[gstreamermm] wrapped elementclass class (simplified writting plugins)

[Marcin Kolny <mkolny src gnome org>]

commit b909987e2032b40ca3b73d7fa9e8bc0e494aca69
Author: Marcin Kolny <marcin kolny flytronic pl>
Date:   Fri Nov 29 13:05:42 2013 +0100

    wrapped elementclass class
    (simplified writting plugins)

 gstreamer/gstreamermm/register.h     |   38 ++++++++++++++++++++++++++++++++-
 tests/plugins/test-foo.h             |   17 +++++---------
 tests/plugins/test-plugin-pushsrc.cc |    8 +++---
 tests/regression/pluginbin.h         |    2 +-
 4 files changed, 47 insertions(+), 18 deletions(-)
---
diff --git a/gstreamer/gstreamermm/register.h b/gstreamer/gstreamermm/register.h
index ccd45b2..5b79bab 100644
--- a/gstreamer/gstreamermm/register.h
+++ b/gstreamer/gstreamermm/register.h
@@ -22,12 +22,42 @@
 
 #include <glib-object.h>
 #include <glibmm/property.h>
+#include <gstreamermm/padtemplate.h>
 
 namespace Gst
 {
 
 template<class DerivedCppType>
 static GType
+register_mm_type(const gchar * type_name=typeid(DerivedCppType).name());
+
+template<typename DerivedCppType>
+class ElementClass
+{
+  friend GType register_mm_type<DerivedCppType>(const gchar * type_name);
+  GstElementClass* klass;
+  ElementClass(typename DerivedCppType::BaseClassType* klass): klass((GstElementClass*)klass){}
+  ElementClass(ElementClass const&);
+  void operator=(ElementClass const&);
+public:
+  void add_pad_template(const Glib::RefPtr<Gst::PadTemplate>& tpl)
+  {
+    gst_element_class_add_pad_template(klass, tpl->gobj());
+  }
+  void set_metadata(const Glib::ustring& longname, const Glib::ustring& classification,
+                    const Glib::ustring& description, const Glib::ustring& author)
+  {
+    gst_element_class_set_metadata(klass, longname.c_str(), classification.c_str(), description.c_str(), 
author.c_str());
+  }
+
+  void add_metadata(const Glib::ustring& key, const Glib::ustring& value)
+  {
+       gst_element_class_add_metadata(klass ,key.c_str(), value.c_str());
+  }
+};
+
+template<class DerivedCppType>
+static GType
 register_mm_type(const gchar * type_name=typeid(DerivedCppType).name())
 {
     struct GlibCppType
@@ -40,7 +70,11 @@ register_mm_type(const gchar * type_name=typeid(DerivedCppType).name())
             instance->self = new DerivedCppType(&instance->parent);
 
         }
-
+        static void base_init(typename DerivedCppType::BaseClassType *klass)
+        {
+            Gst::ElementClass<DerivedCppType> element_class(klass);
+            DerivedCppType::base_init(&element_class);
+        }
         static void finalize(GObject *object)
         {
             //the following will destroy q_data, among which MM wrapper to this "object" is stored. This 
will cause implicit delete on "self", since it is registered as wrapper of "object".
@@ -83,7 +117,7 @@ register_mm_type(const gchar * type_name=typeid(DerivedCppType).name())
         GTypeInfo info;
 
         info.class_size = sizeof(GlibCppTypeClass);
-        info.base_init = (GBaseInitFunc)&DerivedCppType::base_init;
+        info.base_init = (GBaseInitFunc)&GlibCppType::base_init;
         info.base_finalize = 0;
         info.class_init = (GClassInitFunc) &GlibCppTypeClass::init;
         info.class_finalize = 0;
diff --git a/tests/plugins/test-foo.h b/tests/plugins/test-foo.h
index e6dc28a..182ca99 100644
--- a/tests/plugins/test-foo.h
+++ b/tests/plugins/test-foo.h
@@ -19,20 +19,15 @@ class Foo : public Gst::Element
     Glib::Property<Glib::ustring> sample_property;
 
 public:
-    static void base_init(BaseClassType *klass)
+    static void base_init(Gst::ElementClass<Foo> *klass)
     {
-        /* This is another hack.
-         * For now it uses pure C functions, which should be wrapped then.
-         */
-        gst_element_class_set_details_simple(klass, "foo_longname",
+        klass->set_metadata("foo_longname",
                 "foo_classification", "foo_detail_description", "foo_detail_author");
 
-        gst_element_class_add_pad_template(klass,
-                Gst::PadTemplate::create("sink", Gst::PAD_SINK, Gst::PAD_ALWAYS,
-                        Gst::Caps::create_any())->gobj());
-        gst_element_class_add_pad_template(klass,
-                Gst::PadTemplate::create("src", Gst::PAD_SRC, Gst::PAD_ALWAYS,
-                        Gst::Caps::create_any())->gobj());
+        klass->add_pad_template(Gst::PadTemplate::create("sink", Gst::PAD_SINK, Gst::PAD_ALWAYS,
+                        Gst::Caps::create_any()));
+        klass->add_pad_template(Gst::PadTemplate::create("src", Gst::PAD_SRC, Gst::PAD_ALWAYS,
+                        Gst::Caps::create_any()));
     }
 
     Gst::FlowReturn chain(const Glib::RefPtr<Gst::Pad> &pad, Glib::RefPtr<Gst::Buffer> &buf)
diff --git a/tests/plugins/test-plugin-pushsrc.cc b/tests/plugins/test-plugin-pushsrc.cc
index 1525808..138e95b 100644
--- a/tests/plugins/test-plugin-pushsrc.cc
+++ b/tests/plugins/test-plugin-pushsrc.cc
@@ -20,13 +20,13 @@ class FooSrc : public Gst::PushSrc
 
 public:
     static const int COUNT = 5;
-    static void base_init(BaseClassType *klass)
+    static void base_init(Gst::ElementClass<FooSrc> *klass)
     {
-        gst_element_class_set_details_simple(GST_ELEMENT_CLASS(klass), "foosrc_longname",
+        klass->set_metadata("foosrc_longname",
                 "foosrc_classification", "foosrc_detail_description", "foosrc_detail_author");
 
-        gst_element_class_add_pad_template(GST_ELEMENT_CLASS(klass),
-                Gst::PadTemplate::create("src", Gst::PAD_SRC, 
Gst::PAD_ALWAYS,Gst::Caps::create_from_string("x-application/x-foo1"))->gobj());
+        klass->add_pad_template(Gst::PadTemplate::create("src", Gst::PAD_SRC, Gst::PAD_ALWAYS,
+                                                     Gst::Caps::create_from_string("x-application/x-foo1")));
     }
 
     explicit FooSrc(GstPushSrc *gobj)
diff --git a/tests/regression/pluginbin.h b/tests/regression/pluginbin.h
index 865969f..0ee95b2 100644
--- a/tests/regression/pluginbin.h
+++ b/tests/regression/pluginbin.h
@@ -23,7 +23,7 @@ private:
     Glib::Property<Glib::ustring> location;
 
 public:
-    static void base_init(BaseClassType *klass)
+    static void base_init(Gst::ElementClass<PluginBin> *klass)
     {
         GstElementClass* element_klass = (GstElementClass*)klass;
         gst_element_class_set_details_simple(element_klass, "Custom test bin",