cogl: Add an internal utility to maintain a list of callback functions

This adds an internal CoglCallbackList type which is just a GSList of
of function pointers along with a data pointer to form a
closure. There are functions to add and remove items and to invoke the
list of functions. This could be used in a number of places in Cogl.

cogl/Makefile.am

@@ -162,6 +162,8 @@ cogl_sources_c = \
 	$(srcdir)/cogl-bitmask.c                        \
 	$(srcdir)/cogl-shader-private.h			\
 	$(srcdir)/cogl-shader.c                        	\
+	$(srcdir)/cogl-callback-list.h                  \
+	$(srcdir)/cogl-callback-list.c                  \
 	$(NULL)
 
 # glib-mkenums rules

cogl/cogl-callback-list.c

@@ -0,0 +1,107 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2010 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Authors:
+ *  Neil Roberts   <neil@linux.intel.com>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "cogl.h"
+#include "cogl-callback-list.h"
+
+typedef struct _CoglCallbackListClosure
+{
+  CoglCallbackListFunc func;
+  void *user_data;
+} CoglCallbackListClosure;
+
+void
+_cogl_callback_list_init (CoglCallbackList *list)
+{
+  list->funcs = NULL;
+}
+
+void
+_cogl_callback_list_destroy (CoglCallbackList *list)
+{
+  while (list->funcs)
+    {
+      CoglCallbackListClosure *closure = list->funcs->data;
+
+      _cogl_callback_list_remove (list, closure->func, closure->user_data);
+    }
+}
+
+void
+_cogl_callback_list_add (CoglCallbackList *list,
+                         CoglCallbackListFunc func,
+                         void *user_data)
+{
+  CoglCallbackListClosure *closure = g_slice_new (CoglCallbackListClosure);
+
+  closure->func = func;
+  closure->user_data = user_data;
+  list->funcs = g_slist_prepend (list->funcs, closure);
+}
+
+void
+_cogl_callback_list_remove (CoglCallbackList *list,
+                            CoglCallbackListFunc func,
+                            void *user_data)
+{
+  GSList *prev = NULL, *l;
+
+  for (l = list->funcs; l; l = l->next)
+    {
+      CoglCallbackListClosure *closure = l->data;
+
+      if (closure->func == func && closure->user_data == user_data)
+        {
+          g_slice_free (CoglCallbackListClosure, closure);
+
+          if (prev)
+            prev->next = g_slist_delete_link (prev->next, l);
+          else
+            list->funcs = g_slist_delete_link (list->funcs, l);
+
+          break;
+        }
+
+      prev = l;
+    }
+}
+
+void
+_cogl_callback_list_invoke (CoglCallbackList *list)
+{
+  GSList *l;
+
+  for (l = list->funcs; l; l = l->next)
+    {
+      CoglCallbackListClosure *closure = l->data;
+
+      closure->func (closure->user_data);
+    }
+}

cogl/cogl-callback-list.h

@@ -0,0 +1,58 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2010 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef __COGL_CALLBACK_LIST_H__
+#define __COGL_CALLBACK_LIST_H__
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+typedef void (* CoglCallbackListFunc) (void *user_data);
+
+typedef struct _CoglCallbackList
+{
+  GSList *funcs;
+} CoglCallbackList;
+
+void
+_cogl_callback_list_init (CoglCallbackList *list);
+
+void
+_cogl_callback_list_add (CoglCallbackList *list,
+                         CoglCallbackListFunc func,
+                         void *user_data);
+void
+_cogl_callback_list_remove (CoglCallbackList *list,
+                            CoglCallbackListFunc func,
+                            void *user_data);
+
+void
+_cogl_callback_list_invoke (CoglCallbackList *list);
+
+void
+_cogl_callback_list_destroy (CoglCallbackList *list);
+
+G_END_DECLS
+
+#endif /* __COGL_CALLBACK_LIST_H__ */
+