cleanup: js_codegen now returns a js_ast.Program

lib/src/codegen/js_codegen.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet;
 import 'dart:io' show Directory, File;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
@@ skipping 40 matching lines @@
   final _properties = <FunctionDeclaration>[];
   final _privateNames = new HashSet<String>();
   final _pendingPrivateNames = <String>[];
 
   JSCodegenVisitor(LibraryInfo libraryInfo, TypeRules rules)
       : libraryInfo = libraryInfo,
         rules = rules;
 
   Element get currentLibrary => libraryInfo.library;
 
-  JS.Block generateLibrary(
+  JS.Program generateLibrary(
       Iterable<CompilationUnit> units, CheckerReporter reporter) {
     var body = <JS.Statement>[];
     for (var unit in units) {
       // TODO(jmesserly): this is needed because RestrictedTypeRules can send
       // messages to CheckerReporter, for things like missing types.
       // We should probably refactor so this can't happen.
       var source = unit.element.source;
       _constEvaluator = new ConstantEvaluator(source, rules.provider);
       reporter.enterSource(source);
       body.add(_visit(unit));
       reporter.leaveSource();
     }
 
     if (_exports.isNotEmpty) body.add(js.comment('Exports:'));
 
     // TODO(jmesserly): make these immutable in JS?
     for (var name in _exports) {
       body.add(js.statement('$_EXPORTS.# = #;', [name, name]));
     }
 
     var name = jsLibraryName(libraryInfo.library);
-    return new JS.Block([
+    return new JS.Program([
       js.statement('var #;', name),
       js.statement("(function($_EXPORTS) { 'use strict'; #; })(# || (# = {}));",
           [body, name, name])
     ]);
   }
 
   JS.Statement _initPrivateSymbol(String name) =>
       js.statement('let # = Symbol(#);', [name, js.string(name, "'")]);
 
   @override
@@ skipping 1826 matching lines @@
 }
 
 class JSGenerator extends CodeGenerator {
   final JSCodeOptions options;
 
   JSGenerator(String outDir, Uri root, TypeRules rules, this.options)
       : super(outDir, root, rules);
 
   void generateLibrary(Iterable<CompilationUnit> units, LibraryInfo info,
       CheckerReporter reporter) {
-    JS.Block jsTree =
+    JS.Program jsTree =
         new JSCodegenVisitor(info, rules).generateLibrary(units, reporter);
 
     var outputPath = path.join(outDir, jsOutputPath(info, root));
     new Directory(path.dirname(outputPath)).createSync(recursive: true);
 
     if (options.emitSourceMaps) {
       var outFilename = path.basename(outputPath);
       var printer = new srcmaps.Printer(outFilename);
-      var context =
-          new SourceMapPrintingContext(printer, path.dirname(outputPath));
-      _writeLibrary(context, jsTree);
+      _writeNode(
+          new SourceMapPrintingContext(printer, path.dirname(outputPath)),
+          jsTree);
       printer.add('//# sourceMappingURL=$outFilename.map');
       // Write output file and source map
       new File(outputPath).writeAsStringSync(printer.text);
       new File('$outputPath.map').writeAsStringSync(printer.map);
     } else {
-      var context = new JS.SimpleJavaScriptPrintingContext();
-      _writeLibrary(context, jsTree);
-      // Write output file and source map
-      new File(outputPath).writeAsStringSync(context.getText());
+      new File(outputPath).writeAsStringSync(jsNodeToString(jsTree));
     }
   }
-
-  void _writeLibrary(JS.JavaScriptPrintingContext context, JS.Block jsTree) {
-    var opts =
-        new JS.JavaScriptPrintingOptions(avoidKeywordsInIdentifiers: true);
-    new JS.Printer(opts, context).blockOutWithoutBraces(jsTree);
-  }
 }
 
+void _writeNode(JS.JavaScriptPrintingContext context, JS.Node node) {
+  var opts = new JS.JavaScriptPrintingOptions(avoidKeywordsInIdentifiers: true);
+  node.accept(new JS.Printer(opts, context));
+}
+
 /// This is a debugging helper to print a JS node.
-String debugJsNodeToString(JS.Node node) {
+String jsNodeToString(JS.Node node) {
   var context = new JS.SimpleJavaScriptPrintingContext();
-  var opts = new JS.JavaScriptPrintingOptions(avoidKeywordsInIdentifiers: true);
-  new JS.Printer(opts, context).visit(node);
-  // Write output file and source map
+  _writeNode(context, node);
   return context.getText();
 }
 
 /// Choose a canonical name from the library element.
 /// This never uses the library's name (the identifier in the `library`
 /// declaration) as it doesn't have any meaningful rules enforced.
 String jsLibraryName(LibraryElement library) => canonicalLibraryName(library);
 
 /// Path to file that will be generated for [info]. In case it's url is a
 /// `file:` url, we use [root] to determine the relative path from the entry
@@ skipping 64 matching lines @@
 
     // TODO(jmesserly): in many cases marking the end will be unncessary.
     printer.mark(_location(node.end));
   }
 
   String _getIdentifier(AstNode node) {
     if (node is SimpleIdentifier) return node.name;
     return null;
   }
 }