From 8b6d69b645d87302ce47dd76ad0be8905e1525b2 Mon Sep 17 00:00:00 2001
From: Rafael Oleza <rafeca@fb.com>
Date: Tue, 5 Sep 2017 07:10:40 -0700
Subject: [PATCH] Return the inverseDependencies from the Delta Bundler to
 support HMR

Reviewed By: jeanlauliac

Differential Revision: D5763905

fbshipit-source-id: 6b95c8dfded5fc30ec2e7a558ab25550d9a1c333
---
 .../src/DeltaBundler/DeltaTransformer.js      | 58 +++++++++++++++----
 .../metro-bundler/src/DeltaBundler/index.js   | 16 ++++-
 packages/metro-bundler/src/Server/index.js    | 14 +++--
 3 files changed, 67 insertions(+), 21 deletions(-)

diff --git a/packages/metro-bundler/src/DeltaBundler/DeltaTransformer.js b/packages/metro-bundler/src/DeltaBundler/DeltaTransformer.js
index 33315e10..d2836de2 100644
--- a/packages/metro-bundler/src/DeltaBundler/DeltaTransformer.js
+++ b/packages/metro-bundler/src/DeltaBundler/DeltaTransformer.js
@@ -17,14 +17,15 @@ const DeltaCalculator = require('./DeltaCalculator');
 import type Bundler from '../Bundler';
 import type {Options as JSTransformerOptions} from '../JSTransformer/worker';
 import type Resolver from '../Resolver';
-import type {BundleOptions} from '../Server';
 import type {MappingsMap} from '../lib/SourceMap';
 import type Module from '../node-haste/Module';
+import type {Options as BundleOptions} from './';
 
 export type DeltaTransformResponse = {
   +pre: ?string,
   +post: ?string,
   +delta: {[key: string]: ?string},
+  +inverseDependencies: {[key: string]: $ReadOnlyArray<string>},
 };
 
 type Options = {|
@@ -159,10 +160,16 @@ class DeltaTransformer {
         )
       : null;
 
+    // Inverse dependencies are needed for HMR.
+    const inverseDependencies = this._getInverseDependencies(
+      this._deltaCalculator.getInverseDependencies(),
+    );
+
     return {
       pre: prependSources,
       post: appendSources,
       delta: {...modifiedDelta, ...deletedDelta},
+      inverseDependencies,
       reset,
     };
   }
@@ -237,6 +244,23 @@ class DeltaTransformer {
     return sources.join('\n');
   }
 
+  /**
+   * Converts the paths in the inverse dependendencies to module ids.
+   */
+  _getInverseDependencies(
+    inverseDependencies: Map<string, Set<string>>,
+  ): {[key: string]: $ReadOnlyArray<string>} {
+    const output = Object.create(null);
+
+    for (const [key, dependencies] of inverseDependencies) {
+      output[this._getModuleId({path: key})] = Array.from(
+        dependencies,
+      ).map(dep => this._getModuleId({path: dep}));
+    }
+
+    return output;
+  }
+
   async _transformModules(
     modules: Map<string, Module>,
     resolver: Resolver,
@@ -275,17 +299,27 @@ class DeltaTransformer {
 
     const dependencyPairsForModule = dependencyPairs.get(module.path) || [];
 
-    const wrapped = await resolver.wrapModule({
-      module,
-      getModuleId: this._getModuleId,
-      dependencyPairs: dependencyPairsForModule,
-      dependencyOffsets: metadata.dependencyOffsets || [],
-      name,
-      code: metadata.code,
-      map: metadata.map,
-      minify: this._bundleOptions.minify,
-      dev: this._bundleOptions.dev,
-    });
+    const wrapped = this._bundleOptions.wrapModules
+      ? await resolver.wrapModule({
+          module,
+          getModuleId: this._getModuleId,
+          dependencyPairs: dependencyPairsForModule,
+          dependencyOffsets: metadata.dependencyOffsets || [],
+          name,
+          code: metadata.code,
+          map: metadata.map,
+          minify: this._bundleOptions.minify,
+          dev: this._bundleOptions.dev,
+        })
+      : {
+          code: resolver.resolveRequires(
+            module,
+            this._getModuleId,
+            metadata.code,
+            dependencyPairsForModule,
+            metadata.dependencyOffsets || [],
+          ),
+        };
 
     return [this._getModuleId(module), wrapped.code];
   }
diff --git a/packages/metro-bundler/src/DeltaBundler/index.js b/packages/metro-bundler/src/DeltaBundler/index.js
index 8aaaef83..21c06552 100644
--- a/packages/metro-bundler/src/DeltaBundler/index.js
+++ b/packages/metro-bundler/src/DeltaBundler/index.js
@@ -23,6 +23,7 @@ export type DeltaBundle = {
   pre: ?string,
   post: ?string,
   delta: {[key: string]: ?string},
+  inverseDependencies: {[key: string]: $ReadOnlyArray<string>},
 };
 
 type MainOptions = {|
@@ -30,7 +31,13 @@ type MainOptions = {|
   polyfillModuleNames: $ReadOnlyArray<string>,
 |};
 
-type Options = BundleOptions & {+deltaBundleId: ?string};
+type FullBuildOptions = BundleOptions & {
+  +deltaBundleId: ?string,
+};
+
+export type Options = FullBuildOptions & {
+  +wrapModules: boolean,
+};
 
 /**
  * `DeltaBundler` uses the `DeltaTransformer` to build bundle deltas. This
@@ -84,8 +91,11 @@ class DeltaBundler {
     };
   }
 
-  async buildFullBundle(options: Options): Promise<string> {
-    const deltaBundle = await this.build(options);
+  async buildFullBundle(options: FullBuildOptions): Promise<string> {
+    const deltaBundle = await this.build({
+      ...options,
+      wrapModules: true,
+    });
 
     let deltaPatcher = this._deltaPatchers.get(deltaBundle.id);
 
diff --git a/packages/metro-bundler/src/Server/index.js b/packages/metro-bundler/src/Server/index.js
index 6d2c1cd1..12617e5c 100644
--- a/packages/metro-bundler/src/Server/index.js
+++ b/packages/metro-bundler/src/Server/index.js
@@ -291,12 +291,10 @@ class Server {
     this._symbolicateInWorker = symbolicate.createWorker();
     this._nextBundleBuildID = 1;
 
-    if (this._opts.useDeltaBundler) {
-      this._deltaBundler = new DeltaBundler(this._bundler, {
-        getPolyfills: this._opts.getPolyfills,
-        polyfillModuleNames: this._opts.polyfillModuleNames,
-      });
-    }
+    this._deltaBundler = new DeltaBundler(this._bundler, {
+      getPolyfills: this._opts.getPolyfills,
+      polyfillModuleNames: this._opts.polyfillModuleNames,
+    });
   }
 
   end(): mixed {
@@ -315,6 +313,10 @@ class Server {
     }
   }
 
+  getDeltaBundler(): DeltaBundler {
+    return this._deltaBundler;
+  }
+
   async buildBundle(options: BundleOptions): Promise<Bundle> {
     const bundle = await this._bundler.bundle(options);
     const modules = bundle.getModules();