feat: save the original shasum of each package in the store

Rel #585

package.json

@@ -34,6 +34,7 @@
     "common-tags": "1.4.0",
     "cross-spawn": "^5.0.0",
     "delocalize-dependencies": "0.1.0",
+    "dirsum": "0.1.1",
     "execa": "0.6.0",
     "exists-file": "3.0.0",
     "find-up": "2.1.0",

src/fs/dirsum.ts

@@ -0,0 +1,10 @@
+import dirsum = require('dirsum')
+
+export default function (dirpath: string): Promise<string> {
+  return new Promise((resolve, reject) => {
+    dirsum.digest(dirpath, 'sha1', (err: Error, hashes: {hash: string}) => {
+      if (err) return reject(err)
+      resolve(hashes.hash)
+    })
+  })
+}

src/install/fetch.ts

@@ -16,6 +16,7 @@ import {InstallContext} from '../api/install'
 import fetchResolution from './fetchResolution'
 import logStatus from '../logging/logInstallStatus'
 import {PackageMeta} from '../resolve/utils/loadPackageMeta'
+import dirsum from '../fs/dirsum'
 
 export type FetchOptions = {
   keypath?: string[],
@@ -198,7 +199,21 @@ function fetchToStoreCached (opts: FetchToStoreOptions): Promise<void> {
       // fs.rename(oldPath, newPath) is an atomic operation, so we do it at the
       // end
       await fs.rename(targetStage, target)
+
+      createShasum(target)
     }
     const pkg = await requireJson(path.join(target, 'package.json'))
   })
 }
+
+async function createShasum(dirPath: string) {
+  try {
+    const shasum = await dirsum(dirPath)
+    await fs.writeFile(`${dirPath}_shasum`, shasum, 'utf8')
+  } catch (err) {
+    logger.error({
+      message: `Failed to calculate shasum for ${dirPath}`,
+      err,
+    })
+  }
+}

typings/local.d.ts

@@ -232,3 +232,8 @@ declare module 'p-limit' {
   const anything: any;
   export = anything;
 }
+
+declare module 'dirsum' {
+  const anything: any;
+  export = anything;
+}