Add QDBusMessage::createTargetedSignal()

The QDBusMessage::createSignal() static method doesn't take a parameter
for specifying the destination service of the signal. While this is not
a widely used feature, it can be useful to avoid waking up all connected
clients when the service knows what are the clients which are interested
in the signal.

This commit adds a QDBusMessage::createTargetedSignal() method which
also takes the destination service as its first parameter.

Change-Id: I9fdca53673a6944c39c93c1efd69a9d02859684e
Task-number: QTBUG-44704
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/src/dbus/qdbusmessage.cpp b/src/dbus/qdbusmessage.cpp
index 491e1273e7..76e994bbcf 100644
--- a/src/dbus/qdbusmessage.cpp
+++ b/src/dbus/qdbusmessage.cpp
@@ -153,8 +153,10 @@ DBusMessage *QDBusMessagePrivate::toDBusMessage(const QDBusMessage &message, QDB
         }
         break;
     case QDBusMessage::SignalMessage:
-        // nothing can be empty here
+        // only the service name can be empty here
         if (!d_ptr->parametersValidated) {
+            if (!QDBusUtil::checkBusName(d_ptr->service, QDBusUtil::EmptyAllowed, error))
+                return 0;
             if (!QDBusUtil::checkObjectPath(d_ptr->path, QDBusUtil::EmptyNotAllowed, error))
                 return 0;
             if (!QDBusUtil::checkInterfaceName(d_ptr->interface, QDBusUtil::EmptyAllowed, error))
@@ -165,6 +167,7 @@ DBusMessage *QDBusMessagePrivate::toDBusMessage(const QDBusMessage &message, QDB
 
         msg = q_dbus_message_new_signal(d_ptr->path.toUtf8(), d_ptr->interface.toUtf8(),
                                         d_ptr->name.toUtf8());
+        q_dbus_message_set_destination(msg, data(d_ptr->service.toUtf8()));
         break;
     }
 
@@ -372,6 +375,31 @@ QDBusMessage QDBusMessage::createSignal(const QString &path, const QString &inte
 }
 
 /*!
+    \since 5.6
+
+    Constructs a new DBus message with the given \a path, \a interface
+    and \a name, representing a signal emission to \a destination.
+
+    A DBus signal is emitted from one application and is received only by
+    the application owning the destination service name.
+
+    The QDBusMessage object that is returned can be sent using the
+    QDBusConnection::send() function.
+*/
+QDBusMessage QDBusMessage::createTargetedSignal(const QString &service, const QString &path,
+                                                const QString &interface, const QString &name)
+{
+    QDBusMessage message;
+    message.d_ptr->type = SignalMessage;
+    message.d_ptr->service = service;
+    message.d_ptr->path = path;
+    message.d_ptr->interface = interface;
+    message.d_ptr->name = name;
+
+    return message;
+}
+
+/*!
     Constructs a new DBus message representing a method call.
     A method call always informs its destination address
     (\a service, \a path, \a interface and \a method).