[path_provider_linux] Migrate to null safety (flutter#3330)

Author: yash1200

packages/path_provider/path_provider_linux/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.2.0-nullsafety
+
+* Migrate to null safety.
+
 ## 0.1.1+3
 
 * Update Flutter SDK constraint.

packages/path_provider/path_provider_linux/example/integration_test/path_provider_test.dart

@@ -4,40 +4,45 @@
 
 import 'dart:io';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:path_provider/path_provider.dart';
+import 'package:path_provider_linux/path_provider_linux.dart';
 import 'package:integration_test/integration_test.dart';
 
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 
   testWidgets('getTemporaryDirectory', (WidgetTester tester) async {
-    final Directory result = await getTemporaryDirectory();
+    final PathProviderLinux provider = PathProviderLinux();
+    final String result = await provider.getTemporaryPath();
     _verifySampleFile(result, 'temporaryDirectory');
   });
 
   testWidgets('getDownloadDirectory', (WidgetTester tester) async {
     if (!Platform.isLinux) {
       return;
     }
-    final Directory result = await getDownloadsDirectory();
+    final PathProviderLinux provider = PathProviderLinux();
+    final String result = await provider.getDownloadsPath();
     _verifySampleFile(result, 'downloadDirectory');
   });
 
   testWidgets('getApplicationDocumentsDirectory', (WidgetTester tester) async {
-    final Directory result = await getApplicationDocumentsDirectory();
+    final PathProviderLinux provider = PathProviderLinux();
+    final String result = await provider.getApplicationDocumentsPath();
     _verifySampleFile(result, 'applicationDocuments');
   });
 
   testWidgets('getApplicationSupportDirectory', (WidgetTester tester) async {
-    final Directory result = await getApplicationSupportDirectory();
+    final PathProviderLinux provider = PathProviderLinux();
+    final String result = await provider.getApplicationSupportPath();
     _verifySampleFile(result, 'applicationSupport');
   });
 }
 
-/// Verify a file called [name] in [directory] by recreating it with test
+/// Verify a file called [name] in [directoryPath] by recreating it with test
 /// contents when necessary.
-void _verifySampleFile(Directory directory, String name) {
-  final File file = File('${directory.path}/$name');
+void _verifySampleFile(String directoryPath, String name) {
+  final Directory directory = Directory(directoryPath);
+  final File file = File('${directory.path}${Platform.pathSeparator}$name');
 
   if (file.existsSync()) {
     file.deleteSync();

packages/path_provider/path_provider_linux/example/lib/main.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'dart:async';
 
 import 'package:flutter/services.dart';
-import 'package:path_provider/path_provider.dart';
+import 'package:path_provider_linux/path_provider_linux.dart';
 
 void main() async {
   runApp(MyApp());
@@ -19,6 +19,7 @@ class _MyAppState extends State<MyApp> {
   String _downloadsDirectory = 'Unknown';
   String _appSupportDirectory = 'Unknown';
   String _documentsDirectory = 'Unknown';
+  final PathProviderLinux _provider = PathProviderLinux();
 
   @override
   void initState() {
@@ -34,27 +35,27 @@ class _MyAppState extends State<MyApp> {
     String documentsDirectory;
     // Platform messages may fail, so we use a try/catch PlatformException.
     try {
-      tempDirectory = (await getTemporaryDirectory()).path;
+      tempDirectory = await _provider.getTemporaryPath();
     } on PlatformException catch (e, stackTrace) {
       tempDirectory = 'Failed to get temp directory.';
       print('$tempDirectory $e $stackTrace');
     }
     try {
-      downloadsDirectory = (await getDownloadsDirectory()).path;
+      downloadsDirectory = await _provider.getDownloadsPath();
     } on PlatformException catch (e, stackTrace) {
       downloadsDirectory = 'Failed to get downloads directory.';
       print('$downloadsDirectory $e $stackTrace');
     }
 
     try {
-      documentsDirectory = (await getApplicationDocumentsDirectory()).path;
+      documentsDirectory = await _provider.getApplicationDocumentsPath();
     } on PlatformException catch (e, stackTrace) {
       documentsDirectory = 'Failed to get documents directory.';
       print('$documentsDirectory $e $stackTrace');
     }
 
     try {
-      appSupportDirectory = (await getApplicationSupportDirectory()).path;
+      appSupportDirectory = await _provider.getApplicationSupportPath();
     } on PlatformException catch (e, stackTrace) {
       appSupportDirectory = 'Failed to get documents directory.';
       print('$appSupportDirectory $e $stackTrace');

packages/path_provider/path_provider_linux/example/pubspec.yaml

@@ -9,7 +9,7 @@ dependencies:
   flutter:
     sdk: flutter
 
-  path_provider: ^1.6.10
+  path_provider_linux: any
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.

packages/path_provider/path_provider_linux/lib/path_provider_linux.dart

@@ -18,12 +18,12 @@ class PathProviderLinux extends PathProviderPlatform {
   }
 
   @override
-  Future<String> getTemporaryPath() {
+  Future<String?> getTemporaryPath() {
     return Future.value("/tmp");
   }
 
   @override
-  Future<String> getApplicationSupportPath() async {
+  Future<String?> getApplicationSupportPath() async {
     final processName = path.basenameWithoutExtension(
         await File('/proc/self/exe').resolveSymbolicLinks());
     final directory = Directory(path.join(xdg.dataHome.path, processName));
@@ -35,12 +35,12 @@ class PathProviderLinux extends PathProviderPlatform {
   }
 
   @override
-  Future<String> getApplicationDocumentsPath() {
-    return Future.value(xdg.getUserDirectory('DOCUMENTS').path);
+  Future<String?> getApplicationDocumentsPath() {
+    return Future.value(xdg.getUserDirectory('DOCUMENTS')?.path);
   }
 
   @override
-  Future<String> getDownloadsPath() {
-    return Future.value(xdg.getUserDirectory('DOWNLOAD').path);
+  Future<String?> getDownloadsPath() {
+    return Future.value(xdg.getUserDirectory('DOWNLOAD')?.path);
   }
 }

packages/path_provider/path_provider_linux/pubspec.yaml

@@ -1,6 +1,6 @@
 name: path_provider_linux
 description: linux implementation of the path_provider plugin
-version: 0.1.1+3
+version: 0.2.0-nullsafety
 homepage: https://github.com/flutter/plugins/tree/master/packages/path_provider/path_provider_linux
 
 flutter:
@@ -11,17 +11,17 @@ flutter:
         pluginClass: none
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
   flutter: ">=1.10.0"
 
 dependencies:
-  path: ^1.6.4
-  xdg_directories: ^0.1.0
-  path_provider_platform_interface: ^1.0.1
+  path: ^1.8.0-nullsafety.3
+  xdg_directories: ^0.2.0-nullsafety.1
+  path_provider_platform_interface: ^2.0.0-nullsafety
   flutter:
     sdk: flutter
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0-nullsafety.3