Move byte_store.dart and file_byte_store.dart to their own subdirectory.

pkg/front_end/lib/src/incremental/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 'dart:async';
-import 'dart:io';
-import 'dart:isolate';
-
-import 'package:front_end/src/incremental/byte_store.dart';
-import 'package:path/path.dart';
-
-/**
- * The request that is sent from the main isolate to the clean-up isolate.
- */
-class CacheCleanUpRequest {
-  final String cachePath;
-  final int maxSizeBytes;
-  final SendPort replyTo;
-
-  CacheCleanUpRequest(this.cachePath, this.maxSizeBytes, this.replyTo);
-}
-
-/**
- * [ByteStore] that stores values as files and performs cache eviction.
- *
- * Only the process that manages the cache, e.g. Analysis Server, should use
- * this class. Other processes, e.g. Analysis Server plugins, should use
- * [FileByteStore] instead and let the main process to perform eviction.
- */
-class EvictingFileByteStore implements ByteStore {
-  static bool _cleanUpSendPortShouldBePrepared = true;
-  static SendPort _cleanUpSendPort;
-
-  final String _cachePath;
-  final int _maxSizeBytes;
-  final FileByteStore _fileByteStore;
-
-  int _bytesWrittenSinceCleanup = 0;
-  bool _evictionIsolateIsRunning = false;
-
-  EvictingFileByteStore(this._cachePath, this._maxSizeBytes)
-      : _fileByteStore = new FileByteStore(_cachePath) {
-    _requestCacheCleanUp();
-  }
-
-  @override
-  List<int> get(String key) {
-    return _fileByteStore.get(key);
-  }
-
-  @override
-  void put(String key, List<int> bytes) {
-    _fileByteStore.put(key, bytes);
-    // Update the current size.
-    _bytesWrittenSinceCleanup += bytes.length;
-    if (_bytesWrittenSinceCleanup > _maxSizeBytes ~/ 8) {
-      _requestCacheCleanUp();
-    }
-  }
-
-  /**
-   * If the cache clean up process has not been requested yet, request it.
-   */
-  Future<Null> _requestCacheCleanUp() async {
-    if (_cleanUpSendPortShouldBePrepared) {
-      _cleanUpSendPortShouldBePrepared = false;
-      ReceivePort response = new ReceivePort();
-      await Isolate.spawn(_cacheCleanUpFunction, response.sendPort);
-      _cleanUpSendPort = await response.first as SendPort;
-    } else {
-      while (_cleanUpSendPort == null) {
-        await new Future.delayed(new Duration(milliseconds: 100), () {});
-      }
-    }
-
-    if (!_evictionIsolateIsRunning) {
-      _evictionIsolateIsRunning = true;
-      try {
-        ReceivePort response = new ReceivePort();
-        _cleanUpSendPort.send(new CacheCleanUpRequest(
-            _cachePath, _maxSizeBytes, response.sendPort));
-        await response.first;
-      } finally {
-        _evictionIsolateIsRunning = false;
-        _bytesWrittenSinceCleanup = 0;
-      }
-    }
-  }
-
-  /**
-   * This function is started in a new isolate, receives cache folder clean up
-   * requests and evicts older files from the folder.
-   */
-  static void _cacheCleanUpFunction(SendPort initialReplyTo) {
-    ReceivePort port = new ReceivePort();
-    initialReplyTo.send(port.sendPort);
-    port.listen((request) async {
-      if (request is CacheCleanUpRequest) {
-        await _cleanUpFolder(request.cachePath, request.maxSizeBytes);
-        // Let the client know that we're done.
-        request.replyTo.send(true);
-      }
-    });
-  }
-
-  static Future<Null> _cleanUpFolder(String cachePath, int maxSizeBytes) async {
-    // Prepare the list of files and their statistics.
-    List<File> files = <File>[];
-    Map<File, FileStat> fileStatMap = {};
-    int currentSizeBytes = 0;
-    List<FileSystemEntity> resources = new Directory(cachePath).listSync();
-    for (FileSystemEntity resource in resources) {
-      if (resource is File) {
-        try {
-          FileStat fileStat = await resource.stat();
-          files.add(resource);
-          fileStatMap[resource] = fileStat;
-          currentSizeBytes += fileStat.size;
-        } catch (_) {}
-      }
-    }
-    files.sort((a, b) {
-      return fileStatMap[a].accessed.millisecondsSinceEpoch -
-          fileStatMap[b].accessed.millisecondsSinceEpoch;
-    });
-
-    // Delete files until the current size is less than the max.
-    for (File file in files) {
-      if (currentSizeBytes < maxSizeBytes) {
-        break;
-      }
-      try {
-        await file.delete();
-      } catch (_) {}
-      currentSizeBytes -= fileStatMap[file].size;
-    }
-  }
-}
-
-/**
- * [ByteStore] that stores values as files.
- */
-class FileByteStore implements ByteStore {
-  final String _cachePath;
-  final String _tempName = 'temp_$pid';
-
-  FileByteStore(this._cachePath);
-
-  @override
-  List<int> get(String key) {
-    try {
-      return _getFileForKey(key).readAsBytesSync();
-    } catch (_) {
-      return null;
-    }
-  }
-
-  @override
-  void put(String key, List<int> bytes) {
-    try {
-      File tempFile = _getFileForKey(_tempName);
-      tempFile.writeAsBytesSync(bytes);
-      File file = _getFileForKey(key);
-      tempFile.renameSync(file.path);
-    } catch (_) {}
-  }
-
-  File _getFileForKey(String key) {
-    return new File(join(_cachePath, key));
-  }
-}