Code coverage server babysteps.

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

+/// A library for code coverage support for Dart.

[pquitslund, 2013/06/11 17:18:56]

Again.  Probably want a header.

[scheglov, 2013/06/11 19:54:23]

Done.

+library runtime.coverage.server_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

[pquitslund, 2013/06/11 17:18:56]

prepare -> Prepare (upper case)

[scheglov, 2013/06/11 19:54:23]

Done.

+        String path = _basePath + '/' + request.uri.path;

[pquitslund, 2013/06/11 17:18:56]

var path

[scheglov, 2013/06/11 19:54:23]

Done.

+        path = po.normalize(path);
+        logger.info('[$path] Requested.');
+        // may be we have path content

[pquitslund, 2013/06/11 17:18:56]

Upper case 'may'

[scheglov, 2013/06/11 19:54:23]

Done.

+        {
+          String content = rewritePathContent(path);
+          if (content != null) {
+            logger.info('[$path] Request served by path.');
+            response.write(content);
+            response.close();
+            return;
+          }
+        }
+        // get content from file

[pquitslund, 2013/06/11 17:18:56]

More upper case (and below).  Pretty sure the style guide recommends this for
comments.

[scheglov, 2013/06/11 19:54:23]

Done.

+        logger.info('[$path] Serving file.');
+        File file = new File(path);

[pquitslund, 2013/06/11 17:18:56]

var file

[scheglov, 2013/06/11 19:54:23]

Done.

+        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;
+    CompilationUnit unit = _parseCode(code);

[pquitslund, 2013/06/11 17:18:56]

Again, drop the type annotation (var unit).

[scheglov, 2013/06/11 19:54:23]

Done.

+    print(unit);
+    var injector = new StringInjector(code);
+    // inject coverage_lib.dart 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) {
+    Source source = null;

[pquitslund, 2013/06/11 17:18:56]

And here.

[scheglov, 2013/06/11 19:54:23]

Done.

+    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);
+    int offset = node.end;

[pquitslund, 2013/06/11 17:18:56]

And here.

[scheglov, 2013/06/11 19:54:23]

Done.

+    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;
+  }
+}