From 393d7dbc03cc233bc1ff065b9b33a3e243b02566 Mon Sep 17 00:00:00 2001
From: Niklas Fiekas <niklas.fiekas@backscattering.de>
Date: Sat, 11 Jan 2025 17:52:32 +0100
Subject: [PATCH] More precise constness for topics in
 mosquitto_subscribe_multiple

mosquitto_subscribe_multiple and mosquitto_unsubscribe_multiple do not
need to change the characters in the list of topics. Make the signature
more precise to reflect that.

Now works without cast array of const char*, particularly useful for C++
or Rust bindings.

Signed-off-by: Niklas Fiekas <niklas.fiekas@backscattering.de>
---
 client/sub_client.c    |  2 +-
 include/mosquitto.h    |  4 ++--
 lib/actions.c          | 12 ++++++------
 lib/send_mosq.h        |  4 ++--
 lib/send_subscribe.c   |  2 +-
 lib/send_unsubscribe.c |  2 +-
 src/bridge.c           |  4 ++--
 7 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/client/sub_client.c b/client/sub_client.c
index 6e2a1fb4d9..48cb78b52f 100644
--- a/client/sub_client.c
+++ b/client/sub_client.c
@@ -122,7 +122,7 @@ static void my_connect_callback(struct mosquitto *mosq, void *obj, int result, i
 
 	connack_result = result;
 	if(!result){
-		mosquitto_subscribe_multiple(mosq, NULL, cfg.topic_count, cfg.topics, cfg.qos, cfg.sub_opts, cfg.subscribe_props);
+		mosquitto_subscribe_multiple(mosq, NULL, cfg.topic_count, (const char* const*)cfg.topics, cfg.qos, cfg.sub_opts, cfg.subscribe_props);
 
 		for(i=0; i<cfg.unsub_topic_count; i++){
 			mosquitto_unsubscribe_v5(mosq, NULL, cfg.unsub_topics[i], cfg.unsubscribe_props);
diff --git a/include/mosquitto.h b/include/mosquitto.h
index 8262306496..c67041fd5c 100644
--- a/include/mosquitto.h
+++ b/include/mosquitto.h
@@ -1036,7 +1036,7 @@ libmosq_EXPORT int mosquitto_subscribe_v5(struct mosquitto *mosq, int *mid, cons
  *	MOSQ_ERR_OVERSIZE_PACKET - if the resulting packet would be larger than
  *	                           supported by the broker.
  */
-libmosq_EXPORT int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, char *const *const sub, int qos, int options, const mosquitto_property *properties);
+libmosq_EXPORT int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, const char* const *sub, int qos, int options, const mosquitto_property *properties);
 
 /*
  * Function: mosquitto_unsubscribe
@@ -1135,7 +1135,7 @@ libmosq_EXPORT int mosquitto_unsubscribe_v5(struct mosquitto *mosq, int *mid, co
  *	MOSQ_ERR_OVERSIZE_PACKET - if the resulting packet would be larger than
  *	                           supported by the broker.
  */
-libmosq_EXPORT int mosquitto_unsubscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, char *const *const sub, const mosquitto_property *properties);
+libmosq_EXPORT int mosquitto_unsubscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, const char* const *sub, const mosquitto_property *properties);
 
 
 /* ======================================================================
diff --git a/lib/actions.c b/lib/actions.c
index ac61331ac6..ad1008b57c 100644
--- a/lib/actions.c
+++ b/lib/actions.c
@@ -166,17 +166,17 @@ int mosquitto_publish_v5(struct mosquitto *mosq, int *mid, const char *topic, in
 
 int mosquitto_subscribe(struct mosquitto *mosq, int *mid, const char *sub, int qos)
 {
-	return mosquitto_subscribe_multiple(mosq, mid, 1, (char *const *const)&sub, qos, 0, NULL);
+	return mosquitto_subscribe_multiple(mosq, mid, 1, &sub, qos, 0, NULL);
 }
 
 
 int mosquitto_subscribe_v5(struct mosquitto *mosq, int *mid, const char *sub, int qos, int options, const mosquitto_property *properties)
 {
-	return mosquitto_subscribe_multiple(mosq, mid, 1, (char *const *const)&sub, qos, options, properties);
+	return mosquitto_subscribe_multiple(mosq, mid, 1, &sub, qos, options, properties);
 }
 
 
-int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, char *const *const sub, int qos, int options, const mosquitto_property *properties)
+int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, const char* const *sub, int qos, int options, const mosquitto_property *properties)
 {
 	const mosquitto_property *outgoing_properties = NULL;
 	mosquitto_property local_property;
@@ -227,15 +227,15 @@ int mosquitto_subscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count
 
 int mosquitto_unsubscribe(struct mosquitto *mosq, int *mid, const char *sub)
 {
-	return mosquitto_unsubscribe_multiple(mosq, mid, 1, (char *const *const)&sub, NULL);
+	return mosquitto_unsubscribe_multiple(mosq, mid, 1, &sub, NULL);
 }
 
 int mosquitto_unsubscribe_v5(struct mosquitto *mosq, int *mid, const char *sub, const mosquitto_property *properties)
 {
-	return mosquitto_unsubscribe_multiple(mosq, mid, 1, (char *const *const)&sub, properties);
+	return mosquitto_unsubscribe_multiple(mosq, mid, 1, &sub, properties);
 }
 
-int mosquitto_unsubscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, char *const *const sub, const mosquitto_property *properties)
+int mosquitto_unsubscribe_multiple(struct mosquitto *mosq, int *mid, int sub_count, const char* const *sub, const mosquitto_property *properties)
 {
 	const mosquitto_property *outgoing_properties = NULL;
 	mosquitto_property local_property;
diff --git a/lib/send_mosq.h b/lib/send_mosq.h
index 85b51c3744..b395f27b4b 100644
--- a/lib/send_mosq.h
+++ b/lib/send_mosq.h
@@ -34,7 +34,7 @@ int send__pubcomp(struct mosquitto *mosq, uint16_t mid, const mosquitto_property
 int send__publish(struct mosquitto *mosq, uint16_t mid, const char *topic, uint32_t payloadlen, const void *payload, uint8_t qos, bool retain, bool dup, const mosquitto_property *cmsg_props, const mosquitto_property *store_props, uint32_t expiry_interval);
 int send__pubrec(struct mosquitto *mosq, uint16_t mid, uint8_t reason_code, const mosquitto_property *properties);
 int send__pubrel(struct mosquitto *mosq, uint16_t mid, const mosquitto_property *properties);
-int send__subscribe(struct mosquitto *mosq, int *mid, int topic_count, char *const *const topic, int topic_qos, const mosquitto_property *properties);
-int send__unsubscribe(struct mosquitto *mosq, int *mid, int topic_count, char *const *const topic, const mosquitto_property *properties);
+int send__subscribe(struct mosquitto *mosq, int *mid, int topic_count, const char* const *topic, int topic_qos, const mosquitto_property *properties);
+int send__unsubscribe(struct mosquitto *mosq, int *mid, int topic_count, const char* const *topic, const mosquitto_property *properties);
 
 #endif
diff --git a/lib/send_subscribe.c b/lib/send_subscribe.c
index 40e1d43213..ab6442b8d9 100644
--- a/lib/send_subscribe.c
+++ b/lib/send_subscribe.c
@@ -36,7 +36,7 @@ SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #include "util_mosq.h"
 
 
-int send__subscribe(struct mosquitto *mosq, int *mid, int topic_count, char *const *const topic, int topic_qos, const mosquitto_property *properties)
+int send__subscribe(struct mosquitto *mosq, int *mid, int topic_count, const char* const *topic, int topic_qos, const mosquitto_property *properties)
 {
 	struct mosquitto__packet *packet = NULL;
 	uint32_t packetlen;
diff --git a/lib/send_unsubscribe.c b/lib/send_unsubscribe.c
index 0806b819e0..784f3bb3b0 100644
--- a/lib/send_unsubscribe.c
+++ b/lib/send_unsubscribe.c
@@ -35,7 +35,7 @@ SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #include "util_mosq.h"
 
 
-int send__unsubscribe(struct mosquitto *mosq, int *mid, int topic_count, char *const *const topic, const mosquitto_property *properties)
+int send__unsubscribe(struct mosquitto *mosq, int *mid, int topic_count, const char* const *topic, const mosquitto_property *properties)
 {
 	struct mosquitto__packet *packet = NULL;
 	uint32_t packetlen;
diff --git a/src/bridge.c b/src/bridge.c
index f6daf240d0..657558f3dc 100644
--- a/src/bridge.c
+++ b/src/bridge.c
@@ -546,12 +546,12 @@ int bridge__on_connect(struct mosquitto *context)
 					| MQTT_SUB_OPT_RETAIN_AS_PUBLISHED
 					| MQTT_SUB_OPT_SEND_RETAIN_ALWAYS;
 			}
-			if(send__subscribe(context, NULL, 1, &context->bridge->topics[i].remote_topic, sub_opts, NULL)){
+			if(send__subscribe(context, NULL, 1, (const char* const*)&context->bridge->topics[i].remote_topic, sub_opts, NULL)){
 				return 1;
 			}
 		}else{
 			if(context->bridge->attempt_unsubscribe){
-				if(send__unsubscribe(context, NULL, 1, &context->bridge->topics[i].remote_topic, NULL)){
+				if(send__unsubscribe(context, NULL, 1, (const char* const*)&context->bridge->topics[i].remote_topic, NULL)){
 					/* direction = inwards only. This means we should not be subscribed
 					* to the topic. It is possible that we used to be subscribed to
 					* this topic so unsubscribe. */