Added support for skipping redundant dart2js compilations.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
  *   and creating [TestCase]s for those files that meet the relevant criteria.
  * - Preparing tests, including copying files and frameworks to temporary
  *   directories, and computing the command line and arguments to be run.
  */
 #library("test_suite");
 
 #import("dart:io");
 #import("dart:isolate");
 #import("status_file_parser.dart");
 #import("test_runner.dart");
 #import("multitest.dart");
 #import("drt_updater.dart");
+#import("dart:uri");
 
 #source("browser_test.dart");
 
 
 // TODO(rnystrom): Add to dart:core?
 /**
  * A simple function that tests [arg] and returns `true` or `false`.
  */
 typedef bool Predicate<T>(T arg);
 
@@ skipping 403 matching lines @@
       Map configuration, Path directory) {
     final name = directory.filename;
 
     return new StandardTestSuite(configuration,
         name, directory,
         ['$directory/$name.status', '$directory/${name}_dart2js.status'],
         isTestFilePredicate: (filename) => filename.endsWith('_test.dart'),
         recursive: true);
   }
 
+  Collection<Uri> get dart2JsBootstrapDependencies {
+    if (!useDart2JsFromSdk) return [];
+    
+    var snapshotPath = TestUtils.absolutePath(new Path(buildDir).join(
+        new Path('dart-sdk/lib/_internal/compiler/'
+                 'implementation/dart2js.dart.snapshot'))).toString();
+    return [new Uri.fromComponents(scheme: 'file', path: snapshotPath)];
+  }
+
+  bool get useDart2JsFromSdk {
+    return configuration['use_sdk'];
+  }
+
   /**
    * The default implementation assumes a file is a test if
    * it ends in "Test.dart".
    */
   bool isTestFile(String filename) {
     // Use the specified predicate, if provided.
     if (isTestFilePredicate != null) return isTestFilePredicate(filename);
 
     return filename.endsWith("Test.dart");
   }
@@ skipping 235 matching lines @@
                           info: info));
     }
   }
 
   List<Command> makeCommands(TestInformation info, var vmOptions, var args) {
     switch (configuration['compiler']) {
     case 'dart2js':
       args = new List.from(args);
       String tempDir = createOutputDirectory(info.filePath, '');
       args.add('--out=$tempDir/out.js');
-      List<Command> commands = <Command>[new Command(dartShellFileName, args)];
+      List<Command> commands = 
+          <Command>[new Dart2JsCommand("$tempDir/out.js",
+                                       !useDart2JsFromSdk,
+                                       dart2JsBootstrapDependencies,
+                                       dartShellFileName,
+                                       args)];
       if (info.hasCompileError) {
         // Do not attempt to run the compiled result. A compilation
         // error should be reported by the compilation command.
       } else if (configuration['runtime'] == 'd8') {
         commands.add(new Command(d8FileName, ['$tempDir/out.js']));
       } else if (configuration['runtime'] == 'jsshell') {
         commands.add(new Command(jsShellFileName, ['$tempDir/out.js']));
       }
       return commands;
 
@@ skipping 280 matching lines @@
         args.add(inputFile);
         break;
       default:
         Expect.fail('unimplemented compiler $compiler');
     }
     if (executable.endsWith('.dart')) {
       // Run the compiler script via the Dart VM.
       args.insertRange(0, 1, executable);
       executable = dartShellFileName;
     }
+    if (configuration['compiler'] == 'dart2js') {
+      return new Dart2JsCommand(outputFile,
+                                !useDart2JsFromSdk, 
+                                dart2JsBootstrapDependencies,
+                                dartShellFileName,
+                                args);
+    }
     return new Command(executable, args);
   }
 
   /**
    * Create a directory for the generated test.  If a Dart language test
    * needs to be run in a browser, the Dart test needs to be embedded in
    * an HTML page, with a testing framework based on scripting and DOM events.
    * These scripts and pages are written to a generated_test directory
    * inside the build directory of the checkout.
    *
@@ skipping 441 matching lines @@
          '$dartDir/third_party/rhino/1_7R3/js.jar',
          '$dartDir/third_party/hamcrest/v1_3/hamcrest-core-1.3.0RC2.jar',
          '$dartDir/third_party/hamcrest/v1_3/hamcrest-generator-1.3.0RC2.jar',
          '$dartDir/third_party/hamcrest/v1_3/hamcrest-integration-1.3.0RC2.jar',
          '$dartDir/third_party/hamcrest/v1_3/hamcrest-library-1.3.0RC2.jar',
          '$dartDir/third_party/junit/v4_8_2/junit.jar'],
         Platform.operatingSystem == 'windows'? ';': ':');  // Path separator.
   }
 }
 
+class LastModifiedCache {
+  Map<String, Date> _cache = <String, Date>{};
+
+  /**
+   * Returns the last modified date of the given [uri].
+   * 
+   * The return value will be cached for future queries. If [uri] is a local
+   * file, it's last modified [Date] will be returned. If the file does not
+   * exist, null will be returned instead.
+   * In case [uri] is not a local file, this method will always return
+   * the current date.
+   */
+  Date getLastModified(Uri uri) {
+    if (uri.scheme == "file") {
+      if (_cache.containsKey(uri.path)) {
+        return _cache[uri.path];
+      }
+      var file = new File(uri.path);
+      _cache[uri.path] = file.existsSync() ? file.lastModifiedSync() : null;
+      return _cache[uri.path];
+    }
+    return new Date.now();
+  }
+}
+
 class TestUtils {
   /**
    * The libraries in this directory relies on finding various files
    * relative to the 'test.dart' script in '.../dart/tools/test.dart'. If
    * the main script using 'test_suite.dart' is not there, the main
    * script must set this to '.../dart/tools/test.dart'.
    */
   static String testScriptPath = new Options().script;
-
+  static LastModifiedCache lastModifiedCache = new LastModifiedCache();
+  static Path currentWorkingDirectory = new Path(new Directory.current().path);
   /**
    * Creates a directory using a [relativePath] to an existing
    * [base] directory if that [relativePath] does not already exist.
    */
   static Directory mkdirRecursive(Path base, Path relativePath) {
     Directory dir = new Directory.fromPath(base);
     Expect.isTrue(dir.existsSync(),
                   "Expected ${dir} to already exist");
     var segments = relativePath.segments();
     for (String segment in segments) {
@@ skipping 27 matching lines @@
     // waterfall UI.
     return ".flaky.log";
   }
 
   static void ensureExists(String filename, Map configuration) {
     if (!configuration['list'] && !(new File(filename).existsSync())) {
       throw "Executable '$filename' does not exist";
     }
   }
 
+  static Path absolutePath(Path path) {
+    if (!path.isAbsolute) {
+      return currentWorkingDirectory.join(path);
+    }
+    return path;
+  }
+
   static String outputDir(Map configuration) {
     var result = '';
     var system = configuration['system'];
     if (system == 'linux') {
       result = 'out/';
     } else if (system == 'macos') {
       result = 'xcodebuild/';
     } else if (system == 'windows') {
       result = 'build/';
     }
@@ skipping 103 matching lines @@
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
  * $compileErrorSkip tests are skipped on browsers due to compile-time error
 """;
     print(report);
    }
 }