From 538d3418fdfba537bc96f5484e52809325d1b27d Mon Sep 17 00:00:00 2001
From: Michael Scott <mike@foundries.io>
Date: Thu, 12 Jul 2018 10:00:01 -0700
Subject: [PATCH] net: lwm2m: introduce user-code callbacks for obj
 create/delete

LwM2M engine now supports optional resources that may need to be
setup or torn down in user-based code during object instance
creation / deletion.

Let's provide callbacks that can be used for this purpose.

Signed-off-by: Michael Scott <mike@foundries.io>
---
 include/net/lwm2m.h                 |  4 +++
 subsys/net/lib/lwm2m/lwm2m_engine.c | 51 +++++++++++++++++++++++++++++
 subsys/net/lib/lwm2m/lwm2m_object.h |  2 ++
 3 files changed, 57 insertions(+)

diff --git a/include/net/lwm2m.h b/include/net/lwm2m.h
index 19cb5ff4797..a9f42b97ae3 100644
--- a/include/net/lwm2m.h
+++ b/include/net/lwm2m.h
@@ -206,6 +206,10 @@ int lwm2m_engine_register_post_write_callback(char *path,
 					      lwm2m_engine_set_data_cb_t cb);
 int lwm2m_engine_register_exec_callback(char *path,
 					lwm2m_engine_user_cb_t cb);
+int lwm2m_engine_register_create_callback(u16_t obj_id,
+					  lwm2m_engine_user_cb_t cb);
+int lwm2m_engine_register_delete_callback(u16_t obj_id,
+					  lwm2m_engine_user_cb_t cb);
 
 /* resource data bit values */
 #define LWM2M_RES_DATA_READ_ONLY	0
diff --git a/subsys/net/lib/lwm2m/lwm2m_engine.c b/subsys/net/lib/lwm2m/lwm2m_engine.c
index 5f3a735cd69..d6e91ed5f3c 100644
--- a/subsys/net/lib/lwm2m/lwm2m_engine.c
+++ b/subsys/net/lib/lwm2m/lwm2m_engine.c
@@ -685,6 +685,7 @@ int lwm2m_create_obj_inst(u16_t obj_id, u16_t obj_inst_id,
 			  struct lwm2m_engine_obj_inst **obj_inst)
 {
 	struct lwm2m_engine_obj *obj;
+	int ret;
 
 	*obj_inst = NULL;
 	obj = get_engine_obj(obj_id);
@@ -718,6 +719,17 @@ int lwm2m_create_obj_inst(u16_t obj_id, u16_t obj_inst_id,
 	(*obj_inst)->obj = obj;
 	(*obj_inst)->obj_inst_id = obj_inst_id;
 	engine_register_obj_inst(*obj_inst);
+
+	if (obj->user_create_cb) {
+		ret = obj->user_create_cb(obj_inst_id);
+		if (ret < 0) {
+			SYS_LOG_ERR("Error in user obj create %u/%u: %d",
+				    obj_id, obj_inst_id, ret);
+			lwm2m_delete_obj_inst(obj_id, obj_inst_id);
+			return ret;
+		}
+	}
+
 #ifdef CONFIG_LWM2M_RD_CLIENT_SUPPORT
 	engine_trigger_update();
 #endif
@@ -740,6 +752,15 @@ int lwm2m_delete_obj_inst(u16_t obj_id, u16_t obj_inst_id)
 		return -ENOENT;
 	}
 
+	if (obj->user_delete_cb) {
+		ret = obj->user_delete_cb(obj_inst_id);
+		if (ret < 0) {
+			SYS_LOG_ERR("Error in user obj delete %u/%u: %d",
+				    obj_id, obj_inst_id, ret);
+			/* don't return error */
+		}
+	}
+
 	engine_unregister_obj_inst(obj_inst);
 	obj->instance_count--;
 
@@ -1897,6 +1918,36 @@ int lwm2m_engine_register_exec_callback(char *pathstr,
 	return 0;
 }
 
+int lwm2m_engine_register_create_callback(u16_t obj_id,
+					  lwm2m_engine_user_cb_t cb)
+{
+	struct lwm2m_engine_obj *obj = NULL;
+
+	obj = get_engine_obj(obj_id);
+	if (!obj) {
+		SYS_LOG_ERR("unable to find obj: %u", obj_id);
+		return -ENOENT;
+	}
+
+	obj->user_create_cb = cb;
+	return 0;
+}
+
+int lwm2m_engine_register_delete_callback(u16_t obj_id,
+					  lwm2m_engine_user_cb_t cb)
+{
+	struct lwm2m_engine_obj *obj = NULL;
+
+	obj = get_engine_obj(obj_id);
+	if (!obj) {
+		SYS_LOG_ERR("unable to find obj: %u", obj_id);
+		return -ENOENT;
+	}
+
+	obj->user_delete_cb = cb;
+	return 0;
+}
+
 /* generic data handlers */
 
 static int lwm2m_read_handler(struct lwm2m_engine_obj_inst *obj_inst,
diff --git a/subsys/net/lib/lwm2m/lwm2m_object.h b/subsys/net/lib/lwm2m/lwm2m_object.h
index af2976cbb8f..27c9782295f 100644
--- a/subsys/net/lib/lwm2m/lwm2m_object.h
+++ b/subsys/net/lib/lwm2m/lwm2m_object.h
@@ -169,6 +169,8 @@ struct lwm2m_engine_obj {
 	/* object event callbacks */
 	lwm2m_engine_obj_create_cb_t create_cb;
 	lwm2m_engine_obj_delete_cb_t delete_cb;
+	lwm2m_engine_user_cb_t user_create_cb;
+	lwm2m_engine_user_cb_t user_delete_cb;
 
 	/* object member data */
 	u16_t obj_id;