Use G_DECLARE_FINAL_TYPE()

The GObject boilerplate macro's which you need to define a new type can
be quite daunting. GLib added `G_DECLARE_FINAL_TYPE()` to mitigate this
in 2.44 already, which is now also a hard dependency of GStreamer. Let's
use this in our advantage to clean up code for people who want to write
GStreamer for the first time.

3 files changed, 12 insertions, 59 deletions

diff --git a/gst-plugin/src/gstaudiofilter.c b/gst-plugin/src/gstaudiofilter.c
index 5b3ff0c..0c67a9f 100644
--- a/gst-plugin/src/gstaudiofilter.c
+++ b/gst-plugin/src/gstaudiofilter.c
@@ -1,6 +1,7 @@
 /* GStreamer audio filter example class
  * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
  * Copyright (C) <2003> David Schleef <ds@schleef.org>
+ * Copyright (C) <2020> Niels De Graef <niels.degraef@gmail.com>
  * Copyright (C) YEAR AUTHOR_NAME AUTHOR_EMAIL
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -67,20 +68,9 @@
 GST_DEBUG_CATEGORY_STATIC (audiofiltertemplate_debug);
 #define GST_CAT_DEFAULT audiofiltertemplate_debug
 
-typedef struct _GstAudioFilterTemplate GstAudioFilterTemplate;
-typedef struct _GstAudioFilterTemplateClass GstAudioFilterTemplateClass;
-
-/* These are boilerplate cast macros and type check macros */
-#define GST_TYPE_AUDIO_FILTER_TEMPLATE \
-  (gst_audio_filter_template_get_type())
-#define GST_AUDIO_FILTER_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_AUDIO_FILTER_TEMPLATE,GstAudioFilterTemplate))
-#define GST_AUDIO_FILTER_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_AUDIO_FILTER_TEMPLATE,GstAudioFilterTemplateClass))
-#define GST_IS_AUDIO_FILTER_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_AUDIO_FILTER_TEMPLATE))
-#define GST_IS_AUDIO_FILTER_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_AUDIO_FILTER_TEMPLATE))
+#define GST_TYPE_AUDIO_FILTER_TEMPLATE (gst_audio_filter_template_get_type())
+G_DECLARE_FINAL_TYPE (GstAudioFilterTemplate, gst_audio_filter_template,
+    GST, AUDIO_FILTER_TEMPLATE, GstAudioFilter)
 
 struct _GstAudioFilterTemplate
 {
@@ -90,11 +80,6 @@ struct _GstAudioFilterTemplate
    * data such as properties */
 };
 
-struct _GstAudioFilterTemplateClass
-{
-  GstAudioFilterClass audiofilter_class;
-};
-
 
 enum
 {
diff --git a/gst-plugin/src/gstplugin.h b/gst-plugin/src/gstplugin.h
index f1fe4ed..5d6a647 100644
--- a/gst-plugin/src/gstplugin.h
+++ b/gst-plugin/src/gstplugin.h
@@ -2,6 +2,7 @@
  * GStreamer
  * Copyright (C) 2005 Thomas Vander Stichele <thomas@apestaart.org>
  * Copyright (C) 2005 Ronald S. Bultje <rbultje@ronald.bitfreak.net>
+ * Copyright (C) 2020 Niels De Graef <niels.degraef@gmail.com>
  * Copyright (C) YEAR AUTHOR_NAME AUTHOR_EMAIL
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -50,20 +51,9 @@
 
 G_BEGIN_DECLS
 
-/* #defines don't like whitespacey bits */
-#define GST_TYPE_PLUGIN_TEMPLATE \
-  (gst_plugin_template_get_type())
-#define GST_PLUGIN_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTemplate))
-#define GST_PLUGIN_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTemplateClass))
-#define GST_IS_PLUGIN_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PLUGIN_TEMPLATE))
-#define GST_IS_PLUGIN_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PLUGIN_TEMPLATE))
-
-typedef struct _GstPluginTemplate      GstPluginTemplate;
-typedef struct _GstPluginTemplateClass GstPluginTemplateClass;
+#define GST_TYPE_PLUGIN_TEMPLATE (gst_plugin_template_get_type())
+G_DECLARE_FINAL_TYPE (GstPluginTemplate, gst_plugin_template,
+    GST, PLUGIN_TEMPLATE, GstElement)
 
 struct _GstPluginTemplate
 {
@@ -74,13 +64,6 @@ struct _GstPluginTemplate
   gboolean silent;
 };
 
-struct _GstPluginTemplateClass 
-{
-  GstElementClass parent_class;
-};
-
-GType gst_plugin_template_get_type (void);
-
 G_END_DECLS
 
 #endif /* __GST_PLUGIN_TEMPLATE_H__ */
diff --git a/gst-plugin/src/gsttransform.h b/gst-plugin/src/gsttransform.h
index be9ce86..548b2f8 100644
--- a/gst-plugin/src/gsttransform.h
+++ b/gst-plugin/src/gsttransform.h
@@ -1,6 +1,7 @@
 /* 
  * GStreamer
  * Copyright (C) 2006 Stefan Kost <ensonic@users.sf.net>
+ * Copyright (C) 2020 Niels De Graef <niels.degraef@gmail.com>
  * Copyright (C) YEAR AUTHOR_NAME AUTHOR_EMAIL
  *
  * This library is free software; you can redistribute it and/or
@@ -27,19 +28,9 @@
 
 G_BEGIN_DECLS
 
-#define GST_TYPE_PLUGIN_TEMPLATE \
-  (gst_plugin_template_get_type())
-#define GST_PLUGIN_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTemplate))
-#define GST_PLUGIN_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_PLUGIN_TEMPLATE,GstPluginTemplateClass))
-#define GST_IS_PLUGIN_TEMPLATE(obj) \
-  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_PLUGIN_TEMPLATE))
-#define GST_IS_PLUGIN_TEMPLATE_CLASS(klass) \
-  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_PLUGIN_TEMPLATE))
-
-typedef struct _GstPluginTemplate      GstPluginTemplate;
-typedef struct _GstPluginTemplateClass GstPluginTemplateClass;
+#define GST_TYPE_PLUGIN_TEMPLATE (gst_plugin_template_get_type())
+G_DECLARE_FINAL_TYPE (GstPluginTemplate, gst_plugin_template,
+    GST, PLUGIN_TEMPLATE, GstBaseTransform)
 
 struct _GstPluginTemplate {
   GstBaseTransform element;
@@ -47,12 +38,6 @@ struct _GstPluginTemplate {
   gboolean silent;
 };
 
-struct _GstPluginTemplateClass {
-  GstBaseTransformClass parent_class;
-};
-
-GType gst_plugin_template_get_type (void);
-
 G_END_DECLS
 
 #endif /* __GST_PLUGIN_TEMPLATE_H__ */