QIODevice: use QVLA to hold the ring buffers, not QList

The only users of more than one read- or write channel are the SCTP
code and QProcess. SCTP being pretty rare, optimize for the common
case of at most two QRingBuffers for reading (QProcess) and one for
writing.  Even with more channels, QVLA shouldn't be slower than QList
- on the contrary.

Need to adjust tst_toolsupport and TypeInformationVersion, as
QFilePrivate::fileName has changed.

Pick-to: 6.3
Change-Id: I3baf982ba1f4dc51463be8730e414f6164072d8b
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/corelib/io/qiodevice_p.h b/src/corelib/io/qiodevice_p.h
index 83c16eeddc..e9a8af0855 100644
--- a/src/corelib/io/qiodevice_p.h
+++ b/src/corelib/io/qiodevice_p.h
@@ -53,9 +53,9 @@
 
 #include "QtCore/qbytearray.h"
 #include "QtCore/qiodevice.h"
-#include "QtCore/qlist.h"
 #include "QtCore/qobjectdefs.h"
 #include "QtCore/qstring.h"
+#include "QtCore/qvarlengtharray.h"
 #include "private/qringbuffer_p.h"
 #ifndef QT_NO_QOBJECT
 #include "private/qobject_p.h"
@@ -134,8 +134,8 @@ public:
     int readBufferChunkSize = QIODEVICE_BUFFERSIZE;
     int writeBufferChunkSize = 0;
 
-    QList<QRingBuffer> readBuffers;
-    QList<QRingBuffer> writeBuffers;
+    QVarLengthArray<QRingBuffer, 2> readBuffers;
+    QVarLengthArray<QRingBuffer, 1> writeBuffers;
     QString errorString;
     QIODevice::OpenMode openMode = QIODevice::NotOpen;