device: add device object

Make a device object, let the v4l2 monitor create device objects
The device object is responsible for dynamically creating nodes.

spa/include/spa/monitor/device.h

@@ -0,0 +1,90 @@
+/* Simple Plugin API
+ *
+ * Copyright © 2018 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_DEVICE_H__
+#define __SPA_DEVICE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct spa_device;
+
+#include <spa/utils/defs.h>
+#include <spa/utils/dict.h>
+#include <spa/support/plugin.h>
+
+/**
+ * spa_device_callbacks:
+ */
+struct spa_device_callbacks {
+	/** version of the structure */
+#define SPA_VERSION_DEVICE_CALLBACKS	0
+	uint32_t version;
+
+	/**< add a new object managed by the device */
+	void (*add) (void *data, uint32_t id,
+		     const struct spa_handle_factory *factory, uint32_t type,
+		     const struct spa_dict *info);
+	/**< remove an object */
+	void (*remove) (void *data, uint32_t id);
+};
+
+/**
+ * spa_device:
+ *
+ * The device interface.
+ */
+struct spa_device {
+	/* the version of this device. This can be used to expand this
+	 * structure in the future */
+#define SPA_VERSION_DEVICE	0
+	uint32_t version;
+
+	/**
+	 * Extra information about the device
+	 */
+	const struct spa_dict *info;
+
+	/**
+	 * Set callbacks to receive asynchronous notifications from
+	 * the device.
+	 *
+	 * \param device: a #spa_device
+	 * \param callback: a #callbacks
+	 * \return 0 on success
+	 *	   < 0 errno on error
+	 */
+	int (*set_callbacks) (struct spa_device *device,
+			      const struct spa_device_callbacks *callbacks,
+			      void *data);
+};
+
+#define spa_device_set_callbacks(m,...)	(m)->set_callbacks((m),__VA_ARGS__)
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif /* __SPA_DEVICE_H__ */