Add actions/cache/check action

src/checkOnly.ts

@@ -0,0 +1,10 @@
+import restoreImpl from "./restoreImpl";
+import { NullStateProvider } from "./stateProvider";
+
+async function run(): Promise<void> {
+    await restoreImpl(new NullStateProvider(), { lookupOnly: true });
+}
+
+run();
+
+export default run;

src/options.ts

@@ -0,0 +1,11 @@
+/**
+ * Options to control cache restore
+ */
+export interface RestoreOptions {
+    /**
+     * Weather to skip downloading the cache entry.
+     * If lookupOnly is set to true, the restore function will only check if
+     * a matching cache entry exists.
+     */
+    lookupOnly?: boolean;
+}

src/restoreImpl.ts

@@ -2,11 +2,13 @@ import * as cache from "@actions/cache";
 import * as core from "@actions/core";
 
 import { Events, Inputs, Outputs, State } from "./constants";
+import { RestoreOptions } from "./options";
 import { IStateProvider } from "./stateProvider";
 import * as utils from "./utils/actionUtils";
 
 async function restoreImpl(
-    stateProvider: IStateProvider
+    stateProvider: IStateProvider,
+    restoreOptions?: RestoreOptions
 ): Promise<string | undefined> {
     try {
         if (!utils.isCacheFeatureAvailable()) {
@@ -40,7 +42,7 @@ async function restoreImpl(
             cachePaths,
             primaryKey,
             restoreKeys,
-            {},
+            { lookupOnly: restoreOptions?.lookupOnly },
             enableCrossOsArchive
         );