1 files changed, 35 insertions, 58 deletions

diff --git a/src/corelib/tools/qringbuffer.cpp b/src/corelib/tools/qringbuffer.cpp
index 09b0336145..0645759118 100644
--- a/src/corelib/tools/qringbuffer.cpp
+++ b/src/corelib/tools/qringbuffer.cpp
@@ -1,49 +1,19 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Copyright (C) 2015 Alex Trotsenko <alex1973tr@gmail.com>
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtCore module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
+// Copyright (C) 2021 The Qt Company Ltd.
+// Copyright (C) 2015 Alex Trotsenko <alex1973tr@gmail.com>
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #include "private/qringbuffer_p.h"
-#include "private/qbytearray_p.h"
+
+#include <type_traits>
+
 #include <string.h>
 
 QT_BEGIN_NAMESPACE
 
+static_assert(std::is_nothrow_default_constructible_v<QRingChunk>);
+static_assert(std::is_nothrow_move_constructible_v<QRingChunk>);
+static_assert(std::is_nothrow_move_assignable_v<QRingChunk>);
+
 void QRingChunk::allocate(qsizetype alloc)
 {
     Q_ASSERT(alloc > 0 && size() == 0);
@@ -57,31 +27,23 @@ void QRingChunk::detach()
     Q_ASSERT(isShared());
 
     const qsizetype chunkSize = size();
-    QByteArray x(chunkSize, Qt::Uninitialized);
-    ::memcpy(x.data(), chunk.constData() + headOffset, chunkSize);
-    chunk = std::move(x);
+    chunk = QByteArray(std::as_const(*this).data(), chunkSize);
     headOffset = 0;
     tailOffset = chunkSize;
 }
 
-QByteArray QRingChunk::toByteArray()
+QByteArray QRingChunk::toByteArray() &&
 {
+    // ### Replace with std::move(chunk).sliced(head(), size()) once sliced()&& is available
     if (headOffset != 0 || tailOffset != chunk.size()) {
         if (isShared())
-            return chunk.mid(headOffset, size());
-
-        if (headOffset != 0) {
-            char *ptr = chunk.data();
-            ::memmove(ptr, ptr + headOffset, size());
-            tailOffset -= headOffset;
-            headOffset = 0;
-        }
+            return chunk.sliced(head(), size());
 
-        chunk.reserve(0); // avoid that resizing needlessly reallocates
         chunk.resize(tailOffset);
+        chunk.remove(0, headOffset);
     }
 
-    return chunk;
+    return std::move(chunk);
 }
 
 /*!
@@ -128,7 +90,7 @@ void QRingBuffer::free(qint64 bytes)
                     clear(); // try to minify/squeeze us
                 }
             } else {
-                Q_ASSERT(bytes < MaxByteArraySize);
+                Q_ASSERT(bytes < QByteArray::max_size());
                 chunk.advance(bytes);
                 bufferSize -= bytes;
             }
@@ -143,7 +105,7 @@ void QRingBuffer::free(qint64 bytes)
 
 char *QRingBuffer::reserve(qint64 bytes)
 {
-    Q_ASSERT(bytes > 0 && bytes < MaxByteArraySize);
+    Q_ASSERT(bytes > 0 && bytes < QByteArray::max_size());
 
     const qsizetype chunkSize = qMax(qint64(basicBlockSize), bytes);
     qsizetype tail = 0;
@@ -173,7 +135,7 @@ char *QRingBuffer::reserve(qint64 bytes)
 */
 char *QRingBuffer::reserveFront(qint64 bytes)
 {
-    Q_ASSERT(bytes > 0 && bytes < MaxByteArraySize);
+    Q_ASSERT(bytes > 0 && bytes < QByteArray::max_size());
 
     const qsizetype chunkSize = qMax(qint64(basicBlockSize), bytes);
     if (bufferSize == 0) {
@@ -219,7 +181,7 @@ void QRingBuffer::chop(qint64 bytes)
                     clear(); // try to minify/squeeze us
                 }
             } else {
-                Q_ASSERT(bytes < MaxByteArraySize);
+                Q_ASSERT(bytes < QByteArray::max_size());
                 chunk.grow(-bytes);
                 bufferSize -= bytes;
             }
@@ -363,6 +325,21 @@ void QRingBuffer::append(const QByteArray &qba)
     bufferSize += qba.size();
 }
 
+/*!
+    \internal
+
+    Append a new buffer to the end
+*/
+void QRingBuffer::append(QByteArray &&qba)
+{
+    const auto qbaSize = qba.size();
+    if (bufferSize != 0 || buffers.isEmpty())
+        buffers.emplace_back(std::move(qba));
+    else
+        buffers.last().assign(std::move(qba));
+    bufferSize += qbaSize;
+}
+
 qint64 QRingBuffer::readLine(char *data, qint64 maxLength)
 {
     Q_ASSERT(data != nullptr && maxLength > 1);