QNAM: Upload architecture change: Backend and QNetworkReplyImpl changes

Reviewed-by: Thiago Macieira
Reviewed-by: Peter Hartmann

5 files changed, 188 insertions, 134 deletions

diff --git a/src/network/access/qnetworkaccessbackend.cpp b/src/network/access/qnetworkaccessbackend.cpp
index df468b8..b9d1b85 100644
--- a/src/network/access/qnetworkaccessbackend.cpp
+++ b/src/network/access/qnetworkaccessbackend.cpp
@@ -50,6 +50,8 @@
 #include "qnetworkaccesscachebackend_p.h"
 #include "qabstractnetworkcache.h"
 
+#include "private/qnoncontiguousbytedevice_p.h"
+
 QT_BEGIN_NAMESPACE
 
 static bool factoryDataShutdown = false;
@@ -109,17 +111,43 @@ QNetworkAccessBackend *QNetworkAccessManagerPrivate::findBackend(QNetworkAccessM
     return 0;
 }
 
-QNetworkAccessBackend::QNetworkAccessBackend()
+
+QNonContiguousByteDevice* QNetworkAccessBackend::createUploadByteDevice()
 {
+    QNonContiguousByteDevice* device = 0;
+
+    if (reply->outgoingDataBuffer)
+        device = QNonContiguousByteDeviceFactory::create(reply->outgoingDataBuffer);
+    else
+        device = QNonContiguousByteDeviceFactory::create(reply->outgoingData);
+
+    bool bufferDisallowed =
+            reply->request.attribute(QNetworkRequest::DoNotBufferUploadDataAttribute,
+                          QVariant(false)) == QVariant(true);
+    if (bufferDisallowed)
+        device->disableReset();
+
+    // make sure we delete this later
+    device->setParent(this);
+
+    connect(device, SIGNAL(readProgress(qint64,qint64)), this, SLOT(emitReplyUploadProgress(qint64,qint64)));
+
+    return device;
 }
 
-QNetworkAccessBackend::~QNetworkAccessBackend()
+// need to have this function since the reply is a private member variable
+// and the special backends need to access this.
+void QNetworkAccessBackend::emitReplyUploadProgress(qint64 bytesSent, qint64 bytesTotal)
 {
+    reply->emitUploadProgress(bytesSent, bytesTotal);
 }
 
-void QNetworkAccessBackend::upstreamReadyRead()
+QNetworkAccessBackend::QNetworkAccessBackend()
+{
+}
+
+QNetworkAccessBackend::~QNetworkAccessBackend()
 {
-    // do nothing
 }
 
 void QNetworkAccessBackend::downstreamReadyWrite()
@@ -184,23 +212,6 @@ bool QNetworkAccessBackend::isCachingEnabled() const
     return reply->isCachingEnabled();
 }
 
-qint64 QNetworkAccessBackend::upstreamBytesAvailable() const
-{
-    return reply->writeBuffer.size();
-}
-
-void QNetworkAccessBackend::upstreamBytesConsumed(qint64 count)
-{
-    // remove count bytes from the write buffer
-    reply->consume(count);
-}
-
-QByteArray QNetworkAccessBackend::readUpstream()
-{
-    // ### this is expensive. Consider making QRingBuffer::peekAll keep the buffer it returns
-    return reply->writeBuffer.peek(upstreamBytesAvailable());
-}
-
 qint64 QNetworkAccessBackend::nextDownstreamBlockSize() const
 {
     return reply->nextDownstreamBlockSize();
@@ -213,12 +224,12 @@ qint64 QNetworkAccessBackend::downstreamBytesToConsume() const
 
 void QNetworkAccessBackend::writeDownstreamData(const QByteArray &data)
 {
-    reply->feed(data);
+    reply->appendDownstreamData(data);
 }
 
 void QNetworkAccessBackend::writeDownstreamData(QIODevice *data)
 {
-    reply->feed(data);
+    reply->appendDownstreamData(data);
 }
 
 QVariant QNetworkAccessBackend::header(QNetworkRequest::KnownHeaders header) const
diff --git a/src/network/access/qnetworkaccessbackend_p.h b/src/network/access/qnetworkaccessbackend_p.h
index 9012396..6035f3a 100644
--- a/src/network/access/qnetworkaccessbackend_p.h
+++ b/src/network/access/qnetworkaccessbackend_p.h
@@ -70,6 +70,8 @@ class QNetworkAccessManagerPrivate;
 class QNetworkReplyImplPrivate;
 class QAbstractNetworkCache;
 class QNetworkCacheMetaData;
+class QNetworkAccessBackendUploadIODevice;
+class QNonContiguousByteDevice;
 
 // Should support direct file upload from disk or download to disk.
 //
@@ -86,14 +88,13 @@ public:
     // have different names. The Connection has two streams:
     //
     // - Upstream:
-    //   Upstream is data that is being written into this connection,
-    //   from the user. Upstream operates in a "pull" mechanism: the
-    //   connection will be notified that there is more data available
-    //   by a call to "upstreamReadyRead". The number of bytes
-    //   available is given by upstreamBytesAvailable(). A call to
-    //   readUpstream() always yields the entire upstream buffer. When
-    //   the connection has processed a certain amount of bytes from
-    //   that buffer, it should call upstreamBytesConsumed().
+    //   The upstream uses a QNonContiguousByteDevice provided
+    //   by the backend. This device emits the usual readyRead()
+    //   signal when the backend has data available for the connection
+    //   to write. The different backends can listen on this signal
+    //   and then pull upload data from the QNonContiguousByteDevice and
+    //   deal with it.
+    //
     //
     // - Downstream:
     //   Downstream is the data that is being read from this
@@ -111,12 +112,9 @@ public:
 
     virtual void open() = 0;
     virtual void closeDownstreamChannel() = 0;
-    virtual void closeUpstreamChannel() = 0;
     virtual bool waitForDownstreamReadyRead(int msecs) = 0;
-    virtual bool waitForUpstreamBytesWritten(int msecs) = 0;
 
     // slot-like:
-    virtual void upstreamReadyRead();
     virtual void downstreamReadyWrite();
     virtual void copyFinished(QIODevice *);
     virtual void ignoreSslErrors();
@@ -155,18 +153,24 @@ public:
     QVariant attribute(QNetworkRequest::Attribute code) const;
     void setAttribute(QNetworkRequest::Attribute code, const QVariant &value);
 
+    // return true if the QNonContiguousByteDevice of the upload
+    // data needs to support reset(). Currently needed for HTTP.
+    // This will possibly enable buffering of the upload data.
+    virtual bool needsResetableUploadData() {return false;};
+
 protected:
-    // these functions control the upstream mechanism
-    // that is, data coming into the backend and out via the connection
-    qint64 upstreamBytesAvailable() const;
-    void upstreamBytesConsumed(qint64 count);
-    QByteArray readUpstream();
+    // Create the device used for reading the upload data
+    QNonContiguousByteDevice* createUploadByteDevice();
+
 
     // these functions control the downstream mechanism
     // that is, data that has come via the connection and is going out the backend
     qint64 nextDownstreamBlockSize() const;
     qint64 downstreamBytesToConsume() const;
     void writeDownstreamData(const QByteArray &data);
+
+public slots:
+    // for task 251801, needs to be a slot to be called asynchronously
     void writeDownstreamData(QIODevice *data);
 
 protected slots:
@@ -179,10 +183,12 @@ protected slots:
     void metaDataChanged();
     void redirectionRequested(const QUrl &destination);
     void sslErrors(const QList<QSslError> &errors);
+    void emitReplyUploadProgress(qint64 bytesSent, qint64 bytesTotal);
 
 private:
     friend class QNetworkAccessManager;
     friend class QNetworkAccessManagerPrivate;
+    friend class QNetworkAccessBackendUploadIODevice;
     QNetworkAccessManagerPrivate *manager;
     QNetworkReplyImplPrivate *reply;
 };
diff --git a/src/network/access/qnetworkaccessmanager.cpp b/src/network/access/qnetworkaccessmanager.cpp
index bcbeef1..bf06ede 100644
--- a/src/network/access/qnetworkaccessmanager.cpp
+++ b/src/network/access/qnetworkaccessmanager.cpp
@@ -686,7 +686,10 @@ QNetworkReply *QNetworkAccessManager::createRequest(QNetworkAccessManager::Opera
         priv->urlForLastAuthentication = url;
     }
 
-    // third step: setup the reply
+    // third step: find a backend
+    priv->backend = d->findBackend(op, request);
+
+    // fourth step: setup the reply
     priv->setup(op, request, outgoingData);
     if (request.attribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::PreferNetwork).toInt() !=
         QNetworkRequest::AlwaysNetwork)
@@ -695,9 +698,6 @@ QNetworkReply *QNetworkAccessManager::createRequest(QNetworkAccessManager::Opera
     QList<QNetworkProxy> proxyList = d->queryProxy(QNetworkProxyQuery(request.url()));
     priv->proxyList = proxyList;
 #endif
-
-    // fourth step: find a backend
-    priv->backend = d->findBackend(op, request);
     if (priv->backend) {
         priv->backend->setParent(reply);
         priv->backend->reply = priv;
diff --git a/src/network/access/qnetworkreplyimpl.cpp b/src/network/access/qnetworkreplyimpl.cpp
index 79c3d1a..749a462 100644
--- a/src/network/access/qnetworkreplyimpl.cpp
+++ b/src/network/access/qnetworkreplyimpl.cpp
@@ -46,13 +46,15 @@
 #include "QtCore/qcoreapplication.h"
 #include "QtCore/qdatetime.h"
 #include "QtNetwork/qsslconfiguration.h"
+#include "qnetworkaccesshttpbackend_p.h"
 
 #include <QtCore/QCoreApplication>
 
 QT_BEGIN_NAMESPACE
 
 inline QNetworkReplyImplPrivate::QNetworkReplyImplPrivate()
-    : copyDevice(0), networkCache(0),
+    : backend(0), outgoingData(0), outgoingDataBuffer(0),
+      copyDevice(0), networkCache(0),
       cacheEnabled(false), cacheSaveDevice(0),
       bytesDownloaded(0), lastBytesDownloaded(-1), bytesUploaded(-1),
       state(Idle)
@@ -61,8 +63,13 @@ inline QNetworkReplyImplPrivate::QNetworkReplyImplPrivate()
 
 void QNetworkReplyImplPrivate::_q_startOperation()
 {
-    // This function is called exactly once
+    // ensure this function is only being called once
+    if (state == Working) {
+        qDebug("QNetworkReplyImpl::_q_startOperation was called more than once");
+        return;
+    }
     state = Working;
+
     if (!backend) {
         error(QNetworkReplyImpl::ProtocolUnknownError,
               QCoreApplication::translate("QNetworkReply", "Protocol \"%1\" is unknown").arg(url.scheme())); // not really true!;
@@ -74,57 +81,11 @@ void QNetworkReplyImplPrivate::_q_startOperation()
     if (state != Finished) {
         if (operation == QNetworkAccessManager::GetOperation)
             pendingNotifications.append(NotifyDownstreamReadyWrite);
-        if (outgoingData) {
-            _q_sourceReadyRead();
-#if 0 // ### FIXME
-            if (outgoingData->atEndOfStream() && writeBuffer.isEmpty())
-                // empty upload
-                emit q->uploadProgress(0, 0);
-#endif
-        }
 
         handleNotifications();
     }
 }
 
-void QNetworkReplyImplPrivate::_q_sourceReadyRead()
-{
-    // read data from the outgoingData QIODevice into our internal buffer
-    enum { DesiredBufferSize = 32 * 1024 };
-
-    if (writeBuffer.size() >= DesiredBufferSize)
-        return;                 // don't grow the buffer too much
-
-    // read as many bytes are available or up until we fill up the buffer
-    // but always read at least one byte
-    qint64 bytesToRead = qBound<qint64>(1, outgoingData->bytesAvailable(),
-                                        DesiredBufferSize - writeBuffer.size());
-    char *ptr = writeBuffer.reserve(bytesToRead);
-    qint64 bytesActuallyRead = outgoingData->read(ptr, bytesToRead);
-    if (bytesActuallyRead == -1) {
-        // EOF
-        writeBuffer.chop(bytesToRead);
-        backendNotify(NotifyCloseUpstreamChannel);
-        return;
-    }
-
-    if (bytesActuallyRead < bytesToRead)
-        writeBuffer.chop(bytesToRead - bytesActuallyRead);
-
-    // if we did read anything, let the backend know and handle it
-    if (bytesActuallyRead)
-        backendNotify(NotifyUpstreamReadyRead);
-
-    // check for EOF again
-    if (!outgoingData->isSequential() && outgoingData->atEnd())
-        backendNotify(NotifyCloseUpstreamChannel);
-}
-
-void QNetworkReplyImplPrivate::_q_sourceReadChannelFinished()
-{
-    _q_sourceReadyRead();
-}
-
 void QNetworkReplyImplPrivate::_q_copyReadyRead()
 {
     Q_Q(QNetworkReplyImpl);
@@ -143,7 +104,7 @@ void QNetworkReplyImplPrivate::_q_copyReadyRead()
         if (bytesActuallyRead == -1) {
             readBuffer.chop(bytesToRead);
             backendNotify(NotifyCopyFinished);
-            return;
+            break;
         }
 
         if (bytesActuallyRead != bytesToRead)
@@ -151,6 +112,7 @@ void QNetworkReplyImplPrivate::_q_copyReadyRead()
 
         if (!copyDevice->isSequential() && copyDevice->atEnd()) {
             backendNotify(NotifyCopyFinished);
+            bytesDownloaded += bytesActuallyRead;
             break;
         }
 
@@ -174,6 +136,67 @@ void QNetworkReplyImplPrivate::_q_copyReadChannelFinished()
     _q_copyReadyRead();
 }
 
+void QNetworkReplyImplPrivate::_q_bufferOutgoingDataFinished()
+{
+    Q_Q(QNetworkReplyImpl);
+
+    // make sure this is only called once, ever.
+    //_q_bufferOutgoingData may call it or the readChannelFinished emission
+    if (state != Buffering)
+        return;
+
+    // disconnect signals
+    QObject::disconnect(outgoingData, SIGNAL(readyRead()), q, SLOT(_q_bufferOutgoingData()));
+    QObject::disconnect(outgoingData, SIGNAL(readChannelFinished()), q, SLOT(_q_bufferOutgoingDataFinished()));
+
+    // finally, start the request
+    QMetaObject::invokeMethod(q, "_q_startOperation", Qt::QueuedConnection);
+}
+
+void QNetworkReplyImplPrivate::_q_bufferOutgoingData()
+{
+    Q_Q(QNetworkReplyImpl);
+
+    if (!outgoingDataBuffer) {
+        // first call, create our buffer
+        outgoingDataBuffer = new QRingBuffer();
+
+        QObject::connect(outgoingData, SIGNAL(readyRead()), q, SLOT(_q_bufferOutgoingData()));
+        QObject::connect(outgoingData, SIGNAL(readChannelFinished()), q, SLOT(_q_bufferOutgoingDataFinished()));
+    }
+
+    qint64 bytesBuffered = 0;
+    qint64 bytesToBuffer = 0;
+
+    // read data into our buffer
+    forever {
+        bytesToBuffer = outgoingData->bytesAvailable();
+        // unknown? just try 2 kB, this also ensures we always try to read the EOF
+        if (bytesToBuffer <= 0)
+            bytesToBuffer = 2*1024;
+
+        char *dst = outgoingDataBuffer->reserve(bytesToBuffer);
+        bytesBuffered = outgoingData->read(dst, bytesToBuffer);
+
+        if (bytesBuffered == -1) {
+            // EOF has been reached.
+            outgoingDataBuffer->chop(bytesToBuffer);
+
+            _q_bufferOutgoingDataFinished();
+            break;
+        } else if (bytesBuffered == 0) {
+            // nothing read right now, just wait until we get called again
+            outgoingDataBuffer->chop(bytesToBuffer);
+
+            break;
+        } else {
+            // don't break, try to read() again
+            outgoingDataBuffer->chop(bytesToBuffer - bytesBuffered);
+        }
+    }
+}
+
+
 void QNetworkReplyImplPrivate::setup(QNetworkAccessManager::Operation op, const QNetworkRequest &req,
                                      QIODevice *data)
 {
@@ -184,13 +207,42 @@ void QNetworkReplyImplPrivate::setup(QNetworkAccessManager::Operation op, const
     url = request.url();
     operation = op;
 
-    if (outgoingData) {
-        q->connect(outgoingData, SIGNAL(readyRead()), SLOT(_q_sourceReadyRead()));
-        q->connect(outgoingData, SIGNAL(readChannelFinished()), SLOT(_q_sourceReadChannelFinished()));
+    if (outgoingData && backend) {
+        // there is data to be uploaded, e.g. HTTP POST.
+
+        if (!backend->needsResetableUploadData() || !outgoingData->isSequential()) {
+            // backend does not need upload buffering or
+            // fixed size non-sequential
+            // just start the operation
+            QMetaObject::invokeMethod(q, "_q_startOperation", Qt::QueuedConnection);
+        } else {
+            bool bufferingDisallowed =
+                    req.attribute(QNetworkRequest::DoNotBufferUploadDataAttribute,
+                                             false).toBool();
+
+            if (bufferingDisallowed) {
+                // if a valid content-length header for the request was supplied, we can disable buffering
+                // if not, we will buffer anyway
+                if (req.header(QNetworkRequest::ContentLengthHeader).isValid()) {
+                    QMetaObject::invokeMethod(q, "_q_startOperation", Qt::QueuedConnection);
+                } else {
+                    state = Buffering;
+                    QMetaObject::invokeMethod(q, "_q_bufferOutgoingData", Qt::QueuedConnection);
+                }
+            } else {
+                // _q_startOperation will be called when the buffering has finished.
+                state = Buffering;
+                QMetaObject::invokeMethod(q, "_q_bufferOutgoingData", Qt::QueuedConnection);
+            }
+        }
+    } else {
+        // No outgoing data (e.g. HTTP GET request)
+        // or no backend
+        // if no backend, _q_startOperation will handle the error of this
+        QMetaObject::invokeMethod(q, "_q_startOperation", Qt::QueuedConnection);
     }
 
     q->QIODevice::open(QIODevice::ReadOnly);
-    QMetaObject::invokeMethod(q, "_q_startOperation", Qt::QueuedConnection);
 }
 
 void QNetworkReplyImplPrivate::setNetworkCache(QAbstractNetworkCache *nc)
@@ -226,18 +278,10 @@ void QNetworkReplyImplPrivate::handleNotifications()
                 backend->downstreamReadyWrite();
             break;
 
-        case NotifyUpstreamReadyRead:
-            backend->upstreamReadyRead();
-            break;
-
         case NotifyCloseDownstreamChannel:
             backend->closeDownstreamChannel();
             break;
 
-        case NotifyCloseUpstreamChannel:
-            backend->closeUpstreamChannel();
-            break;
-
         case NotifyCopyFinished: {
             QIODevice *dev = copyDevice;
             copyDevice = 0;
@@ -299,29 +343,14 @@ void QNetworkReplyImplPrivate::completeCacheSave()
     cacheEnabled = false;
 }
 
-void QNetworkReplyImplPrivate::consume(qint64 count)
+void QNetworkReplyImplPrivate::emitUploadProgress(qint64 bytesSent, qint64 bytesTotal)
 {
     Q_Q(QNetworkReplyImpl);
-    if (count <= 0) {
-        qWarning("QNetworkConnection: backend signalled that it consumed %ld bytes", long(count));
-        return;
-    }
-
-    if (outgoingData)
-        // schedule another read from the source
-        QMetaObject::invokeMethod(q_func(), "_q_sourceReadyRead", Qt::QueuedConnection);
-
-    writeBuffer.skip(count);
-    if (bytesUploaded == -1)
-        bytesUploaded = count;
-    else
-        bytesUploaded += count;
-
-    QVariant totalSize = request.header(QNetworkRequest::ContentLengthHeader);
-    emit q->uploadProgress(bytesUploaded,
-                           totalSize.isNull() ? Q_INT64_C(-1) : totalSize.toLongLong());
+    bytesUploaded = bytesSent;
+    emit q->uploadProgress(bytesSent, bytesTotal);
 }
 
+
 qint64 QNetworkReplyImplPrivate::nextDownstreamBlockSize() const
 {
     enum { DesiredBufferSize = 32 * 1024 };
@@ -331,7 +360,9 @@ qint64 QNetworkReplyImplPrivate::nextDownstreamBlockSize() const
     return qMax<qint64>(0, readBufferMaxSize - readBuffer.size());
 }
 
-void QNetworkReplyImplPrivate::feed(const QByteArray &data)
+// we received downstream data and send this to the cache
+// and to our readBuffer (which in turn gets read by the user of QNetworkReply)
+void QNetworkReplyImplPrivate::appendDownstreamData(const QByteArray &data)
 {
     Q_Q(QNetworkReplyImpl);
     if (!q->isOpen())
@@ -379,7 +410,8 @@ void QNetworkReplyImplPrivate::feed(const QByteArray &data)
     }
 }
 
-void QNetworkReplyImplPrivate::feed(QIODevice *data)
+// this is used when it was fetched from the cache, right?
+void QNetworkReplyImplPrivate::appendDownstreamData(QIODevice *data)
 {
     Q_Q(QNetworkReplyImpl);
     Q_ASSERT(q->isOpen());
@@ -409,9 +441,11 @@ void QNetworkReplyImplPrivate::finished()
     pendingNotifications.clear();
 
     QVariant totalSize = cookedHeaders.value(QNetworkRequest::ContentLengthHeader);
-    if (bytesDownloaded != lastBytesDownloaded || totalSize.isNull())
+    if (totalSize.isNull() || totalSize == -1) {
         emit q->downloadProgress(bytesDownloaded, bytesDownloaded);
-    if (bytesUploaded == -1 && outgoingData)
+    }
+
+    if (bytesUploaded == -1 && (outgoingData || outgoingDataBuffer))
         emit q->uploadProgress(0, 0);
 
     completeCacheSave();
diff --git a/src/network/access/qnetworkreplyimpl_p.h b/src/network/access/qnetworkreplyimpl_p.h
index ad06f78..8d3c90e 100644
--- a/src/network/access/qnetworkreplyimpl_p.h
+++ b/src/network/access/qnetworkreplyimpl_p.h
@@ -59,6 +59,7 @@
 #include "qnetworkproxy.h"
 #include "QtCore/qmap.h"
 #include "QtCore/qqueue.h"
+#include "QtCore/qbuffer.h"
 #include "private/qringbuffer_p.h"
 
 QT_BEGIN_NAMESPACE
@@ -91,10 +92,10 @@ public:
 
     Q_DECLARE_PRIVATE(QNetworkReplyImpl)
     Q_PRIVATE_SLOT(d_func(), void _q_startOperation())
-    Q_PRIVATE_SLOT(d_func(), void _q_sourceReadyRead())
-    Q_PRIVATE_SLOT(d_func(), void _q_sourceReadChannelFinished())
     Q_PRIVATE_SLOT(d_func(), void _q_copyReadyRead())
     Q_PRIVATE_SLOT(d_func(), void _q_copyReadChannelFinished())
+    Q_PRIVATE_SLOT(d_func(), void _q_bufferOutgoingData())
+    Q_PRIVATE_SLOT(d_func(), void _q_bufferOutgoingDataFinished())
 };
 
 class QNetworkReplyImplPrivate: public QNetworkReplyPrivate
@@ -102,15 +103,13 @@ class QNetworkReplyImplPrivate: public QNetworkReplyPrivate
 public:
     enum InternalNotifications {
         NotifyDownstreamReadyWrite,
-        NotifyUpstreamReadyRead,
         NotifyCloseDownstreamChannel,
-        NotifyCloseUpstreamChannel,
         NotifyCopyFinished
     };
 
     enum State {
         Idle,
-        Opening,
+        Buffering,
         Working,
         Finished,
         Aborted
@@ -125,6 +124,8 @@ public:
     void _q_sourceReadChannelFinished();
     void _q_copyReadyRead();
     void _q_copyReadChannelFinished();
+    void _q_bufferOutgoingData();
+    void _q_bufferOutgoingDataFinished();
 
     void setup(QNetworkAccessManager::Operation op, const QNetworkRequest &request,
                QIODevice *outgoingData);
@@ -138,9 +139,10 @@ public:
     void setCachingEnabled(bool enable);
     bool isCachingEnabled() const;
     void consume(qint64 count);
+    void emitUploadProgress(qint64 bytesSent, qint64 bytesTotal);
     qint64 nextDownstreamBlockSize() const;
-    void feed(const QByteArray &data);
-    void feed(QIODevice *data);
+    void appendDownstreamData(const QByteArray &data);
+    void appendDownstreamData(QIODevice *data);
     void finished();
     void error(QNetworkReply::NetworkError code, const QString &errorString);
     void metaDataChanged();
@@ -149,6 +151,7 @@ public:
 
     QNetworkAccessBackend *backend;
     QIODevice *outgoingData;
+    QRingBuffer *outgoingDataBuffer;
     QIODevice *copyDevice;
     QAbstractNetworkCache *networkCache;