Added command "flipper-pkg checksum"

Summary: Changelog: Added command `flipper-pkg checksum` for computing the total checksum of all the files included into plugin package.

Reviewed By: passy

Differential Revision: D22255125

fbshipit-source-id: a4f91370b4ab16ea4ce4a60e29f9d20fdd5f4331

desktop/pkg/src/utils/computePackageChecksum.ts

@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import packlist from 'npm-packlist';
+import path from 'path';
+import crypto from 'crypto';
+import fs from 'fs-extra';
+
+export default async function computePackageChecksum(
+  dir: string,
+): Promise<string> {
+  const hash = crypto.createHash('sha1');
+  hash.setEncoding('hex');
+  const files = (await packlist({path: dir})).sort();
+  for (const file of files) {
+    // add hash of relative file path
+    hash.write(process.platform === 'win32' ? file.replace(/\\/g, '/') : file);
+
+    const filePath = path.resolve(dir, file);
+
+    if (file === 'package.json') {
+      // add hash of package.json with version set to "0.0.0" to avoid changing hash when only version changed
+      const packageJson = await fs.readJson(filePath);
+      if (packageJson.version) {
+        packageJson.version = '0.0.0';
+      }
+      hash.write(JSON.stringify(packageJson));
+    } else {
+      // add hash of file content
+      const stream = fs.createReadStream(filePath);
+      try {
+        stream.pipe(hash, {end: false});
+        await new Promise((resolve, reject) => {
+          stream.once('end', resolve);
+          stream.once('error', reject);
+        });
+      } finally {
+        stream.close();
+      }
+    }
+  }
+  hash.end();
+  return hash.read();
+}