Merge pull request #5093 from oqlatulesba3/fix/sni-host-proxy-retry

fix(sni): retry Host proxy creation on transient errors

include/modules/sni/host.hpp

@@ -43,6 +43,8 @@ class Host {
   std::size_t watcher_id_;
   GCancellable* cancellable_ = nullptr;
   SnWatcher* watcher_ = nullptr;
+  sigc::connection retry_connection_;
+  unsigned retry_count_ = 0;
   const Json::Value& config_;
   const Bar& bar_;
   const std::function<void(std::unique_ptr<Item>&)> on_add_;

src/modules/sni/host.cpp

@@ -6,6 +6,9 @@
 
 namespace waybar::modules::SNI {
 
+static const unsigned RETRY_DELAY_MS = 200;
+static const unsigned MAX_RETRIES = 10;
+
 Host::Host(const std::size_t id, const Json::Value& config, const Bar& bar,
            const std::function<void(std::unique_ptr<Item>&)>& on_add,
            const std::function<void(std::unique_ptr<Item>&)>& on_remove,
@@ -22,6 +25,7 @@ Host::Host(const std::size_t id, const Json::Value& config, const Bar& bar,
       on_update_(on_update) {}
 
 Host::~Host() {
+  retry_connection_.disconnect();
   if (bus_name_id_ > 0) {
     Gio::DBus::unown_name(bus_name_id_);
     bus_name_id_ = 0;
@@ -53,6 +57,8 @@ void Host::nameAppeared(const Glib::RefPtr<Gio::DBus::Connection>& conn, const G
 }
 
 void Host::nameVanished(const Glib::RefPtr<Gio::DBus::Connection>& conn, const Glib::ustring name) {
+  retry_connection_.disconnect();
+  retry_count_ = 0;
   g_cancellable_cancel(cancellable_);
   g_clear_object(&cancellable_);
   g_clear_object(&watcher_);
@@ -72,11 +78,30 @@ void Host::proxyReady(GObject* src, GAsyncResult* res, gpointer data) {
     return;
   }
   auto host = static_cast<SNI::Host*>(data);
-  host->watcher_ = watcher;
   if (error != nullptr) {
     spdlog::error("Host: {}", error->message);
+    g_clear_object(&host->cancellable_);
+    if (host->retry_count_ >= MAX_RETRIES) {
+      spdlog::warn("Host: giving up on watcher proxy creation after {} retries", host->retry_count_);
+      return;
+    }
+    host->retry_count_ += 1;
+    // Store the timeout connection so it is disconnected in ~Host, avoiding a
+    // use-after-free if the Host is destroyed before the retry fires.
+    host->retry_connection_ = Glib::signal_timeout().connect(
+        [host]() {
+          if (host->watcher_ != nullptr) {
+            return false;
+          }
+          auto conn = Gio::DBus::Connection::get_sync(Gio::DBus::BusType::BUS_TYPE_SESSION);
+          host->nameAppeared(conn, "org.kde.StatusNotifierWatcher", "");
+          return false;
+        },
+        RETRY_DELAY_MS);
     return;
   }
+  host->retry_count_ = 0;
+  host->watcher_ = watcher;
   sn_watcher_call_register_host(host->watcher_, host->object_path_.c_str(), host->cancellable_,
                                 &Host::registerHost, data);
 }