Initial revision

git-svn-id: svn://localhost/trunk/ardour2@4 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/glibmm2/glibmm/wrap.cc

@@ -0,0 +1,161 @@
+// -*- c++ -*-
+/* $Id$ */
+
+/* wrap.cc
+ *
+ * Copyright (C) 1998-2002 The gtkmm Development Team
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <glib-object.h>
+#include <glib/gtypes.h>
+#include <glib/gmacros.h>
+
+#include <vector>
+#include <glibmm/object.h>
+#include <glibmm/quark.h>
+#include <glibmm/wrap.h>
+
+#include <glibmmconfig.h>
+GLIBMM_USING_STD(vector)
+
+
+namespace
+{
+
+// Although the new g_type_set_qdata() interface is used now, we still need
+// a table because we cannot assume that a function pointer fits into void*
+// on any platform.  Nevertheless, indexing a vector costs almost nothing
+// compared to a map lookup.
+
+typedef std::vector<Glib::WrapNewFunction> WrapFuncTable;
+
+static WrapFuncTable* wrap_func_table = 0;
+
+
+static Glib::ObjectBase* create_new_wrapper(GObject* object)
+{
+  g_return_val_if_fail(wrap_func_table != 0, 0);
+
+  bool gtkmm_wrapper_already_deleted = (bool)g_object_get_qdata((GObject*)object, Glib::quark_cpp_wrapper_deleted_);
+  if(gtkmm_wrapper_already_deleted)
+  {
+    g_warning("Glib::create_new_wrapper: Attempted to create a 2nd C++ wrapper for a C instance whose C++ wrapper has been deleted.");
+    return 0;
+  }
+
+  // Traverse upwards through the inheritance hierarchy
+  // to find the most-specialized wrap_new() for this GType.
+  //
+  for(GType type = G_OBJECT_TYPE(object); type != 0; type = g_type_parent(type))
+  {
+    // Look up the wrap table index stored in the type's static data.
+    // If a wrap_new() has been registered for the type then call it.
+    //
+    if(const gpointer idx = g_type_get_qdata(type, Glib::quark_))
+    {
+      const Glib::WrapNewFunction func = (*wrap_func_table)[GPOINTER_TO_UINT(idx)];
+      return (*func)(object);
+    }
+  }
+
+  return 0;
+}
+
+} // anonymous namespace
+
+
+namespace Glib
+{
+
+void wrap_register_init()
+{
+  g_type_init();
+
+  if(!Glib::quark_)
+  {
+    Glib::quark_ = g_quark_from_static_string("glibmm__Glib::quark_");
+    Glib::quark_cpp_wrapper_deleted_ = g_quark_from_static_string("glibmm__Glib::quark_cpp_wrapper_deleted_");
+  }
+
+  if(!wrap_func_table)
+  {
+    // Make the first element a dummy so we can detect unregistered types.
+    // g_type_get_qdata() returns NULL if no data has been set up.
+    wrap_func_table = new WrapFuncTable(1);
+  }
+}
+
+void wrap_register_cleanup()
+{
+  if(wrap_func_table)
+  {
+    delete wrap_func_table;
+    wrap_func_table = 0;
+  }
+}
+
+// Register the unique wrap_new() function of a new C++ wrapper type.
+// The GType argument specifies the parent C type to wrap from.
+//
+void wrap_register(GType type, WrapNewFunction func)
+{
+  const guint idx = wrap_func_table->size();
+  wrap_func_table->push_back(func);
+
+  // Store the table index in the type's static data.
+  g_type_set_qdata(type, Glib::quark_, GUINT_TO_POINTER(idx));
+}
+
+// This is a factory function that converts any type to
+// its C++ wrapper instance by looking up a wrap_new() function in a map.
+//
+ObjectBase* wrap_auto(GObject* object, bool take_copy)
+{
+  if(!object)
+    return 0;
+
+  // Look up current C++ wrapper instance:
+  ObjectBase* pCppObject =
+      static_cast<ObjectBase*>(g_object_get_qdata(object, Glib::quark_));
+
+  if(!pCppObject)
+  {
+    // There's not already a wrapper: generate a new C++ instance.
+    pCppObject = create_new_wrapper(object);
+
+    if(!pCppObject)
+    {
+      g_warning("failed to wrap type of '%s'", G_OBJECT_TYPE_NAME(object));
+      return 0;
+    }
+  }
+
+  // take_copy=true is used where the GTK+ function doesn't do
+  // an extra ref for us, and always for plain struct members.
+  if(take_copy)
+    pCppObject->reference();
+
+  return pCppObject;
+}
+
+Glib::RefPtr<Object> wrap(GObject* object, bool take_copy /* = false */)
+{
+  return Glib::RefPtr<Object>(dynamic_cast<Object*>(wrap_auto(object, take_copy)));
+}
+
+} /* namespace Glib */
+