qt-everywhere-src-5.14.1/qtbase/examples/widgets/mainwindows/sdi/mainwindow.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** 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.
 **
 ** BSD License Usage
 ** Alternatively, you may use this file under the terms of the BSD license
 ** as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtWidgets>

 #include "mainwindow.h"

 MainWindow::MainWindow()
 {
     init();
     setCurrentFile(QString());
 }

 MainWindow::MainWindow(const QString &fileName)
 {
     init();
     loadFile(fileName);
 }

 void MainWindow::closeEvent(QCloseEvent *event)
 {
     if (maybeSave()) {
         writeSettings();
         event->accept();
     } else {
         event->ignore();
     }
 }

 void MainWindow::newFile()
 {
     MainWindow *other = new MainWindow;
     other->tile(this);
     other->show();
 }

 void MainWindow::open()
 {
     const QString fileName = QFileDialog::getOpenFileName(this);
     if (!fileName.isEmpty())
         openFile(fileName);
 }

 void MainWindow::openFile(const QString &fileName)
 {
     MainWindow *existing = findMainWindow(fileName);
     if (existing) {
         existing->show();
         existing->raise();
         existing->activateWindow();
         return;
     }

     if (isUntitled && textEdit->document()->isEmpty() && !isWindowModified()) {
         loadFile(fileName);
         return;
     }

     MainWindow *other = new MainWindow(fileName);
     if (other->isUntitled) {
         delete other;
         return;
     }
     other->tile(this);
     other->show();
 }

 bool MainWindow::save()
 {
     return isUntitled ? saveAs() : saveFile(curFile);
 }

 bool MainWindow::saveAs()
 {
     QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"),
                                                     curFile);
     if (fileName.isEmpty())
         return false;

     return saveFile(fileName);
 }

 void MainWindow::about()
 {
    QMessageBox::about(this, tr("About SDI"),
             tr("The <b>SDI</b> example demonstrates how to write single "
                "document interface applications using Qt."));
 }

 void MainWindow::documentWasModified()
 {
     setWindowModified(true);
 }

 void MainWindow::init()
 {
     setAttribute(Qt::WA_DeleteOnClose);

     isUntitled = true;

     textEdit = new QTextEdit;
     setCentralWidget(textEdit);

     createActions();
     createStatusBar();

     readSettings();

     connect(textEdit->document(), &QTextDocument::contentsChanged,
             this, &MainWindow::documentWasModified);

     setUnifiedTitleAndToolBarOnMac(true);
 }

 void MainWindow::tile(const QMainWindow *previous)
 {
     if (!previous)
         return;
     int topFrameWidth = previous->geometry().top() - previous->pos().y();
     if (!topFrameWidth)
         topFrameWidth = 40;
     const QPoint pos = previous->pos() + 2 * QPoint(topFrameWidth, topFrameWidth);
     if (screen()->availableGeometry().contains(rect().bottomRight() + pos))
         move(pos);
 }

 //! [implicit tr context]
 void MainWindow::createActions()
 {
     QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
 //! [implicit tr context]
     QToolBar *fileToolBar = addToolBar(tr("File"));

     const QIcon newIcon = QIcon::fromTheme("document-new", QIcon(":/images/new.png"));
     QAction *newAct = new QAction(newIcon, tr("&New"), this);
     newAct->setShortcuts(QKeySequence::New);
     newAct->setStatusTip(tr("Create a new file"));
     connect(newAct, &QAction::triggered, this, &MainWindow::newFile);
     fileMenu->addAction(newAct);
     fileToolBar->addAction(newAct);

     const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/images/open.png"));
     QAction *openAct = new QAction(openIcon, tr("&Open..."), this);
     openAct->setShortcuts(QKeySequence::Open);
     openAct->setStatusTip(tr("Open an existing file"));
     connect(openAct, &QAction::triggered, this, &MainWindow::open);
     fileMenu->addAction(openAct);
     fileToolBar->addAction(openAct);

     const QIcon saveIcon = QIcon::fromTheme("document-save", QIcon(":/images/save.png"));
     QAction *saveAct = new QAction(saveIcon, tr("&Save"), this);
     saveAct->setShortcuts(QKeySequence::Save);
     saveAct->setStatusTip(tr("Save the document to disk"));
     connect(saveAct, &QAction::triggered, this, &MainWindow::save);
     fileMenu->addAction(saveAct);
     fileToolBar->addAction(saveAct);

     const QIcon saveAsIcon = QIcon::fromTheme("document-save-as");
     QAction *saveAsAct = fileMenu->addAction(saveAsIcon, tr("Save &As..."), this, &MainWindow::saveAs);
     saveAsAct->setShortcuts(QKeySequence::SaveAs);
     saveAsAct->setStatusTip(tr("Save the document under a new name"));

     fileMenu->addSeparator();

     QMenu *recentMenu = fileMenu->addMenu(tr("Recent..."));
     connect(recentMenu, &QMenu::aboutToShow, this, &MainWindow::updateRecentFileActions);
     recentFileSubMenuAct = recentMenu->menuAction();

     for (int i = 0; i < MaxRecentFiles; ++i) {
         recentFileActs[i] = recentMenu->addAction(QString(), this, &MainWindow::openRecentFile);
         recentFileActs[i]->setVisible(false);
     }

     recentFileSeparator = fileMenu->addSeparator();

     setRecentFilesVisible(MainWindow::hasRecentFiles());

     QAction *closeAct = fileMenu->addAction(tr("&Close"), this, &QWidget::close);
     closeAct->setShortcut(tr("Ctrl+W"));
     closeAct->setStatusTip(tr("Close this window"));

     const QIcon exitIcon = QIcon::fromTheme("application-exit");
     QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), qApp, &QApplication::closeAllWindows);
     exitAct->setShortcuts(QKeySequence::Quit);
     exitAct->setStatusTip(tr("Exit the application"));

     QMenu *editMenu = menuBar()->addMenu(tr("&Edit"));
     QToolBar *editToolBar = addToolBar(tr("Edit"));

 #ifndef QT_NO_CLIPBOARD
     const QIcon cutIcon = QIcon::fromTheme("edit-cut", QIcon(":/images/cut.png"));
     QAction *cutAct = new QAction(cutIcon, tr("Cu&t"), this);
     cutAct->setShortcuts(QKeySequence::Cut);
     cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                             "clipboard"));
     connect(cutAct, &QAction::triggered, textEdit, &QTextEdit::cut);
     editMenu->addAction(cutAct);
     editToolBar->addAction(cutAct);

     const QIcon copyIcon = QIcon::fromTheme("edit-copy", QIcon(":/images/copy.png"));
     QAction *copyAct = new QAction(copyIcon, tr("&Copy"), this);
     copyAct->setShortcuts(QKeySequence::Copy);
     copyAct->setStatusTip(tr("Copy the current selection's contents to the "
                              "clipboard"));
     connect(copyAct, &QAction::triggered, textEdit, &QTextEdit::copy);
     editMenu->addAction(copyAct);
     editToolBar->addAction(copyAct);

     const QIcon pasteIcon = QIcon::fromTheme("edit-paste", QIcon(":/images/paste.png"));
     QAction *pasteAct = new QAction(pasteIcon, tr("&Paste"), this);
     pasteAct->setShortcuts(QKeySequence::Paste);
     pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
                               "selection"));
     connect(pasteAct, &QAction::triggered, textEdit, &QTextEdit::paste);
     editMenu->addAction(pasteAct);
     editToolBar->addAction(pasteAct);

     menuBar()->addSeparator();
 #endif // !QT_NO_CLIPBOARD

     QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
     QAction *aboutAct = helpMenu->addAction(tr("&About"), this, &MainWindow::about);
     aboutAct->setStatusTip(tr("Show the application's About box"));

     QAction *aboutQtAct = helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
     aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));

 #ifndef QT_NO_CLIPBOARD
     cutAct->setEnabled(false);
     copyAct->setEnabled(false);
     connect(textEdit, &QTextEdit::copyAvailable, cutAct, &QAction::setEnabled);
     connect(textEdit, &QTextEdit::copyAvailable, copyAct, &QAction::setEnabled);
 #endif // !QT_NO_CLIPBOARD
 }

 void MainWindow::createStatusBar()
 {
     statusBar()->showMessage(tr("Ready"));
 }

 void MainWindow::readSettings()
 {
     QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
     const QByteArray geometry = settings.value("geometry", QByteArray()).toByteArray();
     if (geometry.isEmpty()) {
         const QRect availableGeometry = screen()->availableGeometry();
         resize(availableGeometry.width() / 3, availableGeometry.height() / 2);
         move((availableGeometry.width() - width()) / 2,
              (availableGeometry.height() - height()) / 2);
     } else {
         restoreGeometry(geometry);
     }
 }

 void MainWindow::writeSettings()
 {
     QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
     settings.setValue("geometry", saveGeometry());
 }

 bool MainWindow::maybeSave()
 {
     if (!textEdit->document()->isModified())
         return true;
     const QMessageBox::StandardButton ret
         = QMessageBox::warning(this, tr("SDI"),
                                tr("The document has been modified.\n"
                                   "Do you want to save your changes?"),
                                QMessageBox::Save | QMessageBox::Discard
                                | QMessageBox::Cancel);
     switch (ret) {
     case QMessageBox::Save:
         return save();
     case QMessageBox::Cancel:
         return false;
     default:
         break;
     }
     return true;
 }

 void MainWindow::loadFile(const QString &fileName)
 {

     QFile file(fileName);
     if (!file.open(QFile::ReadOnly | QFile::Text)) {
         QMessageBox::warning(this, tr("SDI"),
                              tr("Cannot read file %1:\n%2.")
                              .arg(QDir::toNativeSeparators(fileName), file.errorString()));
         return;
     }

     QTextStream in(&file);
     QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     textEdit->setPlainText(in.readAll());
     QGuiApplication::restoreOverrideCursor();

     setCurrentFile(fileName);
     statusBar()->showMessage(tr("File loaded"), 2000);
 }

 void MainWindow::setRecentFilesVisible(bool visible)
 {
     recentFileSubMenuAct->setVisible(visible);
     recentFileSeparator->setVisible(visible);
 }

 static inline QString recentFilesKey() { return QStringLiteral("recentFileList"); }
 static inline QString fileKey() { return QStringLiteral("file"); }

 static QStringList readRecentFiles(QSettings &settings)
 {
     QStringList result;
     const int count = settings.beginReadArray(recentFilesKey());
     for (int i = 0; i < count; ++i) {
         settings.setArrayIndex(i);
         result.append(settings.value(fileKey()).toString());
     }
     settings.endArray();
     return result;
 }

 static void writeRecentFiles(const QStringList &files, QSettings &settings)
 {
     const int count = files.size();
     settings.beginWriteArray(recentFilesKey());
     for (int i = 0; i < count; ++i) {
         settings.setArrayIndex(i);
         settings.setValue(fileKey(), files.at(i));
     }
     settings.endArray();
 }

 bool MainWindow::hasRecentFiles()
 {
     QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
     const int count = settings.beginReadArray(recentFilesKey());
     settings.endArray();
     return count > 0;
 }

 void MainWindow::prependToRecentFiles(const QString &fileName)
 {
     QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());

     const QStringList oldRecentFiles = readRecentFiles(settings);
     QStringList recentFiles = oldRecentFiles;
     recentFiles.removeAll(fileName);
     recentFiles.prepend(fileName);
     if (oldRecentFiles != recentFiles)
         writeRecentFiles(recentFiles, settings);

     setRecentFilesVisible(!recentFiles.isEmpty());
 }

 void MainWindow::updateRecentFileActions()
 {
     QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());

     const QStringList recentFiles = readRecentFiles(settings);
     const int count = qMin(int(MaxRecentFiles), recentFiles.size());
     int i = 0;
     for ( ; i < count; ++i) {
         const QString fileName = MainWindow::strippedName(recentFiles.at(i));
         recentFileActs[i]->setText(tr("&%1 %2").arg(i + 1).arg(fileName));
         recentFileActs[i]->setData(recentFiles.at(i));
         recentFileActs[i]->setVisible(true);
     }
     for ( ; i < MaxRecentFiles; ++i)
         recentFileActs[i]->setVisible(false);
 }

 void MainWindow::openRecentFile()
 {
     if (const QAction *action = qobject_cast<const QAction *>(sender()))
         openFile(action->data().toString());
 }

 bool MainWindow::saveFile(const QString &fileName)
 {
     QString errorMessage;

     QGuiApplication::setOverrideCursor(Qt::WaitCursor);
     QSaveFile file(fileName);
     if (file.open(QFile::WriteOnly | QFile::Text)) {
         QTextStream out(&file);
         out << textEdit->toPlainText();
         if (!file.commit()) {
             errorMessage = tr("Cannot write file %1:\n%2.")
                            .arg(QDir::toNativeSeparators(fileName), file.errorString());
         }
     } else {
         errorMessage = tr("Cannot open file %1 for writing:\n%2.")
                        .arg(QDir::toNativeSeparators(fileName), file.errorString());
     }
     QGuiApplication::restoreOverrideCursor();

     if (!errorMessage.isEmpty()) {
         QMessageBox::warning(this, tr("SDI"), errorMessage);
         return false;
     }

     setCurrentFile(fileName);
     statusBar()->showMessage(tr("File saved"), 2000);
     return true;
 }

 void MainWindow::setCurrentFile(const QString &fileName)
 {
     static int sequenceNumber = 1;

     isUntitled = fileName.isEmpty();
     if (isUntitled) {
         curFile = tr("document%1.txt").arg(sequenceNumber++);
     } else {
         curFile = QFileInfo(fileName).canonicalFilePath();
     }

     textEdit->document()->setModified(false);
     setWindowModified(false);

     if (!isUntitled && windowFilePath() != curFile)
         MainWindow::prependToRecentFiles(curFile);

     setWindowFilePath(curFile);
 }

 QString MainWindow::strippedName(const QString &fullFileName)
 {
     return QFileInfo(fullFileName).fileName();
 }

 MainWindow *MainWindow::findMainWindow(const QString &fileName) const
 {
     QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();

     const QList<QWidget *> topLevelWidgets = QApplication::topLevelWidgets();
     for (QWidget *widget : topLevelWidgets) {
         MainWindow *mainWin = qobject_cast<MainWindow *>(widget);
         if (mainWin && mainWin->curFile == canonicalFilePath)
             return mainWin;
     }

     return nullptr;
 }
	/****************************************************************************
	**
	** Copyright (C) 2016 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** This file is part of the examples of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:BSD$
	** 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.
	**
	** BSD License Usage
	** Alternatively, you may use this file under the terms of the BSD license
	** as follows:
	**
	** "Redistribution and use in source and binary forms, with or without
	** modification, are permitted provided that the following conditions are
	** met:
	** * Redistributions of source code must retain the above copyright
	** notice, this list of conditions and the following disclaimer.
	** * Redistributions in binary form must reproduce the above copyright
	** notice, this list of conditions and the following disclaimer in
	** the documentation and/or other materials provided with the
	** distribution.
	** * Neither the name of The Qt Company Ltd nor the names of its
	** contributors may be used to endorse or promote products derived
	** from this software without specific prior written permission.
	**
	**
	** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	#include <QtWidgets>

	#include "mainwindow.h"

	MainWindow::MainWindow()
	{
	init();
	setCurrentFile(QString());
	}

	MainWindow::MainWindow(const QString &fileName)
	{
	init();
	loadFile(fileName);
	}

	void MainWindow::closeEvent(QCloseEvent *event)
	{
	if (maybeSave()) {
	writeSettings();
	event->accept();
	} else {
	event->ignore();
	}
	}

	void MainWindow::newFile()
	{
	MainWindow *other = new MainWindow;
	other->tile(this);
	other->show();
	}

	void MainWindow::open()
	{
	const QString fileName = QFileDialog::getOpenFileName(this);
	if (!fileName.isEmpty())
	openFile(fileName);
	}

	void MainWindow::openFile(const QString &fileName)
	{
	MainWindow *existing = findMainWindow(fileName);
	if (existing) {
	existing->show();
	existing->raise();
	existing->activateWindow();
	return;
	}

	if (isUntitled && textEdit->document()->isEmpty() && !isWindowModified()) {
	loadFile(fileName);
	return;
	}

	MainWindow *other = new MainWindow(fileName);
	if (other->isUntitled) {
	delete other;
	return;
	}
	other->tile(this);
	other->show();
	}

	bool MainWindow::save()
	{
	return isUntitled ? saveAs() : saveFile(curFile);
	}

	bool MainWindow::saveAs()
	{
	QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"),
	curFile);
	if (fileName.isEmpty())
	return false;

	return saveFile(fileName);
	}

	void MainWindow::about()
	{
	QMessageBox::about(this, tr("About SDI"),
	tr("The <b>SDI</b> example demonstrates how to write single "
	"document interface applications using Qt."));
	}

	void MainWindow::documentWasModified()
	{
	setWindowModified(true);
	}

	void MainWindow::init()
	{
	setAttribute(Qt::WA_DeleteOnClose);

	isUntitled = true;

	textEdit = new QTextEdit;
	setCentralWidget(textEdit);

	createActions();
	createStatusBar();

	readSettings();

	connect(textEdit->document(), &QTextDocument::contentsChanged,
	this, &MainWindow::documentWasModified);

	setUnifiedTitleAndToolBarOnMac(true);
	}

	void MainWindow::tile(const QMainWindow *previous)
	{
	if (!previous)
	return;
	int topFrameWidth = previous->geometry().top() - previous->pos().y();
	if (!topFrameWidth)
	topFrameWidth = 40;
	const QPoint pos = previous->pos() + 2 * QPoint(topFrameWidth, topFrameWidth);
	if (screen()->availableGeometry().contains(rect().bottomRight() + pos))
	move(pos);
	}

	//! [implicit tr context]
	void MainWindow::createActions()
	{
	QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
	//! [implicit tr context]
	QToolBar *fileToolBar = addToolBar(tr("File"));

	const QIcon newIcon = QIcon::fromTheme("document-new", QIcon(":/images/new.png"));
	QAction *newAct = new QAction(newIcon, tr("&New"), this);
	newAct->setShortcuts(QKeySequence::New);
	newAct->setStatusTip(tr("Create a new file"));
	connect(newAct, &QAction::triggered, this, &MainWindow::newFile);
	fileMenu->addAction(newAct);
	fileToolBar->addAction(newAct);

	const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/images/open.png"));
	QAction *openAct = new QAction(openIcon, tr("&Open..."), this);
	openAct->setShortcuts(QKeySequence::Open);
	openAct->setStatusTip(tr("Open an existing file"));
	connect(openAct, &QAction::triggered, this, &MainWindow::open);
	fileMenu->addAction(openAct);
	fileToolBar->addAction(openAct);

	const QIcon saveIcon = QIcon::fromTheme("document-save", QIcon(":/images/save.png"));
	QAction *saveAct = new QAction(saveIcon, tr("&Save"), this);
	saveAct->setShortcuts(QKeySequence::Save);
	saveAct->setStatusTip(tr("Save the document to disk"));
	connect(saveAct, &QAction::triggered, this, &MainWindow::save);
	fileMenu->addAction(saveAct);
	fileToolBar->addAction(saveAct);

	const QIcon saveAsIcon = QIcon::fromTheme("document-save-as");
	QAction *saveAsAct = fileMenu->addAction(saveAsIcon, tr("Save &As..."), this, &MainWindow::saveAs);
	saveAsAct->setShortcuts(QKeySequence::SaveAs);
	saveAsAct->setStatusTip(tr("Save the document under a new name"));

	fileMenu->addSeparator();

	QMenu *recentMenu = fileMenu->addMenu(tr("Recent..."));
	connect(recentMenu, &QMenu::aboutToShow, this, &MainWindow::updateRecentFileActions);
	recentFileSubMenuAct = recentMenu->menuAction();

	for (int i = 0; i < MaxRecentFiles; ++i) {
	recentFileActs[i] = recentMenu->addAction(QString(), this, &MainWindow::openRecentFile);
	recentFileActs[i]->setVisible(false);
	}

	recentFileSeparator = fileMenu->addSeparator();

	setRecentFilesVisible(MainWindow::hasRecentFiles());

	QAction *closeAct = fileMenu->addAction(tr("&Close"), this, &QWidget::close);
	closeAct->setShortcut(tr("Ctrl+W"));
	closeAct->setStatusTip(tr("Close this window"));

	const QIcon exitIcon = QIcon::fromTheme("application-exit");
	QAction *exitAct = fileMenu->addAction(exitIcon, tr("E&xit"), qApp, &QApplication::closeAllWindows);
	exitAct->setShortcuts(QKeySequence::Quit);
	exitAct->setStatusTip(tr("Exit the application"));

	QMenu *editMenu = menuBar()->addMenu(tr("&Edit"));
	QToolBar *editToolBar = addToolBar(tr("Edit"));

	#ifndef QT_NO_CLIPBOARD
	const QIcon cutIcon = QIcon::fromTheme("edit-cut", QIcon(":/images/cut.png"));
	QAction *cutAct = new QAction(cutIcon, tr("Cu&t"), this);
	cutAct->setShortcuts(QKeySequence::Cut);
	cutAct->setStatusTip(tr("Cut the current selection's contents to the "
	"clipboard"));
	connect(cutAct, &QAction::triggered, textEdit, &QTextEdit::cut);
	editMenu->addAction(cutAct);
	editToolBar->addAction(cutAct);

	const QIcon copyIcon = QIcon::fromTheme("edit-copy", QIcon(":/images/copy.png"));
	QAction *copyAct = new QAction(copyIcon, tr("&Copy"), this);
	copyAct->setShortcuts(QKeySequence::Copy);
	copyAct->setStatusTip(tr("Copy the current selection's contents to the "
	"clipboard"));
	connect(copyAct, &QAction::triggered, textEdit, &QTextEdit::copy);
	editMenu->addAction(copyAct);
	editToolBar->addAction(copyAct);

	const QIcon pasteIcon = QIcon::fromTheme("edit-paste", QIcon(":/images/paste.png"));
	QAction *pasteAct = new QAction(pasteIcon, tr("&Paste"), this);
	pasteAct->setShortcuts(QKeySequence::Paste);
	pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
	"selection"));
	connect(pasteAct, &QAction::triggered, textEdit, &QTextEdit::paste);
	editMenu->addAction(pasteAct);
	editToolBar->addAction(pasteAct);

	menuBar()->addSeparator();
	#endif // !QT_NO_CLIPBOARD

	QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
	QAction *aboutAct = helpMenu->addAction(tr("&About"), this, &MainWindow::about);
	aboutAct->setStatusTip(tr("Show the application's About box"));

	QAction *aboutQtAct = helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);
	aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));

	#ifndef QT_NO_CLIPBOARD
	cutAct->setEnabled(false);
	copyAct->setEnabled(false);
	connect(textEdit, &QTextEdit::copyAvailable, cutAct, &QAction::setEnabled);
	connect(textEdit, &QTextEdit::copyAvailable, copyAct, &QAction::setEnabled);
	#endif // !QT_NO_CLIPBOARD
	}

	void MainWindow::createStatusBar()
	{
	statusBar()->showMessage(tr("Ready"));
	}

	void MainWindow::readSettings()
	{
	QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
	const QByteArray geometry = settings.value("geometry", QByteArray()).toByteArray();
	if (geometry.isEmpty()) {
	const QRect availableGeometry = screen()->availableGeometry();
	resize(availableGeometry.width() / 3, availableGeometry.height() / 2);
	move((availableGeometry.width() - width()) / 2,
	(availableGeometry.height() - height()) / 2);
	} else {
	restoreGeometry(geometry);
	}
	}

	void MainWindow::writeSettings()
	{
	QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
	settings.setValue("geometry", saveGeometry());
	}

	bool MainWindow::maybeSave()
	{
	if (!textEdit->document()->isModified())
	return true;
	const QMessageBox::StandardButton ret
	= QMessageBox::warning(this, tr("SDI"),
	tr("The document has been modified.\n"
	"Do you want to save your changes?"),
	QMessageBox::Save \| QMessageBox::Discard
	\| QMessageBox::Cancel);
	switch (ret) {
	case QMessageBox::Save:
	return save();
	case QMessageBox::Cancel:
	return false;
	default:
	break;
	}
	return true;
	}

	void MainWindow::loadFile(const QString &fileName)
	{

	QFile file(fileName);
	if (!file.open(QFile::ReadOnly \| QFile::Text)) {
	QMessageBox::warning(this, tr("SDI"),
	tr("Cannot read file %1:\n%2.")
	.arg(QDir::toNativeSeparators(fileName), file.errorString()));
	return;
	}

	QTextStream in(&file);
	QGuiApplication::setOverrideCursor(Qt::WaitCursor);
	textEdit->setPlainText(in.readAll());
	QGuiApplication::restoreOverrideCursor();

	setCurrentFile(fileName);
	statusBar()->showMessage(tr("File loaded"), 2000);
	}

	void MainWindow::setRecentFilesVisible(bool visible)
	{
	recentFileSubMenuAct->setVisible(visible);
	recentFileSeparator->setVisible(visible);
	}

	static inline QString recentFilesKey() { return QStringLiteral("recentFileList"); }
	static inline QString fileKey() { return QStringLiteral("file"); }

	static QStringList readRecentFiles(QSettings &settings)
	{
	QStringList result;
	const int count = settings.beginReadArray(recentFilesKey());
	for (int i = 0; i < count; ++i) {
	settings.setArrayIndex(i);
	result.append(settings.value(fileKey()).toString());
	}
	settings.endArray();
	return result;
	}

	static void writeRecentFiles(const QStringList &files, QSettings &settings)
	{
	const int count = files.size();
	settings.beginWriteArray(recentFilesKey());
	for (int i = 0; i < count; ++i) {
	settings.setArrayIndex(i);
	settings.setValue(fileKey(), files.at(i));
	}
	settings.endArray();
	}

	bool MainWindow::hasRecentFiles()
	{
	QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());
	const int count = settings.beginReadArray(recentFilesKey());
	settings.endArray();
	return count > 0;
	}

	void MainWindow::prependToRecentFiles(const QString &fileName)
	{
	QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());

	const QStringList oldRecentFiles = readRecentFiles(settings);
	QStringList recentFiles = oldRecentFiles;
	recentFiles.removeAll(fileName);
	recentFiles.prepend(fileName);
	if (oldRecentFiles != recentFiles)
	writeRecentFiles(recentFiles, settings);

	setRecentFilesVisible(!recentFiles.isEmpty());
	}

	void MainWindow::updateRecentFileActions()
	{
	QSettings settings(QCoreApplication::organizationName(), QCoreApplication::applicationName());

	const QStringList recentFiles = readRecentFiles(settings);
	const int count = qMin(int(MaxRecentFiles), recentFiles.size());
	int i = 0;
	for ( ; i < count; ++i) {
	const QString fileName = MainWindow::strippedName(recentFiles.at(i));
	recentFileActs[i]->setText(tr("&%1 %2").arg(i + 1).arg(fileName));
	recentFileActs[i]->setData(recentFiles.at(i));
	recentFileActs[i]->setVisible(true);
	}
	for ( ; i < MaxRecentFiles; ++i)
	recentFileActs[i]->setVisible(false);
	}

	void MainWindow::openRecentFile()
	{
	if (const QAction action = qobject_cast<const QAction >(sender()))
	openFile(action->data().toString());
	}

	bool MainWindow::saveFile(const QString &fileName)
	{
	QString errorMessage;

	QGuiApplication::setOverrideCursor(Qt::WaitCursor);
	QSaveFile file(fileName);
	if (file.open(QFile::WriteOnly \| QFile::Text)) {
	QTextStream out(&file);
	out << textEdit->toPlainText();
	if (!file.commit()) {
	errorMessage = tr("Cannot write file %1:\n%2.")
	.arg(QDir::toNativeSeparators(fileName), file.errorString());
	}
	} else {
	errorMessage = tr("Cannot open file %1 for writing:\n%2.")
	.arg(QDir::toNativeSeparators(fileName), file.errorString());
	}
	QGuiApplication::restoreOverrideCursor();

	if (!errorMessage.isEmpty()) {
	QMessageBox::warning(this, tr("SDI"), errorMessage);
	return false;
	}

	setCurrentFile(fileName);
	statusBar()->showMessage(tr("File saved"), 2000);
	return true;
	}

	void MainWindow::setCurrentFile(const QString &fileName)
	{
	static int sequenceNumber = 1;

	isUntitled = fileName.isEmpty();
	if (isUntitled) {
	curFile = tr("document%1.txt").arg(sequenceNumber++);
	} else {
	curFile = QFileInfo(fileName).canonicalFilePath();
	}

	textEdit->document()->setModified(false);
	setWindowModified(false);

	if (!isUntitled && windowFilePath() != curFile)
	MainWindow::prependToRecentFiles(curFile);

	setWindowFilePath(curFile);
	}

	QString MainWindow::strippedName(const QString &fullFileName)
	{
	return QFileInfo(fullFileName).fileName();
	}

	MainWindow *MainWindow::findMainWindow(const QString &fileName) const
	{
	QString canonicalFilePath = QFileInfo(fileName).canonicalFilePath();

	const QList<QWidget *> topLevelWidgets = QApplication::topLevelWidgets();
	for (QWidget *widget : topLevelWidgets) {
	MainWindow mainWin = qobject_cast<MainWindow >(widget);
	if (mainWin && mainWin->curFile == canonicalFilePath)
	return mainWin;
	}

	return nullptr;
	}