From 2da9c66c78f6f13927bb8823fe666ef00ba01168 Mon Sep 17 00:00:00 2001
From: David Aurelio <davidaurelio@fb.com>
Date: Fri, 28 Apr 2017 12:25:44 -0700
Subject: [PATCH] Unify source map types

Summary: deduplicates / unifies types for source maps across the code base

Reviewed By: jeanlauliac

Differential Revision: D4955924

fbshipit-source-id: 25cb71031dce835dd7d2bc1c27d6b20050906e81
---
 packages/metro-bundler/src/Bundler/Bundle.js  | 23 ++++++------
 .../src/Bundler/source-map/Generator.js       |  6 +--
 .../metro-bundler/src/JSTransformer/index.js  |  6 +--
 .../JSTransformer/worker/constant-folding.js  |  4 +-
 .../src/JSTransformer/worker/inline.js        |  6 +--
 .../src/JSTransformer/worker/worker.js        |  6 +--
 .../src/ModuleGraph/output/source-map.js      | 30 ++-------------
 .../src/ModuleGraph/types.flow.js             |  6 +--
 packages/metro-bundler/src/Resolver/index.js  | 12 +++---
 .../src/Server/symbolicate/symbolicate.js     |  2 +-
 .../metro-bundler/src/lib/ModuleTransport.js  |  4 +-
 packages/metro-bundler/src/lib/SourceMap.js   | 37 +++++++++++--------
 .../metro-bundler/src/lib/TransformCache.js   |  6 +--
 .../src/lib/relativizeSourceMap.js            | 10 +++--
 .../metro-bundler/src/node-haste/Module.js    |  4 +-
 15 files changed, 74 insertions(+), 88 deletions(-)

diff --git a/packages/metro-bundler/src/Bundler/Bundle.js b/packages/metro-bundler/src/Bundler/Bundle.js
index 582853ec..45d130e7 100644
--- a/packages/metro-bundler/src/Bundler/Bundle.js
+++ b/packages/metro-bundler/src/Bundler/Bundle.js
@@ -20,8 +20,9 @@ const debug = require('debug')('RNP:Bundle');
 const invariant = require('fbjs/lib/invariant');
 
 const {fromRawMappings} = require('./source-map');
+const {isMappingsMap} = require('../lib/SourceMap');
 
-import type {SourceMap, CombinedSourceMap, MixedSourceMap} from '../lib/SourceMap';
+import type {IndexMap, MappingsMap, SourceMap} from '../lib/SourceMap';
 import type {GetSourceOptions, FinalizeOptions} from './BundleBase';
 
 export type Unbundle = {
@@ -206,7 +207,7 @@ class Bundle extends BundleBase {
    * that makes use of of the `sections` field to combine sourcemaps by adding
    * an offset. This is supported only by Chrome for now.
    */
-  _getCombinedSourceMaps(options: {excludeSource?: boolean}): CombinedSourceMap {
+  _getCombinedSourceMaps(options: {excludeSource?: boolean}): IndexMap {
     const result = {
       version: 3,
       file: this._getSourceMapFile(),
@@ -215,22 +216,22 @@ class Bundle extends BundleBase {
 
     let line = 0;
     this.getModules().forEach(module => {
-      let map = module.map == null || module.virtual
+      invariant(
+        !Array.isArray(module.map),
+        `Unexpected raw mappings for ${module.sourcePath}`,
+      );
+      let map: SourceMap = module.map == null || module.virtual
         ? generateSourceMapForVirtualModule(module)
         : module.map;
 
-      invariant(
-        !Array.isArray(map),
-        `Unexpected raw mappings for ${module.sourcePath}`,
-      );
 
-      if (options.excludeSource && 'sourcesContent' in map) {
+      if (options.excludeSource && isMappingsMap(map)) {
         map = {...map, sourcesContent: []};
       }
 
       result.sections.push({
         offset: {line, column: 0},
-        map: (map: MixedSourceMap),
+        map: map,
       });
       line += module.code.split('\n').length;
     });
@@ -238,7 +239,7 @@ class Bundle extends BundleBase {
     return result;
   }
 
-  getSourceMap(options: {excludeSource?: boolean}): MixedSourceMap {
+  getSourceMap(options: {excludeSource?: boolean}): SourceMap {
     this.assertFinalized();
 
     return this._sourceMapFormat === 'indexed'
@@ -314,7 +315,7 @@ class Bundle extends BundleBase {
   }
 }
 
-function generateSourceMapForVirtualModule(module): SourceMap {
+function generateSourceMapForVirtualModule(module): MappingsMap {
   // All lines map 1-to-1
   let mappings = 'AAAA;';
 
diff --git a/packages/metro-bundler/src/Bundler/source-map/Generator.js b/packages/metro-bundler/src/Bundler/source-map/Generator.js
index 35427c8b..cce6a1d2 100644
--- a/packages/metro-bundler/src/Bundler/source-map/Generator.js
+++ b/packages/metro-bundler/src/Bundler/source-map/Generator.js
@@ -13,7 +13,7 @@
 
 const B64Builder = require('./B64Builder');
 
-import type {SourceMap} from 'babel-core';
+import type {MappingsMap} from '../../lib/SourceMap';
 
 /**
  * Generates a source map from raw mappings.
@@ -39,7 +39,7 @@ class Generator {
   names: IndexedSet;
   source: number;
   sources: Array<string>;
-  sourcesContent: Array<string>;
+  sourcesContent: Array<?string>;
 
   constructor() {
     this.builder = new B64Builder();
@@ -141,7 +141,7 @@ class Generator {
   /**
    * Return the source map as object.
    */
-  toMap(file?: string): SourceMap {
+  toMap(file?: string): MappingsMap {
     return {
       version: 3,
       file,
diff --git a/packages/metro-bundler/src/JSTransformer/index.js b/packages/metro-bundler/src/JSTransformer/index.js
index 6cc7e56e..a084bbce 100644
--- a/packages/metro-bundler/src/JSTransformer/index.js
+++ b/packages/metro-bundler/src/JSTransformer/index.js
@@ -21,7 +21,7 @@ const util = require('util');
 const workerFarm = require('worker-farm');
 
 import type {Data as TransformData, Options as TransformOptions} from './worker/worker';
-import type {SourceMap} from '../lib/SourceMap';
+import type {MappingsMap} from '../lib/SourceMap';
 
 // Avoid memory leaks caused in workers. This number seems to be a good enough number
 // to avoid any memory leak while not slowing down initial builds.
@@ -62,8 +62,8 @@ class Transformer {
   minify: (
     filename: string,
     code: string,
-    sourceMap: SourceMap,
-  ) => Promise<{code: string, map: SourceMap}>;
+    sourceMap: MappingsMap,
+  ) => Promise<{code: string, map: MappingsMap}>;
 
   constructor(transformModulePath: string, maxWorkerCount: number) {
     invariant(path.isAbsolute(transformModulePath), 'transform module path should be absolute');
diff --git a/packages/metro-bundler/src/JSTransformer/worker/constant-folding.js b/packages/metro-bundler/src/JSTransformer/worker/constant-folding.js
index 3ab0b1d2..36cfbf62 100644
--- a/packages/metro-bundler/src/JSTransformer/worker/constant-folding.js
+++ b/packages/metro-bundler/src/JSTransformer/worker/constant-folding.js
@@ -13,7 +13,7 @@
 
 const babel = require('babel-core');
 
-import type {Ast, SourceMap} from 'babel-core';
+import type {Ast, SourceMap as MappingsMap} from 'babel-core';
 const t = babel.types;
 
 const Conditional = {
@@ -73,7 +73,7 @@ const plugin = {
 function constantFolding(filename: string, transformResult: {
   ast: Ast,
   code?: ?string,
-  map: ?SourceMap,
+  map: ?MappingsMap,
 }) {
   return babel.transformFromAst(transformResult.ast, transformResult.code, {
     filename,
diff --git a/packages/metro-bundler/src/JSTransformer/worker/inline.js b/packages/metro-bundler/src/JSTransformer/worker/inline.js
index 9952f229..6094a7cb 100644
--- a/packages/metro-bundler/src/JSTransformer/worker/inline.js
+++ b/packages/metro-bundler/src/JSTransformer/worker/inline.js
@@ -14,7 +14,7 @@
 const babel = require('babel-core');
 const invariant = require('fbjs/lib/invariant');
 
-import type {Ast, SourceMap} from 'babel-core';
+import type {Ast, SourceMap as MappingsMap} from 'babel-core';
 const t = babel.types;
 
 const React = {name: 'React'};
@@ -164,12 +164,12 @@ function checkRequireArgs(args, dependencyId) {
 type AstResult = {
   ast: Ast,
   code: ?string,
-  map: ?SourceMap,
+  map: ?MappingsMap,
 };
 
 function inline(
   filename: string,
-  transformResult: {ast?: ?Ast, code: string, map: ?SourceMap},
+  transformResult: {ast?: ?Ast, code: string, map: ?MappingsMap},
   options: {+dev: boolean, +platform: string},
 ): AstResult {
   const code = transformResult.code;
diff --git a/packages/metro-bundler/src/JSTransformer/worker/worker.js b/packages/metro-bundler/src/JSTransformer/worker/worker.js
index a3e97820..5c437810 100644
--- a/packages/metro-bundler/src/JSTransformer/worker/worker.js
+++ b/packages/metro-bundler/src/JSTransformer/worker/worker.js
@@ -18,13 +18,13 @@ const invariant = require('fbjs/lib/invariant');
 const minify = require('./minify');
 
 import type {LogEntry} from '../../Logger/Types';
-import type {Ast, SourceMap} from 'babel-core';
+import type {Ast, SourceMap as MappingsMap} from 'babel-core';
 
 export type TransformedCode = {
   code: string,
   dependencies: Array<string>,
   dependencyOffsets: Array<number>,
-  map?: ?SourceMap,
+  map?: ?MappingsMap,
 };
 
 type Transformer = {
@@ -32,7 +32,7 @@ type Transformer = {
     filename: string,
     sourceCode: string,
     options: ?{},
-  ) => {ast: ?Ast, code: string, map: ?SourceMap}
+  ) => {ast: ?Ast, code: string, map: ?MappingsMap}
 };
 
 export type TransformOptions = {|
diff --git a/packages/metro-bundler/src/ModuleGraph/output/source-map.js b/packages/metro-bundler/src/ModuleGraph/output/source-map.js
index bade8fec..7f45ac9c 100644
--- a/packages/metro-bundler/src/ModuleGraph/output/source-map.js
+++ b/packages/metro-bundler/src/ModuleGraph/output/source-map.js
@@ -10,37 +10,15 @@
  */
 'use strict';
 
+import type {FBSourceMap, IndexMapSection, IndexMap} from '../../lib/SourceMap';
+
+export type {FBSourceMap};
+
 type CreateIndexMapOptions = {|
   file?: string,
   sections?: Array<IndexMapSection>
 |};
 
-type IndexMap = MapBase & {
-  sections: Array<IndexMapSection>,
-};
-
-type IndexMapSection = {
-  map: IndexMap | MappingsMap,
-  offset: {line: number, column: number},
-};
-
-type MapBase = {
-  // always the first entry in the source map entry object per
-  // https://fburl.com/source-map-spec#heading=h.qz3o9nc69um5
-  version: 3,
-  file?: string,
-};
-
-type MappingsMap = MapBase & {
-  mappings: string,
-  names: Array<string>,
-  sourceRoot?: string,
-  sources: Array<string>,
-  sourcesContent?: Array<?string>,
-};
-
-export type SourceMap = IndexMap | MappingsMap;
-
 exports.createIndexMap = (opts?: CreateIndexMapOptions): IndexMap => ({
   version: 3,
   file: opts && opts.file,
diff --git a/packages/metro-bundler/src/ModuleGraph/types.flow.js b/packages/metro-bundler/src/ModuleGraph/types.flow.js
index fd27309e..1e250df0 100644
--- a/packages/metro-bundler/src/ModuleGraph/types.flow.js
+++ b/packages/metro-bundler/src/ModuleGraph/types.flow.js
@@ -10,7 +10,7 @@
  */
 'use strict';
 
-import type {SourceMap} from './output/source-map';
+import type {MappingsMap, SourceMap} from '../lib/SourceMap';
 import type {Ast} from 'babel-core';
 import type {Console} from 'console';
 
@@ -102,7 +102,7 @@ type ResolveOptions = {
 export type TransformerResult = {|
   ast: ?Ast,
   code: string,
-  map: ?SourceMap,
+  map: ?MappingsMap,
 |};
 
 export type Transformer = {
@@ -111,7 +111,7 @@ export type Transformer = {
     filename: string,
     options: ?{},
     plugins?: Array<string | Object | [string | Object, any]>,
-  ) => {ast: ?Ast, code: string, map: ?SourceMap}
+  ) => {ast: ?Ast, code: string, map: ?MappingsMap}
 };
 
 export type TransformResult = {|
diff --git a/packages/metro-bundler/src/Resolver/index.js b/packages/metro-bundler/src/Resolver/index.js
index 4613050b..f96ab082 100644
--- a/packages/metro-bundler/src/Resolver/index.js
+++ b/packages/metro-bundler/src/Resolver/index.js
@@ -18,14 +18,14 @@ const pathJoin = require('path').join;
 
 import type ResolutionResponse from '../node-haste/DependencyGraph/ResolutionResponse';
 import type Module, {HasteImpl, TransformCode} from '../node-haste/Module';
-import type {SourceMap} from '../lib/SourceMap';
+import type {MappingsMap} from '../lib/SourceMap';
 import type {Options as JSTransformerOptions} from '../JSTransformer/worker/worker';
 import type {Reporter} from '../lib/reporting';
 import type {GetTransformCacheKey} from '../lib/TransformCache';
 import type {GlobalTransformCache} from '../lib/GlobalTransformCache';
 
-type MinifyCode = (filePath: string, code: string, map: SourceMap) =>
-  Promise<{code: string, map: SourceMap}>;
+type MinifyCode = (filePath: string, code: string, map: MappingsMap) =>
+  Promise<{code: string, map: MappingsMap}>;
 
 type ContainsTransformerOptions = {+transformer: JSTransformerOptions}
 
@@ -195,7 +195,7 @@ class Resolver {
     resolutionResponse: ResolutionResponse<Module, T>,
     module: Module,
     name: string,
-    map: SourceMap,
+    map: MappingsMap,
     code: string,
     meta?: {
       dependencyOffsets?: Array<number>,
@@ -227,8 +227,8 @@ class Resolver {
   }
 
   minifyModule(
-    {path, code, map}: {path: string, code: string, map: SourceMap},
-  ): Promise<{code: string, map: SourceMap}> {
+    {path, code, map}: {path: string, code: string, map: MappingsMap},
+  ): Promise<{code: string, map: MappingsMap}> {
     return this._minifyCode(path, code, map);
   }
 
diff --git a/packages/metro-bundler/src/Server/symbolicate/symbolicate.js b/packages/metro-bundler/src/Server/symbolicate/symbolicate.js
index 5fbb5ac1..3ea3c089 100644
--- a/packages/metro-bundler/src/Server/symbolicate/symbolicate.js
+++ b/packages/metro-bundler/src/Server/symbolicate/symbolicate.js
@@ -20,7 +20,7 @@ const {LazyPromise, LockingPromise} = require('./util');
 const {fork} = require('child_process');
 
 export type {SourceMap as SourceMap};
-import type {MixedSourceMap as SourceMap} from '../../lib/SourceMap';
+import type {SourceMap} from '../../lib/SourceMap';
 
 export type Stack = Array<{file: string, lineNumber: number, column: number}>;
 export type Symbolicate =
diff --git a/packages/metro-bundler/src/lib/ModuleTransport.js b/packages/metro-bundler/src/lib/ModuleTransport.js
index 840de0e9..1c4e48bd 100644
--- a/packages/metro-bundler/src/lib/ModuleTransport.js
+++ b/packages/metro-bundler/src/lib/ModuleTransport.js
@@ -12,9 +12,9 @@
 'use strict';
 
 import type {RawMapping} from '../Bundler/source-map';
-import type {MixedSourceMap} from './SourceMap';
+import type {SourceMap} from './SourceMap';
 
-type SourceMapOrMappings = MixedSourceMap | Array<RawMapping>;
+type SourceMapOrMappings = SourceMap | Array<RawMapping>;
 
 type Metadata = {
   dependencies?: ?Array<string>,
diff --git a/packages/metro-bundler/src/lib/SourceMap.js b/packages/metro-bundler/src/lib/SourceMap.js
index d356cddb..afbce101 100644
--- a/packages/metro-bundler/src/lib/SourceMap.js
+++ b/packages/metro-bundler/src/lib/SourceMap.js
@@ -11,23 +11,28 @@
 
 'use strict';
 
-import type {SourceMap as BabelSourceMap} from 'babel-core';
+import type {SourceMap as MappingsMap} from 'babel-core';
 
-export type SourceMap = BabelSourceMap;
-
-export type CombinedSourceMap = {
-  version: number,
-  file?: string,
-  sections: Array<{
-    offset: {line: number, column: number},
-    map: MixedSourceMap,
-  }>,
+export type IndexMapSection = {
+  map: SourceMap,
+  offset: {line: number, column: number},
 };
 
-type FBExtensions = {x_facebook_offsets?: Array<number>};
+type FBExtensions = {x_facebook_offsets: Array<number>};
 
-export type MixedSourceMap
-  = SourceMap
-  | CombinedSourceMap
-  | (SourceMap & FBExtensions)
-  | (CombinedSourceMap & FBExtensions);
+export type {MappingsMap};
+export type IndexMap = {
+  file?: string,
+  mappings?: void, // avoids SourceMap being a disjoint union
+  sections: Array<IndexMapSection>,
+  version: number,
+};
+
+export type SourceMap = IndexMap | MappingsMap;
+export type FBSourceMap = (IndexMap & FBExtensions) | (MappingsMap & FBExtensions);
+
+function isMappingsMap(map: SourceMap)/*: %checks*/ {
+  return map.mappings !== undefined;
+}
+
+exports.isMappingsMap = isMappingsMap;
diff --git a/packages/metro-bundler/src/lib/TransformCache.js b/packages/metro-bundler/src/lib/TransformCache.js
index 64d4c3dd..652ba7d9 100644
--- a/packages/metro-bundler/src/lib/TransformCache.js
+++ b/packages/metro-bundler/src/lib/TransformCache.js
@@ -21,7 +21,7 @@ const terminal = require('../lib/terminal');
 const writeFileAtomicSync = require('write-file-atomic').sync;
 
 import type {Options as TransformOptions} from '../JSTransformer/worker/worker';
-import type {SourceMap} from './SourceMap';
+import type {MappingsMap} from './SourceMap';
 import type {Reporter} from './reporting';
 
 type CacheFilePaths = {transformedCode: string, metadata: string};
@@ -94,7 +94,7 @@ export type CachedResult = {
   code: string,
   dependencies: Array<string>,
   dependencyOffsets: Array<number>,
-  map?: ?SourceMap,
+  map?: ?MappingsMap,
 };
 
 export type TransformCacheResult = {|
@@ -281,7 +281,7 @@ function readMetadataFileSync(
   cachedSourceHash: string,
   dependencies: Array<string>,
   dependencyOffsets: Array<number>,
-  sourceMap: ?SourceMap,
+  sourceMap: ?MappingsMap,
 } {
   const metadataStr = fs.readFileSync(metadataFilePath, 'utf8');
   let metadata;
diff --git a/packages/metro-bundler/src/lib/relativizeSourceMap.js b/packages/metro-bundler/src/lib/relativizeSourceMap.js
index 4b9050d8..28f35b49 100644
--- a/packages/metro-bundler/src/lib/relativizeSourceMap.js
+++ b/packages/metro-bundler/src/lib/relativizeSourceMap.js
@@ -13,10 +13,12 @@
 
 const path = require('path');
 
-import type {MixedSourceMap} from './SourceMap';
+const {isMappingsMap} = require('./SourceMap');
 
-function relativizeSourceMapInternal(sourceMap: any, sourcesRoot: string) {
-  if (sourceMap.sections) {
+import type {SourceMap} from './SourceMap';
+
+function relativizeSourceMapInternal(sourceMap: SourceMap, sourcesRoot: string) {
+  if (!isMappingsMap(sourceMap)) {
     for (let i = 0; i < sourceMap.sections.length; i++) {
       relativizeSourceMapInternal(sourceMap.sections[i].map, sourcesRoot);
     }
@@ -27,7 +29,7 @@ function relativizeSourceMapInternal(sourceMap: any, sourcesRoot: string) {
   }
 }
 
-function relativizeSourceMap(sourceMap: MixedSourceMap, sourcesRoot?: string): MixedSourceMap {
+function relativizeSourceMap(sourceMap: SourceMap, sourcesRoot?: string): SourceMap {
   if (!sourcesRoot) {
     return sourceMap;
   }
diff --git a/packages/metro-bundler/src/node-haste/Module.js b/packages/metro-bundler/src/node-haste/Module.js
index 2a5a7957..793fc2ea 100644
--- a/packages/metro-bundler/src/node-haste/Module.js
+++ b/packages/metro-bundler/src/node-haste/Module.js
@@ -24,7 +24,7 @@ const {join: joinPath, relative: relativePath, extname} = require('path');
 
 import type {TransformedCode, Options as TransformOptions} from '../JSTransformer/worker/worker';
 import type {GlobalTransformCache} from '../lib/GlobalTransformCache';
-import type {SourceMap} from '../lib/SourceMap';
+import type {MappingsMap} from '../lib/SourceMap';
 import type {GetTransformCacheKey} from '../lib/TransformCache';
 import type {ReadTransformProps} from '../lib/TransformCache';
 import type {Reporter} from '../lib/reporting';
@@ -35,7 +35,7 @@ export type ReadResult = {
   +code: string,
   +dependencies: Array<string>,
   +dependencyOffsets?: ?Array<number>,
-  +map?: ?SourceMap,
+  +map?: ?MappingsMap,
   +source: string,
 };