From 7864896a1bfbc27764de4c13ff7dfa762e4b71c7 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Mon, 1 Oct 2012 14:09:19 +0200
Subject: [PATCH] add support for deferring a reply to a method invoke call

---
 libubus.c | 21 +++++++++++++--------
 libubus.h | 12 ++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/libubus.c b/libubus.c
index 5488f3b..6291e75 100644
--- a/libubus.c
+++ b/libubus.c
@@ -342,11 +342,18 @@ static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t
 	return NULL;
 }
 
+void ubus_complete_deferred_request(struct ubus_context *ctx, struct ubus_request_data *req, int ret)
+{
+	blob_buf_init(&b, 0);
+	blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
+	blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
+	ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_STATUS, req->peer);
+}
+
 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 {
 	struct ubus_request_data req;
 	struct ubus_object *obj;
-	uint32_t objid = 0;
 	int method;
 	int ret = 0;
 
@@ -357,14 +364,14 @@ static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hd
 	if (!attrbuf[UBUS_ATTR_OBJID])
 		return;
 
-	objid = blob_get_u32(attrbuf[UBUS_ATTR_OBJID]);
+	req.object = blob_get_u32(attrbuf[UBUS_ATTR_OBJID]);
 
 	if (!attrbuf[UBUS_ATTR_METHOD]) {
 		ret = UBUS_STATUS_INVALID_ARGUMENT;
 		goto send;
 	}
 
-	obj = avl_find_element(&ctx->objects, &objid, obj, avl);
+	obj = avl_find_element(&ctx->objects, &req.object, obj, avl);
 	if (!obj) {
 		ret = UBUS_STATUS_NOT_FOUND;
 		goto send;
@@ -381,16 +388,14 @@ static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hd
 	goto send;
 
 found:
-	req.object = objid;
 	ret = obj->methods[method].handler(ctx, obj, &req,
 					   blob_data(attrbuf[UBUS_ATTR_METHOD]),
 					   attrbuf[UBUS_ATTR_DATA]);
+	if (req.deferred)
+		return;
 
 send:
-	blob_buf_init(&b, 0);
-	blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
-	blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
-	ubus_send_msg(ctx, req.seq, b.head, UBUS_MSG_STATUS, req.peer);
+	ubus_complete_deferred_request(ctx, &req, ret);
 }
 
 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
diff --git a/libubus.h b/libubus.h
index 99cbbb4..59d981e 100644
--- a/libubus.h
+++ b/libubus.h
@@ -132,6 +132,7 @@ struct ubus_request_data {
 	uint32_t object;
 	uint32_t peer;
 	uint32_t seq;
+	bool deferred;
 };
 
 struct ubus_request {
@@ -220,6 +221,17 @@ int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method
 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 		    struct blob_attr *msg);
 
+static inline void ubus_defer_request(struct ubus_context *ctx,
+				      struct ubus_request_data *req,
+				      struct ubus_request_data *new_req)
+{
+    memcpy(new_req, req, sizeof(*req));
+    req->deferred = true;
+}
+
+void ubus_complete_deferred_request(struct ubus_context *ctx,
+				    struct ubus_request_data *req, int ret);
+
 /* ----------- events ----------- */
 
 int ubus_send_event(struct ubus_context *ctx, const char *id,
-- 
2.25.1