Migrate status file entries when migrating files. Yay!

tools/migration/lib/src/test_directories.dart

+// Copyright (c) 2017, 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.
+
+/// Manages the directories where tests can appear and the relationships
+/// between them.
+
+import 'package:path/path.dart' as p;
+
+const oneRootDirs = const [
+  "corelib",
+  "html",
+  "isolate",
+  "language",
+  "lib",
+];
+
+const strongRootDirs = const [
+  "corelib_strong",
+  "language_strong",
+  "lib_strong",
+];
+
+const twoRootDirs = const [
+  "corelib_2",
+  "language_2",
+  "lib_2",
+];
+
+final fromRootDirs = oneRootDirs.toList()..addAll(strongRootDirs);
+
+// Note: The order is significant. "html" and "isolate" need to come first so
+// that they don't get handled by the general "lib" directory.
+final _directories = [
+  new _Directory("corelib", "corelib_strong", "corelib_2"),
+  new _Directory("html", p.join("lib_strong", "html"), p.join("lib_2", "html")),
+  new _Directory(
+      "isolate", p.join("lib_strong", "isolate"), p.join("lib_2", "isolate")),
+  new _Directory("language", "language_strong", "language_2"),
+  new _Directory("lib", "lib_strong", "lib_2"),
+];
+
+/// Maps a Dart 1.0 or DDC root directory to its resulting migration Dart 2.0
+/// directory.
+String toTwoDirectory(String fromDir) {
+  for (var dir in _directories) {
+    if (dir.one == fromDir || dir.strong == fromDir) return dir.two;
+  }
+
+  throw new ArgumentError.value(fromDir, "fromDir");
+}
+
+/// Given a path within a Dart 1.0 or strong mode directory, returns the
+/// corresponding Dart 2.0 path.
+String toTwoPath(String fromPath) {
+  for (var dir in _directories) {
+    if (p.isWithin(dir.one, fromPath)) {
+      var relative = p.relative(fromPath, from: dir.one);
+      return p.join(dir.two, relative);
+    }
+
+    if (p.isWithin(dir.strong, fromPath)) {
+      var relative = p.relative(fromPath, from: dir.strong);
+      return p.join(dir.two, relative);
+    }
+  }
+
+  throw new ArgumentError.value(fromPath, "fromPath");
+}
+
+/// Given a path within a Dart 2.0 directory, returns the corresponding Dart 1.0
+/// path.
+String toOnePath(String twoPath) {
+  for (var dir in _directories) {
+    if (p.isWithin(dir.two, twoPath)) {
+      var relative = p.relative(twoPath, from: dir.two);
+      return p.join(dir.one, relative);
+    }
+  }
+
+  throw new ArgumentError.value(twoPath, "twoPath");
+}
+
+/// Given a path within a Dart 2.0 directory, returns the corresponding DDC
+/// strong mode.
+String toStrongPath(String twoPath) {
+  for (var dir in _directories) {
+    if (p.isWithin(dir.two, twoPath)) {
+      var relative = p.relative(twoPath, from: dir.two);
+      return p.join(dir.strong, relative);
+    }
+  }
+
+  throw new ArgumentError.value(twoPath, "twoPath");
+}
+
+class _Directory {
+  final String one;
+  final String strong;
+  final String two;
+
+  _Directory(this.one, this.strong, this.two);
+}