blob: 738ccdc6cba2d31845fa72fa1ae737486a986524 [file] [log] [blame]
// Copyright 2013 The Flutter Authors. 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:convert' show json;
import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:flutter/foundation.dart' show debugPrint, visibleForTesting;
import 'package:path/path.dart' as path;
import 'package:path_provider_linux/path_provider_linux.dart';
import 'package:shared_preferences_platform_interface/shared_preferences_platform_interface.dart';
/// The Linux implementation of [SharedPreferencesStorePlatform].
///
/// This class implements the `package:shared_preferences` functionality for Linux.
class SharedPreferencesLinux extends SharedPreferencesStorePlatform {
/// Deprecated instance of [SharedPreferencesLinux].
/// Use [SharedPreferencesStorePlatform.instance] instead.
@Deprecated('Use `SharedPreferencesStorePlatform.instance` instead.')
static SharedPreferencesLinux instance = SharedPreferencesLinux();
static const String _defaultPrefix = 'flutter.';
/// Registers the Linux implementation.
static void registerWith() {
SharedPreferencesStorePlatform.instance = SharedPreferencesLinux();
}
/// Local copy of preferences
Map<String, Object>? _cachedPreferences;
/// File system used to store to disk. Exposed for testing only.
@visibleForTesting
FileSystem fs = const LocalFileSystem();
/// The path_provider_linux instance used to find the support directory.
@visibleForTesting
PathProviderLinux pathProvider = PathProviderLinux();
/// Gets the file where the preferences are stored.
Future<File?> _getLocalDataFile() async {
final String? directory = await pathProvider.getApplicationSupportPath();
if (directory == null) {
return null;
}
return fs.file(path.join(directory, 'shared_preferences.json'));
}
/// Gets the preferences from the stored file and saves them in cache.
Future<Map<String, Object>> _reload() async {
Map<String, Object> preferences = <String, Object>{};
final File? localDataFile = await _getLocalDataFile();
if (localDataFile != null && localDataFile.existsSync()) {
final String stringMap = localDataFile.readAsStringSync();
if (stringMap.isNotEmpty) {
final Object? data = json.decode(stringMap);
if (data is Map) {
preferences = data.cast<String, Object>();
}
}
}
_cachedPreferences = preferences;
return preferences;
}
/// Checks for cached preferences and returns them or loads preferences from
/// file and returns and caches them.
Future<Map<String, Object>> _readPreferences() async {
return _cachedPreferences ?? await _reload();
}
/// Writes the cached preferences to disk. Returns [true] if the operation
/// succeeded.
Future<bool> _writePreferences(Map<String, Object> preferences) async {
try {
final File? localDataFile = await _getLocalDataFile();
if (localDataFile == null) {
debugPrint('Unable to determine where to write preferences.');
return false;
}
if (!localDataFile.existsSync()) {
localDataFile.createSync(recursive: true);
}
final String stringMap = json.encode(preferences);
localDataFile.writeAsStringSync(stringMap);
} catch (e) {
debugPrint('Error saving preferences to disk: $e');
return false;
}
return true;
}
@override
Future<bool> clear() async {
return clearWithPrefix(_defaultPrefix);
}
@override
Future<bool> clearWithPrefix(String prefix) async {
final Map<String, Object> preferences = await _readPreferences();
preferences.removeWhere((String key, _) => key.startsWith(prefix));
return _writePreferences(preferences);
}
@override
Future<Map<String, Object>> getAll() async {
return getAllWithPrefix(_defaultPrefix);
}
@override
Future<Map<String, Object>> getAllWithPrefix(String prefix) async {
final Map<String, Object> withPrefix =
Map<String, Object>.from(await _readPreferences());
withPrefix.removeWhere((String key, _) => !key.startsWith(prefix));
return withPrefix;
}
@override
Future<bool> remove(String key) async {
final Map<String, Object> preferences = await _readPreferences();
preferences.remove(key);
return _writePreferences(preferences);
}
@override
Future<bool> setValue(String valueType, String key, Object value) async {
final Map<String, Object> preferences = await _readPreferences();
preferences[key] = value;
return _writePreferences(preferences);
}
}