refactor(ivy): ngcc - extract file writing out into a class (#29092)

This is in preparation of having different file writing strategies.

PR Close #29092

packages/compiler-cli/ngcc/src/main.ts

@@ -18,6 +18,8 @@ import {EntryPointFormat, EntryPointJsonProperty, SUPPORTED_FORMAT_PROPERTIES, g
 import {makeEntryPointBundle} from './packages/entry_point_bundle';
 import {EntryPointFinder} from './packages/entry_point_finder';
 import {Transformer} from './packages/transformer';
+import {FileWriter} from './writing/file_writer';
+import {InPlaceFileWriter} from './writing/in_place_file_writer';
 
 
 /**
@@ -62,6 +64,7 @@ export function mainNgcc({basePath, targetEntryPointPath,
   const host = new DependencyHost();
   const resolver = new DependencyResolver(host);
   const finder = new EntryPointFinder(resolver);
+  const fileWriter = getFileWriter();
 
   const absoluteTargetEntryPointPath = targetEntryPointPath ?
       AbsoluteFsPath.from(resolve(basePath, targetEntryPointPath)) :
@@ -116,7 +119,8 @@ export function mainNgcc({basePath, targetEntryPointPath,
             compiledFormats.size === 0);
         if (bundle) {
           console.warn(`Compiling ${entryPoint.name} : ${property} as ${format}`);
-          transformer.transform(bundle);
+          const transformedFiles = transformer.transform(bundle);
+          fileWriter.writeBundle(entryPoint, bundle, transformedFiles);
           compiledFormats.add(formatPath);
         } else {
           console.warn(
@@ -139,3 +143,7 @@ export function mainNgcc({basePath, targetEntryPointPath,
     }
   });
 }
+
+function getFileWriter(): FileWriter {
+  return new InPlaceFileWriter();
+}

packages/compiler-cli/ngcc/src/packages/transformer.ts

@@ -5,9 +5,6 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {dirname} from 'canonical-path';
-import {existsSync, writeFileSync} from 'fs';
-import {mkdir, mv} from 'shelljs';
 import * as ts from 'typescript';
 
 import {CompiledFile, DecorationAnalyzer} from '../analysis/decoration_analyzer';
@@ -22,7 +19,6 @@ import {Esm5Renderer} from '../rendering/esm5_renderer';
 import {EsmRenderer} from '../rendering/esm_renderer';
 import {FileInfo, Renderer} from '../rendering/renderer';
 
-import {EntryPoint} from './entry_point';
 import {EntryPointBundle} from './entry_point_bundle';
 
 
@@ -54,8 +50,9 @@ export class Transformer {
   /**
    * Transform the source (and typings) files of a bundle.
    * @param bundle the bundle to transform.
+   * @returns information about the files that were transformed.
    */
-  transform(bundle: EntryPointBundle): void {
+  transform(bundle: EntryPointBundle): FileInfo[] {
     const isCore = bundle.isCore;
     const reflectionHost = this.getHost(isCore, bundle);
 
@@ -69,8 +66,7 @@ export class Transformer {
         decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses,
         moduleWithProvidersAnalyses);
 
-    // Write out all the transformed files.
-    renderedFiles.forEach(file => this.writeFile(file));
+    return renderedFiles;
   }
 
   getHost(isCore: boolean, bundle: EntryPointBundle): NgccReflectionHost {
@@ -122,15 +118,6 @@ export class Transformer {
     return {decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses,
             moduleWithProvidersAnalyses};
   }
-
-  writeFile(file: FileInfo): void {
-    mkdir('-p', dirname(file.path));
-    const backPath = file.path + '.bak';
-    if (existsSync(file.path) && !existsSync(backPath)) {
-      mv(file.path, backPath);
-    }
-    writeFileSync(file.path, file.contents, 'utf8');
-  }
 }
 
 

packages/compiler-cli/ngcc/src/writing/file_writer.ts

@@ -0,0 +1,19 @@
+
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {EntryPoint} from '../packages/entry_point';
+import {EntryPointBundle} from '../packages/entry_point_bundle';
+import {FileInfo} from '../rendering/renderer';
+
+
+/**
+ * Responsible for writing out the transformed files to disk.
+ */
+export interface FileWriter {
+  writeBundle(entryPoint: EntryPoint, bundle: EntryPointBundle, transformedFiles: FileInfo[]): void;
+}

packages/compiler-cli/ngcc/src/writing/in_place_file_writer.ts

@@ -0,0 +1,40 @@
+
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {dirname} from 'canonical-path';
+import {existsSync, writeFileSync} from 'fs';
+import {mkdir, mv} from 'shelljs';
+
+import {EntryPoint} from '../packages/entry_point';
+import {EntryPointBundle} from '../packages/entry_point_bundle';
+import {FileInfo} from '../rendering/renderer';
+
+import {FileWriter} from './file_writer';
+
+/**
+ * This FileWriter overwrites the transformed file, in-place, while creating
+ * a back-up of the original file with an extra `.bak` extension.
+ */
+export class InPlaceFileWriter implements FileWriter {
+  writeBundle(_entryPoint: EntryPoint, _bundle: EntryPointBundle, transformedFiles: FileInfo[]) {
+    transformedFiles.forEach(file => this.writeFileAndBackup(file));
+  }
+  protected writeFileAndBackup(file: FileInfo): void {
+    mkdir('-p', dirname(file.path));
+    const backPath = file.path + '.__ivy_ngcc_bak';
+    if (existsSync(backPath)) {
+      throw new Error(
+          `Tried to overwrite ${backPath} with an ngcc back up file, which is disallowed.`);
+    }
+    if (existsSync(file.path)) {
+      mv(file.path, backPath);
+    }
+    writeFileSync(file.path, file.contents, 'utf8');
+  }
+}

packages/compiler-cli/ngcc/test/BUILD.bazel

@@ -34,6 +34,7 @@ jasmine_node_test(
         "//tools/testing:node_no_angular",
         "@npm//canonical-path",
         "@npm//convert-source-map",
+        "@npm//shelljs",
     ],
 )
 

packages/compiler-cli/ngcc/test/writing/in_place_file_writer_spec.ts

@@ -0,0 +1,87 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {existsSync, readFileSync} from 'fs';
+import * as mockFs from 'mock-fs';
+
+import {EntryPoint} from '../../src/packages/entry_point';
+import {EntryPointBundle} from '../../src/packages/entry_point_bundle';
+import {InPlaceFileWriter} from '../../src/writing/in_place_file_writer';
+
+function createMockFileSystem() {
+  mockFs({
+    '/package/path': {
+      'top-level.js': 'ORIGINAL TOP LEVEL',
+      'folder-1': {
+        'file-1.js': 'ORIGINAL FILE 1',
+        'file-2.js': 'ORIGINAL FILE 2',
+      },
+      'folder-2': {
+        'file-3.js': 'ORIGINAL FILE 3',
+        'file-4.js': 'ORIGINAL FILE 4',
+      },
+      'already-backed-up.js.__ivy_ngcc_bak': 'BACKED UP',
+    }
+  });
+}
+
+function restoreRealFileSystem() {
+  mockFs.restore();
+}
+
+describe('InPlaceFileWriter', () => {
+  beforeEach(createMockFileSystem);
+  afterEach(restoreRealFileSystem);
+
+  it('should write all the FileInfo to the disk', () => {
+    const fileWriter = new InPlaceFileWriter();
+    fileWriter.writeBundle({} as EntryPoint, {} as EntryPointBundle, [
+      {path: '/package/path/top-level.js', contents: 'MODIFIED TOP LEVEL'},
+      {path: '/package/path/folder-1/file-1.js', contents: 'MODIFIED FILE 1'},
+      {path: '/package/path/folder-2/file-4.js', contents: 'MODIFIED FILE 4'},
+      {path: '/package/path/folder-3/file-5.js', contents: 'NEW FILE 5'},
+    ]);
+    expect(readFileSync('/package/path/top-level.js', 'utf8')).toEqual('MODIFIED TOP LEVEL');
+    expect(readFileSync('/package/path/folder-1/file-1.js', 'utf8')).toEqual('MODIFIED FILE 1');
+    expect(readFileSync('/package/path/folder-1/file-2.js', 'utf8')).toEqual('ORIGINAL FILE 2');
+    expect(readFileSync('/package/path/folder-2/file-3.js', 'utf8')).toEqual('ORIGINAL FILE 3');
+    expect(readFileSync('/package/path/folder-2/file-4.js', 'utf8')).toEqual('MODIFIED FILE 4');
+    expect(readFileSync('/package/path/folder-3/file-5.js', 'utf8')).toEqual('NEW FILE 5');
+  });
+
+  it('should create backups of all files that previously existed', () => {
+    const fileWriter = new InPlaceFileWriter();
+    fileWriter.writeBundle({} as EntryPoint, {} as EntryPointBundle, [
+      {path: '/package/path/top-level.js', contents: 'MODIFIED TOP LEVEL'},
+      {path: '/package/path/folder-1/file-1.js', contents: 'MODIFIED FILE 1'},
+      {path: '/package/path/folder-2/file-4.js', contents: 'MODIFIED FILE 4'},
+      {path: '/package/path/folder-3/file-5.js', contents: 'NEW FILE 5'},
+    ]);
+    expect(readFileSync('/package/path/top-level.js.__ivy_ngcc_bak', 'utf8'))
+        .toEqual('ORIGINAL TOP LEVEL');
+    expect(readFileSync('/package/path/folder-1/file-1.js.__ivy_ngcc_bak', 'utf8'))
+        .toEqual('ORIGINAL FILE 1');
+    expect(existsSync('/package/path/folder-1/file-2.js.__ivy_ngcc_bak')).toBe(false);
+    expect(existsSync('/package/path/folder-2/file-3.js.__ivy_ngcc_bak')).toBe(false);
+    expect(readFileSync('/package/path/folder-2/file-4.js.__ivy_ngcc_bak', 'utf8'))
+        .toEqual('ORIGINAL FILE 4');
+    expect(existsSync('/package/path/folder-3/file-5.js.__ivy_ngcc_bak')).toBe(false);
+  });
+
+  it('should error if the backup file already exists', () => {
+    const fileWriter = new InPlaceFileWriter();
+    expect(
+        () => fileWriter.writeBundle(
+            {} as EntryPoint, {} as EntryPointBundle,
+            [
+              {path: '/package/path/already-backed-up.js', contents: 'MODIFIED BACKED UP'},
+            ]))
+        .toThrowError(
+            'Tried to overwrite /package/path/already-backed-up.js.__ivy_ngcc_bak with an ngcc back up file, which is disallowed.');
+  });
+});