Merge pull request #95 from saltosystems/feature/alloc-vtable-in-the-…

…heap

delegates: allocate VTable in heap

internal/codegen/templates/delegate.tmpl

@@ -29,21 +29,29 @@ var releaseChannels{{.Name}} = &{{.Name | toLower}}ReleaseChannels {
 }
 
 func New{{.Name}}(iid *ole.GUID, callback {{.Name}}Callback) *{{.Name}} {
+	// create type instance
 	size := unsafe.Sizeof(*(*{{.Name}})(nil))
 	instPtr := kernel32.Malloc(size)
 	inst := (*{{.Name}})(instPtr)
 
+	// get the callbacks for the VTable
 	callbacks := delegate.RegisterCallbacks(instPtr, inst)
 
-	// Initialize all properties: the malloc may contain garbage
-	inst.RawVTable = (*interface{})(unsafe.Pointer(&{{.Name}}Vtbl{
-		IUnknownVtbl: ole.IUnknownVtbl{
+	// the VTable should also be allocated in the heap
+	sizeVTable := unsafe.Sizeof(*(*{{.Name}}Vtbl)(nil))
+	vTablePtr := kernel32.Malloc(sizeVTable)
+
+	inst.RawVTable = (*interface{})(vTablePtr)
+
+	vTable := (*{{.Name}}Vtbl)(vTablePtr)
+	vTable.IUnknownVtbl = ole.IUnknownVtbl{
 			QueryInterface: callbacks.QueryInterface,
 			AddRef:         callbacks.AddRef,
 			Release:        callbacks.Release,
-		},
-		Invoke: callbacks.Invoke,
-	}))
+	}
+	vTable.Invoke = callbacks.Invoke
+
+	// Initialize all properties: the malloc may contain garbage
 	inst.IID = *iid // copy contents
 	inst.Mutex = sync.Mutex{}
 	inst.refs = 0
@@ -119,6 +127,7 @@ func (instance *{{.Name}}) Release() uint64 {
 		// https://github.com/golang/go/issues/55015
 		releaseChannels{{.Name}}.release(instancePtr)
 
+		kernel32.Free(unsafe.Pointer(instance.RawVTable))
 		kernel32.Free(instancePtr)
 	}
 	return rem