Stream/Client: IQ handling: Automatically parse stanza errors

This changes the behaviour of the IQ handling. If an IQ response of type
error is received, the stanza error is parsed and returned as
QXmppError. This reduces the amout of further code on side of the user
(and makes the binaries smaller). It makes it impossible to parse the
rest of an error IQ though. However a function for that purpose may
still be added later.

src/base/QXmppFutureUtils_p.h

@@ -157,12 +157,6 @@ auto parseIq(Input &&sendResult, Converter convert) -> decltype(convert({}))
                           [convert = std::move(convert)](const QDomElement &element) -> Result {
                               IqType iq;
                               iq.parse(element);
-                              if (iq.type() == QXmppIq::Error) {
-                                  if (auto err = iq.errorOptional()) {
-                                      return QXmppError { err->text(), std::move(*err) };
-                                  }
-                                  return QXmppError { QStringLiteral("Unknown error.") };
-                              }
                               return convert(std::move(iq));
                           },
                           [](QXmppError error) -> Result {

src/base/QXmppStream.cpp

@@ -73,8 +73,8 @@ QXmppStreamPrivate::~QXmppStreamPrivate()
 ///
 /// \typedef QXmppStream::IqResult
 ///
-/// Contains a QDomElement containing the IQ response or if the request couldn't
-/// be sent a QXmpp::PacketState.
+/// Contains a QDomElement if an IQ response of type 'result' has been received. In case of an
+/// error response of if an error occurred while sending the IQ request, a QXmppError is used.
 ///
 /// \warning THIS API IS NOT FINALIZED YET!
 ///
@@ -503,7 +503,23 @@ bool QXmppStream::handleIqResponse(const QDomElement &stanza)
             return false;
         }
 
-        itr.value().interface.finish(stanza);
+        // report IQ errors as QXmppError (this makes it impossible to parse the full error IQ,
+        // but that is okay for now)
+        if (iqType == QStringLiteral("error")) {
+            QXmppIq iq;
+            iq.parse(stanza);
+            if (auto err = iq.errorOptional()) {
+                // report stanza error
+                itr.value().interface.finish(QXmppError { err->text(), *err });
+            } else {
+                // this shouldn't happen (no <error/> element in IQ of type error)
+                using Err = QXmppStanza::Error;
+                itr.value().interface.finish(QXmppError { QStringLiteral("IQ error"), Err(Err::Cancel, Err::UndefinedCondition) });
+            }
+        } else {
+            // report stanza element for parsing
+            itr.value().interface.finish(stanza);
+        }
 
         d->runningIqs.erase(itr);
         return true;

src/client/QXmppClient.cpp

@@ -171,9 +171,9 @@ bool process(QXmppClient *client, const QList<QXmppClientExtension *> &extension
 ///
 /// \typedef QXmppClient::IqResult
 ///
-/// Result of an IQ request, either contains the QDomElement of the IQ answer
-/// (with type 'error' or 'result') or it contains the packet error, if the
-/// request couldn't be sent.
+/// Result of an IQ request, either contains the QDomElement of the IQ reponse (in case of an
+/// 'result' IQ type) or it contains an QXmppError with a QXmppStanza::Error (on type 'error') or
+/// a QXmpp::SendError.
 ///
 /// \since QXmpp 1.5
 ///
@@ -496,6 +496,9 @@ QXmppTask<QXmpp::SendResult> QXmppClient::reply(QXmppStanza &&stanza, const std:
 /// QDomElement. If you don't expect a special response, you may want use
 /// sendGenericIq().
 ///
+/// IQs of type 'error' are parsed automatically and returned as QXmppError with a contained
+/// QXmppStanza::Error.
+///
 /// This does not do any end-to-encryption on the IQ.
 ///
 /// \sa sendSensitiveIq()
@@ -518,6 +521,9 @@ QXmppTask<QXmppClient::IqResult> QXmppClient::sendIq(QXmppIq &&iq, const std::op
 /// encrypted or it only makes little sense to do so. This is why the default
 /// sendIq() does not do any additional end-to-end encryption.
 ///
+/// IQs of type 'error' are parsed automatically and returned as QXmppError with a contained
+/// QXmppStanza::Error.
+///
 /// \warning THIS API IS NOT FINALIZED YET!
 ///
 /// \since QXmpp 1.5