monitor: add device event

Add device events and signal soft volume with an object config
event.

spa/include/spa/monitor/event.h

@@ -0,0 +1,54 @@
+/* Simple Plugin API
+ *
+ * Copyright © 2020 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef SPA_EVENT_DEVICE_H
+#define SPA_EVENT_DEVICE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <spa/pod/event.h>
+
+/* object id of SPA_TYPE_EVENT_Device */
+enum spa_device_event {
+	SPA_DEVICE_EVENT_ObjectConfig,
+};
+
+#define SPA_DEVICE_EVENT_ID(ev)	SPA_EVENT_ID(ev, SPA_TYPE_EVENT_Device)
+#define SPA_DEVICE_EVENT_INIT(id) SPA_EVENT_INIT(SPA_TYPE_EVENT_Device, id)
+
+/* properties for SPA_TYPE_EVENT_Device */
+enum spa_event_device {
+	SPA_EVENT_DEVICE_START,
+
+	SPA_EVENT_DEVICE_Object,	/* an object id (Int) */
+	SPA_EVENT_DEVICE_Props,		/* properties for an object (SPA_TYPE_OBJECT_Props) */
+};
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif /* SPA_EVENT_DEVICE */