cashew: defer all D-Bus signal processing to main loop

src/device.cc

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/device.h"
 
 #include <glog/logging.h>
 
 #include "src/byte_counter.h"
 #include "src/service.h"
@@ skipping 29 matching lines @@
       get_properties_source_id_(0), retrying_get_properties_(false),
       byte_counter_(NULL), byte_counter_running_(false) {
   // schedule a GetProperties() call to our Flimflam service path to init state
   // we'll keep trying periodically until we succeed
   // we'll subsequently update this state by monitoring PropertyChanged signals
   get_properties_source_id_ =
       g_idle_add(StaticGetDevicePropertiesCallback, this);
   if (get_properties_source_id_ == 0) {
     LOG(ERROR) << path_ << ": ctor: g_idle_add failed";
   }
+  property_changed_handler_.delegate(this);
 }
 
 Device::~Device() {
   StopByteCounter();
   if (get_properties_source_id_ != 0 &&
       !g_source_remove(get_properties_source_id_)) {
     DLOG(WARNING) << path_ << ": dtor: g_source_remove failed";
   }
 }
 
@@ skipping 11 matching lines @@
 
 const std::string& Device::GetInterface() const {
   return interface_;
 }
 
 // Flimflam Device D-Bus Proxy methods
 
 void Device::PropertyChanged(const std::string& property_name,
                              const DBus::Variant& new_value) {
   DLOG(INFO) << path_ << ": PropertyChanged: property_name = " << property_name;
+  // Queue a tuple representing this signal for later processing from the glib
+  // main loop. We do this to avoid libdbus-c++ deadlocks that can occur when
+  // sending a dbus message from within a dbus callback like this one.
+  PropertyChangedSignal signal(property_name, new_value);
+  property_changed_handler_.EnqueueSignal(signal);
+}
+
+// PropertyChangedDelegate methods
+
+void Device::OnPropertyChanged(const PropertyChangedHandler *handler,
+                               const std::string& property_name,
+                               const DBus::Variant& new_value) {
+  DCHECK(handler == &property_changed_handler_);
+  DLOG(INFO) << path_ << ": OnPropertyChanged: property_name = "
+      << property_name;
   if (property_name == kFlimflamDeviceCarrierProperty) {
     OnCarrierUpdate(new_value.reader().get_string());
   } else if (property_name == kFlimflamDeviceInterfaceProperty) {
     OnInterfaceUpdate(new_value.reader().get_string());
   } else if (property_name == kFlimflamDeviceTypeProperty) {
     OnTypeUpdate(new_value.reader().get_string());
   } else {
     // we don't care about this property
   }
 }
@@ skipping 257 matching lines @@
 
 void Device::DeleteByteCounter() {
   DLOG(INFO) << path_ << ": DeleteByteCounter";
   if (byte_counter_ != NULL) {
     delete byte_counter_;
     byte_counter_ = NULL;
   }
 }
 
 }  // namespace cashew