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Diamond Inspect Facet

@perfect-abstractions/compose/diamond/DiamondInspectFacet.sol

It lets you inspect the diamond’s routing table and retrieve the registered facet list.

Key Features
  • Query which facet a function selector is routed to.
  • Enumerate registered facets (and their exported selectors).
  • Read the diamond’s composition from shared diamond storage (DIAMOND_STORAGE_POSITION).

Storage​

State Variables​

PropertyTypeDescriptionDIAMOND_STORAGE_POSITIONbytes32Diamond storage slot position for this module (Value: keccak256("erc8153.diamond"))

Diamond Storage​

Definition
/** storage-location: erc8042:erc8153.diamond */
struct DiamondStorage {
  mapping(bytes4 functionSelector => FacetNode) facetNodes;
  FacetList facetList;
}

struct FacetList {
  bytes4 headFacetNodeId;
  bytes4 tailFacetNodeId;
  uint32 facetCount;
  uint32 selectorCount;
}

struct FacetNode {
  address facet;
  bytes4 prevFacetNodeId;
  bytes4 nextFacetNodeId;
}

Facet​

Used as a return type for the facets function.

Definition
struct Facet {
  address facet;
  bytes4[] functionSelectors;
}

Functions​

facetAddress​

Gets the facet address that handles the given selector. If facet is not found, return address(0).

function facetAddress(bytes4 _functionSelector) external view returns (address facet);

Parameters:

PropertyTypeDescription_functionSelectorbytes4The function selector to lookup

Returns:

PropertyTypeDescriptionfacetaddressThe facet address that handles the given selector. (If not found return address(0))

facetFunctionSelectors​

Gets the function selectors exported by the given facet and returns them as bytes4[].

function facetFunctionSelectors(address _facet) external view returns (bytes4[] memory facetSelectors);

Parameters:

PropertyTypeDescription_facetaddressFacet contract address. Must implement exportSelectors()</b> (packed bytes4 selectors).

Returns:

PropertyTypeDescriptionfacetSelectorsbytes4[]Unpacked selectors returned by facet.exportSelectors(), or an empty array if the facet is not registered.

facetAddresses​

Gets the facet addresses used by the diamond.

If no facets are registered, this returns an empty array.

function facetAddresses() external view returns (address[] memory allFacets);

Returns:

PropertyTypeDescriptionallFacetsaddress[]Facet addresses in the diamond's internal traversal order.

facets​

Returns the facet address and function selectors of all facets in the diamond.

function facets() external view returns (Facet[] memory facetsAndSelectors);

Returns:

PropertyTypeDescriptionfacetsAndSelectorsFacet[]An array of Facet structs containing each facet address and its function selectors.

Selector Packing Notes (exportSelectors())​

exportSelectors() returns a packed bytes blob where each bytes4 selector is encoded into 4 consecutive bytes (a bytes.concat(sel1, sel2, ...) style packing).

DiamondInspectFacet follows that convention:

Best Practices​

Security Considerations​

Most functions are view/pure and do not mutate state.

However, facetFunctionSelectors() and facets() perform external calls to IFacet(facet).exportSelectors().

If the provided address is not a valid IFacet implementation (or if exportSelectors() reverts / returns unexpected data), these calls can revert.

That being said, always make sure to provide verified and trusted facet addresses.
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