Use own linked list for storing disused contexts for freeing.

Seemed to be a problem with getting it to work under a hash and there
isn't really any need for a hash.

lib/mosquitto_internal.h

@@ -235,7 +235,7 @@ struct mosquitto {
 #ifdef WITH_BROKER
 	UT_hash_handle hh_id;
 	UT_hash_handle hh_sock;
-	UT_hash_handle hh_for_free;
+	struct mosquitto *for_free_next;
 #  ifdef WITH_BRIDGE
 	UT_hash_handle hh_bridge;
 #  endif

src/context.c

@@ -142,11 +142,6 @@ void mqtt3_context_cleanup(struct mosquitto_db *db, struct mosquitto *context, b
 		context->address = NULL;
 	}
 
-	HASH_FIND(hh_for_free, db->contexts_for_free, context, sizeof(void *), ctx_tmp);
-	if(ctx_tmp){
-		HASH_DELETE(hh_for_free, db->contexts_for_free, context);
-	}
-
 	if(context->id){
 		assert(db); /* db can only be NULL here if the client hasn't sent a
 					   CONNECT and hence wouldn't have an id. */
@@ -202,3 +197,26 @@ void mqtt3_context_disconnect(struct mosquitto_db *db, struct mosquitto *ctxt)
 	_mosquitto_socket_close(db, ctxt);
 }
 
+void mosquitto__add_context_to_disused(struct mosquitto_db *db, struct mosquitto *context)
+{
+	if(db->ll_for_free){
+		context->for_free_next = db->ll_for_free;
+		db->ll_for_free = context;
+	}else{
+		db->ll_for_free = context;
+	}
+}
+
+void mosquitto__free_disused_contexts(struct mosquitto_db *db)
+{
+	assert(db);
+	struct mosquitto *context, *next;
+
+	context = db->ll_for_free;
+	while(context){
+		next = context->for_free_next;
+		mqtt3_context_cleanup(db, context, true);
+		context = next;
+	}
+}
+

src/loop.c

@@ -93,10 +93,7 @@ int mosquitto_main_loop(struct mosquitto_db *db, int *listensock, int listensock
 	}
 
 	while(run){
-		HASH_ITER(hh_for_free, db->contexts_for_free, context, ctxt_tmp){
-			HASH_DELETE(hh_for_free, db->contexts_for_free, context);
-			mqtt3_context_cleanup(db, context, true);
-		}
+		mosquitto__free_disused_contexts(db);
 #ifdef WITH_SYS_TREE
 		if(db->config->sys_interval > 0){
 			mqtt3_db_sys_update(db, db->config->sys_interval, start_time);
@@ -367,7 +364,7 @@ void do_disconnect(struct mosquitto_db *db, struct mosquitto *context)
 #else
 		if(context->clean_session){
 #endif
-			HASH_ADD_KEYPTR(hh_for_free, db->contexts_for_free, context, sizeof(void *), context);
+			mosquitto__add_context_to_disused(db, context);
 			if(context->id){
 				HASH_DELETE(hh_id, db->contexts_by_id, context);
 				_mosquitto_free(context->id);

src/mosquitto.c

@@ -381,10 +381,7 @@ int main(int argc, char *argv[])
 		mqtt3_context_cleanup(&int_db, ctxt, true);
 	}
 #endif
-	HASH_ITER(hh_for_free, int_db.contexts_for_free, ctxt, ctxt_tmp){
-		HASH_DELETE(hh_for_free, int_db.contexts_for_free, ctxt);
-		mqtt3_context_cleanup(&int_db, ctxt, true);
-	}
+	mosquitto__free_disused_contexts(&int_db);
 
 	mqtt3_db_close(&int_db);
 

src/mosquitto_broker.h

@@ -223,6 +223,7 @@ struct mosquitto_db{
 	int subscription_count;
 	int retained_count;
 #endif
+	struct mosquitto *ll_for_free;
 };
 
 enum mqtt3_bridge_direction{
@@ -400,6 +401,8 @@ int mqtt3_subs_clean_session(struct mosquitto_db *db, struct mosquitto *context,
 struct mosquitto *mqtt3_context_init(struct mosquitto_db *db, int sock);
 void mqtt3_context_cleanup(struct mosquitto_db *db, struct mosquitto *context, bool do_free);
 void mqtt3_context_disconnect(struct mosquitto_db *db, struct mosquitto *context);
+void mosquitto__add_context_to_disused(struct mosquitto_db *db, struct mosquitto *context);
+void mosquitto__free_disused_contexts(struct mosquitto_db *db);
 
 /* ============================================================
  * Logging functions

src/read_handle_server.c

@@ -500,16 +500,16 @@ int mqtt3_handle_connect(struct mosquitto_db *db, struct mosquitto *context)
 				ws_ctxt_user_head = ws_ctxt_user_head->next;
 			}
 			ws_ctxt_user_head->next = ws_ctxt_user;
-			HASH_ADD_KEYPTR(hh_for_free, db->contexts_for_free, context, sizeof(void *), context);
+			mosquitto__add_context_to_disused(db, context);
 		}else{
-			HASH_ADD_KEYPTR(hh_for_free, db->contexts_for_free, context, sizeof(void *), context);
+			mosquitto__add_context_to_disused(db, context);
 
 			HASH_DELETE(hh_sock, db->contexts_by_sock, context);
 			context->sock = INVALID_SOCKET;
 			HASH_ADD(hh_sock, db->contexts_by_sock, sock, sizeof(found_context->sock), found_context);
 		}
 #else
-		HASH_ADD_KEYPTR(hh_for_free, db->contexts_for_free, context, sizeof(void *), context);
+		mosquitto__add_context_to_disused(db, context);
 
 		HASH_DELETE(hh_sock, db->contexts_by_sock, context);
 		context->sock = INVALID_SOCKET;