Handle NS_RETURNS_RETAINED

dart-archive · Nov 1, 2023 · 610d1dc · 610d1dc
1 parent d22cf20
commit 610d1dc
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Showing 8 changed files with 135 additions and 18 deletions.
diff --git a/lib/src/code_generator/func.dart b/lib/src/code_generator/func.dart
@@ -42,6 +42,7 @@ class Func extends LookUpBinding {
   final bool exposeSymbolAddress;
   final bool exposeFunctionTypedefs;
   final bool isLeaf;
+  final bool objCReturnsRetained;
   final FfiNativeConfig ffiNativeConfig;
   late final String funcPointerName;
 
@@ -61,6 +62,7 @@ class Func extends LookUpBinding {
     this.exposeSymbolAddress = false,
     this.exposeFunctionTypedefs = false,
     this.isLeaf = false,
+    this.objCReturnsRetained = false,
     super.isInternal,
     this.ffiNativeConfig = const FfiNativeConfig(enabled: false),
   })  : functionType = FunctionType(
@@ -133,7 +135,7 @@ class Func extends LookUpBinding {
         w,
         '$funcVarName($argString)',
         ffiNativeConfig.enabled ? 'lib' : 'this',
-        objCRetain: true,
+        objCRetain: !objCReturnsRetained,
       );
     } else {
       dartReturnType = ffiReturnType;

diff --git a/lib/src/header_parser/sub_parsers/functiondecl_parser.dart b/lib/src/header_parser/sub_parsers/functiondecl_parser.dart
@@ -2,6 +2,8 @@
 // for details. 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:ffi';
+
 import 'package:ffigen/src/code_generator.dart';
 import 'package:ffigen/src/config_provider/config_types.dart';
 import 'package:ffigen/src/header_parser/data.dart';
@@ -20,6 +22,7 @@ class _ParserFunc {
   List<Func> funcs = [];
   bool incompleteStructParameter = false;
   bool unimplementedParameterType = false;
+  bool objCReturnsRetained = false;
   _ParserFunc();
 }
 
@@ -69,6 +72,13 @@ List<Func>? parseFunctionDeclaration(clang_types.CXCursor cursor) {
       return _stack.pop().funcs;
     }
 
+    // Look for any annotations on the function.
+    clang.clang_visitChildren(
+        cursor,
+        _parseAnnotationVisitorPtr ??= Pointer.fromFunction(
+            _parseAnnotationVisitor, exceptional_visitor_return),
+        nullptr);
+
     // Initialized with a single value with no prefix and empty var args.
     var varArgFunctions = [VarArgFunction('', [])];
     if (config.varArgFunctions.containsKey(funcName)) {
@@ -97,6 +107,7 @@ List<Func>? parseFunctionDeclaration(clang_types.CXCursor cursor) {
         exposeFunctionTypedefs:
             config.exposeFunctionTypedefs.shouldInclude(funcName),
         isLeaf: config.leafFunctions.shouldInclude(funcName),
+        objCReturnsRetained: _stack.top.objCReturnsRetained,
         ffiNativeConfig: config.ffiNativeConfig,
       ));
     }
@@ -147,3 +158,19 @@ List<Parameter> _getParameters(clang_types.CXCursor cursor, String funcName) {
 Type _getParameterType(clang_types.CXCursor cursor) {
   return cursor.toCodeGenType();
 }
+
+Pointer<
+        NativeFunction<
+            Int32 Function(
+                clang_types.CXCursor, clang_types.CXCursor, Pointer<Void>)>>?
+    _parseAnnotationVisitorPtr;
+int _parseAnnotationVisitor(clang_types.CXCursor cursor,
+    clang_types.CXCursor parent, Pointer<Void> clientData) {
+  switch (cursor.kind) {
+    case clang_types.CXCursorKind.CXCursor_NSReturnsRetained:
+      _stack.top.objCReturnsRetained = true;
+      break;
+    default:
+  }
+  return clang_types.CXChildVisitResult.CXChildVisit_Continue;
+}
diff --git a/test/native_objc_test/automated_ref_count_test.m b/test/native_objc_test/automated_ref_count_test.m
@@ -89,6 +89,8 @@ - (ArcTestObject*)returnsRetained NS_RETURNS_RETAINED {
 
 @end
 
+// Pass around the NSAutoreleasePool as a void* to bypass the Dart wrappers so
+// that we can precisely control the life cycle.
 void* createAutoreleasePool() {
   return (void*)[NSAutoreleasePool new];
 }

diff --git a/test/native_objc_test/static_func_config.yaml b/test/native_objc_test/static_func_config.yaml
@@ -9,7 +9,8 @@ functions:
     - staticFuncOfObject
     - staticFuncOfNullableObject
     - staticFuncOfBlock
-    - staticFuncReturningNSString
+    - staticFuncReturnsRetained
+    - staticFuncReturnsRetainedArg
 headers:
   entry-points:
     - 'static_func_test.m'

diff --git a/test/native_objc_test/static_func_native_config.yaml b/test/native_objc_test/static_func_native_config.yaml
@@ -10,7 +10,8 @@ functions:
     - staticFuncOfObject
     - staticFuncOfNullableObject
     - staticFuncOfBlock
-    - staticFuncReturningNSString
+    - staticFuncReturnsRetained
+    - staticFuncReturnsRetainedArg
 headers:
   entry-points:
     - 'static_func_test.m'

diff --git a/test/native_objc_test/static_func_native_test.dart b/test/native_objc_test/static_func_native_test.dart
@@ -44,11 +44,6 @@ void main() {
       calloc.free(gcNow);
     }
 
-    test('Static function returning NSString', () {
-      expect(staticFuncReturningNSString(lib).length, 12);
-      expect(staticFuncReturningNSString(lib).toString(), "Hello World!");
-    });
-
     Pointer<Int32> staticFuncOfObjectRefCountTest(Allocator alloc) {
       final counter = alloc<Int32>();
       counter.value = 0;
@@ -112,5 +107,50 @@ void main() {
       doGC();
       expect(getBlockRetainCount(rawBlock), 0);
     });
+
+    Pointer<Int32> staticFuncReturnsRetainedRefCountTest(Allocator alloc) {
+      final counter = alloc<Int32>();
+      counter.value = 0;
+
+      final outputObj = staticFuncReturnsRetained(lib, counter);
+      expect(counter.value, 1);
+
+      return counter;
+    }
+
+    test(
+        'Objects returned from static functions with NS_RETURNS_RETAINED '
+        'have correct ref counts', () {
+      using((Arena arena) {
+        final (counter) = staticFuncReturnsRetainedRefCountTest(arena);
+        doGC();
+        expect(counter.value, 0);
+      });
+    });
+
+    Pointer<Int32> staticFuncOfObjectReturnsRetainedRefCountTest(
+        Allocator alloc) {
+      final counter = alloc<Int32>();
+      counter.value = 0;
+
+      final obj = StaticFuncTestObj.newWithCounter_(lib, counter);
+      expect(counter.value, 1);
+
+      final outputObj = staticFuncReturnsRetainedArg(lib, obj);
+      expect(obj, outputObj);
+      expect(counter.value, 1);
+
+      return counter;
+    }
+
+    test(
+        'Objects passed through static functions with NS_RETURNS_RETAINED '
+        'have correct ref counts', () {
+      using((Arena arena) {
+        final (counter) = staticFuncOfObjectReturnsRetainedRefCountTest(arena);
+        doGC();
+        expect(counter.value, 0);
+      });
+    });
   });
 }
diff --git a/test/native_objc_test/static_func_test.dart b/test/native_objc_test/static_func_test.dart
@@ -44,11 +44,6 @@ void main() {
       calloc.free(gcNow);
     }
 
-    test('Static function returning NSString', () {
-      expect(lib.staticFuncReturningNSString().length, 12);
-      expect(lib.staticFuncReturningNSString().toString(), "Hello World!");
-    });
-
     Pointer<Int32> staticFuncOfObjectRefCountTest(Allocator alloc) {
       final counter = alloc<Int32>();
       counter.value = 0;
@@ -112,5 +107,50 @@ void main() {
       doGC();
       expect(lib.getBlockRetainCount(rawBlock), 0);
     });
+
+    Pointer<Int32> staticFuncReturnsRetainedRefCountTest(Allocator alloc) {
+      final counter = alloc<Int32>();
+      counter.value = 0;
+
+      final outputObj = lib.staticFuncReturnsRetained(counter);
+      expect(counter.value, 1);
+
+      return counter;
+    }
+
+    test(
+        'Objects returned from static functions with NS_RETURNS_RETAINED '
+        'have correct ref counts', () {
+      using((Arena arena) {
+        final (counter) = staticFuncReturnsRetainedRefCountTest(arena);
+        doGC();
+        expect(counter.value, 0);
+      });
+    });
+
+    Pointer<Int32> staticFuncOfObjectReturnsRetainedRefCountTest(
+        Allocator alloc) {
+      final counter = alloc<Int32>();
+      counter.value = 0;
+
+      final obj = StaticFuncTestObj.newWithCounter_(lib, counter);
+      expect(counter.value, 1);
+
+      final outputObj = lib.staticFuncReturnsRetainedArg(obj);
+      expect(obj, outputObj);
+      expect(counter.value, 1);
+
+      return counter;
+    }
+
+    test(
+        'Objects passed through static functions with NS_RETURNS_RETAINED '
+        'have correct ref counts', () {
+      using((Arena arena) {
+        final (counter) = staticFuncOfObjectReturnsRetainedRefCountTest(arena);
+        doGC();
+        expect(counter.value, 0);
+      });
+    });
   });
 }
diff --git a/test/native_objc_test/static_func_test.m b/test/native_objc_test/static_func_test.m
@@ -1,3 +1,4 @@
+
 // Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
@@ -6,9 +7,6 @@
 
 #include "util.h"
 
-// Take and return object, nullable, and block
-// ref counting tests
-
 @interface StaticFuncTestObj : NSObject {
   int32_t* counter;
 }
@@ -55,6 +53,12 @@ IntBlock staticFuncOfBlock(IntBlock a) {
   return a;
 }
 
-NSString* staticFuncReturningNSString() {
-  return @"Hello World!";
+NS_RETURNS_RETAINED StaticFuncTestObj* staticFuncReturnsRetained(
+    int32_t* counter) {
+  return [StaticFuncTestObj newWithCounter: counter];
+}
+
+NS_RETURNS_RETAINED StaticFuncTestObj* staticFuncReturnsRetainedArg(
+    StaticFuncTestObj* a) {
+  return [a retain];
 }