184d66caa5
This adds a way to resume reading from a stream after a ReadPastEnd error. This is done by introducing a stream read transaction mechanism that keeps read data in an internal buffer and rolls it back on failure. [ChangeLog][QtCore] Added QDataStream startTransaction(), commitTransaction(), rollbackTransaction(), abortTransaction() functions to support read transactions. Task-number: QTBUG-44418 Change-Id: Ibf946e1939a5573c4182fea7e26608947218c2d9 Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
128 lines
3.5 KiB
C++
128 lines
3.5 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2015 The Qt Company Ltd.
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** Contact: http://www.qt.io/licensing/
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** You may use this file under the terms of the BSD license as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include <QtNetwork>
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#include "fortunethread.h"
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FortuneThread::FortuneThread(QObject *parent)
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: QThread(parent), quit(false)
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{
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}
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//! [0]
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FortuneThread::~FortuneThread()
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{
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mutex.lock();
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quit = true;
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cond.wakeOne();
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mutex.unlock();
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wait();
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}
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//! [0]
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//! [1] //! [2]
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void FortuneThread::requestNewFortune(const QString &hostName, quint16 port)
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{
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//! [1]
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QMutexLocker locker(&mutex);
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this->hostName = hostName;
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this->port = port;
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//! [3]
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if (!isRunning())
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start();
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else
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cond.wakeOne();
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}
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//! [2] //! [3]
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//! [4]
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void FortuneThread::run()
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{
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mutex.lock();
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//! [4] //! [5]
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QString serverName = hostName;
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quint16 serverPort = port;
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mutex.unlock();
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//! [5]
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//! [6]
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while (!quit) {
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//! [7]
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const int Timeout = 5 * 1000;
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QTcpSocket socket;
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socket.connectToHost(serverName, serverPort);
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//! [6] //! [8]
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if (!socket.waitForConnected(Timeout)) {
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emit error(socket.error(), socket.errorString());
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return;
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}
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//! [8] //! [11]
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QDataStream in(&socket);
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in.setVersion(QDataStream::Qt_4_0);
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QString fortune;
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//! [11] //! [12]
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do {
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if (!socket.waitForReadyRead(Timeout)) {
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emit error(socket.error(), socket.errorString());
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return;
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}
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in.startTransaction();
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in >> fortune;
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} while (!in.commitTransaction());
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//! [12] //! [15]
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mutex.lock();
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emit newFortune(fortune);
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//! [7]
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cond.wait(&mutex);
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serverName = hostName;
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serverPort = port;
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mutex.unlock();
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}
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//! [15]
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}
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