more hacking

Move plugin API to separate directory for now
Add ringbuffer and way to get ringbuffer from a port

spa/plugins/audiomixer/plugin.c

@@ -0,0 +1,78 @@
+/* Spa Audiomixer plugin
+ * Copyright (C) 2016 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <spa/plugin.h>
+#include <spa/node.h>
+
+SpaHandle * spa_audiomixer_new (void);
+
+static SpaResult
+audiomixer_instantiate (const SpaHandleFactory  *factory,
+                        SpaHandle              **handle)
+{
+  if (factory == NULL || handle == NULL)
+    return SPA_RESULT_INVALID_ARGUMENTS;
+
+  *handle = spa_audiomixer_new ();
+
+  return SPA_RESULT_OK;
+}
+
+static const SpaInterfaceInfo audiomixer_interfaces[] =
+{
+  { SPA_INTERFACE_ID_NODE,
+    SPA_INTERFACE_ID_NODE_NAME,
+    SPA_INTERFACE_ID_NODE_DESCRIPTION,
+  },
+};
+
+static SpaResult
+audiomixer_enum_interface_info (const SpaHandleFactory  *factory,
+                                unsigned int             index,
+                                const SpaInterfaceInfo **info)
+{
+  if (index >= 1)
+    return SPA_RESULT_ENUM_END;
+
+  *info = &audiomixer_interfaces[index];
+
+  return SPA_RESULT_OK;
+}
+
+static const SpaHandleFactory factories[] =
+{
+  { "audiomixer",
+    NULL,
+    audiomixer_instantiate,
+    audiomixer_enum_interface_info,
+  },
+};
+
+
+SpaResult
+spa_enum_handle_factory (unsigned int             index,
+                         const SpaHandleFactory **factory)
+{
+  if (index >= 1)
+    return SPA_RESULT_ENUM_END;
+
+  *factory = &factories[index];
+
+  return SPA_RESULT_OK;
+}