API for the new AnalysisDriver.

pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart

+// Copyright (c) 2015, 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.
+
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/dart/analysis/byte_store.dart';
+
+/**
+ * [ByteStore] that stores values as [File]s.

[Paul Berry, 2016/10/23 10:39:19]

Should this class implement some sort of LRU policy so that the folder doesn't
grow without bound?

[scheglov, 2016/10/23 20:54:34]

Yes, we should.
I'm adding TODO.

+ */
+class FileByteStore implements ByteStore {
+  final Folder folder;
+
+  FileByteStore(this.folder);
+
+  @override
+  List<int> get(String key) {
+    try {
+      File file = folder.getChildAssumingFile(key);
+      return file.readAsBytesSync();
+    } catch (_) {
+      return null;
+    }
+  }
+
+  @override
+  void put(String key, List<int> bytes) {
+    try {
+      File file = folder.getChildAssumingFile(key);
+      file.writeAsBytesSync(bytes);
+    } catch (_) {}
+  }
+}