refactor(compiler): make the new ngc API independent of tsickle (#18739)

This changes `performCompile` / `program.emit` to not tsickle automatically,
but allows to pass in an `emitCallback` in which tsickle can be executed.

packages/compiler-cli/src/main.ts

@@ -14,6 +14,7 @@ import * as ts from 'typescript';
 import * as tsc from '@angular/tsc-wrapped';
 import * as fs from 'fs';
 import * as path from 'path';
+import * as tsickle from 'tsickle';
 import * as api from './transformers/api';
 import * as ngc from './transformers/entry_points';
 import {performCompilation, readConfiguration, formatDiagnostics, Diagnostics, ParsedConfiguration} from './perform-compile';
@@ -31,7 +32,8 @@ export function main(
   if (options.disableTransformerPipeline) {
     return disabledTransformerPipelineNgcMain(parsedArgs, consoleError);
   }
-  const {diagnostics: compileDiags} = performCompilation(rootNames, options);
+  const {diagnostics: compileDiags} =
+      performCompilation({rootNames, options, emitCallback: createEmitCallback(options)});
   return Promise.resolve(reportErrorsAndExit(options, compileDiags, consoleError));
 }
 
@@ -42,10 +44,45 @@ export function mainSync(
   if (configErrors.length) {
     return reportErrorsAndExit(options, configErrors, consoleError);
   }
-  const {diagnostics: compileDiags} = performCompilation(rootNames, options);
+  const {diagnostics: compileDiags} =
+      performCompilation({rootNames, options, emitCallback: createEmitCallback(options)});
   return reportErrorsAndExit(options, compileDiags, consoleError);
 }
 
+function createEmitCallback(options: api.CompilerOptions): api.TsEmitCallback {
+  const tsickleOptions: tsickle.TransformerOptions = {
+    googmodule: false,
+    untyped: true,
+    convertIndexImportShorthand: true,
+    transformDecorators: options.annotationsAs !== 'decorators',
+    transformTypesToClosure: options.annotateForClosureCompiler,
+  };
+
+  const tsickleHost: tsickle.TransformerHost = {
+    shouldSkipTsickleProcessing: (fileName) => /\.d\.ts$/.test(fileName),
+    pathToModuleName: (context, importPath) => '',
+    shouldIgnoreWarningsForPath: (filePath) => false,
+    fileNameToModuleId: (fileName) => fileName,
+  };
+
+  return ({
+           program,
+           targetSourceFile,
+           writeFile,
+           cancellationToken,
+           emitOnlyDtsFiles,
+           customTransformers = {},
+           host,
+           options
+         }) =>
+             tsickle.emitWithTsickle(
+                 program, tsickleHost, tsickleOptions, host, options, targetSourceFile, writeFile,
+                 cancellationToken, emitOnlyDtsFiles, {
+                   beforeTs: customTransformers.before,
+                   afterTs: customTransformers.after,
+                 });
+}
+
 function readCommandLineAndConfiguration(args: any): ParsedConfiguration {
   const project = args.p || args.project || '.';
   const allDiagnostics: Diagnostics = [];

packages/compiler-cli/src/perform-compile.ts

@@ -105,10 +105,16 @@ export function readConfiguration(
 }
 
 export function performCompilation(
-    rootNames: string[], options: api.CompilerOptions, host?: api.CompilerHost,
-    oldProgram?: api.Program): {
+    {rootNames, options, host, oldProgram, emitCallback, customTransformers}: {
+      rootNames: string[],
+      options: api.CompilerOptions,
+      host?: api.CompilerHost,
+      oldProgram?: api.Program,
+      emitCallback?: api.TsEmitCallback,
+      customTransformers?: api.CustomTransformers
+    }): {
   program?: api.Program,
-  emitResult?: api.EmitResult,
+  emitResult?: ts.EmitResult,
   diagnostics: Diagnostics,
 } {
   const [major, minor] = ts.version.split('.');
@@ -128,7 +134,7 @@ export function performCompilation(
   }
 
   let program: api.Program|undefined;
-  let emitResult: api.EmitResult|undefined;
+  let emitResult: ts.EmitResult|undefined;
   try {
     if (!host) {
       host = ng.createCompilerHost({options});
@@ -155,7 +161,9 @@ export function performCompilation(
     shouldEmit = shouldEmit && checkDiagnostics(program !.getNgSemanticDiagnostics());
 
     if (shouldEmit) {
-      const emitResult = program !.emit({
+      emitResult = program !.emit({
+        emitCallback,
+        customTransformers,
         emitFlags: api.EmitFlags.Default |
             ((options.skipMetadataEmit || options.flatModuleOutFile) ? 0 : api.EmitFlags.Metadata)
       });

packages/compiler-cli/src/transformers/api.ts

@@ -167,17 +167,24 @@ export enum EmitFlags {
   All = DTS | JS | Metadata | I18nBundle | Summary
 }
 
-// TODO(chuckj): Support CustomTransformers once we require TypeScript 2.3+
-// export interface CustomTransformers {
-//   beforeTs?: ts.TransformerFactory<ts.SourceFile>[];
-//   afterTs?: ts.TransformerFactory<ts.SourceFile>[];
-// }
-
-export interface EmitResult extends ts.EmitResult {
-  modulesManifest: {modules: string[]; fileNames: string[];};
-  externs: {[fileName: string]: string;};
+export interface CustomTransformers {
+  beforeTs?: ts.TransformerFactory<ts.SourceFile>[];
+  afterTs?: ts.TransformerFactory<ts.SourceFile>[];
 }
 
+export interface TsEmitArguments {
+  program: ts.Program;
+  host: CompilerHost;
+  options: CompilerOptions;
+  targetSourceFile?: ts.SourceFile;
+  writeFile?: ts.WriteFileCallback;
+  cancellationToken?: ts.CancellationToken;
+  emitOnlyDtsFiles?: boolean;
+  customTransformers?: ts.CustomTransformers;
+}
+
+export interface TsEmitCallback { (args: TsEmitArguments): ts.EmitResult; }
+
 export interface Program {
   /**
    * Retrieve the TypeScript program used to produce semantic diagnostics and emit the sources.
@@ -254,10 +261,10 @@ export interface Program {
    *
    * Angular structural information is required to emit files.
    */
-  emit({// transformers,
-        emitFlags, cancellationToken}: {
-    emitFlags: EmitFlags,
-    // transformers?: CustomTransformers, // See TODO above
+  emit({emitFlags, cancellationToken, customTransformers, emitCallback}: {
+    emitFlags?: EmitFlags,
     cancellationToken?: ts.CancellationToken,
-  }): EmitResult;
+    customTransformers?: CustomTransformers,
+    emitCallback?: TsEmitCallback
+  }): ts.EmitResult;
 }

packages/compiler-cli/src/transformers/program.ts

@@ -10,13 +10,12 @@ import {AotCompiler, AotCompilerHost, AotCompilerOptions, GeneratedFile, NgAnaly
 import {createBundleIndexHost} from '@angular/tsc-wrapped';
 import * as fs from 'fs';
 import * as path from 'path';
-import * as tsickle from 'tsickle';
 import * as ts from 'typescript';
 
 import {BaseAotCompilerHost} from '../compiler_host';
 import {TypeChecker} from '../diagnostics/check_types';
 
-import {CompilerHost, CompilerOptions, Diagnostic, EmitFlags, EmitResult, Program} from './api';
+import {CompilerHost, CompilerOptions, CustomTransformers, Diagnostic, EmitFlags, Program, TsEmitArguments, TsEmitCallback} from './api';
 import {LowerMetadataCache, getExpressionLoweringTransformFactory} from './lower_expressions';
 import {getAngularEmitterTransformFactory} from './node_emitter_transform';
 
@@ -30,6 +29,13 @@ const emptyModules: NgAnalyzedModules = {
   files: []
 };
 
+const defaultEmitCallback: TsEmitCallback =
+    ({program, targetSourceFile, writeFile, cancellationToken, emitOnlyDtsFiles,
+      customTransformers}) =>
+        program.emit(
+            targetSourceFile, writeFile, cancellationToken, emitOnlyDtsFiles, customTransformers);
+
+
 class AngularCompilerProgram implements Program {
   private tsProgram: ts.Program;
   private aotCompilerHost: AotCompilerHost;
@@ -128,35 +134,35 @@ class AngularCompilerProgram implements Program {
 
   getLazyRoutes(cancellationToken?: ts.CancellationToken): {[route: string]: string} { return {}; }
 
-  emit({emitFlags = EmitFlags.Default, cancellationToken}:
-           {emitFlags?: EmitFlags, cancellationToken?: ts.CancellationToken}): EmitResult {
+  emit({emitFlags = EmitFlags.Default, cancellationToken, customTransformers,
+        emitCallback = defaultEmitCallback}: {
+    emitFlags?: EmitFlags,
+    cancellationToken?: ts.CancellationToken,
+    customTransformers?: CustomTransformers,
+    emitCallback?: TsEmitCallback
+  }): ts.EmitResult {
     const emitMap = new Map<string, string>();
 
-    const tsickleCompilerHostOptions: tsickle.TransformerOptions = {
-      googmodule: false,
-      untyped: true,
-      convertIndexImportShorthand: true,
-      transformDecorators: this.options.annotationsAs !== 'decorators',
-      transformTypesToClosure: this.options.annotateForClosureCompiler,
-    };
-
-    const tsickleHost: tsickle.TransformerHost = {
-      shouldSkipTsickleProcessing: (fileName) => /\.d\.ts$/.test(fileName),
-      pathToModuleName: (context, importPath) => '',
-      shouldIgnoreWarningsForPath: (filePath) => false,
-      fileNameToModuleId: (fileName) => fileName,
-    };
-
     const expectedOut = this.options.expectedOut ?
         this.options.expectedOut.map(f => path.resolve(process.cwd(), f)) :
         undefined;
 
-    const result = tsickle.emitWithTsickle(
-        this.programWithStubs, tsickleHost, tsickleCompilerHostOptions, this.host, this.options,
-        /* targetSourceFile */ undefined,
-        createWriteFileCallback(emitFlags, this.host, this.metadataCache, emitMap, expectedOut),
-        cancellationToken, (emitFlags & (EmitFlags.DTS | EmitFlags.JS)) == EmitFlags.DTS,
-        this.calculateTransforms());
+    // Ensure that expected output files exist.
+    for (const out of expectedOut || []) {
+      this.host.writeFile(out, '', false);
+    }
+
+    const emitResult = emitCallback({
+      program: this.programWithStubs,
+      host: this.host,
+      options: this.options,
+      targetSourceFile: undefined,
+      writeFile:
+          createWriteFileCallback(emitFlags, this.host, this.metadataCache, emitMap, expectedOut),
+      cancellationToken,
+      emitOnlyDtsFiles: (emitFlags & (EmitFlags.DTS | EmitFlags.JS)) == EmitFlags.DTS,
+      customTransformers: this.calculateTransforms(customTransformers)
+    });
 
     this.generatedFiles.forEach(file => {
       // In order not to replicate the TS calculation of the out folder for files
@@ -174,12 +180,7 @@ class AngularCompilerProgram implements Program {
       }
     });
 
-    // Ensure that expected output files exist.
-    for (const out of expectedOut || []) {
-      fs.appendFileSync(out, '', 'utf8');
-    }
-
-    return result;
+    return emitResult;
   }
 
   // Private members
@@ -228,7 +229,7 @@ class AngularCompilerProgram implements Program {
     return this.generatedFiles && this._generatedFileDiagnostics !;
   }
 
-  private calculateTransforms(): tsickle.EmitTransformers {
+  private calculateTransforms(customTransformers?: CustomTransformers): ts.CustomTransformers {
     const beforeTs: ts.TransformerFactory<ts.SourceFile>[] = [];
     if (!this.options.disableExpressionLowering) {
       beforeTs.push(getExpressionLoweringTransformFactory(this.metadataCache));
@@ -236,7 +237,11 @@ class AngularCompilerProgram implements Program {
     if (!this.options.skipTemplateCodegen) {
       beforeTs.push(getAngularEmitterTransformFactory(this.generatedFiles));
     }
-    return {beforeTs};
+    if (customTransformers && customTransformers.beforeTs) {
+      beforeTs.push(...customTransformers.beforeTs);
+    }
+    const afterTs = customTransformers ? customTransformers.afterTs : undefined;
+    return {before: beforeTs, after: afterTs};
   }
 
   private catchAnalysisError(e: any): NgAnalyzedModules {
@@ -370,7 +375,8 @@ function getAotCompilerOptions(options: CompilerOptions): AotCompilerOptions {
 }
 
 function writeMetadata(
-    emitFilePath: string, sourceFile: ts.SourceFile, metadataCache: LowerMetadataCache) {
+    host: ts.CompilerHost, emitFilePath: string, sourceFile: ts.SourceFile,
+    metadataCache: LowerMetadataCache) {
   if (/\.js$/.test(emitFilePath)) {
     const path = emitFilePath.replace(/\.js$/, '.metadata.json');
 
@@ -386,7 +392,7 @@ function writeMetadata(
     const metadata = metadataCache.getMetadata(collectableFile);
     if (metadata) {
       const metadataText = JSON.stringify([metadata]);
-      fs.writeFileSync(path, metadataText, {encoding: 'utf-8'});
+      host.writeFile(path, metadataText, false);
     }
   }
 }
@@ -412,7 +418,7 @@ function createWriteFileCallback(
       host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles);
 
       if (srcFile && !generatedFile && (emitFlags & EmitFlags.Metadata) != 0) {
-        writeMetadata(fileName, srcFile, metadataCache);
+        writeMetadata(host, fileName, srcFile, metadataCache);
       }
     }
   };

tools/ngc-wrapped/index.ts

@@ -23,7 +23,7 @@ function main(args: string[]) {
   const {basePath} = calcProjectFileAndBasePath(project);
   const ngOptions = createNgCompilerOptions(basePath, config, tsOptions);
 
-  const {diagnostics} = performCompilation(files, ngOptions);
+  const {diagnostics} = performCompilation({rootNames: files, options: ngOptions});
   if (diagnostics.length) {
     console.error(formatDiagnostics(ngOptions, diagnostics));
   }