Call get_dispatch_status function to handle Disconnected signal.

dbus/bus.cc

Index: dbus/bus.cc
diff --git a/dbus/bus.cc b/dbus/bus.cc
index 4096049417884f76044a275adbadb5e060f59636..7d235aa4b115bbe11c96844f64e60121d2c2d136 100644
--- a/dbus/bus.cc
+++ b/dbus/bus.cc
@@ -24,6 +24,11 @@ namespace dbus {
 
 namespace {
 
+const char kDisconnectedSignal[] = "Disconnected";
+const char kDisconnectedMatchRule[] =
+    "type='signal', path='/org/freedesktop/DBus/Local',"
+    "interface='org.freedesktop.DBus.Local', member='Disconnected'";
+
 // The class is used for watching the file descriptor used for D-Bus
 // communication.
 class Watch : public base::MessagePumpLibevent::Watcher {
@@ -364,6 +369,10 @@ bool Bus::Connect() {
   // We shouldn't exit on the disconnected signal.
   dbus_connection_set_exit_on_disconnect(connection_, false);
 
+  // Watch Disconnected signal.
+  AddFilterFunction(Bus::OnConnectionDisconnectedFilter, this);
+  AddMatch(kDisconnectedMatchRule, error.get());
+
   return true;
 }
 
@@ -704,9 +713,12 @@ void Bus::ProcessAllIncomingDataIfAny() {
   AssertOnDBusThread();
 
   // As mentioned at the class comment in .h file, connection_ can be NULL.
-  if (!connection_ || !dbus_connection_get_is_connected(connection_))
+  if (!connection_)
     return;
 
+  // It is safe and necessary to call dbus_connection_get_dispatch_status even
+  // if the connection is lost. Otherwise we will miss "Disconnected" signal.
+  // (crbug.com/174431)
   if (dbus_connection_get_dispatch_status(connection_) ==
       DBUS_DISPATCH_DATA_REMAINS) {
     while (dbus_connection_dispatch(connection_) ==
@@ -842,9 +854,6 @@ void Bus::OnDispatchStatusChanged(DBusConnection* connection,
   DCHECK_EQ(connection, connection_);
   AssertOnDBusThread();
 
-  if (!dbus_connection_get_is_connected(connection))
-    return;
-
   // We cannot call ProcessAllIncomingDataIfAny() here, as calling
   // dbus_connection_dispatch() inside DBusDispatchStatusFunction is
   // prohibited by the D-Bus library. Hence, we post a task here instead.
@@ -854,6 +863,16 @@ void Bus::OnDispatchStatusChanged(DBusConnection* connection,
                                   this));
 }
 
+void Bus::OnConnectionDisconnected(DBusConnection* connection) {

[satorux1, 2013/02/06 03:15:39]

on what thread this function is called? Please annotate with AssertOn*

[Seigo Nonaka, 2013/02/06 04:57:22]

Done.

+  if (!connection)
+    return;
+
+  DCHECK_EQ(connection, connection_);
+  DCHECK(!dbus_connection_get_is_connected(connection));
+
+  ShutdownAndBlock();
+}
+
 dbus_bool_t Bus::OnAddWatchThunk(DBusWatch* raw_watch, void* data) {
   Bus* self = static_cast<Bus*>(data);
   return self->OnAddWatch(raw_watch);
@@ -891,4 +910,18 @@ void Bus::OnDispatchStatusChangedThunk(DBusConnection* connection,
   self->OnDispatchStatusChanged(connection, status);
 }
 
+DBusHandlerResult Bus::OnConnectionDisconnectedFilter(
+    DBusConnection *connection,
+    DBusMessage *message,
+    void *data) {

[satorux1, 2013/02/06 03:15:39]

ditto. please annotate the thread.

[Seigo Nonaka, 2013/02/06 04:57:22]

Done.

+  if (dbus_message_is_signal(message,
+                             DBUS_INTERFACE_LOCAL,
+                             kDisconnectedSignal)) {
+    Bus* self = static_cast<Bus*>(data);
+    self->OnConnectionDisconnected(connection);
+    return DBUS_HANDLER_RESULT_HANDLED;
+  }
+  return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
 }  // namespace dbus