Fixed the offsets of fields when using multiple inheritance.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -515,7 +515,7 @@ namespace CppSharp.Generators.CSharp
 
             TypePrinter.PushContext(CSharpTypePrinterContextKind.Native);
 
-            GenerateClassFields(@class, GenerateClassInternalsField, true);
+            GenerateClassFields(@class, @class, GenerateClassInternalsField, true);
             if (@class.IsGenerated)
             {
                 if (@class.IsDynamic)
@@ -709,7 +709,8 @@ namespace CppSharp.Generators.CSharp
                 Write(" : {0}", string.Join(", ", bases));
         }
 
-        public void GenerateClassFields(Class @class, Action<Field> action, bool nativeFields = false)
+        public void GenerateClassFields(Class owner, Class @class,
+            Action<Class, Field> action, bool nativeFields = false)
         {
             foreach (var @base in @class.Bases.Where(b => b.Class != null))
             {
@@ -718,17 +719,17 @@ namespace CppSharp.Generators.CSharp
                     @base.Class.OriginalClass == @class)
                     continue;
 
-                GenerateClassFields(@base.Class, action, nativeFields);
+                GenerateClassFields(owner, @base.Class, action, nativeFields);
             }
 
             foreach (var field in @class.Fields)
             {
                 if (ASTUtils.CheckIgnoreField(field, nativeFields)) continue;
-                action(field);
+                action(owner, field);
             }
         }
 
-        private void GenerateClassInternalsField(Field field)
+        private void GenerateClassInternalsField(Class owner, Field field)
         {
             // we do not support dependent fields yet, see https://github.com/mono/CppSharp/issues/197
             Class @class;
@@ -746,7 +747,8 @@ namespace CppSharp.Generators.CSharp
 
             PushBlock(CSharpBlockKind.Field);
 
-            WriteLine("[FieldOffset({0})]", field.OffsetInBytes);
+            WriteLine("[FieldOffset({0})]", field.OffsetInBytes +
+                owner.ComputeNonVirtualBaseClassOffsetTo((Class) field.Namespace));
 
             TypePrinter.PushMarshalKind(CSharpMarshalKind.NativeField);
             var fieldTypePrinted = field.QualifiedType.CSharpType(TypePrinter);
@@ -782,10 +784,11 @@ namespace CppSharp.Generators.CSharp
                         Name = string.Format("{0}_{1}_{2}", Helpers.DummyIdentifier,
                             safeIdentifier, i),
                         QualifiedType = new QualifiedType(arrayType.Type),
-                        Offset = (uint)(field.Offset + (i * arrayType.ElementSize))
+                        Offset = (uint) (field.Offset + i * arrayType.ElementSize),
+                        Namespace = owner
                     };
 
-                    GenerateClassInternalsField(dummy);
+                    GenerateClassInternalsField(owner, dummy);
                 }
             }
         }

tests/CSharp/CSharp.Tests.cs

@@ -479,7 +479,20 @@ public class CSharpTests : GeneratorTestFixture
     {
         using (new QApplication())
         {
-            new QWidget();
+            using (new QWidget())
+            {
+            }
+        }
+    }
+
+    [Test]
+    public void TestMultipleInheritanceFieldOffsets()
+    {
+        using (var multipleInheritanceFieldOffsets = new MultipleInheritanceFieldOffsets())
+        {
+            Assert.That(multipleInheritanceFieldOffsets.Primary, Is.EqualTo(1));
+            Assert.That(multipleInheritanceFieldOffsets.Secondary, Is.EqualTo(2));
+            Assert.That(multipleInheritanceFieldOffsets.Own, Is.EqualTo(3));
         }
     }
 }

tests/CSharp/CSharp.cpp

@@ -894,3 +894,15 @@ char* HasSamePropertyInDerivedAbstractType::property()
 InheritsFromHasSamePropertyInDerivedAbstractType::InheritsFromHasSamePropertyInDerivedAbstractType()
 {
 }
+
+MultipleInheritanceFieldOffsetsSecondaryBase::MultipleInheritanceFieldOffsetsSecondaryBase() : secondary(2)
+{
+}
+
+MultipleInheritanceFieldOffsetsPrimaryBase::MultipleInheritanceFieldOffsetsPrimaryBase() : primary(1)
+{
+}
+
+MultipleInheritanceFieldOffsets::MultipleInheritanceFieldOffsets() : own(3)
+{
+}

tests/CSharp/CSharp.h

@@ -806,3 +806,25 @@ public:
     InheritsFromHasSamePropertyInDerivedAbstractType();
     virtual int property() = 0;
 };
+
+
+class DLL_API MultipleInheritanceFieldOffsetsSecondaryBase
+{
+public:
+    MultipleInheritanceFieldOffsetsSecondaryBase();
+    int secondary;
+};
+
+class DLL_API MultipleInheritanceFieldOffsetsPrimaryBase
+{
+public:
+    MultipleInheritanceFieldOffsetsPrimaryBase();
+    int primary;
+};
+
+class DLL_API MultipleInheritanceFieldOffsets : public MultipleInheritanceFieldOffsetsPrimaryBase, public MultipleInheritanceFieldOffsetsSecondaryBase
+{
+public:
+    MultipleInheritanceFieldOffsets();
+    int own;
+};