packages/path_provider/lib/path_provider.dart

// Copyright 2017 The Chromium 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:io';

import 'package:flutter/services.dart';

const MethodChannel _channel =
    MethodChannel('plugins.flutter.io/path_provider');

/// Path to the temporary directory on the device that is not backed up and is
/// suitable for storing caches of downloaded files.
///
/// Files in this directory may be cleared at any time. This does *not* return
/// a new temporary directory. Instead, the caller is responsible for creating
/// (and cleaning up) files or directories within this directory. This
/// directory is scoped to the calling application.
///
/// On iOS, this uses the `NSCachesDirectory` API.
///
/// On Android, this uses the `getCacheDir` API on the context.
Future<Directory> getTemporaryDirectory() async {
  final String path =
      await _channel.invokeMethod<String>('getTemporaryDirectory');
  if (path == null) {
    return null;
  }
  return Directory(path);
}

/// Path to a directory where the application may place application support
/// files.
///
/// Use this for files you don’t want exposed to the user. Your app should not
/// use this directory for user data files.
///
/// On iOS, this uses the `NSApplicationSupportDirectory` API.
/// If this directory does not exist, it is created automatically.
///
/// On Android, this function throws an [UnsupportedError].
Future<Directory> getApplicationSupportDirectory() async {
  if (!Platform.isIOS)
    throw UnsupportedError("getApplicationSupportDirectory requires iOS");
  final String path =
      await _channel.invokeMethod<String>('getApplicationSupportDirectory');
  if (path == null) {
    return null;
  }
  return Directory(path);
}

/// Path to a directory where the application may place data that is
/// user-generated, or that cannot otherwise be recreated by your application.
///
/// On iOS, this uses the `NSDocumentDirectory` API. Consider using
/// [getApplicationSupportDirectory] instead if the data is not user-generated.
///
/// On Android, this uses the `getDataDirectory` API on the context. Consider
/// using getExternalStorageDirectory instead if data is intended to be visible
/// to the user.
Future<Directory> getApplicationDocumentsDirectory() async {
  final String path =
      await _channel.invokeMethod<String>('getApplicationDocumentsDirectory');
  if (path == null) {
    return null;
  }
  return Directory(path);
}

/// Path to a directory where the application may access top level storage.
/// The current operating system should be determined before issuing this
/// function call, as this functionality is only available on Android.
///
/// On iOS, this function throws an [UnsupportedError] as it is not possible
/// to access outside the app's sandbox.
///
/// On Android this uses the `getExternalStorageDirectory` API.
Future<Directory> getExternalStorageDirectory() async {
  if (Platform.isIOS)
    throw UnsupportedError("Functionality not available on iOS");
  final String path =
      await _channel.invokeMethod<String>('getStorageDirectory');
  if (path == null) {
    return null;
  }
  return Directory(path);
}