Add getCacheKey() to the open source transformer

Reviewed By: davidaurelio

Differential Revision: D4965737

fbshipit-source-id: a343d0cd2e8832567e4e2eed1e2ac0b1657d91a0

packages/metro-bundler/src/Bundler/index.js

@@ -193,8 +193,8 @@ class Bundler {
     /* $FlowFixMe: in practice it's always here. */
     this._transformer = new Transformer(opts.transformModulePath, maxWorkerCount);
 
-    const getTransformCacheKey = (src, filename, options) => {
-      return transformCacheKey + getCacheKey(src, filename, options);
+    const getTransformCacheKey = (options) => {
+      return transformCacheKey + getCacheKey(options);
     };
 
     this._resolverPromise = Resolver.load({

packages/metro-bundler/src/lib/GlobalTransformCache.js

@@ -229,7 +229,7 @@ class URIBasedGlobalTransformCache {
     const hash = crypto.createHash('sha1');
     const {sourceCode, filePath, transformOptions} = props;
     hash.update(this._optionsHasher.getTransformWorkerOptionsDigest(transformOptions));
-    const cacheKey = props.getTransformCacheKey(sourceCode, filePath, transformOptions);
+    const cacheKey = props.getTransformCacheKey(transformOptions);
     hash.update(JSON.stringify(cacheKey));
     hash.update(crypto.createHash('sha1').update(sourceCode).digest('hex'));
     const digest = hash.digest('hex');

packages/metro-bundler/src/lib/TransformCache.js

@@ -25,7 +25,7 @@ import type {MappingsMap} from './SourceMap';
 import type {Reporter} from './reporting';
 
 type CacheFilePaths = {transformedCode: string, metadata: string};
-export type GetTransformCacheKey = (sourceCode: string, filename: string, options: {}) => string;
+export type GetTransformCacheKey = (options: {}) => string;
 
 const CACHE_NAME = 'react-native-packager-cache';
 const CACHE_SUB_DIR = 'cache';
@@ -62,11 +62,7 @@ function hashSourceCode(props: {
   transformOptionsKey: string,
 }): string {
   return crypto.createHash('sha1')
-    .update(props.getTransformCacheKey(
-      props.sourceCode,
-      props.filePath,
-      props.transformOptions,
-    ))
+    .update(props.getTransformCacheKey(props.transformOptions))
     .update(props.sourceCode)
     .digest('hex');
 }

packages/metro-bundler/transformer.js

@@ -11,6 +11,7 @@
 'use strict';
 
 const babel = require('babel-core');
+const crypto = require('crypto');
 const externalHelpersPlugin = require('babel-plugin-external-helpers');
 const fs = require('fs');
 const generate = require('babel-generator').default;
@@ -22,6 +23,13 @@ const resolvePlugins = require('babel-preset-react-native/lib/resolvePlugins');
 
 const {compactMapping} = require('./src/Bundler/source-map');
 
+const cacheKeyParts = [
+  fs.readFileSync(__filename),
+  require('babel-plugin-external-helpers/package.json').version,
+  require('babel-preset-fbjs/package.json').version,
+  require('babel-preset-react-native/package.json').version,
+];
+
 /**
  * Return a memoized function that checks for the existence of a
  * project level .babelrc file, and if it doesn't exist, reads the
@@ -126,4 +134,13 @@ function transform(src, filename, options) {
   }
 }
 
-module.exports.transform = transform;
+function getCacheKey(options) {
+  var key = crypto.createHash('md5');
+  cacheKeyParts.forEach(part => key.update(part));
+  return key.digest('hex');
+}
+
+module.exports = {
+  transform,
+  getCacheKey,
+};