Commented the pass about internal impls of abstract classes. Cosmetic fixes.

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

src/AST/Function.cs

@@ -165,27 +165,30 @@ namespace CppSharp.AST
 
         public virtual QualifiedType GetFunctionType()
         {
-            var functionType = new FunctionType();
-            functionType.CallingConvention = CallingConvention;
-            functionType.ReturnType = ReturnType;
+            var functionType = new FunctionType
+                                {
+                                    CallingConvention = this.CallingConvention,
+                                    ReturnType = this.ReturnType
+                                };
             functionType.Parameters.AddRange(Parameters);
+            ReplaceIndirectReturnParamWithRegular(functionType);
+            var pointerType = new PointerType { QualifiedPointee = new QualifiedType(functionType) };
+            return new QualifiedType(pointerType);
+        }
+
+        private static void ReplaceIndirectReturnParamWithRegular(FunctionType functionType)
+        {
             for (int i = functionType.Parameters.Count - 1; i >= 0; i--)
             {
                 var parameter = functionType.Parameters[i];
                 if (parameter.Kind == ParameterKind.IndirectReturnType)
                 {
-                    var retParam = new Parameter();
-                    retParam.Name = parameter.Name;
-                    var ptrType = new PointerType();
-                    ptrType.QualifiedPointee = new QualifiedType(parameter.Type);
-                    retParam.QualifiedType = new QualifiedType(ptrType);
+                    var ptrType = new PointerType { QualifiedPointee = new QualifiedType(parameter.Type) };
+                    var retParam = new Parameter { Name = parameter.Name, QualifiedType = new QualifiedType(ptrType) };
                     functionType.Parameters.RemoveAt(i);
                     functionType.Parameters.Insert(i, retParam);
                 }
             }
-            var pointerType = new PointerType();
-            pointerType.QualifiedPointee = new QualifiedType(functionType);
-            return new QualifiedType(pointerType);
         }
     }
 }

src/AST/Method.cs

@@ -127,10 +127,11 @@ namespace CppSharp.AST
             {
                 FunctionType functionType;
                 qualifiedType.Type.IsPointerTo(out functionType);
-                var instance = new Parameter();
-                instance.Name = "instance";
-                instance.QualifiedType = new QualifiedType(
-                    new BuiltinType(PrimitiveType.IntPtr));
+                var instance = new Parameter
+                                {
+                                    Name = "instance",
+                                    QualifiedType = new QualifiedType(new BuiltinType(PrimitiveType.IntPtr))
+                                };
                 functionType.Parameters.Insert(0, instance);
             }
             return qualifiedType;

src/Generator/AST/VTables.cs

@@ -83,41 +83,18 @@ namespace CppSharp.AST
             throw new NotSupportedException();
         }
 
-        public static string GetVirtualCallDelegate(INamedDecl method, Class @class,
-            bool is32Bit, out string delegateId)
+        public static int GetVTableIndex(INamedDecl method, Class @class)
         {
-            var virtualCallBuilder = new StringBuilder();
-            virtualCallBuilder.AppendFormat(
-                "void* vtable = *((void**) {0}.ToPointer());",
-                Helpers.InstanceIdentifier);
-            virtualCallBuilder.AppendLine();
-
-            int i;
             switch (@class.Layout.ABI)
             {
                 case CppAbi.Microsoft:
-                    i = (from table in @class.Layout.VFTables
-                         let j = table.Layout.Components.FindIndex(m => m.Method == method)
-                         where j >= 0
-                         select j).First();
-                    break;
+                    return (from table in @class.Layout.VFTables
+                            let j = table.Layout.Components.FindIndex(m => m.Method == method)
+                            where j >= 0
+                            select j).First();
                 default:
-                    i = @class.Layout.Layout.Components.FindIndex(m => m.Method == method);
-                    break;
+                    return @class.Layout.Layout.Components.FindIndex(m => m.Method == method);
             }
-
-            virtualCallBuilder.AppendFormat(
-                "void* slot = *((void**) vtable + {0} * {1});", i, is32Bit ? 4 : 8);
-            virtualCallBuilder.AppendLine();
-
-            string @delegate = method.Name + "Delegate";
-            delegateId = Generator.GeneratedIdentifier(@delegate);
-
-            virtualCallBuilder.AppendFormat(
-                "var {1} = ({0}) Marshal.GetDelegateForFunctionPointer(new IntPtr(slot), typeof({0}));",
-                @delegate, delegateId);
-            virtualCallBuilder.AppendLine();
-            return virtualCallBuilder.ToString();
         }
     }
 }

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -626,8 +626,7 @@ namespace CppSharp.Generators.CSharp
             Write(Helpers.GetAccess(@class));
             Write("unsafe ");
 
-            if (Driver.Options.GenerateAbstractImpls &&
-                @class.IsAbstract)
+            if (Driver.Options.GenerateAbstractImpls && @class.IsAbstract)
                 Write("abstract ");
 
             if (Options.GeneratePartialClasses)
@@ -1365,8 +1364,7 @@ namespace CppSharp.Generators.CSharp
             PushBlock(CSharpBlockKind.Method);
             string className = @class.Name;
             string safeIdentifier = SafeIdentifier(className);
-            if (@class.Access == AccessSpecifier.Private &&
-                className.EndsWith("Internal"))
+            if (@class.Access == AccessSpecifier.Private && className.EndsWith("Internal"))
             {
                 className = className.Substring(0,
                     safeIdentifier.LastIndexOf("Internal", StringComparison.Ordinal));
@@ -1379,8 +1377,7 @@ namespace CppSharp.Generators.CSharp
             PopBlock(NewLineKind.BeforeNextBlock);
 
             PushBlock(CSharpBlockKind.Method);
-            WriteLine("internal {0}({1}.Internal native)", safeIdentifier,
-                className);
+            WriteLine("internal {0}({1}.Internal native)", safeIdentifier, className);
             WriteLineIndent(": this(&native)");
             WriteStartBraceIndent();
             WriteCloseBraceIndent();
@@ -1574,10 +1571,34 @@ namespace CppSharp.Generators.CSharp
         private void GenerateVirtualTableFunctionCall(Function method, Class @class)
         {
             string delegateId;
-            Write(VTables.GetVirtualCallDelegate(method, @class, Driver.Options.Is32Bit, out delegateId));
+            Write(GetVirtualCallDelegate(method, @class, Driver.Options.Is32Bit, out delegateId));
             GenerateFunctionCall(delegateId, method.Parameters, method);
         }
 
+        public static string GetVirtualCallDelegate(INamedDecl method, Class @class,
+            bool is32Bit, out string delegateId)
+        {
+            var virtualCallBuilder = new StringBuilder();
+            virtualCallBuilder.AppendFormat("void* vtable = *((void**) {0}.ToPointer());",
+                Helpers.InstanceIdentifier);
+            virtualCallBuilder.AppendLine();
+
+            var i = VTables.GetVTableIndex(method, @class);
+
+            virtualCallBuilder.AppendFormat(
+                "void* slot = *((void**) vtable + {0} * {1});", i, is32Bit ? 4 : 8);
+            virtualCallBuilder.AppendLine();
+
+            string @delegate = method.Name + "Delegate";
+            delegateId = Generator.GeneratedIdentifier(@delegate);
+
+            virtualCallBuilder.AppendFormat(
+                "var {1} = ({0}) Marshal.GetDelegateForFunctionPointer(new IntPtr(slot), typeof({0}));",
+                @delegate, delegateId);
+            virtualCallBuilder.AppendLine();
+            return virtualCallBuilder.ToString();
+        }
+
         private void GenerateOperator(Method method, Class @class)
         {
             if (method.IsSynthetized)

src/Generator/Passes/GenerateAbstractImplementationsPass.cs

@@ -5,6 +5,11 @@ using CppSharp.Utils;
 
 namespace CppSharp.Passes
 {
+    /// <summary>
+    /// This pass generates internal classes that implement abstract classes.
+    /// When the return type of a function is abstract, these internal classes provide - 
+    /// since the real type cannot be resolved while binding - an allocatable class that supports proper polymorphism.
+    /// </summary>
     public class GenerateAbstractImplementationsPass : TranslationUnitPass
     {
         private readonly List<Class> classes = new List<Class>();
@@ -39,9 +44,12 @@ namespace CppSharp.Passes
             foreach (var abstractMethod in abstractMethods)
             {
                 internalImpl.Methods.Add(new Method(abstractMethod));
-                var @delegate = new TypedefDecl { Name = abstractMethod.Name + "Delegate" };
-                @delegate.QualifiedType = abstractMethod.GetFunctionType();
-                @delegate.IgnoreFlags = abstractMethod.IgnoreFlags;
+                var @delegate = new TypedefDecl
+                                {
+                                    Name = abstractMethod.Name + "Delegate",
+                                    QualifiedType = abstractMethod.GetFunctionType(),
+                                    IgnoreFlags = abstractMethod.IgnoreFlags
+                                };
                 internalImpl.Typedefs.Add(@delegate);
             }
 
@@ -59,10 +67,12 @@ namespace CppSharp.Passes
 
         private static Class GetInternalImpl(Declaration @class)
         {
-            var internalImpl = new Class();
-            internalImpl.Name = @class.Name + "Internal";
-            internalImpl.Access = AccessSpecifier.Private;
-            internalImpl.Namespace = @class.Namespace;
+            var internalImpl = new Class
+                                {
+                                    Name = @class.Name + "Internal",
+                                    Access = AccessSpecifier.Private,
+                                    Namespace = @class.Namespace
+                                };
             var @base = new BaseClassSpecifier { Type = new TagType(@class) };
             internalImpl.Bases.Add(@base);
             return internalImpl;