Allow dbus clients to silence logging when a service is unavailable.

dbus/object_proxy.cc

Index: dbus/object_proxy.cc
diff --git a/dbus/object_proxy.cc b/dbus/object_proxy.cc
index 5da5901f888c0b5dbc73f0d81b4670d15662fec8..675c025198816f6240165eb3fca48bf88c82c41b 100644
--- a/dbus/object_proxy.cc
+++ b/dbus/object_proxy.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <string.h>
+
 #include "dbus/bus.h"
 
 #include "base/bind.h"
@@ -17,6 +19,8 @@
 
 namespace {
 
+const char kErrorServiceUnknown[] = "org.freedesktop.DBus.Error.ServiceUnknown";
+
 // Used for success ratio histograms. 1 for success, 0 for failure.
 const int kSuccessRatioHistogramMaxValue = 2;
 
@@ -39,11 +43,14 @@ namespace dbus {
 
 ObjectProxy::ObjectProxy(Bus* bus,
                          const std::string& service_name,
-                         const std::string& object_path)
+                         const std::string& object_path,
+                         ServiceUnknownBehavior service_unknown_behavior)
     : bus_(bus),
       service_name_(service_name),
       object_path_(object_path),
-      filter_added_(false) {
+      filter_added_(false),
+      log_unknown_service_errors_(
+          service_unknown_behavior == LOG_SERVICE_UNKNOWN_ERRORS) {
 }
 
 ObjectProxy::~ObjectProxy() {
@@ -75,8 +82,13 @@ Response* ObjectProxy::CallMethodAndBlock(MethodCall* method_call,
                             kSuccessRatioHistogramMaxValue);
 
   if (!response_message) {
-    LOG(ERROR) << "Failed to call method: "
-               << (error.is_set() ? error.message() : "");
+    const bool error_is_set = error.is_set();

[satorux1, 2012/02/10 08:12:52]

The caching is unnecessary. You'll only save two bytes "()".

[adamk, 2012/02/10 17:57:16]

It wasn't obvious to me that error.is_set() was cheap. Changed to not cache.

+    const char* error_name = error_is_set ? error.name() : "";
+    if (log_unknown_service_errors_ ||
+        strcmp(error_name, kErrorServiceUnknown)) {

[satorux1, 2012/02/10 08:12:52]

strcmp() is hard to read. Please make it something like

 std::string(error_name) != kErrorServiceUnknown

[adamk, 2012/02/10 17:57:16]

Changed error_name to be a base::StringPiece.

+      LOG(ERROR) << "Failed to call method: "
+                 << (error_is_set ? error.message() : "");
+    }
     return NULL;
   }
   // Record time spent for the method call. Don't include failures.
@@ -234,10 +246,13 @@ void ObjectProxy::RunResponseCallback(ResponseCallback response_callback,
         dbus::ErrorResponse::FromRawMessage(response_message));
     // Error message may contain the error message as string.
     dbus::MessageReader reader(error_response.get());
-    std::string error_message;
-    reader.PopString(&error_message);
-    LOG(ERROR) << "Failed to call method: " << error_response->GetErrorName()
-               << ": " << error_message;
+    std::string error_name = error_response->GetErrorName();
+    if (log_unknown_service_errors_ || error_name != kErrorServiceUnknown) {
+      std::string error_message;
+      reader.PopString(&error_message);
+      LOG(ERROR) << "Failed to call method: " << error_name
+                 << ": " << error_message;
+    }
     // We don't give the error message to the callback.
     response_callback.Run(NULL);
   } else {