QNetworkAccessManager: HTTP download performance improvements

Better usage of move semantics with implicit sharing to avoid
detaching (=malloc/memcpy). Also some other improvements.
Download performance improvement is around 20% according
to the httpDownloadPerformance autotest.

Reviewed-by: Thiago Macieira

1 files changed, 5 insertions, 1 deletions

diff --git a/src/network/access/qnetworkaccessdatabackend.cpp b/src/network/access/qnetworkaccessdatabackend.cpp
index 609f0c5..4436cf4 100644
--- a/src/network/access/qnetworkaccessdatabackend.cpp
+++ b/src/network/access/qnetworkaccessdatabackend.cpp
@@ -117,7 +117,11 @@ void QNetworkAccessDataBackend::open()
             setHeader(QNetworkRequest::ContentLengthHeader, payload.size());
             emit metaDataChanged();
 
-            writeDownstreamData(payload);
+            QByteDataBuffer list;
+            list.append(payload);
+            payload.clear(); // important because of implicit sharing!
+            writeDownstreamData(list);
+
             finished();
             return;
         }