Strip more unused features.

lib/main.ts

-require('source-map-support').install();
-import {SourceMapGenerator} from 'source-map';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as ts from 'typescript';
 
-import {TranspilerBase} from './base';
+import {Set, TranspilerBase} from './base';
+
 import mkdirP from './mkdirp';
-import CallTranspiler from './call';
 import DeclarationTranspiler from './declaration';
-import ExpressionTranspiler from './expression';
+import * as merge from './merge';
 import ModuleTranspiler from './module';
-import StatementTranspiler from './statement';
 import TypeTranspiler from './type';
-import LiteralTranspiler from './literal';
-import {FacadeConverter} from './facade_converter';
+import {FacadeConverter, NameRewriter} from './facade_converter';
 import * as dartStyle from 'dart-style';
 
 export interface TranspilerOptions {
   /**
    * Fail on the first error, do not collect multiple. Allows easier debugging as stack traces lead
    * directly to the offending line.
    */
   failFast?: boolean;
   /** Whether to generate 'library a.b.c;' names from relative file paths. */
   generateLibraryName?: boolean;
-  /** Whether to generate source maps. */
-  generateSourceMap?: boolean;
   /**
    * A base path to relativize absolute file paths against. This is useful for library name
    * generation (see above) and nicer file names in error messages.
    */
   basePath?: string;
   /**
-   * Translate calls to builtins, i.e. seemlessly convert from `Array` to `List`, and convert the
-   * corresponding methods. Requires type checking.
+   * Use dart:html instead of the raw JavaScript DOM when generated Dart code.
    */
-  translateBuiltins?: boolean;
+  useHtml?: boolean;
   /**
    * Enforce conventions of public/private keyword and underscore prefix
    */
   enforceUnderscoreConventions?: boolean;
   /**
    * Sets a root path to look for typings used by the facade converter.
    */
   typingsRoot?: string;
+
+  /**
+   * Experimental JS Interop specific option to promote properties with function
+   * types to methods instead of properties with a function type. This the makes
+   * the Dart code more readable at the cost of disallowing setting the value of
+   * the property.
+   * Example JS library that benifits from this option:
+   * https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/chartjs/chart.d.ts
+   */
+  promoteFunctionLikeMembers?: boolean;
 }
 
 export const COMPILER_OPTIONS: ts.CompilerOptions = {
   allowNonTsExtensions: true,
   experimentalDecorators: true,
   module: ts.ModuleKind.CommonJS,
   target: ts.ScriptTarget.ES5,
 };
 
+/**
+ * Context to ouput code into.
+ */
+export enum OutputContext {
+  Import = 0,
+  Header = 1,
+  Default = 2,
+}
+
+const NUM_OUTPUT_CONTEXTS = 3;
+
 export class Transpiler {
-  private output: Output;
+  private outputs: Output[];
+  private outputStack: Output[];
   private currentFile: ts.SourceFile;
-
+  importsEmitted: Set;
   // Comments attach to all following AST nodes before the next 'physical' token. Track the earliest
   // offset to avoid printing comments multiple times.
   private lastCommentIdx: number = -1;
   private errors: string[] = [];
 
   private transpilers: TranspilerBase[];
+  private declarationTranspiler: DeclarationTranspiler;
   private fc: FacadeConverter;
+  private nameRewriter: NameRewriter;
 
   constructor(private options: TranspilerOptions = {}) {
-    // TODO: Remove the angular2 default when angular uses typingsRoot.
-    this.fc = new FacadeConverter(this, options.typingsRoot || 'angular2/typings/');
+    this.nameRewriter = new NameRewriter();
+    this.fc = new FacadeConverter(this, options.typingsRoot, this.nameRewriter, options.useHtml);
+    this.declarationTranspiler = new DeclarationTranspiler(
+        this, this.fc, options.enforceUnderscoreConventions, options.promoteFunctionLikeMembers);
     this.transpilers = [
-      new CallTranspiler(this, this.fc),  // Has to come before StatementTranspiler!
-      new DeclarationTranspiler(this, this.fc, options.enforceUnderscoreConventions),
-      new ExpressionTranspiler(this, this.fc),
-      new LiteralTranspiler(this, this.fc),
+      this.declarationTranspiler,
       new ModuleTranspiler(this, this.fc, options.generateLibraryName),
-      new StatementTranspiler(this),
       new TypeTranspiler(this, this.fc),
     ];
   }
 
   /**
    * Transpiles the given files to Dart.
    * @param fileNames The input files.
    * @param destination Location to write files to. Creates files next to their sources if absent.
    */
   transpile(fileNames: string[], destination?: string): void {
     if (this.options.basePath) {
       this.options.basePath = this.normalizeSlashes(path.resolve(this.options.basePath));
     }
     fileNames = fileNames.map((f) => this.normalizeSlashes(f));
     let host = this.createCompilerHost();
     if (this.options.basePath && destination === undefined) {
       throw new Error(
           'Must have a destination path when a basePath is specified ' + this.options.basePath);
     }
     let destinationRoot = destination || this.options.basePath || '';
     let program = ts.createProgram(fileNames, this.getCompilerOptions(), host);
-    if (this.options.translateBuiltins) {
-      this.fc.setTypeChecker(program.getTypeChecker());
-    }
+    this.fc.setTypeChecker(program.getTypeChecker());
+    this.declarationTranspiler.setTypeChecker(program.getTypeChecker());
 
     // Only write files that were explicitly passed in.
     let fileSet: {[s: string]: boolean} = {};
     fileNames.forEach((f) => fileSet[f] = true);
+    let sourceFiles = program.getSourceFiles().filter((sourceFile) => fileSet[sourceFile.fileName]);
 
     this.errors = [];
-    program.getSourceFiles()
-        .filter((sourceFile) => fileSet[sourceFile.fileName])
-        // Do not generate output for .d.ts files.
-        .filter((sourceFile: ts.SourceFile) => !sourceFile.fileName.match(/\.d\.ts$/))
-        .forEach((f: ts.SourceFile) => {
-          let dartCode = this.translate(f);
-          let outputFile = this.getOutputPath(path.resolve(f.fileName), destinationRoot);
-          mkdirP(path.dirname(outputFile));
-          fs.writeFileSync(outputFile, dartCode);
-        });
+
+    sourceFiles.forEach((f: ts.SourceFile) => {
+      let dartCode = this.translate(f);
+      let outputFile = this.getOutputPath(path.resolve(f.fileName), destinationRoot);
+      mkdirP(path.dirname(outputFile));
+      fs.writeFileSync(outputFile, dartCode);
+    });
     this.checkForErrors(program);
   }
 
   translateProgram(program: ts.Program): {[path: string]: string} {
-    if (this.options.translateBuiltins) {
-      this.fc.setTypeChecker(program.getTypeChecker());
-    }
+    this.fc.setTypeChecker(program.getTypeChecker());
+    this.declarationTranspiler.setTypeChecker(program.getTypeChecker());
+
     let paths: {[path: string]: string} = {};
     this.errors = [];
     program.getSourceFiles()
         .filter(
             (sourceFile: ts.SourceFile) =>
                 (!sourceFile.fileName.match(/\.d\.ts$/) && !!sourceFile.fileName.match(/\.[jt]s$/)))
         .forEach((f) => paths[f.fileName] = this.translate(f));
     this.checkForErrors(program);
     return paths;
   }
@@ skipping 27 matching lines @@
       getCurrentDirectory: () => '',
       getNewLine: () => '\n',
     };
     compilerHost.resolveModuleNames = getModuleResolver(compilerHost);
     return compilerHost;
   }
 
   // Visible for testing.
   getOutputPath(filePath: string, destinationRoot: string): string {
     let relative = this.getRelativeFileName(filePath);
-    let dartFile = relative.replace(/.(js|es6|ts)$/, '.dart');
+    let dartFile = relative.replace(/.(js|es6|d\.ts|ts)$/, '.dart');
     return this.normalizeSlashes(path.join(destinationRoot, dartFile));
   }
 
+  public pushContext(context: OutputContext) { this.outputStack.push(this.outputs[context]); }
+
+  public popContext() {
+    if (this.outputStack.length === 0) {
+      this.reportError(null, 'Attempting to pop output stack when already empty');
+    }
+    this.outputStack.pop();
+  }
+
   private translate(sourceFile: ts.SourceFile): string {
     this.currentFile = sourceFile;
-    this.output =
-        new Output(sourceFile, this.getRelativeFileName(), this.options.generateSourceMap);
+    this.outputs = [];
+    this.outputStack = [];
+    this.importsEmitted = {};
+    for (let i = 0; i < NUM_OUTPUT_CONTEXTS; ++i) {
+      this.outputs.push(new Output());
+    }
+
     this.lastCommentIdx = -1;
+    merge.normalizeSourceFile(sourceFile);
+    this.pushContext(OutputContext.Default);
     this.visit(sourceFile);
-    let result = this.output.getResult();
+    this.popContext();
+    if (this.outputStack.length > 0) {
+      this.reportError(
+          sourceFile, 'Internal error managing output contexts. ' +
+              'Inconsistent push and pop context calls.');
+    }
+    let result = '';
+    for (let output of this.outputs) {
+      result += output.getResult();
+    }
     return this.formatCode(result, sourceFile);
   }
 
   private formatCode(code: string, context: ts.Node) {
     let result = dartStyle.formatCode(code);
     if (result.error) {
       this.reportError(context, result.error);
     }
     return result.code;
   }
 
   private checkForErrors(program: ts.Program) {
     let errors = this.errors;
 
     let diagnostics = program.getGlobalDiagnostics().concat(program.getSyntacticDiagnostics());
 
-    if ((errors.length || diagnostics.length) && this.options.translateBuiltins) {
-      // Only report semantic diagnostics if ts2dart failed; this code is not a generic compiler, so
-      // only yields TS errors if they could be the cause of ts2dart issues.
+    if ((errors.length || diagnostics.length)) {
+      // Only report semantic diagnostics if facade generation failed; this
+      // code is not a generic compiler, so only yields TS errors if they could
+      // be the cause of facade generation issues.
       // This greatly speeds up tests and execution.
       diagnostics = diagnostics.concat(program.getSemanticDiagnostics());
     }
 
     let diagnosticErrs = diagnostics.map((d) => {
       let msg = '';
       if (d.file) {
         let pos = d.file.getLineAndCharacterOfPosition(d.start);
         let fn = this.getRelativeFileName(d.file.fileName);
         msg += ` ${fn}:${pos.line + 1}:${pos.character + 1}`;
       }
       msg += ': ';
       msg += ts.flattenDiagnosticMessageText(d.messageText, '\n');
       return msg;
     });
     if (diagnosticErrs.length) errors = errors.concat(diagnosticErrs);
 
     if (errors.length) {
       let e = new Error(errors.join('\n'));
-      e.name = 'TS2DartError';
+      e.name = 'DartFacadeError';
       throw e;
     }
   }
 
   /**
    * Returns `filePath`, relativized to the program's `basePath`.
    * @param filePath Optional path to relativize, defaults to the current file's path.
    */
   getRelativeFileName(filePath?: string) {
     if (filePath === undefined) filePath = path.resolve(this.currentFile.fileName);
     // TODO(martinprobst): Use path.isAbsolute on node v0.12.
     if (this.normalizeSlashes(path.resolve('/x/', filePath)) !== filePath) {
       return filePath;  // already relative.
     }
     let base = this.options.basePath || '';
     if (filePath.indexOf(base) !== 0 && !filePath.match(/\.d\.ts$/)) {
       throw new Error(`Files must be located under base, got ${filePath} vs ${base}`);
     }
     return this.normalizeSlashes(path.relative(base, filePath));
   }
 
-  emit(s: string) { this.output.emit(s); }
-  emitNoSpace(s: string) { this.output.emitNoSpace(s); }
+  private get currentOutput(): Output { return this.outputStack[this.outputStack.length - 1]; }
+
+  emit(s: string) { this.currentOutput.emit(s); }
+  emitNoSpace(s: string) { this.currentOutput.emitNoSpace(s); }
+  enterCodeComment() { return this.currentOutput.enterCodeComment(); }
+  exitCodeComment() { return this.currentOutput.exitCodeComment(); }
 
   reportError(n: ts.Node, message: string) {
     let file = n.getSourceFile() || this.currentFile;
     let fileName = this.getRelativeFileName(file.fileName);
     let start = n.getStart(file);
     let pos = file.getLineAndCharacterOfPosition(start);
     // Line and character are 0-based.
     let fullMessage = `${fileName}:${pos.line + 1}:${pos.character + 1}: ${message}`;
     if (this.options.failFast) throw new Error(fullMessage);
     this.errors.push(fullMessage);
   }
 
   visit(node: ts.Node) {
-    this.output.addSourceMapping(node);
+    if (!node) return;
     let comments = ts.getLeadingCommentRanges(this.currentFile.text, node.getFullStart());
     if (comments) {
       comments.forEach((c) => {
+        // Warning: the following check means that comments will only be
+        // emitted correctly if Dart code is emitted in the same order it
+        // appeared in the JavaScript AST.
         if (c.pos <= this.lastCommentIdx) return;
         this.lastCommentIdx = c.pos;
         let text = this.currentFile.text.substring(c.pos, c.end);
-        this.emitNoSpace('\n');
+        this.currentOutput.maybeLineBreak();
         this.emit(this.translateComment(text));
         if (c.hasTrailingNewLine) this.emitNoSpace('\n');
       });
     }
 
     for (let i = 0; i < this.transpilers.length; i++) {
       if (this.transpilers[i].visitNode(node)) return;
     }
 
     this.reportError(
         node,
         'Unsupported node type ' + (<any>ts).SyntaxKind[node.kind] + ': ' + node.getFullText());
   }
 
   private normalizeSlashes(path: string) { return path.replace(/\\/g, '/'); }
 
   private translateComment(comment: string): string {
     comment = comment.replace(/\{@link ([^\}]+)\}/g, '[$1]');
 
     // Remove the following tags and following comments till end of line.
     comment = comment.replace(/@param.*$/gm, '');
     comment = comment.replace(/@throws.*$/gm, '');
     comment = comment.replace(/@return.*$/gm, '');
 
     // Remove the following tags.
     comment = comment.replace(/@module/g, '');
     comment = comment.replace(/@description/g, '');
     comment = comment.replace(/@deprecated/g, '');
 
+    // Hack to make comment indentation does not look as bad when dart format is
+    // run on files with multiple nested modules.
+    comment = comment.replace(/\n  ( +[*])/g, '\n$1');
     return comment;
   }
 }
 
 export function getModuleResolver(compilerHost: ts.CompilerHost) {
   return (moduleNames: string[], containingFile: string): ts.ResolvedModule[] => {
     let res: ts.ResolvedModule[] = [];
     for (let mod of moduleNames) {
       let lookupRes =
           ts.nodeModuleNameResolver(mod, containingFile, COMPILER_OPTIONS, compilerHost);
       if (lookupRes.resolvedModule) {
         res.push(lookupRes.resolvedModule);
         continue;
       }
       lookupRes = ts.classicNameResolver(mod, containingFile, COMPILER_OPTIONS, compilerHost);
       if (lookupRes.resolvedModule) {
         res.push(lookupRes.resolvedModule);
         continue;
       }
       res.push(undefined);
     }
     return res;
   };
 }
 
 class Output {
   private result: string = '';
-  private column: number = 1;
-  private line: number = 1;
+  private firstColumn: boolean = true;
 
-  // Position information.
-  private generateSourceMap: boolean;
-  private sourceMap: SourceMapGenerator;
+  private insideCodeComment: boolean = false;
+  private codeCommentResult: string = '';
 
-  constructor(
-      private currentFile: ts.SourceFile, private relativeFileName: string,
-      generateSourceMap: boolean) {
-    if (generateSourceMap) {
-      this.sourceMap = new SourceMapGenerator({file: relativeFileName + '.dart'});
-      this.sourceMap.setSourceContent(relativeFileName, this.currentFile.text);
+  /**
+   * Line break if the current line is not empty.
+   */
+  maybeLineBreak() {
+    if (this.insideCodeComment) {
+      // Avoid line breaks inside code comments.
+      return;
+    }
+
+    if (!this.firstColumn) {
+      this.emitNoSpace('\n');
     }
   }
 
   emit(str: string) {
     this.emitNoSpace(' ');
     this.emitNoSpace(str);
   }
 
   emitNoSpace(str: string) {
+    if (str.length === 0) return;
+    if (this.insideCodeComment) {
+      this.codeCommentResult += str;
+      return;
+    }
     this.result += str;
-    for (let i = 0; i < str.length; i++) {
-      if (str[i] === '\n') {
-        this.line++;
-        this.column = 0;
-      } else {
-        this.column++;
-      }
-    }
+    this.firstColumn = str[str.length - 1] === '\n';
   }
 
-  getResult(): string { return this.result + this.generateSourceMapComment(); }
-
-  addSourceMapping(n: ts.Node) {
-    if (!this.generateSourceMap) return;  // source maps disabled.
-    let file = n.getSourceFile() || this.currentFile;
-    let start = n.getStart(file);
-    let pos = file.getLineAndCharacterOfPosition(start);
-
-    let mapping: SourceMap.Mapping = {
-      original: {line: pos.line + 1, column: pos.character},
-      generated: {line: this.line, column: this.column},
-      source: this.relativeFileName,
-    };
-
-    this.sourceMap.addMapping(mapping);
+  enterCodeComment() {
+    if (this.insideCodeComment) {
+      throw 'Cannot nest code comments';
+    }
+    this.insideCodeComment = true;
+    this.codeCommentResult = '';
   }
 
-  private generateSourceMapComment() {
-    if (!this.sourceMap) return '';
-    let base64map = new Buffer(JSON.stringify(this.sourceMap)).toString('base64');
-    return '\n\n//# sourceMappingURL=data:application/json;base64,' + base64map;
+  exitCodeComment() {
+    if (!this.insideCodeComment) {
+      throw 'Exit code comment called while not within a code comment.';
+    }
+    this.insideCodeComment = false;
+    this.emit('/*');
+    let result = dartStyle.formatCode(this.codeCommentResult);
+    if (result.error) {
+      // Fall back to the raw expression if the formatter returns an error.
+      // Ideally the formatter would handle a wider range of dart expressions.
+      this.emit(this.codeCommentResult.trim());
+    } else {
+      this.emit(result.code.trim());
+    }
+    this.emit('*/');
+    // Don't really need an exact column, just need to track
+    // that we aren't on the first column.
+    this.firstColumn = false;
+    this.codeCommentResult = '';
+  }
+
+  getResult(): string {
+    if (this.insideCodeComment) {
+      throw 'Code comment not property terminated.';
+    }
+    return this.result;
   }
 }
 
 // CLI entry point
 if (require.main === module) {
   let args = require('minimist')(process.argv.slice(2), {base: 'string'});
   try {
     let transpiler = new Transpiler(args);
     console.error('Transpiling', args._, 'to', args.destination);
     transpiler.transpile(args._, args.destination);
   } catch (e) {
-    if (e.name !== 'TS2DartError') throw e;
+    if (e.name !== 'DartFacadeError') throw e;
     console.error(e.message);
     process.exit(1);
   }
 }