fix: check against null strings

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.21)
-project(rohrkabel LANGUAGES CXX VERSION 5.0)
+project(rohrkabel LANGUAGES CXX VERSION 5.1)
 
 # --------------------------------------------------------------------------------------------------------
 # Library options

src/events/metadata.events.cpp

@@ -20,7 +20,7 @@ namespace pipewire
         m_impl->events.property = [](void *data, std::uint32_t subject, const char *key, const char *type,
                                      const char *value) {
             auto &events  = *reinterpret_cast<listener::events *>(data);
-            auto property = metadata_property{type, value, subject};
+            auto property = metadata_property{type ? type : "", value ? value : "", subject};
 
             return events.at<metadata_event::property>().during(0, key, std::move(property)).value_or(0);
         };

src/events/registry.events.cpp

@@ -19,7 +19,7 @@ namespace pipewire
         m_impl->events.global = [](void *data, std::uint32_t id, std::uint32_t permissions, const char *type,
                                    std::uint32_t version, const spa_dict *props) {
             auto &events = *reinterpret_cast<listener::events *>(data);
-            events.at<registry_event::global>().fire(global{id, version, permissions, props, type});
+            events.at<registry_event::global>().fire(global{id, version, permissions, props, type ? type : ""});
         };
 
         m_impl->events.global_remove = [](void *data, std::uint32_t id) {

src/info/core.info.cpp

@@ -10,10 +10,10 @@ namespace pipewire
             .props     = info->props,
             .id        = info->id,
             .cookie    = info->cookie,
-            .name      = info->name,
-            .version   = info->version,
-            .user_name = info->user_name,
-            .host_name = info->host_name,
+            .name      = info->name ? info->name : "",
+            .version   = info->version ? info->version : "",
+            .user_name = info->user_name ? info->user_name : "",
+            .host_name = info->host_name ? info->host_name : "",
         };
     }
 } // namespace pipewire