Contract Address Details

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

// The functions in DiamondLoupeFacet MUST be added to a diamond.
// The EIP-2535 Diamond standard requires these functions.

import { LibDiamond } from "../libraries/LibDiamond.sol";
import { IDiamondLoupe } from "../interfaces/IDiamondLoupe.sol";
import { IERC165 } from "../interfaces/IERC165.sol";

contract DiamondLoupeFacet is IDiamondLoupe, IERC165 {
    // Diamond Loupe Functions
    ////////////////////////////////////////////////////////////////////
    /// These functions are expected to be called frequently by tools.
    //
    // struct Facet {
    //     address facetAddress;
    //     bytes4[] functionSelectors;
    // }
    /// @notice Gets all facets and their selectors.
    /// @return facets_ Facet
    function facets() external view override returns (Facet[] memory facets_) {
        LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
        uint256 selectorCount = ds.selectors.length;
        // create an array set to the maximum size possible
        facets_ = new Facet[](selectorCount);
        // create an array for counting the number of selectors for each facet
        uint16[] memory numFacetSelectors = new uint16[](selectorCount);
        // total number of facets
        uint256 numFacets;
        // loop through function selectors
        for (
            uint256 selectorIndex;
            selectorIndex < selectorCount;
            selectorIndex++
        ) {
            bytes4 selector = ds.selectors[selectorIndex];
            address facetAddress_ = ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress;
            bool continueLoop = false;
            // find the functionSelectors array for selector and add selector to it
            for (uint256 facetIndex; facetIndex < numFacets; facetIndex++) {
                if (facets_[facetIndex].facetAddress == facetAddress_) {
                    facets_[facetIndex].functionSelectors[
                        numFacetSelectors[facetIndex]
                    ] = selector;
                    numFacetSelectors[facetIndex]++;
                    continueLoop = true;
                    break;
                }
            }
            // if functionSelectors array exists for selector then continue loop
            if (continueLoop) {
                continueLoop = false;
                continue;
            }
            // create a new functionSelectors array for selector
            facets_[numFacets].facetAddress = facetAddress_;
            facets_[numFacets].functionSelectors = new bytes4[](selectorCount);
            facets_[numFacets].functionSelectors[0] = selector;
            numFacetSelectors[numFacets] = 1;
            numFacets++;
        }
        for (uint256 facetIndex; facetIndex < numFacets; facetIndex++) {
            uint256 numSelectors = numFacetSelectors[facetIndex];
            bytes4[] memory selectors = facets_[facetIndex].functionSelectors;
            // setting the number of selectors
            assembly {
                mstore(selectors, numSelectors)
            }
        }
        // setting the number of facets
        assembly {
            mstore(facets_, numFacets)
        }
    }

    /// @notice Gets all the function selectors supported by a specific facet.
    /// @param _facet The facet address.
    /// @return _facetFunctionSelectors The selectors associated with a facet address.
    function facetFunctionSelectors(
        address _facet
    ) external view override returns (bytes4[] memory _facetFunctionSelectors) {
        LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
        uint256 selectorCount = ds.selectors.length;
        uint256 numSelectors;
        _facetFunctionSelectors = new bytes4[](selectorCount);
        // loop through function selectors
        for (
            uint256 selectorIndex;
            selectorIndex < selectorCount;
            selectorIndex++
        ) {
            bytes4 selector = ds.selectors[selectorIndex];
            address facetAddress_ = ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress;
            if (_facet == facetAddress_) {
                _facetFunctionSelectors[numSelectors] = selector;
                numSelectors++;
            }
        }
        // Set the number of selectors in the array
        assembly {
            mstore(_facetFunctionSelectors, numSelectors)
        }
    }

    /// @notice Get all the facet addresses used by a diamond.
    /// @return facetAddresses_
    function facetAddresses()
        external
        view
        override
        returns (address[] memory facetAddresses_)
    {
        LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
        uint256 selectorCount = ds.selectors.length;
        // create an array set to the maximum size possible
        facetAddresses_ = new address[](selectorCount);
        uint256 numFacets;
        // loop through function selectors
        for (
            uint256 selectorIndex;
            selectorIndex < selectorCount;
            selectorIndex++
        ) {
            bytes4 selector = ds.selectors[selectorIndex];
            address facetAddress_ = ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress;
            bool continueLoop = false;
            // see if we have collected the address already and break out of loop if we have
            for (uint256 facetIndex; facetIndex < numFacets; facetIndex++) {
                if (facetAddress_ == facetAddresses_[facetIndex]) {
                    continueLoop = true;
                    break;
                }
            }
            // continue loop if we already have the address
            if (continueLoop) {
                continueLoop = false;
                continue;
            }
            // include address
            facetAddresses_[numFacets] = facetAddress_;
            numFacets++;
        }
        // Set the number of facet addresses in the array
        assembly {
            mstore(facetAddresses_, numFacets)
        }
    }

    /// @notice Gets the facet address 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 override returns (address facetAddress_) {
        LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
        facetAddress_ = ds
            .facetAddressAndSelectorPosition[_functionSelector]
            .facetAddress;
    }

    // This implements ERC-165.
    function supportsInterface(
        bytes4 _interfaceId
    ) external view override returns (bool) {
        LibDiamond.DiamondStorage storage ds = LibDiamond.diamondStorage();
        return ds.supportedInterfaces[_interfaceId];
    }
}
        

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

interface IDiamond {
    enum FacetCutAction {
        Add,
        Replace,
        Remove
    }
    // Add=0, Replace=1, Remove=2

    struct FacetCut {
        address facetAddress;
        FacetCutAction action;
        bytes4[] functionSelectors;
    }

    event DiamondCut(FacetCut[] _diamondCut, address _init, bytes _calldata);
}
          

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

import { IDiamond } from "./IDiamond.sol";

interface IDiamondCut is IDiamond {
    /// @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 ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: 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 ^0.8.0;

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 ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
import { IDiamond } from "../interfaces/IDiamond.sol";
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 NoSelectorsGivenToAdd();
error NotContractOwner(address _user, address _contractOwner);
error NoSelectorsProvidedForFacetForCut(address _facetAddress);
error CannotAddSelectorsToZeroAddress(bytes4[] _selectors);
error NoBytecodeAtAddress(address _contractAddress, string _message);
error IncorrectFacetCutAction(uint8 _action);
error CannotAddFunctionToDiamondThatAlreadyExists(bytes4 _selector);
error CannotReplaceFunctionsFromFacetWithZeroAddress(bytes4[] _selectors);
error CannotReplaceImmutableFunction(bytes4 _selector);
error CannotReplaceFunctionWithTheSameFunctionFromTheSameFacet(
    bytes4 _selector
);
error CannotReplaceFunctionThatDoesNotExists(bytes4 _selector);
error RemoveFacetAddressMustBeZeroAddress(address _facetAddress);
error CannotRemoveFunctionThatDoesNotExist(bytes4 _selector);
error CannotRemoveImmutableFunction(bytes4 _selector);
error InitializationFunctionReverted(
    address _initializationContractAddress,
    bytes _calldata
);

library LibDiamond {
    bytes32 constant DIAMOND_STORAGE_POSITION =
        keccak256("diamond.standard.diamond.storage");

    struct FacetAddressAndSelectorPosition {
        address facetAddress;
        uint16 selectorPosition;
    }

    struct DiamondStorage {
        // function selector => facet address and selector position in selectors array
        mapping(bytes4 => FacetAddressAndSelectorPosition) facetAddressAndSelectorPosition;
        bytes4[] selectors;
        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 {
        if (msg.sender != diamondStorage().contractOwner) {
            revert NotContractOwner(msg.sender, diamondStorage().contractOwner);
        }
    }

    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++
        ) {
            bytes4[] memory functionSelectors = _diamondCut[facetIndex]
                .functionSelectors;
            address facetAddress = _diamondCut[facetIndex].facetAddress;
            if (functionSelectors.length == 0) {
                revert NoSelectorsProvidedForFacetForCut(facetAddress);
            }
            IDiamondCut.FacetCutAction action = _diamondCut[facetIndex].action;
            if (action == IDiamond.FacetCutAction.Add) {
                addFunctions(facetAddress, functionSelectors);
            } else if (action == IDiamond.FacetCutAction.Replace) {
                replaceFunctions(facetAddress, functionSelectors);
            } else if (action == IDiamond.FacetCutAction.Remove) {
                removeFunctions(facetAddress, functionSelectors);
            } else {
                revert IncorrectFacetCutAction(uint8(action));
            }
        }
        emit DiamondCut(_diamondCut, _init, _calldata);
        initializeDiamondCut(_init, _calldata);
    }

    function addFunctions(
        address _facetAddress,
        bytes4[] memory _functionSelectors
    ) internal {
        if (_facetAddress == address(0)) {
            revert CannotAddSelectorsToZeroAddress(_functionSelectors);
        }
        DiamondStorage storage ds = diamondStorage();
        uint16 selectorCount = uint16(ds.selectors.length);
        enforceHasContractCode(
            _facetAddress,
            "LibDiamondCut: Add facet has no code"
        );
        for (
            uint256 selectorIndex;
            selectorIndex < _functionSelectors.length;
            selectorIndex++
        ) {
            bytes4 selector = _functionSelectors[selectorIndex];
            address oldFacetAddress = ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress;
            if (oldFacetAddress != address(0)) {
                revert CannotAddFunctionToDiamondThatAlreadyExists(selector);
            }
            ds.facetAddressAndSelectorPosition[
                selector
            ] = FacetAddressAndSelectorPosition(_facetAddress, selectorCount);
            ds.selectors.push(selector);
            selectorCount++;
        }
    }

    function replaceFunctions(
        address _facetAddress,
        bytes4[] memory _functionSelectors
    ) internal {
        DiamondStorage storage ds = diamondStorage();
        if (_facetAddress == address(0)) {
            revert CannotReplaceFunctionsFromFacetWithZeroAddress(
                _functionSelectors
            );
        }
        enforceHasContractCode(
            _facetAddress,
            "LibDiamondCut: Replace facet has no code"
        );
        for (
            uint256 selectorIndex;
            selectorIndex < _functionSelectors.length;
            selectorIndex++
        ) {
            bytes4 selector = _functionSelectors[selectorIndex];
            address oldFacetAddress = ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress;
            // can't replace immutable functions -- functions defined directly in the diamond in this case
            if (oldFacetAddress == address(this)) {
                revert CannotReplaceImmutableFunction(selector);
            }
            if (oldFacetAddress == _facetAddress) {
                revert CannotReplaceFunctionWithTheSameFunctionFromTheSameFacet(
                    selector
                );
            }
            if (oldFacetAddress == address(0)) {
                revert CannotReplaceFunctionThatDoesNotExists(selector);
            }
            // replace old facet address
            ds
                .facetAddressAndSelectorPosition[selector]
                .facetAddress = _facetAddress;
        }
    }

    function removeFunctions(
        address _facetAddress,
        bytes4[] memory _functionSelectors
    ) internal {
        DiamondStorage storage ds = diamondStorage();
        uint256 selectorCount = ds.selectors.length;
        if (_facetAddress != address(0)) {
            revert RemoveFacetAddressMustBeZeroAddress(_facetAddress);
        }
        for (
            uint256 selectorIndex;
            selectorIndex < _functionSelectors.length;
            selectorIndex++
        ) {
            bytes4 selector = _functionSelectors[selectorIndex];
            FacetAddressAndSelectorPosition
                memory oldFacetAddressAndSelectorPosition = ds
                    .facetAddressAndSelectorPosition[selector];
            if (oldFacetAddressAndSelectorPosition.facetAddress == address(0)) {
                revert CannotRemoveFunctionThatDoesNotExist(selector);
            }

            // can't remove immutable functions -- functions defined directly in the diamond
            if (
                oldFacetAddressAndSelectorPosition.facetAddress == address(this)
            ) {
                revert CannotRemoveImmutableFunction(selector);
            }
            // replace selector with last selector
            selectorCount--;
            if (
                oldFacetAddressAndSelectorPosition.selectorPosition !=
                selectorCount
            ) {
                bytes4 lastSelector = ds.selectors[selectorCount];
                ds.selectors[
                    oldFacetAddressAndSelectorPosition.selectorPosition
                ] = lastSelector;
                ds
                    .facetAddressAndSelectorPosition[lastSelector]
                    .selectorPosition = oldFacetAddressAndSelectorPosition
                    .selectorPosition;
            }
            // delete last selector
            ds.selectors.pop();
            delete ds.facetAddressAndSelectorPosition[selector];
        }
    }

    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)
        }
        if (contractSize == 0) {
            revert NoBytecodeAtAddress(_contract, _errorMessage);
        }
    }
}