Remove loopback network example

It doesn't showcase anything interesting that other examples
don't already show off.

Change-Id: Ie95c3ddb3ff52b3beab54bd6fa75fb75ae5c7ba5
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Konrad Kujawa <konrad.kujawa@qt.io>
(cherry picked from commit 826b606a5d8f274c55f525119299aef2fe143aaf)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

doc/global/manifest-meta.qdocconf

@@ -157,7 +157,6 @@ manifestmeta.ios.names              =  "QtCore/Contiguous Cache Example" \
                                        "QtCore/Queued Custom Type Example" \
                                        "QtGui/OpenGL Window Example" \
                                        "QtGui/Raster Window Example" \
-                                       "QtNetwork/Loopback Example" \
                                        "QtNetwork/Network Chat Example" \
                                        "QtNetwork/Torrent Example" \
                                        "QtOpenGL/2D Painting Example" \

examples/network/CMakeLists.txt

@@ -12,7 +12,6 @@ if(TARGET Qt6::Widgets)
     qt_internal_add_example(broadcastreceiver)
     qt_internal_add_example(broadcastsender)
     qt_internal_add_example(http)
-    qt_internal_add_example(loopback)
     qt_internal_add_example(threadedfortuneserver)
     qt_internal_add_example(torrent)
     qt_internal_add_example(multicastreceiver)

examples/network/doc/src/loopback.qdoc

@@ -1,14 +0,0 @@
-// Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
-
-/*!
-    \example loopback
-    \title Loopback Example
-    \ingroup examples-network
-    \brief Demonstrates the client-server communication on a local host.
-
-    The example demonstrates how the clients and servers on a local host
-    communicate with each other.
-
-    \image loopback-example.png
-*/

examples/network/loopback/CMakeLists.txt

@@ -1,38 +0,0 @@
-# Copyright (C) 2022 The Qt Company Ltd.
-# SPDX-License-Identifier: BSD-3-Clause
-
-cmake_minimum_required(VERSION 3.16)
-project(loopback LANGUAGES CXX)
-
-if(NOT DEFINED INSTALL_EXAMPLESDIR)
-    set(INSTALL_EXAMPLESDIR "examples")
-endif()
-
-set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/network/loopback")
-
-find_package(Qt6 REQUIRED COMPONENTS Core Gui Network Widgets)
-
-qt_standard_project_setup()
-
-qt_add_executable(loopback
-    dialog.cpp dialog.h
-    main.cpp
-)
-
-set_target_properties(loopback PROPERTIES
-    WIN32_EXECUTABLE TRUE
-    MACOSX_BUNDLE TRUE
-)
-
-target_link_libraries(loopback PRIVATE
-    Qt6::Core
-    Qt6::Gui
-    Qt6::Network
-    Qt6::Widgets
-)
-
-install(TARGETS loopback
-    RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
-    BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
-    LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
-)

examples/network/loopback/dialog.cpp

@@ -1,155 +0,0 @@
-// Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
-
-#include "dialog.h"
-
-#include <QtNetwork>
-#include <QtWidgets>
-
-static const int TotalBytes = 50 * 1024 * 1024;
-static const int PayloadSize = 64 * 1024; // 64 KB
-
-Dialog::Dialog(QWidget *parent)
-    : QDialog(parent)
-{
-    clientProgressBar = new QProgressBar;
-    clientStatusLabel = new QLabel(tr("Client ready"));
-    serverProgressBar = new QProgressBar;
-    serverStatusLabel = new QLabel(tr("Server ready"));
-
-    startButton = new QPushButton(tr("&Start"));
-    quitButton = new QPushButton(tr("&Quit"));
-
-    buttonBox = new QDialogButtonBox;
-    buttonBox->addButton(startButton, QDialogButtonBox::ActionRole);
-    buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);
-
-    connect(startButton, &QAbstractButton::clicked, this, &Dialog::start);
-    connect(quitButton, &QAbstractButton::clicked, qApp, &QCoreApplication::quit);
-    connect(&tcpServer, &QTcpServer::newConnection,
-            this, &Dialog::acceptConnection);
-    connect(&tcpClient, &QAbstractSocket::connected, this, &Dialog::startTransfer);
-    connect(&tcpClient, &QIODevice::bytesWritten,
-            this, &Dialog::updateClientProgress);
-    connect(&tcpClient, &QAbstractSocket::errorOccurred,
-            this, &Dialog::displayError);
-
-    QVBoxLayout *mainLayout = new QVBoxLayout;
-    mainLayout->addWidget(clientProgressBar);
-    mainLayout->addWidget(clientStatusLabel);
-    mainLayout->addWidget(serverProgressBar);
-    mainLayout->addWidget(serverStatusLabel);
-    mainLayout->addStretch(1);
-    mainLayout->addSpacing(10);
-    mainLayout->addWidget(buttonBox);
-    setLayout(mainLayout);
-
-    setWindowTitle(tr("Loopback"));
-}
-
-void Dialog::start()
-{
-    startButton->setEnabled(false);
-
-#ifndef QT_NO_CURSOR
-    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
-#endif
-
-    bytesWritten = 0;
-    bytesReceived = 0;
-
-    while (!tcpServer.isListening() && !tcpServer.listen()) {
-        QMessageBox::StandardButton ret = QMessageBox::critical(this,
-                                        tr("Loopback"),
-                                        tr("Unable to start the test: %1.")
-                                        .arg(tcpServer.errorString()),
-                                        QMessageBox::Retry
-                                        | QMessageBox::Cancel);
-        if (ret == QMessageBox::Cancel)
-            return;
-    }
-
-    serverStatusLabel->setText(tr("Listening"));
-    clientStatusLabel->setText(tr("Connecting"));
-    tcpClient.connectToHost(QHostAddress::LocalHost, tcpServer.serverPort());
-}
-
-void Dialog::acceptConnection()
-{
-    tcpServerConnection = tcpServer.nextPendingConnection();
-    if (!tcpServerConnection) {
-        serverStatusLabel->setText(tr("Error: got invalid pending connection!"));
-        return;
-    }
-
-    connect(tcpServerConnection, &QIODevice::readyRead,
-            this, &Dialog::updateServerProgress);
-    connect(tcpServerConnection, &QAbstractSocket::errorOccurred,
-            this, &Dialog::displayError);
-    connect(tcpServerConnection, &QTcpSocket::disconnected,
-            tcpServerConnection, &QTcpSocket::deleteLater);
-
-    serverStatusLabel->setText(tr("Accepted connection"));
-    tcpServer.close();
-}
-
-void Dialog::startTransfer()
-{
-    // called when the TCP client connected to the loopback server
-    bytesToWrite = TotalBytes - int(tcpClient.write(QByteArray(PayloadSize, '@')));
-    clientStatusLabel->setText(tr("Connected"));
-}
-
-void Dialog::updateServerProgress()
-{
-    bytesReceived += int(tcpServerConnection->bytesAvailable());
-    tcpServerConnection->readAll();
-
-    serverProgressBar->setMaximum(TotalBytes);
-    serverProgressBar->setValue(bytesReceived);
-    serverStatusLabel->setText(tr("Received %1MB")
-                               .arg(bytesReceived / (1024 * 1024)));
-
-    if (bytesReceived == TotalBytes) {
-        tcpServerConnection->close();
-        startButton->setEnabled(true);
-#ifndef QT_NO_CURSOR
-        QGuiApplication::restoreOverrideCursor();
-#endif
-    }
-}
-
-void Dialog::updateClientProgress(qint64 numBytes)
-{
-    // called when the TCP client has written some bytes
-    bytesWritten += int(numBytes);
-
-    // only write more if not finished and when the Qt write buffer is below a certain size.
-    if (bytesToWrite > 0 && tcpClient.bytesToWrite() <= 4 * PayloadSize)
-        bytesToWrite -= tcpClient.write(QByteArray(qMin(bytesToWrite, PayloadSize), '@'));
-
-    clientProgressBar->setMaximum(TotalBytes);
-    clientProgressBar->setValue(bytesWritten);
-    clientStatusLabel->setText(tr("Sent %1MB").arg(bytesWritten / (1024 * 1024)));
-}
-
-void Dialog::displayError(QAbstractSocket::SocketError socketError)
-{
-    if (socketError == QTcpSocket::RemoteHostClosedError)
-        return;
-
-    QMessageBox::information(this, tr("Network error"),
-                             tr("The following error occurred: %1.")
-                             .arg(tcpClient.errorString()));
-
-    tcpClient.close();
-    tcpServer.close();
-    clientProgressBar->reset();
-    serverProgressBar->reset();
-    clientStatusLabel->setText(tr("Client ready"));
-    serverStatusLabel->setText(tr("Server ready"));
-    startButton->setEnabled(true);
-#ifndef QT_NO_CURSOR
-    QGuiApplication::restoreOverrideCursor();
-#endif
-}

examples/network/loopback/dialog.h

@@ -1,51 +0,0 @@
-// Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
-
-#ifndef DIALOG_H
-#define DIALOG_H
-
-#include <QDialog>
-#include <QTcpServer>
-#include <QTcpSocket>
-
-QT_BEGIN_NAMESPACE
-class QDialogButtonBox;
-class QLabel;
-class QProgressBar;
-class QPushButton;
-QT_END_NAMESPACE
-
-class Dialog : public QDialog
-{
-    Q_OBJECT
-
-public:
-    Dialog(QWidget *parent = nullptr);
-
-public slots:
-    void start();
-    void acceptConnection();
-    void startTransfer();
-    void updateServerProgress();
-    void updateClientProgress(qint64 numBytes);
-    void displayError(QAbstractSocket::SocketError socketError);
-
-private:
-    QProgressBar *clientProgressBar = nullptr;
-    QProgressBar *serverProgressBar = nullptr;
-    QLabel *clientStatusLabel = nullptr;
-    QLabel *serverStatusLabel = nullptr;
-
-    QPushButton *startButton = nullptr;
-    QPushButton *quitButton = nullptr;
-    QDialogButtonBox *buttonBox = nullptr;
-
-    QTcpServer tcpServer;
-    QTcpSocket tcpClient;
-    QTcpSocket *tcpServerConnection = nullptr;
-    int bytesToWrite = 0;
-    int bytesWritten = 0;
-    int bytesReceived = 0;
-};
-
-#endif

examples/network/loopback/loopback.pro

@@ -1,9 +0,0 @@
-QT += network widgets
-
-HEADERS       = dialog.h
-SOURCES       = dialog.cpp \
-                main.cpp
-
-# install
-target.path = $$[QT_INSTALL_EXAMPLES]/network/loopback
-INSTALLS += target

examples/network/loopback/main.cpp

@@ -1,14 +0,0 @@
-// Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
-
-#include "dialog.h"
-
-#include <QApplication>
-
-int main(int argc, char *argv[])
-{
-    QApplication app(argc, argv);
-    Dialog dialog;
-    dialog.show();
-    return app.exec();
-}

examples/network/network.pro

@@ -9,7 +9,6 @@ qtHaveModule(widgets) {
                 broadcastreceiver \
                 broadcastsender \
                 http \
-                loopback \
                 threadedfortuneserver \
                 torrent \
                 multicastreceiver \

src/network/doc/src/examples.qdoc

@@ -26,7 +26,6 @@
     \li  \l{network/fortuneclient}{Fortune Client}\raisedaster
     \li  \l{network/fortuneserver}{Fortune Server}\raisedaster
     \li  \l{network/http}{HTTP}
-    \li  \l{network/loopback}{Loopback}
     \li  \l{network/threadedfortuneserver}{Threaded Fortune Server}\raisedaster
     \li  \l{network/torrent}{Torrent}
     \li  \l{network/securesocketclient}{Secure Socket Client}

src/network/socket/qtcpserver.cpp

@@ -44,7 +44,7 @@
     connection is available or a timeout expires.
 
     \sa QTcpSocket, {Fortune Server}, {Threaded Fortune Server},
-        {Loopback Example}, {Torrent Example}
+        {Torrent Example}
 */
 
 /*! \fn void QTcpServer::newConnection()

src/network/socket/qtcpsocket.cpp

@@ -25,7 +25,7 @@
     \sa QTcpServer, QUdpSocket, QNetworkAccessManager,
     {Fortune Server}, {Fortune Client},
     {Threaded Fortune Server}, {Blocking Fortune Client},
-    {Loopback Example}, {Torrent Example}
+    {Torrent Example}
 */
 
 #include "qtcpsocket.h"