A FileManager implementation to keep each index file in a separate file system file.

pkg/analysis_server/lib/src/index/store/separate_file_manager.dart

+// Copyright (c) 2014, 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 index.store.separate_file_mananer;
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:analysis_server/src/index/store/split_store.dart';
+import 'package:path/path.dart' as pathos;
+
+
+/**
+ * An implementation of [FileManager] that keeps each file in a separate file
+ * system file.
+ */
+class SeparateFileManager implements FileManager {
+  final Directory _base;
+
+  SeparateFileManager(this._base) {
+    clear();
+  }
+
+  @override
+  void clear() {
+    List<FileSystemEntity> entries = _base.listSync();
+    for (FileSystemEntity entry in entries) {
+      entry.deleteSync(recursive: true);
+    }
+  }
+
+  @override
+  void delete(String name) {
+    File file = _getFile(name);
+    if (file.existsSync()) {
+      file.deleteSync();

[Brian Wilkerson, 2014/06/23 19:52:32]

Is it a problem to call deleteSync for a file that doesn't exist? If so, there
is a timing issue here because the file could be deleted externally between the
calls to existsSync and deleteSync. If not, I'm guessing that it's probably
faster to not check.

[scheglov, 2014/06/23 20:00:22]

Done.

+    }
+  }
+
+  @override
+  Future<List<int>> read(String name) {
+    File file = _getFile(name);
+    return file.exists().then((bool exists) {
+      if (!exists) {
+        return null;
+      }
+      return file.readAsBytes();

[Brian Wilkerson, 2014/06/23 19:52:32]

Similar question. If readAsBytes throws an exception when the file doesn't
exist, it might be faster and equally safe (because of possible external
changes) to just try reading it and handle the exception when it is thrown.

[scheglov, 2014/06/23 20:00:22]

Done.

+    });
+  }
+
+  @override
+  Future write(String name, List<int> bytes) {
+    return _getFile(name).writeAsBytes(bytes);
+  }
+
+  File _getFile(String name) {
+    String path = pathos.join(_base.path, name);
+    return new File(path);
+  }
+}