Added a pass to generate interfaces with the purpose of simulating multiple inheritance.

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

src/Generator/Driver.cs

@@ -144,6 +144,7 @@ namespace CppSharp
             TranslationUnitPasses.AddPass(new CheckAmbiguousFunctions());
             TranslationUnitPasses.AddPass(new CheckOperatorsOverloadsPass());
             TranslationUnitPasses.AddPass(new CheckVirtualOverrideReturnCovariance());
+            TranslationUnitPasses.AddPass(new MultipleInheritancePass());
 
             Generator.SetupPasses();
             TranslationUnitPasses.AddPass(new FieldToPropertyPass());

src/Generator/Passes/MultipleInheritancePass.cs

@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Linq;
+using CppSharp.AST;
+
+namespace CppSharp.Passes
+{
+    public class MultipleInheritancePass : TranslationUnitPass
+    {
+        /// <summary>
+        /// Collects all interfaces in a unit to be added at the end because the unit cannot be changed while it's being iterated though.
+        /// </summary>
+        private readonly Dictionary<Class, Class> interfaces = new Dictionary<Class, Class>();
+
+        public override bool VisitTranslationUnit(TranslationUnit unit)
+        {
+            bool result = base.VisitTranslationUnit(unit);
+            foreach (var @interface in interfaces)
+                @interface.Key.Namespace.Classes.Add(@interface.Value);
+            interfaces.Clear();
+            return result;
+        }
+
+        public override bool VisitClassDecl(Class @class)
+        {
+            for (int i = 1; i < @class.Bases.Count; i++)
+            {
+                var @base = @class.Bases[i].Class;
+                var name = "I" + @base.Name;
+                if (!interfaces.ContainsKey(@base) && @base.Namespace.Classes.All(c => c.Name != name))
+                {
+                    Class @interface = new Class { Name = name, Namespace = @class.Namespace };
+                    @interface.IsAbstract = true;
+                    @interface.Methods.AddRange(@class.Methods);
+                    @interface.Properties.AddRange(@class.Properties);
+                    @interface.Events.AddRange(@class.Events);
+                    @interfaces.Add(@class, @interface);
+                }
+            }
+            return base.VisitClassDecl(@class);
+        }
+    }
+}