.facetFunctionSelectors[_facetAddress].facetAddressPosition;
}
}
function initializeDiamondCut(address _init, bytes memory _calldata) internal {
if (_init == address(0)) {
require(_calldata.length == 0, "LibDiamondCut: _init is address(0) but_calldata is not empty");
} else {
require(_calldata.length > 0, "LibDiamondCut: _calldata is empty but _init is not address(0)");
if (_init != address(this)) {
enforceHasContractCode(_init, "LibDiamondCut: _init address has no code");
}
(bool success, bytes memory error) = _init.delegatecall(_calldata);
if (!success) {
if (error.length > 0) {
// bubble up the error
revert(string(error));
} else {
revert("LibDiamondCut: _init function reverted");
}
}
}
}
function enforceHasContractCode(address _contract, string memory _errorMessage) internal view {
uint256 contractSize;
assembly {
contractSize := extcodesize(_contract)
}
require(contractSize > 0, _errorMessage);
}
}