Use non-null properties in messages.dart, use objc associated for the…

… document picker callback.

packages/file_selector/file_selector_ios/example/ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-platform :ios, '11.0'
+# platform :ios, '11.0'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'

packages/file_selector/file_selector_ios/example/ios/RunnerTests/FileSelectorTests.m

@@ -23,7 +23,7 @@ - (void)testPickerPresents {
   plugin.documentPickerViewControllerOverride = picker;
   plugin.presentingViewControllerOverride = mockPresentingVC;
 
-  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:nil
+  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:@[]
                                                      allowMultiSelection:@NO]
                           completion:^(NSArray<NSString *> *paths, FlutterError *error){
                           }];
@@ -40,7 +40,8 @@ - (void)testReturnsPickedFiles {
   UIDocumentPickerViewController *picker =
       [[UIDocumentPickerViewController alloc] initWithDocumentTypes:@[]
                                                              inMode:UIDocumentPickerModeImport];
-  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:nil
+  plugin.documentPickerViewControllerOverride = picker;
+  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:@[]
                                                      allowMultiSelection:@YES]
                           completion:^(NSArray<NSString *> *paths, FlutterError *error) {
                             NSArray *expectedPaths = @[ @"/file1.txt", @"/file2.txt" ];
@@ -52,7 +53,6 @@ - (void)testReturnsPickedFiles {
         [NSURL URLWithString:@"file:///file1.txt"], [NSURL URLWithString:@"file:///file2.txt"]
       ]];
   [self waitForExpectations:@[ completionWasCalled ] timeout:1.0];
-  XCTAssertNil(plugin.pendingCompletion);
 }
 
 - (void)testReturnsPickedFileLegacy {
@@ -63,7 +63,7 @@ - (void)testReturnsPickedFileLegacy {
       [[UIDocumentPickerViewController alloc] initWithDocumentTypes:@[]
                                                              inMode:UIDocumentPickerModeImport];
   plugin.documentPickerViewControllerOverride = picker;
-  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:nil
+  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:@[]
                                                      allowMultiSelection:@NO]
                           completion:^(NSArray<NSString *> *paths, FlutterError *error) {
                             NSArray *expectedPaths = @[ @"/file1.txt" ];
@@ -75,7 +75,6 @@ - (void)testReturnsPickedFileLegacy {
   [plugin documentPicker:picker didPickDocumentAtURL:[NSURL URLWithString:@"file:///file1.txt"]];
 #pragma GCC diagnostic pop
   [self waitForExpectations:@[ completionWasCalled ] timeout:1.0];
-  XCTAssertNil(plugin.pendingCompletion);
 }
 
 - (void)testCancellingPickerReturnsNil {
@@ -86,32 +85,14 @@ - (void)testCancellingPickerReturnsNil {
   plugin.documentPickerViewControllerOverride = picker;
 
   XCTestExpectation *completionWasCalled = [[XCTestExpectation alloc] init];
-  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:nil
+  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:@[]
                                                      allowMultiSelection:@NO]
                           completion:^(NSArray<NSString *> *paths, FlutterError *error) {
                             XCTAssertEqual(paths.count, 0);
                             [completionWasCalled fulfill];
                           }];
   [plugin documentPickerWasCancelled:picker];
   [self waitForExpectations:@[ completionWasCalled ] timeout:1.0];
-  XCTAssertNil(plugin.pendingCompletion);
-}
-
-- (void)testOpenFileSelectorWithPendingCompletionReturnsError {
-  FFSFileSelectorPlugin *plugin = [[FFSFileSelectorPlugin alloc] init];
-  plugin.pendingCompletion = ^(NSArray<NSString *> *paths, FlutterError *error) {
-  };
-
-  XCTestExpectation *completionWasCalled =
-      [[XCTestExpectation alloc] initWithDescription:@"Completion was called"];
-  [plugin openFileSelectorWithConfig:[FFSFileSelectorConfig makeWithUtis:nil
-                                                     allowMultiSelection:@NO]
-                          completion:^(NSArray<NSString *> *paths, FlutterError *error) {
-                            XCTAssertNotNil(error);
-                            [completionWasCalled fulfill];
-                          }];
-
-  [self waitForExpectations:@[ completionWasCalled ] timeout:1.0];
 }
 
 @end

packages/file_selector/file_selector_ios/ios/Classes/FFSFileSelectorPlugin.m

@@ -6,33 +6,32 @@
 #import "FFSFileSelectorPlugin_Test.h"
 #import "messages.g.h"
 
+#import <objc/runtime.h>
+
 @implementation FFSFileSelectorPlugin
 
 #pragma mark - FFSFileSelectorApi
 
 - (void)openFileSelectorWithConfig:(FFSFileSelectorConfig *)config
-                        completion:(void (^)(NSArray<NSString *> * _Nullable,
-                                             FlutterError * _Nullable))completion {
-  if (self.pendingCompletion) {
-    completion(nil, [FlutterError errorWithCode:@"error"
-                                        message:@"There is already a pending file picker request."
-                                        details:nil]);
-    return;
-  }
-
-  UIDocumentPickerViewController *documentPicker = self.documentPickerViewControllerOverride ?:
-  [[UIDocumentPickerViewController alloc] initWithDocumentTypes:config.utis
-                                                         inMode:UIDocumentPickerModeImport];
+                        completion:(void (^)(NSArray<NSString *> *_Nullable,
+                                             FlutterError *_Nullable))completion {
+  UIDocumentPickerViewController *documentPicker =
+      self.documentPickerViewControllerOverride
+          ?: [[UIDocumentPickerViewController alloc]
+                 initWithDocumentTypes:config.utis
+                                inMode:UIDocumentPickerModeImport];
   documentPicker.delegate = self;
   if (@available(iOS 11.0, *)) {
     documentPicker.allowsMultipleSelection = config.allowMultiSelection.boolValue;
   }
 
-  UIViewController *presentingVC = self.presentingViewControllerOverride ?:
-      UIApplication.sharedApplication.delegate.window.rootViewController;
+  UIViewController *presentingVC =
+      self.presentingViewControllerOverride
+          ?: UIApplication.sharedApplication.delegate.window.rootViewController;
   if (presentingVC) {
+    objc_setAssociatedObject(documentPicker, @selector(openFileSelectorWithConfig:completion:),
+                             completion, OBJC_ASSOCIATION_COPY_NONATOMIC);
     [presentingVC presentViewController:documentPicker animated:YES completion:nil];
-    self.pendingCompletion = completion;
   } else {
     completion(nil, [FlutterError errorWithCode:@"error"
                                         message:@"Missing root view controller."
@@ -50,30 +49,35 @@ + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
 #pragma mark - UIDocumentPickerDelegate
 
 - (void)documentPicker:(UIDocumentPickerViewController *)controller
-  didPickDocumentAtURL:(NSURL *)url {
+    didPickDocumentAtURL:(NSURL *)url {
   // This method is only called in iOS < 11.0.
-  if (self.pendingCompletion) {
-    self.pendingCompletion(@[ url.path ], nil);
-    self.pendingCompletion = nil;
-  }
+  [self sendBackResults:@[ url.path ] error:nil forPicker:controller];
 }
 
 - (void)documentPicker:(UIDocumentPickerViewController *)controller
     didPickDocumentsAtURLs:(NSArray<NSURL *> *)urls {
-  if (self.pendingCompletion) {
-    NSMutableArray *paths = [NSMutableArray arrayWithCapacity:urls.count];
-    [urls enumerateObjectsUsingBlock:^(NSURL *url, NSUInteger idx, BOOL *stop) {
-      [paths addObject:url.path];
-    }];
-    self.pendingCompletion(paths, nil);
-    self.pendingCompletion = nil;
-  }
+  NSMutableArray *paths = [NSMutableArray arrayWithCapacity:urls.count];
+  [urls enumerateObjectsUsingBlock:^(NSURL *url, NSUInteger idx, BOOL *stop) {
+    [paths addObject:url.path];
+  }];
+  [self sendBackResults:paths error:nil forPicker:controller];
 }
 
 - (void)documentPickerWasCancelled:(UIDocumentPickerViewController *)controller {
-  if (self.pendingCompletion) {
-    self.pendingCompletion(nil, nil);
-    self.pendingCompletion = nil;
+  [self sendBackResults:@[] error:nil forPicker:controller];
+}
+
+#pragma mark - Helper Methods
+
+- (void)sendBackResults:(NSArray<NSString *> *)results
+                  error:(FlutterError *)error
+              forPicker:(UIDocumentPickerViewController *)picker {
+  void (^completionBlock)(NSArray<NSString *> *, FlutterError *) =
+      objc_getAssociatedObject(picker, @selector(openFileSelectorWithConfig:completion:));
+  if (completionBlock) {
+    completionBlock(results, error);
+    objc_setAssociatedObject(picker, @selector(openFileSelectorWithConfig:completion:), nil,
+                             OBJC_ASSOCIATION_ASSIGN);
   }
 }
 

packages/file_selector/file_selector_ios/ios/Classes/FFSFileSelectorPlugin_Test.h

@@ -5,12 +5,6 @@
 // This header is available in the Test module. Import via "@import file_selector_ios.Test;".
 @interface FFSFileSelectorPlugin() <FFSFileSelectorApi, UIDocumentPickerDelegate>
 
-/**
- * The completion block of a FFSFileSelectorApi request.
- * It is saved and invoked later in a UIDocumentPickerDelegate method.
- */
-@property(nonatomic) void (^_Nullable pendingCompletion)
-    (NSArray<NSString *> *_Nullable, FlutterError *_Nullable);
 /**
  * Overrides the view controller used for presenting the document picker.
  */

packages/file_selector/file_selector_ios/ios/Classes/FileSelectorPlugin.modulemap

@@ -7,4 +7,4 @@ framework module file_selector_ios {
   explicit module Test {
     header "FFSFileSelectorPlugin_Test.h"
   }
-}
+}

packages/file_selector/file_selector_ios/ios/Classes/messages.g.h

@@ -14,10 +14,12 @@ NS_ASSUME_NONNULL_BEGIN
 @class FFSFileSelectorConfig;
 
 @interface FFSFileSelectorConfig : NSObject
-+ (instancetype)makeWithUtis:(nullable NSArray<NSString *> *)utis
-    allowMultiSelection:(nullable NSNumber *)allowMultiSelection;
-@property(nonatomic, strong, nullable) NSArray<NSString *> * utis;
-@property(nonatomic, strong, nullable) NSNumber * allowMultiSelection;
+/// `init` unavailable to enforce nonnull fields, see the `make` class method.
+- (instancetype)init NS_UNAVAILABLE;
++ (instancetype)makeWithUtis:(NSArray<NSString *> *)utis
+    allowMultiSelection:(NSNumber *)allowMultiSelection;
+@property(nonatomic, strong) NSArray<NSString *> * utis;
+@property(nonatomic, strong) NSNumber * allowMultiSelection;
 @end
 
 /// The codec used by FFSFileSelectorApi.

packages/file_selector/file_selector_ios/ios/Classes/messages.g.m

@@ -41,8 +41,8 @@ - (NSDictionary *)toMap;
 @end
 
 @implementation FFSFileSelectorConfig
-+ (instancetype)makeWithUtis:(nullable NSArray<NSString *> *)utis
-    allowMultiSelection:(nullable NSNumber *)allowMultiSelection {
++ (instancetype)makeWithUtis:(NSArray<NSString *> *)utis
+    allowMultiSelection:(NSNumber *)allowMultiSelection {
   FFSFileSelectorConfig* pigeonResult = [[FFSFileSelectorConfig alloc] init];
   pigeonResult.utis = utis;
   pigeonResult.allowMultiSelection = allowMultiSelection;
@@ -51,7 +51,9 @@ + (instancetype)makeWithUtis:(nullable NSArray<NSString *> *)utis
 + (FFSFileSelectorConfig *)fromMap:(NSDictionary *)dict {
   FFSFileSelectorConfig *pigeonResult = [[FFSFileSelectorConfig alloc] init];
   pigeonResult.utis = GetNullableObject(dict, @"utis");
+  NSAssert(pigeonResult.utis != nil, @"");
   pigeonResult.allowMultiSelection = GetNullableObject(dict, @"allowMultiSelection");
+  NSAssert(pigeonResult.allowMultiSelection != nil, @"");
   return pigeonResult;
 }
 + (nullable FFSFileSelectorConfig *)nullableFromMap:(NSDictionary *)dict { return (dict) ? [FFSFileSelectorConfig fromMap:dict] : nil; }

packages/file_selector/file_selector_ios/lib/file_selector_ios.dart

@@ -21,11 +21,11 @@ class FileSelectorIOS extends FileSelectorPlatform {
     String? initialDirectory,
     String? confirmButtonText,
   }) async {
-    final List<String>? path = (await _hostApi.openFile(FileSelectorConfig(
+    final List<String> path = (await _hostApi.openFile(FileSelectorConfig(
             utis: _allowedUtiListFromTypeGroups(acceptedTypeGroups),
             allowMultiSelection: false)))
-        ?.cast<String>();
-    return path == null ? null : XFile(path.first);
+        .cast<String>();
+    return path.isEmpty ? null : XFile(path.first);
   }
 
   @override
@@ -34,24 +34,24 @@ class FileSelectorIOS extends FileSelectorPlatform {
     String? initialDirectory,
     String? confirmButtonText,
   }) async {
-    final List<String>? pathList = (await _hostApi.openFile(FileSelectorConfig(
+    final List<String> pathList = (await _hostApi.openFile(FileSelectorConfig(
             utis: _allowedUtiListFromTypeGroups(acceptedTypeGroups),
             allowMultiSelection: true)))
-        ?.cast<String>();
-    return pathList?.map((String path) => XFile(path)).toList() ?? <XFile>[];
+        .cast<String>();
+    return pathList.map((String path) => XFile(path)).toList();
   }
 
   // Converts the type group list into a list of all allowed UTIs, since
   // iOS doesn't support filter groups.
-  List<String>? _allowedUtiListFromTypeGroups(List<XTypeGroup>? typeGroups) {
+  List<String> _allowedUtiListFromTypeGroups(List<XTypeGroup>? typeGroups) {
     if (typeGroups == null || typeGroups.isEmpty) {
-      return null;
+      return [];
     }
     final List<String> allowedUTIs = <String>[];
     for (final XTypeGroup typeGroup in typeGroups) {
       // If any group allows everything, no filtering should be done.
       if (typeGroup.allowsAny) {
-        return null;
+        return [];
       }
       if (typeGroup.macUTIs?.isEmpty ?? true) {
         throw ArgumentError('The provided type group $typeGroup should either '

packages/file_selector/file_selector_ios/lib/src/messages.g.dart

@@ -12,12 +12,12 @@ import 'package:flutter/services.dart';
 
 class FileSelectorConfig {
   FileSelectorConfig({
-    this.utis,
-    this.allowMultiSelection,
+    required this.utis,
+    required this.allowMultiSelection,
   });
 
-  List<String?>? utis;
-  bool? allowMultiSelection;
+  List<String?> utis;
+  bool allowMultiSelection;
 
   Object encode() {
     final Map<Object?, Object?> pigeonMap = <Object?, Object?>{};
@@ -29,8 +29,8 @@ class FileSelectorConfig {
   static FileSelectorConfig decode(Object message) {
     final Map<Object?, Object?> pigeonMap = message as Map<Object?, Object?>;
     return FileSelectorConfig(
-      utis: (pigeonMap['utis'] as List<Object?>?)?.cast<String?>(),
-      allowMultiSelection: pigeonMap['allowMultiSelection'] as bool?,
+      utis: (pigeonMap['utis'] as List<Object?>?)!.cast<String?>(),
+      allowMultiSelection: pigeonMap['allowMultiSelection']! as bool,
     );
   }
 }
@@ -70,7 +70,7 @@ class FileSelectorApi {
 
   static const MessageCodec<Object?> codec = _FileSelectorApiCodec();
 
-  Future<List<String?>?> openFile(FileSelectorConfig arg_config) async {
+  Future<List<String?>> openFile(FileSelectorConfig arg_config) async {
     final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
         'dev.flutter.pigeon.FileSelectorApi.openFile', codec, binaryMessenger: _binaryMessenger);
     final Map<Object?, Object?>? replyMap =
@@ -87,8 +87,13 @@ class FileSelectorApi {
         message: error['message'] as String?,
         details: error['details'],
       );
+    } else if (replyMap['result'] == null) {
+      throw PlatformException(
+        code: 'null-error',
+        message: 'Host platform returned null value for non-null return value.',
+      );
     } else {
-      return (replyMap['result'] as List<Object?>?)?.cast<String?>();
+      return (replyMap['result'] as List<Object?>?)!.cast<String?>();
     }
   }
 }

packages/file_selector/file_selector_ios/pigeons/messages.dart

@@ -17,13 +17,13 @@ import 'package:pigeon/pigeon.dart';
 class FileSelectorConfig {
   FileSelectorConfig(
       {this.utis = const <String?>[], this.allowMultiSelection = false});
-  List<String?>? utis;
-  bool? allowMultiSelection;
+  List<String?> utis;
+  bool allowMultiSelection;
 }
 
 @HostApi(dartHostTestHandler: 'TestFileSelectorApi')
 abstract class FileSelectorApi {
   @async
   @ObjCSelector('openFileSelectorWithConfig:')
-  List<String>? openFile(FileSelectorConfig config);
+  List<String> openFile(FileSelectorConfig config);
 }

packages/file_selector/file_selector_ios/pubspec.yaml

@@ -1,6 +1,6 @@
 name: file_selector_ios
 description: iOS implementation of the file_selector plugin.
-repository: https://github.com/flutter/plugins/tree/master/packages/file_selector/file_selector_ios
+repository: https://github.com/flutter/plugins/tree/main/packages/file_selector/file_selector_ios
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+file_selector%22
 version: 0.5.0
 

packages/file_selector/file_selector_ios/test/file_selector_ios_test.mocks.dart

@@ -31,8 +31,8 @@ class MockTestFileSelectorApi extends _i1.Mock
   }
 
   @override
-  _i3.Future<List<String?>?> openFile(_i4.FileSelectorConfig? config) =>
+  _i3.Future<List<String?>> openFile(_i4.FileSelectorConfig? config) =>
       (super.noSuchMethod(Invocation.method(#openFile, [config]),
-              returnValue: _i3.Future<List<String?>?>.value())
-          as _i3.Future<List<String?>?>);
+              returnValue: _i3.Future<List<String?>>.value(<String?>[]))
+          as _i3.Future<List<String?>>);
 }

packages/file_selector/file_selector_ios/test/test_api.dart

@@ -43,7 +43,7 @@ class _TestFileSelectorApiCodec extends StandardMessageCodec {
 abstract class TestFileSelectorApi {
   static const MessageCodec<Object?> codec = _TestFileSelectorApiCodec();
 
-  Future<List<String?>?> openFile(FileSelectorConfig config);
+  Future<List<String?>> openFile(FileSelectorConfig config);
   static void setup(TestFileSelectorApi? api,
       {BinaryMessenger? binaryMessenger}) {
     {
@@ -61,7 +61,7 @@ abstract class TestFileSelectorApi {
               (args[0] as FileSelectorConfig?);
           assert(arg_config != null,
               'Argument for dev.flutter.pigeon.FileSelectorApi.openFile was null, expected non-null FileSelectorConfig.');
-          final List<String?>? output = await api.openFile(arg_config!);
+          final List<String?> output = await api.openFile(arg_config!);
           return <Object?, Object?>{'result': output};
         });
       }