Examples: add an example that converts between different file formats

This example converts to and from:
 - Binary JSON
 - CBOR
 - CBOR Diagnostic notation (output only)
 - JSON
 - Null (output only)
 - QDataStream
 - QVariant dump (output only)
 - Text
 - XML

Change-Id: Ibab69e0efefb40bdbf94fffd150b59f8c0da3174
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 160 insertions, 0 deletions

diff --git a/examples/corelib/serialization/convert/textconverter.cpp b/examples/corelib/serialization/convert/textconverter.cpp
new file mode 100644
index 0000000000..e80e69a0b5
--- /dev/null
+++ b/examples/corelib/serialization/convert/textconverter.cpp
@@ -0,0 +1,160 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 Intel Corporation.
+** 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 "textconverter.h"
+
+#include <QFile>
+#include <QTextStream>
+
+static void dumpVariant(QTextStream &out, const QVariant &v)
+{
+    switch (v.userType()) {
+    case QVariant::List: {
+        const QVariantList list = v.toList();
+        for (const QVariant &item : list)
+            dumpVariant(out, item);
+        break;
+    }
+
+    case QVariant::String: {
+        const QStringList list = v.toStringList();
+        for (const QString &s : list)
+            out << s << endl;
+        break;
+    }
+
+    case QVariant::Map: {
+        const QVariantMap map = v.toMap();
+        for (auto it = map.begin(); it != map.end(); ++it) {
+            out << it.key() << " => ";
+            dumpVariant(out, it.value());
+        }
+        break;
+    }
+
+    case QMetaType::Nullptr:
+        out << "(null)" << endl;
+        break;
+
+    default:
+        out << v.toString() << endl;
+        break;
+    }
+}
+
+QString TextConverter::name()
+{
+    return QStringLiteral("text");
+}
+
+Converter::Direction TextConverter::directions()
+{
+    return InOut;
+}
+
+Converter::Options TextConverter::outputOptions()
+{
+    return {};
+}
+
+const char *TextConverter::optionsHelp()
+{
+    return nullptr;
+}
+
+bool TextConverter::probeFile(QIODevice *f)
+{
+    if (QFile *file = qobject_cast<QFile *>(f))
+        return file->fileName().endsWith(QLatin1String(".txt"));
+    return false;
+}
+
+QVariant TextConverter::loadFile(QIODevice *f, Converter *&outputConverter)
+{
+    if (!outputConverter)
+        outputConverter = this;
+
+    QVariantList list;
+    QTextStream in(f);
+    QString line ;
+    while (!in.atEnd()) {
+        in.readLineInto(&line);
+
+        bool ok;
+        qint64 v = line.toLongLong(&ok);
+        if (ok) {
+            list.append(v);
+            continue;
+        }
+
+        double d = line.toDouble(&ok);
+        if (ok) {
+            list.append(d);
+            continue;
+        }
+
+        list.append(line);
+    }
+
+    return list;
+}
+
+void TextConverter::saveFile(QIODevice *f, const QVariant &contents, const QStringList &options)
+{
+    if (!options.isEmpty()) {
+        fprintf(stderr, "Unknown option '%s' to text output. This format has no options.\n", qPrintable(options.first()));
+        exit(EXIT_FAILURE);
+    }
+
+    QTextStream out(f);
+    dumpVariant(out, contents);
+}
+
+static TextConverter textConverter;