Implementation of python's caching (#266)

src/cache-distributions/cache-distributor.ts

@@ -0,0 +1,53 @@
+import * as cache from '@actions/cache';
+import * as core from '@actions/core';
+
+export enum State {
+  STATE_CACHE_PRIMARY_KEY = 'cache-primary-key',
+  CACHE_MATCHED_KEY = 'cache-matched-key',
+  CACHE_PATHS = 'cache-paths'
+}
+
+abstract class CacheDistributor {
+  protected CACHE_KEY_PREFIX = 'setup-python';
+  constructor(
+    protected packageManager: string,
+    protected cacheDependencyPath: string
+  ) {}
+
+  protected abstract getCacheGlobalDirectories(): Promise<string[]>;
+  protected abstract computeKeys(): Promise<{
+    primaryKey: string;
+    restoreKey: string[] | undefined;
+  }>;
+
+  public async restoreCache() {
+    const {primaryKey, restoreKey} = await this.computeKeys();
+    if (primaryKey.endsWith('-')) {
+      throw new Error(
+        `No file in ${process.cwd()} matched to [${this.cacheDependencyPath
+          .split('\n')
+          .join(',')}], make sure you have checked out the target repository`
+      );
+    }
+
+    const cachePath = await this.getCacheGlobalDirectories();
+
+    core.saveState(State.CACHE_PATHS, cachePath);
+    core.saveState(State.STATE_CACHE_PRIMARY_KEY, primaryKey);
+
+    const matchedKey = await cache.restoreCache(
+      cachePath,
+      primaryKey,
+      restoreKey
+    );
+
+    if (matchedKey) {
+      core.saveState(State.CACHE_MATCHED_KEY, matchedKey);
+      core.info(`Cache restored from key: ${matchedKey}`);
+    } else {
+      core.info(`${this.packageManager} cache is not found`);
+    }
+  }
+}
+
+export default CacheDistributor;