In-App purchasing demo

 /****************************************************************************
 **
 ** Copyright (C) 2021 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."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #ifndef INAPPSTORE_H
 #define INAPPSTORE_H

 #include <QObject>
 #include <QMutex>
 #include <QHash>

 #include "inappproduct.h"
 #include "inapppurchasebackend.h"

 class InAppProduct;
 class InAppTransaction;
 class InAppPurchaseBackend;
 class InAppStorePrivate
 {
 public:
     InAppStorePrivate()
         : backend(0)
         , hasCalledInitialize(false)
         , pendingRestorePurchases(false)
     {
     }

     ~InAppStorePrivate()
     {
         delete backend;
     }

     QHash<QString, InAppProduct::ProductType> pendingProducts;
     QHash<QString, InAppProduct *> registeredProducts;
     InAppPurchaseBackend *backend;
     bool hasCalledInitialize;
     bool pendingRestorePurchases;
 };
 class InAppStore: public QObject
 {
     Q_OBJECT

 public:
     explicit InAppStore(QObject *parent = nullptr);
     ~InAppStore();

     Q_INVOKABLE void restorePurchases();
     Q_INVOKABLE void registerProduct(InAppProduct::ProductType productType, const QString &identifier);
     Q_INVOKABLE InAppProduct *registeredProduct(const QString &identifier) const;
     Q_INVOKABLE void setPlatformProperty(const QString &propertyName, const QString &value);

 signals:
     void productRegistered(InAppProduct *product);
     void productUnknown(InAppProduct::ProductType productType, const QString &identifier);
     void transactionReady(InAppTransaction *transaction);

 private Q_SLOTS:
     void registerPendingProducts();
     void registerProduct(InAppProduct *);

 private:
     void setupBackend();

     Q_DISABLE_COPY(InAppStore)
     QSharedPointer<InAppStorePrivate> d;
 };

 #endif // INAPPSTORE_H