Parse and emit connection timeout stream error

src/base/QXmppStanza.h

@@ -137,6 +137,7 @@ class QXMPP_EXPORT QXmppStanza : public QXmppNonza
             UnexpectedRequest,          ///< The request was unexpected.
             PolicyViolation,            ///< The entity has violated a local server policy. \since QXmpp 1.3
             EmailConfirmationRequired,  ///< The server requires the entitiy to confirm an email message that the server sent to the entity. \since QXmpp 1.6
+            ConnectionTimeout,          ///< The server closed the connection to the entity because the server did not receive a response to a request from it. \since QXmpp 1.6
         };
 
         Error();

src/client/QXmppOutgoingClient.cpp

@@ -561,6 +561,8 @@ void QXmppOutgoingClient::handleStanza(const QDomElement &nodeRecv)
             d->xmppStreamError = QXmppStanza::Error::Conflict;
         } else if (!nodeRecv.firstChildElement("not-authorized").isNull()) {
             d->xmppStreamError = QXmppStanza::Error::NotAuthorized;
+        } else if (!nodeRecv.firstChildElement("connection-timeout").isNull()) {
+            d->xmppStreamError = QXmppStanza::Error::ConnectionTimeout;
         } else {
             d->xmppStreamError = QXmppStanza::Error::UndefinedCondition;
         }

src/client/QXmppRegistrationManager.h

@@ -153,10 +153,12 @@ class QXmppRegistrationManagerPrivate;
 ///
 /// <h4>Filling out the registration form</h4>
 ///
-/// Now you need to fill out the registration form. If this requires user
-/// interaction, it is recommended that you disconnect from the server at this
-/// point now. This is required, because some servers will kick inactive, not
-/// authorized clients after a few seconds.
+/// Now you need to fill out the registration form. If that takes some time, which is often the case
+/// when user interaction is required, the server can close the connection triggering
+/// QXmppClient::error() to emit QXmppStanza::Error::ConnectionTimeout before the completed form is
+/// submitted to the server. That is due to some servers kicking unauthorized clients after a few
+/// seconds when they are inactive. In order to support account creation for both servers closing
+/// the connection and servers keeping it open, you need to handle those cases appropriately.
 ///
 /// If the returned IQ contains a data form, that can be displayed to a user or
 /// can be filled out in another way.
@@ -173,24 +175,20 @@ class QXmppRegistrationManagerPrivate;
 ///
 /// <h4>Sending the completed form to the server</h4>
 ///
-/// <b>Option A</b>: If filling out the form goes very quick, you can set the
-/// filled out form directly using setRegistrationFormToSend() and then
-/// directly trigger the form to be sent using sendCachedRegistrationForm().
+/// <b>Option A</b>: If the connection is still open once the form is filled out, set the form using
+/// setRegistrationFormToSend() and then trigger the form to be directly sent using
+/// sendCachedRegistrationForm().
 ///
 /// \code
 /// registrationManager->setRegistrationFormToSend(completedForm);
 /// registrationManager->sendCachedRegistrationForm();
 /// \endcode
 ///
-/// <b>Option B</b>: If filling out the form takes longer, i.e. because user
-/// interaction is required, you should disconnect now. As soon as you have
-/// completed the form, you can set it using setRegistrationFormToSend(). After
-/// that you can reconnect to the server and the registration manager will
-/// automatically send the set form.
+/// <b>Option B</b>: If the connection is closed before the form is filled out, set the form using
+/// setRegistrationFormToSend() and connect to the server again. The registration manager will
+/// automatically send the set form once connected.
 ///
 /// \code
-/// client->disconnectFromServer();
-/// // user fills out form ...
 /// registrationManager->setRegistrationFormToSend(completedForm);
 ///
 /// // As before, you only need to provide a domain to connectToServer()
@@ -294,13 +292,6 @@ class QXMPP_EXPORT QXmppRegistrationManager : public QXmppClientExtension
     ///
     /// Emitted, when a registration form has been received.
     ///
-    /// When registering an account on the server and user interaction is
-    /// required now to complete the form, it is recommended to disconnect and
-    /// sending the completed registration form on reconnect using
-    /// QXmppRegistrationManager::setRegistrationFormToSend(). Some servers
-    /// (i.e. ejabberd) kick their clients after a timeout when they are not
-    /// active. This can be avoided this way.
-    ///
     /// \param iq The received form. If it does not contain a valid data form
     /// (see QXmppRegisterIq::form()), the required fields should be marked by
     /// empty (but not null) strings in the QXmppRegisterIq (i.e.