Contract Source Code:
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.19;
/******************************************************************************\
* 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 "./shared/libraries/LibDiamond.sol";
import {IDiamondCut} from "./shared/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.
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 = address(bytes20(ds.facets[msg.sig]));
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: Apache-2.0
pragma solidity 0.8.19;
/******************************************************************************\
* 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;
event DiamondCut(FacetCut[] _diamondCut, address _init, bytes _calldata);
}
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.19;
/******************************************************************************\
* 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 constant DIAMOND_STORAGE_POSITION =
keccak256("diamond.standard.diamond.storage");
struct DiamondStorage {
// maps function selectors to the facets that execute the functions.
// and maps the selectors to their position in the selectorSlots array.
// func selector => address facet, selector position
mapping(bytes4 => bytes32) facets;
// array of slots of function selectors.
// each slot holds 8 function selectors.
mapping(uint256 => bytes32) selectorSlots;
// The number of function selectors in selectorSlots
uint16 selectorCount;
// 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
);
bytes32 constant CLEAR_ADDRESS_MASK =
bytes32(uint256(0xffffffffffffffffffffffff));
bytes32 constant CLEAR_SELECTOR_MASK = bytes32(uint256(0xffffffff << 224));
// Internal function version of diamondCut
// This code is almost the same as the external diamondCut,
// except it is using 'Facet[] memory _diamondCut' instead of
// 'Facet[] calldata _diamondCut'.
// The code is duplicated to prevent copying calldata to memory which
// causes an error for a two dimensional array.
function diamondCut(
IDiamondCut.FacetCut[] memory _diamondCut,
address _init,
bytes memory _calldata
) internal {
DiamondStorage storage ds = diamondStorage();
uint256 originalSelectorCount = ds.selectorCount;
uint256 selectorCount = originalSelectorCount;
bytes32 selectorSlot;
// Check if last selector slot is not full
// "selectorCount & 7" is a gas efficient modulo by eight "selectorCount % 8"
if (selectorCount & 7 > 0) {
// get last selectorSlot
// "selectorSlot >> 3" is a gas efficient division by 8 "selectorSlot / 8"
selectorSlot = ds.selectorSlots[selectorCount >> 3];
}
// loop through diamond cut
for (uint256 facetIndex; facetIndex < _diamondCut.length; ) {
(selectorCount, selectorSlot) = addReplaceRemoveFacetSelectors(
selectorCount,
selectorSlot,
_diamondCut[facetIndex].facetAddress,
_diamondCut[facetIndex].action,
_diamondCut[facetIndex].functionSelectors
);
unchecked {
facetIndex++;
}
}
if (selectorCount != originalSelectorCount) {
ds.selectorCount = uint16(selectorCount);
}
// If last selector slot is not full
// "selectorCount & 7" is a gas efficient modulo by eight "selectorCount % 8"
if (selectorCount & 7 > 0) {
// "selectorSlot >> 3" is a gas efficient division by 8 "selectorSlot / 8"
ds.selectorSlots[selectorCount >> 3] = selectorSlot;
}
emit DiamondCut(_diamondCut, _init, _calldata);
initializeDiamondCut(_init, _calldata);
}
function addReplaceRemoveFacetSelectors(
uint256 _selectorCount,
bytes32 _selectorSlot,
address _newFacetAddress,
IDiamondCut.FacetCutAction _action,
bytes4[] memory _selectors
) internal returns (uint256, bytes32) {
DiamondStorage storage ds = diamondStorage();
require(
_selectors.length > 0,
"LibDiamondCut: No selectors in facet to cut"
);
if (_action == IDiamondCut.FacetCutAction.Add) {
enforceHasContractCode(
_newFacetAddress,
"LibDiamondCut: Add facet has no code"
);
for (uint256 selectorIndex; selectorIndex < _selectors.length; ) {
bytes4 selector = _selectors[selectorIndex];
bytes32 oldFacet = ds.facets[selector];
require(
address(bytes20(oldFacet)) == address(0),
"LibDiamondCut: Can't add function that already exists"
);
// add facet for selector
ds.facets[selector] =
bytes20(_newFacetAddress) |
bytes32(_selectorCount);
// "_selectorCount & 7" is a gas efficient modulo by eight "_selectorCount % 8"
// " << 5 is the same as multiplying by 32 ( * 32)
uint256 selectorInSlotPosition = (_selectorCount & 7) << 5;
// clear selector position in slot and add selector
_selectorSlot =
(_selectorSlot &
~(CLEAR_SELECTOR_MASK >> selectorInSlotPosition)) |
(bytes32(selector) >> selectorInSlotPosition);
// if slot is full then write it to storage
if (selectorInSlotPosition == 224) {
// "_selectorSlot >> 3" is a gas efficient division by 8 "_selectorSlot / 8"
ds.selectorSlots[_selectorCount >> 3] = _selectorSlot;
_selectorSlot = 0;
}
_selectorCount++;
unchecked {
selectorIndex++;
}
}
} else if (_action == IDiamondCut.FacetCutAction.Replace) {
enforceHasContractCode(
_newFacetAddress,
"LibDiamondCut: Replace facet has no code"
);
for (uint256 selectorIndex; selectorIndex < _selectors.length; ) {
bytes4 selector = _selectors[selectorIndex];
bytes32 oldFacet = ds.facets[selector];
address oldFacetAddress = address(bytes20(oldFacet));
// only useful if immutable functions exist
require(
oldFacetAddress != address(this),
"LibDiamondCut: Can't replace immutable function"
);
require(
oldFacetAddress != _newFacetAddress,
"LibDiamondCut: Can't replace function with same function"
);
require(
oldFacetAddress != address(0),
"LibDiamondCut: Can't replace function that doesn't exist"
);
// replace old facet address
ds.facets[selector] =
(oldFacet & CLEAR_ADDRESS_MASK) |
bytes20(_newFacetAddress);
unchecked {
selectorIndex++;
}
}
} else if (_action == IDiamondCut.FacetCutAction.Remove) {
require(
_newFacetAddress == address(0),
"LibDiamondCut: Remove facet address must be address(0)"
);
// "_selectorCount >> 3" is a gas efficient division by 8 "_selectorCount / 8"
uint256 selectorSlotCount = _selectorCount >> 3;
// "_selectorCount & 7" is a gas efficient modulo by eight "_selectorCount % 8"
uint256 selectorInSlotIndex = _selectorCount & 7;
for (uint256 selectorIndex; selectorIndex < _selectors.length; ) {
if (_selectorSlot == 0) {
// get last selectorSlot
selectorSlotCount--;
_selectorSlot = ds.selectorSlots[selectorSlotCount];
selectorInSlotIndex = 7;
} else {
selectorInSlotIndex--;
}
bytes4 lastSelector;
uint256 oldSelectorsSlotCount;
uint256 oldSelectorInSlotPosition;
// adding a block here prevents stack too deep error
{
bytes4 selector = _selectors[selectorIndex];
bytes32 oldFacet = ds.facets[selector];
require(
address(bytes20(oldFacet)) != address(0),
"LibDiamondCut: Can't remove function that doesn't exist"
);
// only useful if immutable functions exist
require(
address(bytes20(oldFacet)) != address(this),
"LibDiamondCut: Can't remove immutable function"
);
// replace selector with last selector in ds.facets
// gets the last selector
// " << 5 is the same as multiplying by 32 ( * 32)
lastSelector = bytes4(
_selectorSlot << (selectorInSlotIndex << 5)
);
if (lastSelector != selector) {
// update last selector slot position info
ds.facets[lastSelector] =
(oldFacet & CLEAR_ADDRESS_MASK) |
bytes20(ds.facets[lastSelector]);
}
delete ds.facets[selector];
uint256 oldSelectorCount = uint16(uint256(oldFacet));
// "oldSelectorCount >> 3" is a gas efficient division by 8 "oldSelectorCount / 8"
oldSelectorsSlotCount = oldSelectorCount >> 3;
// "oldSelectorCount & 7" is a gas efficient modulo by eight "oldSelectorCount % 8"
// " << 5 is the same as multiplying by 32 ( * 32)
oldSelectorInSlotPosition = (oldSelectorCount & 7) << 5;
}
if (oldSelectorsSlotCount != selectorSlotCount) {
bytes32 oldSelectorSlot = ds.selectorSlots[
oldSelectorsSlotCount
];
// clears the selector we are deleting and puts the last selector in its place.
oldSelectorSlot =
(oldSelectorSlot &
~(CLEAR_SELECTOR_MASK >>
oldSelectorInSlotPosition)) |
(bytes32(lastSelector) >> oldSelectorInSlotPosition);
// update storage with the modified slot
ds.selectorSlots[oldSelectorsSlotCount] = oldSelectorSlot;
} else {
// clears the selector we are deleting and puts the last selector in its place.
_selectorSlot =
(_selectorSlot &
~(CLEAR_SELECTOR_MASK >>
oldSelectorInSlotPosition)) |
(bytes32(lastSelector) >> oldSelectorInSlotPosition);
}
if (selectorInSlotIndex == 0) {
delete ds.selectorSlots[selectorSlotCount];
_selectorSlot = 0;
}
unchecked {
selectorIndex++;
}
}
_selectorCount = selectorSlotCount * 8 + selectorInSlotIndex;
} else {
revert("LibDiamondCut: Incorrect FacetCutAction");
}
return (_selectorCount, _selectorSlot);
}
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);
}
}