Add a filesystem descriptor library to scheduled_test.

pkg/scheduled_test/lib/src/descriptor/directory.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.
+
+library descriptor.file;
+
+import 'dart:async';
+import 'dart:io' as io;
+
+import 'package:pathos/path.dart' as path;
+
+import '../../descriptor.dart' as descriptor;
+import '../../scheduled_test.dart';
+import '../utils.dart';
+import 'utils.dart';
+
+/// A descriptor describing a directory containing multiple files.
+class Directory extends descriptor.Entry {
+  /// The entries contained within this directory.
+  final Iterable<descriptor.Entry> contents;
+
+  Directory(Pattern name, this.contents)
+      : super(name);
+
+  Future create([String parent]) => schedule(() {
+    if (parent == null) parent = descriptor.defaultRoot;
+    var fullPath = path.join(parent, stringName);
+    return new io.Directory(fullPath).create(recursive: true).then((_) {
+      return Future.wait(
+          contents.map((entry) => entry.create(fullPath)).toList());
+    });
+  }, 'creating directory:\n${describe()}');
+
+  Future validate([String parent]) => schedule(() {
+    if (parent == null) parent = descriptor.defaultRoot;
+    var fullPath = entryMatchingPattern('Directory', parent, name);
+    return Future.wait(
+        contents.map((entry) => entry.validate(fullPath)).toList());
+  }, 'validating directory:\n${describe()}');
+
+  Stream<List<int>> load(String pathToLoad) {
+    return futureStream(new Future.immediate(null).then((_) {
+      if (path.isAbsolute(pathToLoad)) {
+        throw "Can't load absolute path '$pathToLoad'.";
+      }
+
+      var split = path.split(path.normalize(pathToLoad));
+      if (split.isEmpty || split.first == '.' || split.first == '..') {
+        throw "Can't load '$pathToLoad' from within $nameDescription.";
+      }
+
+      var matchingEntries = contents.where((entry) =>
+          entry.stringName == split.first).toList();
+
+      if (matchingEntries.length == 0) {
+        throw "Couldn't find an entry named '${split.first}' within "
+            "$nameDescription.";
+      } else if (matchingEntries.length > 1) {
+        throw "Found multiple entries named '${split.first}' within "
+            "$nameDescription.";
+      } else {
+        var remainingPath = split.getRange(1, split.length - 1);
+        if (remainingPath.isEmpty) {
+          return matchingEntries.first.read();
+        } else {
+          return matchingEntries.first.load(path.joinAll(remainingPath));
+        }
+      }
+    }));
+  }
+
+  Stream<List<int>> read() => errorStream("Can't read the contents of "
+      "$nameDescription: is a directory.");
+
+  String describe() {
+    var description = name;
+    if (name is! String) description = 'directory matching $nameDescription';
+    if (contents.isEmpty) return description;
+
+    var buffer = new StringBuffer();
+    buffer.writeln(description);
+    for (var entry in contents.take(contents.length - 1)) {
+      var entryString = prefixLines(entry.describe(), prefix: '|   ')
+          .replaceFirst('|   ', '|-- ');
+      buffer.writeln(entryString);
+    }
+
+    var lastEntryString = prefixLines(contents.last.describe(), prefix: '    ')
+        .replaceFirst('    ', "'-- ");
+    buffer.add(lastEntryString);
+    return buffer.toString();
+  }
+}