adds facet helpers

Author: 0xCourtney

lib/diamonds.ts

@@ -0,0 +1,98 @@
+import { Contract } from 'ethers';
+
+export interface Facet {
+  target: string;
+  selectors: string[];
+}
+
+enum FacetCutAction {
+  Add,
+  Replace,
+  Remove,
+}
+
+export interface FacetCut extends Facet {
+  action: FacetCutAction;
+}
+
+export function getContractSignatures(contract: Contract) {
+  return Object.keys(contract.interface.functions);
+}
+
+export function getContractSelectors(contract: Contract) {
+  const signatures = getContractSignatures(contract);
+  const selectors = signatures.reduce((acc: string[], val: string) => {
+    acc.push(contract.interface.getSighash(val));
+    return acc;
+  }, []);
+
+  return selectors;
+}
+
+export function selectorExistsInFacet(selector: string, facets: Facet[]) {
+  for (const facet of facets) {
+    if (facet.selectors.includes(selector)) return true;
+  }
+
+  return false;
+}
+
+export function printFacetCuts(
+  target: string,
+  selectors: string[],
+  action: number = 0,
+) {
+  return {
+    target: target,
+    action: action,
+    selectors: selectors,
+  };
+}
+
+// attempts to add a selector, if selector already exists, function will throw
+export async function insertUnregisteredSelector(
+  diamond: Contract,
+  facets: Contract[],
+) {}
+
+// adds selectors, if selector already exists function will update with new address
+export async function upsertSelectors(diamond: Contract, facets: Contract[]) {}
+
+// removes registered selectors if they are not present in the contracts
+export async function removeRegisteredSelectors(
+  diamond: Contract,
+  contracts: Contract[],
+) {
+  const registeredFacets: Facet[] = await diamond.facets();
+
+  let facets: Facet[] = [];
+  contracts.forEach((contract) => {
+    facets.push({
+      target: contract.address,
+      selectors: getContractSelectors(contract),
+    });
+  });
+
+  let facetCuts: FacetCut[] = [];
+  // if registered selector is not found in the contracts then it should be removed from the diamond
+  registeredFacets.forEach((registeredFacet) => {
+    registeredFacet.selectors.forEach((selector) => {
+      const target = registeredFacet.target;
+      if (
+        target !== diamond.address &&
+        !selectorExistsInFacet(selector, facets)
+      ) {
+        // TODO: Group removed selectors together in a single object
+        facetCuts.push(
+          printFacetCuts(
+            registeredFacet.target,
+            [selector],
+            FacetCutAction.Remove,
+          ),
+        );
+      }
+    });
+  });
+
+  return facetCuts;
+}