From 7bf81286bdbde02b6c7ceaf62346e7b236caa9c5 Mon Sep 17 00:00:00 2001
From: Alex Trotsenko <alex1973tr@gmail.com>
Date: Mon, 31 Oct 2016 16:40:19 +0200
Subject: [PATCH] QSocks5SocketEngine: improve buffering in CONNECT mode

Replace QByteArray-based read buffer with a more efficient QRingBuffer.

Change-Id: Id43427a0692463481dfc4dfbe915772afb093364
Reviewed-by: Jesus Fernandez <jesus.fernandez@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 src/network/socket/qsocks5socketengine.cpp | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/network/socket/qsocks5socketengine.cpp b/src/network/socket/qsocks5socketengine.cpp
index a1a8e4649d..89261ce789 100644
--- a/src/network/socket/qsocks5socketengine.cpp
+++ b/src/network/socket/qsocks5socketengine.cpp
@@ -54,6 +54,7 @@
 #include "qurl.h"
 #include "qauthenticator.h"
 #include "private/qiodevice_p.h"
+#include "private/qringbuffer_p.h"
 #include <qendian.h>
 #include <qnetworkinterface.h>
 
@@ -280,7 +281,7 @@ struct QSocks5Data
 
 struct QSocks5ConnectData : public QSocks5Data
 {
-    QByteArray readBuffer;
+    QRingBuffer readBuffer;
 };
 
 struct QSocks5BindData : public QSocks5Data
@@ -1193,7 +1194,7 @@ void QSocks5SocketEnginePrivate::_q_controlSocketReadNotification()
             }
             if (buf.size()) {
                 QSOCKS5_DEBUG << dump(buf);
-                connectData->readBuffer += buf;
+                connectData->readBuffer.append(buf);
                 emitReadNotification();
             }
             break;
@@ -1513,7 +1514,7 @@ qint64 QSocks5SocketEngine::read(char *data, qint64 maxlen)
     Q_D(QSocks5SocketEngine);
     QSOCKS5_Q_DEBUG << "read( , maxlen = " << maxlen << ')';
     if (d->mode == QSocks5SocketEnginePrivate::ConnectMode) {
-        if (d->connectData->readBuffer.size() == 0) {
+        if (d->connectData->readBuffer.isEmpty()) {
             if (d->data->controlSocket->state() == QAbstractSocket::UnconnectedState) {
                 //imitate remote closed
                 close();
@@ -1525,9 +1526,7 @@ qint64 QSocks5SocketEngine::read(char *data, qint64 maxlen)
                 return 0;       // nothing to be read
             }
         }
-        qint64 copy = qMin<qint64>(d->connectData->readBuffer.size(), maxlen);
-        memcpy(data, d->connectData->readBuffer.constData(), copy);
-        d->connectData->readBuffer.remove(0, copy);
+        const qint64 copy = d->connectData->readBuffer.read(data, maxlen);
         QSOCKS5_DEBUG << "read" << dump(QByteArray(data, copy));
         return copy;
 #ifndef QT_NO_UDPSOCKET