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pkg/analyzer_experimental/lib/src/services/runtime/coverage_impl.dart

-// Copyright (c) 2013, 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.
-
-/// A library for code coverage support for Dart.
-library runtime.coverage_impl;
-
-import "dart:io";
-
-import "package:logging/logging.dart" as log;
-import "package:pathos/path.dart" as po;
-
-import 'package:analyzer_experimental/src/generated/source.dart' show Source;
-import 'package:analyzer_experimental/src/generated/scanner.dart' show StringScanner;
-import 'package:analyzer_experimental/src/generated/parser.dart' show Parser;
-import 'package:analyzer_experimental/src/generated/ast.dart';
-import 'package:analyzer_experimental/src/generated/engine.dart' show RecordingErrorListener;
-
-
-log.Logger logger = log.Logger.root;
-
-/// Abstract server that listens requests and serves files, may be rewriting them.
-abstract class RewriteServer {
-  String _basePath;
-  RewriteServer(this._basePath);
-  void start() {
-    HttpServer.bind("127.0.0.1", 3445).then((HttpServer server) {
-      logger.info('RewriteServer is listening at: ${server.port}.');
-      server.listen((HttpRequest request) {
-        var response = request.response;
-        // Prepare path.
-        var path = _basePath + '/' + request.uri.path;
-        path = po.normalize(path);
-        logger.info('[$path] Requested.');
-        // May be serve using just path.
-        {
-          String content = rewritePathContent(path);
-          if (content != null) {
-            logger.info('[$path] Request served by path.');
-            response.write(content);
-            response.close();
-            return;
-          }
-        }
-        // Serve from file.
-        logger.info('[$path] Serving file.');
-        var file = new File(path);
-        file.exists().then((bool found) {
-          if (found) {
-            logger.finest('[$path] Found file.');
-            file.readAsString().then((String content) {
-              logger.finest('[$path] Got file content.');
-              var sw = new Stopwatch();
-              sw.start();
-              try {
-                content = rewriteFileContent(path, content);
-              } finally {
-                sw.stop();
-                logger.fine('[$path] Rewritten in ${sw.elapsedMilliseconds} ms.');
-              }
-              response.write(content);
-              response.close();
-            });
-          } else {
-            logger.severe('[$path] File not found.');
-            response.statusCode = HttpStatus.NOT_FOUND;
-            response.close();
-          }
-        });
-      });
-    });
-  }
-
-  /// Subclasses implement this method to rewrite the provided [code] of the file with [path].
-  /// Returns some content or `null` if file content should be requested.
-  String rewritePathContent(String path);
-
-  /// Subclasses implement this method to rewrite the provided [code] of the file with [path].
-  String rewriteFileContent(String path, String code);
-}
-
-/// Server that rewrites Dart code so that it reports execution of statements and other nodes.
-class CoverageServer extends RewriteServer {
-  CoverageServer(String basePath) : super(basePath);
-
-  String rewritePathContent(String path) {
-    if (path.endsWith('__coverage_impl.dart')) {
-      String implPath = po.joinAll([
-          po.dirname(new Options().script),
-          '..', 'lib', 'src', 'services', 'runtime', 'coverage_lib.dart']);
-      return new File(implPath).readAsStringSync();
-    }
-    return null;
-  }
-
-  String rewriteFileContent(String path, String code) {
-    if (po.extension(path).toLowerCase() != '.dart') return code;
-    if (path.contains('packages')) return code;
-    var unit = _parseCode(code);
-    var injector = new StringInjector(code);
-    // Inject coverage library import.
-    var directives = unit.directives;
-    if (directives.isNotEmpty && directives[0] is LibraryDirective) {
-      injector.inject(directives[0].end, 'import "__coverage_impl.dart" as __cc;');
-    } else {
-      throw new Exception('Only single library coverage is implemented.');
-    }
-    // Insert touch() invocations.
-    unit.accept(new InsertTouchInvocationsVisitor(injector));
-    // Done.
-    code = injector.code;
-    logger.finest('[$path] Rewritten content\n$code');
-    return code;
-  }
-
-  CompilationUnit _parseCode(String code) {
-    var source = null;
-    var errorListener = new RecordingErrorListener();
-    var parser = new Parser(source, errorListener);
-    var scanner = new StringScanner(source, code, errorListener);
-    var token = scanner.tokenize();
-    return parser.parseCompilationUnit(token);
-  }
-}
-
-/// The visitor that inserts `touch` method invocations.
-class InsertTouchInvocationsVisitor extends GeneralizingASTVisitor {
-  StringInjector injector;
-  InsertTouchInvocationsVisitor(this.injector);
-  visitStatement(Statement node) {
-    super.visitStatement(node);
-    var offset = node.end;
-    if (node is Block) {
-      offset--;
-    }
-    if (node is Block && node.parent is BlockFunctionBody) return null;
-    injector.inject(offset, '__cc.touch(${node.offset});');
-    return null;
-  }
-}
-
-/// Helper for injecting fragments into some existing [String].
-class StringInjector {
-  String code;
-  int _lastOffset = -1;
-  int _delta = 0;
-  StringInjector(this.code);
-  void inject(int offset, String fragment) {
-    if (offset < _lastOffset) {
-      throw new ArgumentError('Only forward inserts are supported, was $_lastOffset given $offset');
-    }
-    _lastOffset = offset;
-    offset += _delta;
-    code = code.substring(0, offset) + fragment + code.substring(offset);
-    _delta += fragment.length;
-  }
-}