Add a converter from Dart Stream to NSInputStream

pkgs/ffigen/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Bump minimum Dart version to 3.4.
 - Dedupe `ObjCBlock` trampolines to reduce generated ObjC code.
+- Update to latest `package:objective_c`.
 - ObjC objects now include the methods from the protocols they implement. Both
   required and optional methods are included. Optional methods will throw an
   exception if the method isn't implemented.

pkgs/ffigen/lib/src/code_generator/objc_built_in_functions.dart

@@ -45,8 +45,10 @@ class ObjCBuiltInFunctions {
       ObjCImport('UnimplementedOptionalMethodException');
 
   // Keep in sync with pkgs/objective_c/ffigen_objc.yaml.
+
   @visibleForTesting
   static const builtInInterfaces = {
+    'DartInputStreamAdapter',
     'DartProxy',
     'DartProxyBuilder',
     'NSArray',
@@ -58,6 +60,7 @@ class ObjCBuiltInFunctions {
     'NSEnumerator',
     'NSError',
     'NSIndexSet',
+    'NSInputStream',
     'NSInvocation',
     'NSItemProvider',
     'NSLocale',
@@ -73,8 +76,11 @@ class ObjCBuiltInFunctions {
     'NSNumber',
     'NSObject',
     'NSOrderedSet',
+    'NSOutputStream',
     'NSProxy',
+    'NSRunLoop',
     'NSSet',
+    'NSStream',
     'NSString',
     'NSURL',
     'NSURLHandle',
@@ -104,13 +110,19 @@ class ObjCBuiltInFunctions {
     'NSKeyValueSetMutationKind',
     'NSOrderedCollectionDifferenceCalculationOptions',
     'NSSortOptions',
+    'NSStreamEvent',
+    'NSStreamStatus',
     'NSStringCompareOptions',
     'NSStringEncodingConversionOptions',
     'NSStringEnumerationOptions',
     'NSURLBookmarkCreationOptions',
     'NSURLBookmarkResolutionOptions',
     'NSURLHandleStatus',
   };
+  @visibleForTesting
+  static const builtInProtocols = {
+    'NSStreamDelegate',
+  };
 
   // TODO(https://github.com/dart-lang/native/issues/1173): Ideally this check
   // would be based on more than just the name.
@@ -120,6 +132,8 @@ class ObjCBuiltInFunctions {
       generateForPackageObjectiveC ? null : builtInCompounds[name];
   bool isBuiltInEnum(String name) =>
       !generateForPackageObjectiveC && builtInEnums.contains(name);
+  bool isBuiltInProtocol(String name) =>
+      !generateForPackageObjectiveC && builtInProtocols.contains(name);
   static bool isNSObject(String name) => name == 'NSObject';
 
   // We need to load a separate instance of objc_msgSend for each signature. If

pkgs/ffigen/lib/src/code_generator/objc_protocol.dart

@@ -32,10 +32,11 @@ class ObjCProtocol extends NoLookUpBinding with ObjCMethods {
 
   @override
   void sort() => sortMethods();
+  bool get _isBuiltIn => builtInFunctions.isBuiltInProtocol(originalName);
 
   @override
   BindingString toBindingString(Writer w) {
-    if (!generateBindings) {
+    if (!generateBindings || _isBuiltIn) {
       return const BindingString(
           type: BindingStringType.objcProtocol, string: '');
     }

pkgs/ffigen/pubspec.yaml

@@ -38,7 +38,7 @@ dev_dependencies:
   dart_flutter_team_lints: ^2.0.0
   json_schema: ^5.1.1
   leak_tracker: ^10.0.7
-  objective_c: ^2.1.0
+  objective_c: ^3.0.0
   test: ^1.16.2
 
 dependency_overrides:

pkgs/objective_c/CHANGELOG.md

@@ -1,5 +1,13 @@
-## 2.1.0-wip
-
+## 3.0.0-wip
+
+- Add the following stream-related types to the core package:
+  - `NSInputStream`
+  - `NSOutputStream`
+  - `NSRunLoop`
+  - `NSStream`
+  - `NSStreamDelegate`
+  - `NSStreamEvent`
+  - `NSStreamStatus`
 - Add `UnimplementedOptionalMethodException`, which is thrown by the ObjC
   bindings if an optional method is invoked, and the instance doesn't implement
   the method.

pkgs/objective_c/ffigen_objc.yaml

@@ -8,6 +8,7 @@ output:
 headers:
   entry-points:
     - 'src/foundation.h'
+    - 'src/input_stream_adapter.h'
     - 'src/proxy.h'
 ffi-native:
 exclude-all-by-default: true
@@ -22,6 +23,7 @@ external-versions:
 objc-interfaces:
   # Keep in sync with ffigen's ObjCBuiltInFunctions.builtInInterfaces.
   include:
+    - DartInputStreamAdapter
     - DartProxy
     - DartProxyBuilder
     - NSArray
@@ -33,6 +35,7 @@ objc-interfaces:
     - NSEnumerator
     - NSError
     - NSIndexSet
+    - NSInputStream
     - NSInvocation
     - NSItemProvider
     - NSLocale
@@ -47,14 +50,20 @@ objc-interfaces:
     - NSNotification
     - NSNumber
     - NSObject
+    - NSOutputStream
     - NSOrderedSet
     - NSProxy
+    - NSRunLoop
     - NSSet
+    - NSStream
     - NSString
     - NSURL
     - NSURLHandle
     - NSValue
     - Protocol
+objc-protocols:
+  include:
+    - NSStreamDelegate
 structs:
   include:
     - _NSRange
@@ -79,12 +88,17 @@ enums:
     - NSKeyValueSetMutationKind
     - NSOrderedCollectionDifferenceCalculationOptions
     - NSSortOptions
+    - NSStreamEvent
+    - NSStreamStatus
     - NSStringCompareOptions
     - NSStringEncodingConversionOptions
     - NSStringEnumerationOptions
     - NSURLBookmarkCreationOptions
     - NSURLBookmarkResolutionOptions
     - NSURLHandleStatus
+globals:
+  include:
+    - NSLocalizedDescriptionKey
 preamble: |
   // Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
   // for details. All rights reserved. Use of this source code is governed by a

pkgs/objective_c/ios/Classes/objective_c.m

@@ -4,6 +4,7 @@
 
 // Relative import to be able to reuse the ObjC sources.
 // See the comment in ../objective_c.podspec for more information.
+#include "../../src/input_stream_adapter.m"
 #include "../../src/objective_c.m"
 #include "../../src/objective_c_bindings_generated.m"
 #include "../../src/proxy.m"

pkgs/objective_c/lib/objective_c.dart

@@ -19,6 +19,7 @@ export 'src/internal.dart'
         isValidClass,
         isValidObject;
 export 'src/ns_data.dart';
+export 'src/ns_input_stream.dart';
 export 'src/ns_mutable_data.dart';
 export 'src/ns_string.dart';
 // Keep in sync with pkgs/objective_c/ffigen_objc.yaml.
@@ -45,6 +46,7 @@ export 'src/objective_c_bindings_generated.dart'
         NSError,
         NSFastEnumerationState,
         NSIndexSet,
+        NSInputStream,
         NSInvocation,
         NSItemProvider,
         NSItemProviderFileOptions,
@@ -66,10 +68,16 @@ export 'src/objective_c_bindings_generated.dart'
         NSObject,
         NSOrderedCollectionDifferenceCalculationOptions,
         NSOrderedSet,
+        NSOutputStream,
         NSProxy,
         NSRange,
+        NSRunLoop,
         NSSet,
         NSSortOptions,
+        NSStream,
+        NSStreamDelegate,
+        NSStreamEvent,
+        NSStreamStatus,
         NSString,
         NSStringCompareOptions,
         NSStringEncodingConversionOptions,

pkgs/objective_c/lib/src/ns_input_stream.dart

@@ -0,0 +1,57 @@
+import 'dart:async';
+import 'dart:ffi';
+import 'dart:isolate';
+
+import 'ns_data.dart';
+import 'ns_string.dart';
+import 'objective_c_bindings_generated.dart';
+
+extension NSInputStreamStreamExtension on Stream<List<int>> {
+  /// Return a [NSInputStream] that, when read, will contain the contents of
+  /// the [Stream].
+  ///
+  /// > [!IMPORTANT]
+  /// > [NSInputStream.read_maxLength_] must be called from a different thread
+  /// > or [Isolate] than the one that calls [toNSInputStream]. Otherwise,
+  /// > [NSInputStream.read_maxLength_] will deadlock waiting for data to be
+  /// > added from the [Stream].
+  NSInputStream toNSInputStream() {
+    // Eagerly add data until `maxReadAheadSize` is buffered.
+    const maxReadAheadSize = 4096;
+
+    final port = ReceivePort();
+    final inputStream =
+        DartInputStreamAdapter.inputStreamWithPort_(port.sendPort.nativePort);
+    late final StreamSubscription<dynamic> dataSubscription;
+
+    dataSubscription = listen((data) {
+      if (inputStream.addData_(data.toNSData()) > maxReadAheadSize) {
+        dataSubscription.pause();
+      }
+    }, onError: (Object e) {
+      final d = NSMutableDictionary.new1();
+      d.setObject_forKey_(e.toString().toNSString(), NSLocalizedDescriptionKey);
+      inputStream.setError_(NSError.errorWithDomain_code_userInfo_(
+          'DartError'.toNSString(), 0, d));
+      port.close();
+    }, onDone: () {
+      inputStream.setDone();
+      port.close();
+    }, cancelOnError: true);
+
+    dataSubscription.pause();
+    port.listen((count) {
+      // -1 indicates that the `NSInputStream` is closed. All other values
+      // indicate that the `NSInputStream` needs more data.
+      if (count == -1) {
+        dataSubscription.cancel();
+      } else {
+        dataSubscription.resume();
+      }
+    }, onDone: () {
+      dataSubscription.cancel();
+    });
+
+    return inputStream;
+  }
+}