use asynchronous DNS SRV lookups to avoid freezing clients during lookup

7 files changed, 135 insertions, 21 deletions

diff --git a/src/QXmppOutgoingClient.cpp b/src/QXmppOutgoingClient.cpp
index ed51eb9c..08f557a9 100644
--- a/src/QXmppOutgoingClient.cpp
+++ b/src/QXmppOutgoingClient.cpp
@@ -144,25 +144,41 @@ QXmppConfiguration& QXmppOutgoingClient::configuration()
 
 void QXmppOutgoingClient::connectToHost()
 {
+    const QString host = configuration().host();
+    const quint16 port = configuration().port();
+
+    // if an explicit host was provided, connect to it
+    if (!host.isEmpty() && port)
+    {
+        info(QString("Connecting to %1:%2").arg(host, QString::number(port)));
+        socket()->setProxy(configuration().networkProxy());
+        socket()->connectToHost(host, port);
+        return;
+    }
+
+    // otherwise, lookup server
+    const QString domain = configuration().domain();
+    debug(QString("Looking up server for domain %1").arg(domain));
+    QXmppSrvInfo::lookupService("_xmpp-client._tcp." + domain, this,
+                                SLOT(connectToHost(QXmppSrvInfo)));
+}
+
+void QXmppOutgoingClient::connectToHost(const QXmppSrvInfo &serviceInfo)
+{
     const QString domain = configuration().domain();
     QString host = configuration().host();
     quint16 port = configuration().port();
 
-    // if we do not have no explicit host was provided, look it up
-    if (host.isEmpty() || !port)
+    if (!serviceInfo.records().isEmpty())
     {
-        debug(QString("Looking up server for domain %1").arg(domain));
-        QXmppSrvInfo serviceInfo = QXmppSrvInfo::fromName("_xmpp-client._tcp." + domain);
-        if (!serviceInfo.records().isEmpty())
-        {
-            // take the first returned record
-            host = serviceInfo.records().first().target();
-            port = serviceInfo.records().first().port();
-        } else {
-            // as a fallback, use domain as the host name
-            warning(QString("Lookup for domain %1 failed: %2").arg(domain, serviceInfo.errorString()));
-            host = domain;
-        }
+        // take the first returned record
+        host = serviceInfo.records().first().target();
+        port = serviceInfo.records().first().port();
+    } else {
+        // as a fallback, use domain as the host name
+        warning(QString("Lookup for domain %1 failed: %2")
+                .arg(domain, serviceInfo.errorString()));
+        host = domain;
     }
 
     // connect to server
diff --git a/src/QXmppOutgoingClient.h b/src/QXmppOutgoingClient.h
index c87c5b14..3d744854 100644
--- a/src/QXmppOutgoingClient.h
+++ b/src/QXmppOutgoingClient.h
@@ -39,6 +39,7 @@ class QXmppIq;
 class QXmppMessage;
 class QXmppRpcResponseIq;
 class QXmppRpcErrorIq;
+class QXmppSrvInfo;
 
 class QXmppOutgoingClientPrivate;
 
@@ -87,6 +88,7 @@ protected:
     /// \endcond
 
 private slots:
+    void connectToHost(const QXmppSrvInfo &serviceInfo);
     void socketError(QAbstractSocket::SocketError);
     void socketSslErrors(const QList<QSslError>&);
 
diff --git a/src/QXmppOutgoingServer.cpp b/src/QXmppOutgoingServer.cpp
index a7c92a56..93fcc703 100644
--- a/src/QXmppOutgoingServer.cpp
+++ b/src/QXmppOutgoingServer.cpp
@@ -77,12 +77,18 @@ QXmppOutgoingServer::~QXmppOutgoingServer()
 void QXmppOutgoingServer::connectToHost(const QString &domain)
 {
     d->remoteDomain = domain;
-    QString host;
-    quint16 port;
 
     // lookup server for domain
     debug(QString("Looking up server for domain %1").arg(domain));
-    QXmppSrvInfo serviceInfo = QXmppSrvInfo::fromName("_xmpp-server._tcp." + domain);
+    QXmppSrvInfo::lookupService("_xmpp-server._tcp." + domain, this,
+                                SLOT(connectHost(serviceInfo)));
+}
+
+void QXmppOutgoingServer::connectToHost(const QXmppSrvInfo &serviceInfo)
+{
+    QString host;
+    quint16 port;
+
     if (!serviceInfo.records().isEmpty())
     {
         // take the first returned record
@@ -90,8 +96,8 @@ void QXmppOutgoingServer::connectToHost(const QString &domain)
         port = serviceInfo.records().first().port();
     } else {
         // as a fallback, use domain as the host name
-        warning(QString("Lookup for domain %1 failed: %2").arg(domain, serviceInfo.errorString()));
-        host = domain;
+        warning(QString("Lookup for domain %1 failed: %2").arg(d->remoteDomain, serviceInfo.errorString()));
+        host = d->remoteDomain;
         port = 5269;
     }
 
diff --git a/src/QXmppOutgoingServer.h b/src/QXmppOutgoingServer.h
index 055fe133..8298d9c0 100644
--- a/src/QXmppOutgoingServer.h
+++ b/src/QXmppOutgoingServer.h
@@ -30,6 +30,7 @@ class QSslError;
 class QXmppDialback;
 class QXmppOutgoingServer;
 class QXmppOutgoingServerPrivate;
+class QXmppSrvInfo;
 
 /// \brief The QXmppOutgoingServer class represents an outgoing XMPP stream
 /// to another XMPP server.
@@ -64,6 +65,7 @@ protected:
     /// \endcond
 
 private slots:
+    void connectToHost(const QXmppSrvInfo &serviceInfo);
     void slotSslErrors(const QList<QSslError> &errors);
 
 private:
diff --git a/src/QXmppSrvInfo.cpp b/src/QXmppSrvInfo.cpp
index 4a0a95ea..7c2b06d8 100644
--- a/src/QXmppSrvInfo.cpp
+++ b/src/QXmppSrvInfo.cpp
@@ -22,9 +22,12 @@
  */
 
 #include "QXmppSrvInfo.h"
+#include "QXmppSrvInfo_p.h"
 
+#include <QCoreApplication>
 #include <QLibrary>
 #include <QMetaObject>
+#include <QMetaType>
 
 #if defined(Q_OS_WIN)
 #include <windows.h>
@@ -41,6 +44,8 @@
 #include <resolv.h>
 #endif
 
+Q_GLOBAL_STATIC(QXmppSrvInfoLookupManager, theSrvInfoLookupManager)
+
 #if defined(Q_OS_WIN)
 typedef DNS_STATUS (*dns_query_utf8_proto)(PCSTR,WORD,DWORD,PIP4_ARRAY,PDNS_RECORD*,PVOID*);
 static dns_query_utf8_proto local_dns_query_utf8 = 0;
@@ -535,7 +540,29 @@ QXmppSrvInfo QXmppSrvInfo::fromName(const QString &dname)
 
 void QXmppSrvInfo::lookupService(const QString &name, QObject *receiver, const char *member)
 {
-    QXmppSrvInfo result = QXmppSrvInfo::fromName(name);
-    QMetaObject::invokeMethod(receiver, member, Qt::QueuedConnection, Q_ARG(QXmppSrvInfo, result));
+    qRegisterMetaType<QXmppSrvInfo>("QXmppSrvInfo");
+
+    QXmppSrvInfoLookupManager *manager = theSrvInfoLookupManager();
+    if (manager)
+    {
+        // the application is still alive
+        QXmppSrvInfoLookupRunnable *runnable = new QXmppSrvInfoLookupRunnable(name);
+        QObject::connect(runnable, SIGNAL(foundInfo(QXmppSrvInfo)), receiver, member);
+        manager->start(runnable);
+    }
+}
+
+QXmppSrvInfoLookupManager::QXmppSrvInfoLookupManager()
+{
+    moveToThread(QCoreApplication::instance()->thread());
+    connect(QCoreApplication::instance(), SIGNAL(destroyed()),
+            SLOT(waitForThreadPoolDone()), Qt::DirectConnection);
+    setMaxThreadCount(5); // do 5 SRV lookups in parallel
+}
+
+void QXmppSrvInfoLookupRunnable::run()
+{
+    const QXmppSrvInfo result = QXmppSrvInfo::fromName(lookupName);
+    emit foundInfo(result);
 }
 
diff --git a/src/QXmppSrvInfo_p.h b/src/QXmppSrvInfo_p.h
new file mode 100644
index 00000000..59076c70
--- /dev/null
+++ b/src/QXmppSrvInfo_p.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2008-2010 The QXmpp developers
+ *
+ * Author:
+ *  Jeremy Lainé
+ *
+ * Source:
+ *  http://code.google.com/p/qxmpp
+ *
+ * This file is a part of QXmpp library.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ */
+
+#ifndef QXMPPSRVINFO_P_H
+#define QXMPPSRVINFO_P_H
+
+#include <QRunnable>
+#include <QThreadPool>
+
+class QXmppSrvInfo;
+
+class QXmppSrvInfoLookupManager : public QThreadPool
+{
+    Q_OBJECT
+
+public:
+    QXmppSrvInfoLookupManager();
+
+private slots:
+    void waitForThreadPoolDone() { waitForDone(); }
+};
+
+class QXmppSrvInfoLookupRunnable : public QObject, public QRunnable
+{
+    Q_OBJECT
+
+public:
+    QXmppSrvInfoLookupRunnable(const QString &name)
+        : lookupName(name)
+    { }
+    void run();
+
+signals:
+    void foundInfo(const QXmppSrvInfo &info);
+
+private:
+    QString lookupName;
+};
+
+#endif
diff --git a/src/src.pro b/src/src.pro
index 0ee158d5..7fc88239 100644
--- a/src/src.pro
+++ b/src/src.pro
@@ -81,6 +81,7 @@ INSTALL_HEADERS = QXmppUtils.h \
     QXmppVersionManager.h
 
 HEADERS += $$INSTALL_HEADERS
+HEADERS += QXmppSrvInfo_p.h
 
 # Source files
 SOURCES += QXmppUtils.cpp \