dbus: Make Bus::GetManagedObjects skip unavailable services.

dbus/object_manager.cc

Index: dbus/object_manager.cc
diff --git a/dbus/object_manager.cc b/dbus/object_manager.cc
index 56143c758b4bb9b40f72e0f55075e0caa1f77ddc..1e165af141c07496805ae65de0d9314a8bd880e7 100644
--- a/dbus/object_manager.cc
+++ b/dbus/object_manager.cc
@@ -37,12 +37,17 @@ ObjectManager::ObjectManager(Bus* bus,
       object_path_(object_path),
       setup_success_(false),
       cleanup_called_(false),
+      service_initially_available_(false),
+      signals_are_connected_(false),
       weak_ptr_factory_(this) {
   DVLOG(1) << "Creating ObjectManager for " << service_name_
            << " " << object_path_.value();
   DCHECK(bus_);
   bus_->AssertOnOriginThread();
   object_proxy_ = bus_->GetObjectProxy(service_name_, object_path_);
+  object_proxy_->WaitForServiceToBeAvailable(
+      base::Bind(&ObjectManager::OnServiceInitiallyAvailable,
+                 weak_ptr_factory_.GetWeakPtr()));
   object_proxy_->SetNameOwnerChangedCallback(
       base::Bind(&ObjectManager::NameOwnerChanged,
                  weak_ptr_factory_.GetWeakPtr()));
@@ -167,6 +172,18 @@ void ObjectManager::CleanUp() {
   match_rule_.clear();
 }
 
+void ObjectManager::OnServiceInitiallyAvailable(bool service_is_available) {
+  if (!service_is_available) {
+    LOG(WARNING) << service_name_ << " " << object_path_.value()
+                 << ": Failed to wait for service to become available";
+    return;
+  }
+
+  service_initially_available_ = true;
+  if (signals_are_connected_)
+    GetManagedObjects();
+}
+
 void ObjectManager::InitializeObjects() {
   DCHECK(bus_);
   DCHECK(object_proxy_);
@@ -193,7 +210,9 @@ void ObjectManager::InitializeObjects() {
       base::Bind(&ObjectManager::InterfacesRemovedConnected,
                  weak_ptr_factory_.GetWeakPtr()));
 
-  GetManagedObjects();
+  signals_are_connected_ = true;
+  if (service_initially_available_)
+    GetManagedObjects();

[hashimoto, 2016/09/01 03:26:07]

How about calling WaitForServiceToBeAvailable() here instead of in the ctor so
that we don't need to manage signals_are_connected_ and
service_initially_available_?
Are SetupMatchRuleAndFilter() and WaitForServiceToBeAvailable() too slow to
perform them sequentially?

[Daniel Erat, 2016/09/01 04:15:55]

thanks, that seems like a good suggestion! and no, i'd expect that the delay
wouldn't cause any issues. i'll ping you when i've uploaded a new version.

 }
 
 bool ObjectManager::SetupMatchRuleAndFilter() {