Add QtPurchasing module as an example under Qt demos

QtPurchasing module is deprecated in Qt6. However, the purchasing
code is moved as example/demo under qtdoc to demonstrate the use of
in-app purchases in Android/iOS.

The demo is under demos\hangman.

Few fixes done to the original code:
* Ported the code to Qt 6.
* Removed reinterpret_casts and QQmlListPropertys.
* Fixed few QML warnings.
* Added documentation
	* Fixed documentation
* Added CMake port
	* Fixed Cmake for iOS
* Modified Fonts in qml file
* project name changed from qthangmanpurchasing to hangman

Task-number: QTBUG-84776
Pick-to: 6.2
Change-Id: I86051b29d54cfb4a48b310ebc8d538c806fbf8da
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Nicholas Bennett <nicholas.bennett@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

12 files changed, 2182 insertions, 0 deletions

diff --git a/examples/demos/hangman/purchasing/android/androidinappproduct.cpp b/examples/demos/hangman/purchasing/android/androidinappproduct.cpp
new file mode 100644
index 000000000..8c968eeee
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinappproduct.cpp
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "androidinappproduct.h"
+#include "androidinapppurchasebackend.h"
+
+QT_BEGIN_NAMESPACE
+
+AndroidInAppProduct::AndroidInAppProduct(AndroidInAppPurchaseBackend *backend,
+                                           const QString &price,
+                                           const QString &title,
+                                           const QString &description,
+                                           ProductType productType,
+                                           const QString &identifier,
+                                           QObject *parent)
+    : InAppProduct(price, title, description, productType, identifier, parent)
+    , m_backend(backend)
+{
+}
+
+void AndroidInAppProduct::purchase()
+{
+    m_backend->purchaseProduct(this);
+}
diff --git a/examples/demos/hangman/purchasing/android/androidinappproduct.h b/examples/demos/hangman/purchasing/android/androidinappproduct.h
new file mode 100644
index 000000000..1e7b6eb7f
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinappproduct.h
@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** 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 ANDROIDINAPPPRODUCT_H
+#define ANDROIDINAPPPRODUCT_H
+
+#include "../inapp/inappproduct.h"
+
+class AndroidInAppPurchaseBackend;
+class AndroidInAppProduct : public InAppProduct
+{
+    Q_OBJECT
+public:
+    explicit AndroidInAppProduct(AndroidInAppPurchaseBackend *backend,
+                                  const QString &price,
+                                  const QString &title,
+                                  const QString &description,
+                                  ProductType productType,
+                                  const QString &identifier,
+                                  QObject *parent = 0);
+
+    QString getProductId();
+    void purchase();
+
+private:
+    AndroidInAppPurchaseBackend *m_backend;
+};
+
+#endif // ANDROIDINAPPPRODUCT_H
diff --git a/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.cpp b/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.cpp
new file mode 100644
index 000000000..63470137c
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.cpp
@@ -0,0 +1,332 @@
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QDebug>
+
+#include <QJniEnvironment>
+#include <QtCore>
+
+#include "androidinapppurchasebackend.h"
+#include "androidinappproduct.h"
+#include "androidinapptransaction.h"
+#include "../inapp/inappstore.h"
+
+
+QT_BEGIN_NAMESPACE
+
+AndroidInAppPurchaseBackend::AndroidInAppPurchaseBackend(QObject *parent)
+    : InAppPurchaseBackend(parent)
+    , m_isReady(false)
+{
+    m_javaObject = QJniObject("org/qtproject/qt/android/purchasing/InAppPurchase",
+                              "(Landroid/content/Context;J)V",
+                              QNativeInterface::QAndroidApplication::context(),
+                              this);
+
+    if (!m_javaObject.isValid()) {
+        qWarning("Cannot initialize IAP backend for Android due to missing dependency: InAppPurchase class");
+        return;
+    }
+}
+
+void AndroidInAppPurchaseBackend::initialize()
+{
+    m_javaObject.callMethod<void>("initializeConnection");
+}
+
+bool AndroidInAppPurchaseBackend::isReady() const
+{
+    QMutexLocker locker(&m_mutex);
+    return m_isReady;
+}
+
+void AndroidInAppPurchaseBackend::restorePurchases()
+{
+    for (const QString &purchasedUnlockeble : purchasedUnlockebles) {
+        InAppProduct *product = store()->registeredProduct(purchasedUnlockeble);
+        Q_ASSERT(product != 0);
+
+        checkFinalizationStatus(product, InAppTransaction::PurchaseRestored);
+    }
+
+}
+
+void AndroidInAppPurchaseBackend::queryProducts(const QList<Product> &products)
+{
+    QMutexLocker locker(&m_mutex);
+    QJniEnvironment environment;
+
+    QStringList newProducts;
+    for (int i = 0; i < products.size(); ++i) {
+        const Product &product = products.at(i);
+        if (m_productTypeForPendingId.contains(product.identifier)) {
+            qWarning("Product query already pending for %s", qPrintable(product.identifier));
+            continue;
+        }
+        else{
+            m_productTypeForPendingId[product.identifier] = product.productType;
+            newProducts.append(product.identifier);
+        }
+    }
+
+    if (newProducts.isEmpty())
+        return;
+
+    jclass cls = environment->FindClass("java/lang/String");
+    jobjectArray productIds = environment->NewObjectArray(newProducts.size(), cls, 0);
+    environment->DeleteLocalRef(cls);
+
+    for (int i = 0; i < newProducts.size(); ++i) {
+        QJniObject identifier = QJniObject::fromString(newProducts.at(i));
+        environment->SetObjectArrayElement(productIds, i, identifier.object());
+    }
+
+    m_javaObject.callMethod<void>("queryDetails",
+                                  "([Ljava/lang/String;)V",
+                                  productIds);
+    environment->DeleteLocalRef(productIds);
+}
+
+void AndroidInAppPurchaseBackend::queryProduct(InAppProduct::ProductType productType,
+                                                const QString &identifier)
+{
+    queryProducts(QList<Product>() << Product(productType, identifier));
+}
+
+void AndroidInAppPurchaseBackend::setPlatformProperty(const QString &propertyName, const QString &value)
+{
+    QMutexLocker locker(&m_mutex);
+    if (propertyName.compare(QStringLiteral("AndroidPublicKey"), Qt::CaseInsensitive) == 0) {
+        m_javaObject.callMethod<void>("setPublicKey",
+                                      "(Ljava/lang/String;)V",
+                                      QJniObject::fromString(value).object<jstring>());
+    }
+}
+
+void AndroidInAppPurchaseBackend::consumeTransaction(const QString &purchaseToken)
+{
+    QMutexLocker locker(&m_mutex);
+    m_javaObject.callMethod<void>("consumePurchase",
+                                  "(Ljava/lang/String;)V",
+                                  QJniObject::fromString(purchaseToken).object<jstring>());
+}
+
+void AndroidInAppPurchaseBackend::registerFinalizedUnlockable(const QString &purchaseToken)
+{
+    QMutexLocker locker(&m_mutex);
+    m_javaObject.callMethod<void>("acknowledgeUnlockablePurchase",
+                                  "(Ljava/lang/String;)V",
+                                  QJniObject::fromString(purchaseToken).object<jstring>());
+}
+
+bool AndroidInAppPurchaseBackend::transactionFinalizedForProduct(InAppProduct *product)
+{
+    Q_ASSERT(m_infoForPurchase.contains(product->identifier()));
+
+    if (product->productType() != InAppProduct::Consumable && purchasedUnlockebles.contains(product->identifier()))
+    {
+        return true;
+    }
+    return false;
+}
+
+void AndroidInAppPurchaseBackend::checkFinalizationStatus(InAppProduct *product,
+                                                           InAppTransaction::TransactionStatus status)
+{
+    // Verifies the finalization status of an item based on the following logic:
+    // 1. If the item is not purchased yet, do nothing (it's either never been purchased, or it's a
+    //    consumed consumable.
+    // 2. If the item is purchased, and it's a consumable, it's unfinalized. Emit a new transaction.
+    //    Consumable items are consumed when they are finalized.
+    // 3. If the item is purchased, and it's an unlockable, check the local cache for finalized
+    //    unlockable purchases. If it's not there, then the transaction is unfinalized. This means
+    //    that if the cache gets deleted or corrupted, the worst-case scenario is that the transactions
+    //    are republished.
+    QHash<QString, PurchaseInfo>::iterator it = m_infoForPurchase.find(product->identifier());
+
+    if (it == m_infoForPurchase.end()) {
+        return;
+    }
+
+    const PurchaseInfo &info = it.value();
+    if (transactionFinalizedForProduct(product)) {
+        AndroidInAppTransaction *transaction = new AndroidInAppTransaction(info.signature,
+                                                                             info.data,
+                                                                             info.purchaseToken,
+                                                                             info.orderId,
+                                                                             status,
+                                                                             product,
+                                                                             info.timestamp,
+                                                                             InAppTransaction::NoFailure,
+                                                                             QString(),
+                                                                             this);
+        emit transactionReady(transaction);
+    }
+}
+
+void AndroidInAppPurchaseBackend::registerProduct(const QString &productId,
+                                                   const QString &price,
+                                                   const QString &title,
+                                                   const QString &description)
+{
+    QMutexLocker locker(&m_mutex);
+    QHash<QString, InAppProduct::ProductType>::iterator it = m_productTypeForPendingId.find(productId);
+    Q_ASSERT(it != m_productTypeForPendingId.end());
+
+    AndroidInAppProduct *product = new AndroidInAppProduct(this, price, title, description, it.value(), it.key(), this);
+
+    emit productQueryDone(product);
+}
+
+void AndroidInAppPurchaseBackend::registerPurchased(const QString &identifier,
+                                                     const QString &signature,
+                                                     const QString &data,
+                                                     const QString &purchaseToken,
+                                                     const QString &orderId,
+                                                     const QDateTime &timestamp)
+{
+    QMutexLocker locker(&m_mutex);
+    m_infoForPurchase.insert(identifier, PurchaseInfo(signature, data, purchaseToken, orderId, timestamp));
+
+    QHash<QString, InAppProduct::ProductType>::iterator it = m_productTypeForPendingId.find(identifier);
+    if (it.value() == InAppProduct::Unlockable && !purchasedUnlockebles.contains(identifier))
+        purchasedUnlockebles.append(identifier);
+
+
+}
+
+void AndroidInAppPurchaseBackend::registerReady()
+{
+    QMutexLocker locker(&m_mutex);
+    m_isReady = true;
+    emit ready();
+}
+
+void AndroidInAppPurchaseBackend::purchaseProduct(AndroidInAppProduct *product)
+{
+    QMutexLocker locker(&m_mutex);
+    if (!m_javaObject.isValid()) {
+        purchaseFailed(product, InAppTransaction::ErrorOccurred, QStringLiteral("Java backend is not initialized"));
+        return;
+    }
+
+    int requestCode = 0;
+    while (m_activePurchaseRequests.contains(requestCode)) {
+        requestCode++;
+        if (requestCode == 0) {
+            qWarning("No available request code for purchase request.");
+            return;
+        }
+    }
+
+    m_activePurchaseRequests[requestCode] = product;
+
+    m_javaObject.callMethod<void>("launchBillingFlow",
+                                  "(Ljava/lang/String;I)V",
+                                  QJniObject::fromString(product->identifier()).object<jstring>(),
+                                  requestCode);
+}
+
+void AndroidInAppPurchaseBackend::purchaseFailed(int requestCode, int failureReason, const QString &errorString)
+{
+    QMutexLocker locker(&m_mutex);
+    InAppProduct *product = m_activePurchaseRequests.take(requestCode);
+    if (product == 0) {
+        qWarning("No product registered for requestCode %d", requestCode);
+        return;
+    }
+
+    purchaseFailed(product, failureReason, errorString);
+}
+
+void AndroidInAppPurchaseBackend::purchaseFailed(InAppProduct *product, int failureReason, const QString &errorString)
+{
+    InAppTransaction *transaction = new AndroidInAppTransaction(QString(),
+                                                                  QString(),
+                                                                  QString(),
+                                                                  QString(),
+                                                                  InAppTransaction::PurchaseFailed,
+                                                                  product,
+                                                                  QDateTime(),
+                                                                  InAppTransaction::FailureReason(failureReason),
+                                                                  errorString,
+                                                                  this);
+    emit transactionReady(transaction);
+}
+
+void AndroidInAppPurchaseBackend::purchaseSucceeded(int requestCode,
+                                                     const QString &signature,
+                                                     const QString &data,
+                                                     const QString &purchaseToken,
+                                                     const QString &orderId,
+                                                     const QDateTime &timestamp)
+
+{
+    QMutexLocker locker(&m_mutex);
+    InAppProduct *product = m_activePurchaseRequests.take(requestCode);
+    if (product == 0) {
+        qWarning("No product registered for requestCode %d", requestCode);
+        return;
+    }
+
+    m_infoForPurchase.insert(product->identifier(), PurchaseInfo(signature, data, purchaseToken, orderId, timestamp));
+    InAppTransaction *transaction = new AndroidInAppTransaction(signature,
+                                                                  data,
+                                                                  purchaseToken,
+                                                                  orderId,
+                                                                  InAppTransaction::PurchaseApproved,
+                                                                  product,
+                                                                  timestamp,
+                                                                  InAppTransaction::NoFailure,
+                                                                  QString(),
+                                                                  this);
+    emit transactionReady(transaction);
+}
+QT_END_NAMESPACE
diff --git a/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.h b/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.h
new file mode 100644
index 000000000..0c66fb5e3
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinapppurchasebackend.h
@@ -0,0 +1,145 @@
+/****************************************************************************
+**
+** 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 ANDROIDINAPPPURCHASEBACKEND_H
+#define ANDROIDINAPPPURCHASEBACKEND_H
+
+#include <QMutex>
+#include <QSet>
+#include <QDateTime>
+#include <QJniObject>
+#include <QJniEnvironment>
+
+#include "../inapp/inapppurchasebackend.h"
+#include "../inapp/inappproduct.h"
+#include "../inapp/inapptransaction.h"
+
+QT_BEGIN_NAMESPACE
+class AndroidInAppProduct;
+class AndroidInAppPurchaseBackend : public InAppPurchaseBackend
+{
+    Q_OBJECT
+public:
+    explicit AndroidInAppPurchaseBackend(QObject *parent = 0);
+
+    void initialize();
+    bool isReady() const;
+
+    void queryProducts(const QList<Product> &products);
+    void queryProduct(InAppProduct::ProductType productType, const QString &identifier);
+    void restorePurchases();
+
+    void setPlatformProperty(const QString &propertyName, const QString &value);
+
+    void purchaseProduct(AndroidInAppProduct *product);
+
+    void consumeTransaction(const QString &purchaseToken);
+    void registerFinalizedUnlockable(const QString &identifier);
+
+    // Callbacks from Java
+    Q_INVOKABLE void registerProduct(const QString &productId,
+                                     const QString &price,
+                                     const QString &title,
+                                     const QString &description);
+    Q_INVOKABLE void registerPurchased(const QString &identifier,
+                                       const QString &signature,
+                                       const QString &data,
+                                       const QString &purchaseToken,
+                                       const QString &orderId,
+                                       const QDateTime &timestamp);
+    Q_INVOKABLE void purchaseSucceeded(int requestCode,
+                                       const QString &signature,
+                                       const QString &data,
+                                       const QString &purchaseToken,
+                                       const QString &orderId,
+                                       const QDateTime &timestamp);
+    Q_INVOKABLE void purchaseFailed(int requestCode,
+                                    int failureReason,
+                                    const QString &errorString);
+    Q_INVOKABLE void registerReady();
+
+private:
+    void checkFinalizationStatus(InAppProduct *product,
+                                 InAppTransaction::TransactionStatus status = InAppTransaction::PurchaseApproved);
+    bool transactionFinalizedForProduct(InAppProduct *product);
+    void purchaseFailed(InAppProduct *product,
+                        int failureReason,
+                        const QString &errorString);
+
+    struct PurchaseInfo
+    {
+        PurchaseInfo(const QString &signature_, const QString &data_, const QString &purchaseToken_, const QString &orderId_, const QDateTime &timestamp_)
+            : signature(signature_)
+            , data(data_)
+            , purchaseToken(purchaseToken_)
+            , orderId(orderId_)
+            , timestamp(timestamp_)
+        {
+        }
+
+        QString signature;
+        QString data;
+        QString purchaseToken;
+        QString orderId;
+        QDateTime timestamp;
+    };
+
+    mutable QRecursiveMutex m_mutex;
+    bool m_isReady;
+    QList<QString> purchasedUnlockebles;
+    QJniObject m_javaObject;
+    QScopedPointer<AndroidInAppPurchaseBackend> d;
+    QHash<QString, InAppProduct::ProductType> m_productTypeForPendingId;
+    QHash<QString, PurchaseInfo> m_infoForPurchase;
+    QHash<int, InAppProduct *> m_activePurchaseRequests;
+};
+QT_END_NAMESPACE
+
+#endif // ANDROIDINAPPPURCHASEBACKEND_H
diff --git a/examples/demos/hangman/purchasing/android/androidinapptransaction.cpp b/examples/demos/hangman/purchasing/android/androidinapptransaction.cpp
new file mode 100644
index 000000000..397336f2b
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinapptransaction.cpp
@@ -0,0 +1,124 @@
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "../inapp/inappproduct.h"
+#include "androidinapptransaction.h"
+#include "androidinapppurchasebackend.h"
+
+QT_BEGIN_NAMESPACE
+
+AndroidInAppTransaction::AndroidInAppTransaction(const QString &signature,
+                                                   const QString &data,
+                                                   const QString &purchaseToken,
+                                                   const QString &orderId,
+                                                   TransactionStatus status,
+                                                   InAppProduct *product,
+                                                   const QDateTime &timestamp,
+                                                   FailureReason failureReason,
+                                                   const QString &errorString,
+                                                   QObject *parent)
+    : InAppTransaction(status, product, parent)
+    , m_signature(signature)
+    , m_data(data)
+    , m_purchaseToken(purchaseToken)
+    , m_orderId(orderId)
+    , m_timestamp(timestamp)
+    , m_errorString(errorString)
+    , m_failureReason(failureReason)
+{
+    Q_ASSERT(qobject_cast<AndroidInAppPurchaseBackend *>(parent) != 0);
+}
+
+QString AndroidInAppTransaction::orderId() const
+{
+    return m_orderId;
+}
+
+QDateTime AndroidInAppTransaction::timestamp() const
+{
+    return m_timestamp;
+}
+
+QString AndroidInAppTransaction::errorString() const
+{
+    return m_errorString;
+}
+
+InAppTransaction::FailureReason AndroidInAppTransaction::failureReason() const
+{
+    return m_failureReason;
+}
+
+QString AndroidInAppTransaction::platformProperty(const QString &propertyName) const
+{
+    if (propertyName.compare(QStringLiteral("AndroidSignature"), Qt::CaseInsensitive) == 0)
+        return m_signature;
+    else if (propertyName.compare(QStringLiteral("AndroidPurchaseData"), Qt::CaseInsensitive) == 0)
+        return m_data;
+    else
+        return InAppTransaction::platformProperty(propertyName);
+}
+
+void AndroidInAppTransaction::finalize()
+{
+    AndroidInAppPurchaseBackend *backend = qobject_cast<AndroidInAppPurchaseBackend *>(parent());
+    if (status() == PurchaseApproved || status() == PurchaseRestored) {
+        if (product()->productType() == InAppProduct::Consumable){
+            backend->consumeTransaction(m_purchaseToken);}
+        else if (product()->productType() == InAppProduct::Unlockable){
+            backend->registerFinalizedUnlockable(m_purchaseToken);}
+        else {
+            qWarning("Product type not implemented.");
+        }
+    }
+
+    deleteLater();
+}
+QT_END_NAMESPACE
diff --git a/examples/demos/hangman/purchasing/android/androidinapptransaction.h b/examples/demos/hangman/purchasing/android/androidinapptransaction.h
new file mode 100644
index 000000000..5bba856eb
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidinapptransaction.h
@@ -0,0 +1,90 @@
+/****************************************************************************
+**
+** 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 ANDROIDINAPPTRANSACTION_H
+#define ANDROIDINAPPTRANSACTION_H
+
+
+#include "../inapp/inapptransaction.h"
+
+class AndroidInAppTransaction : public InAppTransaction
+{
+    Q_OBJECT
+public:
+    explicit AndroidInAppTransaction(const QString &signature,
+                                      const QString &data,
+                                      const QString &purchaseToken,
+                                      const QString &orderId,
+                                      TransactionStatus status,
+                                      InAppProduct *product,
+                                      const QDateTime &timestamp,
+                                      FailureReason failureReason,
+                                      const QString &errorString,
+                                      QObject *parent = 0);
+
+    void finalize();
+
+    QString orderId() const;
+    QString errorString() const;
+    FailureReason failureReason() const;
+    QDateTime timestamp() const;
+    QString platformProperty(const QString &propertyName) const;
+
+private:
+    QString m_signature;
+    QString m_data;
+    QString m_purchaseToken;
+    QString m_orderId;
+    QDateTime m_timestamp;
+    QString m_errorString;
+    FailureReason m_failureReason;
+};
+
+#endif // ANDROIDINAPPTRANSACTION_H
diff --git a/examples/demos/hangman/purchasing/android/androidjni.cpp b/examples/demos/hangman/purchasing/android/androidjni.cpp
new file mode 100644
index 000000000..03e6d752b
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/androidjni.cpp
@@ -0,0 +1,153 @@
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtCore/qdatetime.h>
+#include <jni.h>
+#include <QJniObject>
+
+#include "androidinapppurchasebackend.h"
+
+QT_USE_NAMESPACE
+
+static void purchasedProductsQueried(JNIEnv *, jclass, jlong nativePointer)
+{
+    AndroidInAppPurchaseBackend *backend = reinterpret_cast<AndroidInAppPurchaseBackend *>(nativePointer);
+    QMetaObject::invokeMethod(backend,
+                              "registerReady",
+                              Qt::AutoConnection);
+}
+
+static void registerProduct(JNIEnv *, jclass, jlong nativePointer, jstring productId, jstring price, jstring title, jstring description)
+{
+    AndroidInAppPurchaseBackend *backend = reinterpret_cast<AndroidInAppPurchaseBackend *>(nativePointer);
+    QMetaObject::invokeMethod(backend,
+                              "registerProduct",
+                              Qt::AutoConnection,
+                              Q_ARG(QString, QJniObject(productId).toString()),
+                              Q_ARG(QString, QJniObject(price).toString()),
+                              Q_ARG(QString, QJniObject(title).toString()),
+                              Q_ARG(QString, QJniObject(description).toString()));
+}
+
+static void registerPurchased(JNIEnv *, jclass, jlong nativePointer, jstring identifier,
+                              jstring signature, jstring data, jstring purchaseToken, jstring orderId, jlong timestamp)
+{
+    QDateTime dateTime = QDateTime::fromMSecsSinceEpoch(qint64(timestamp));
+    dateTime.setTimeSpec(Qt::LocalTime);
+
+    AndroidInAppPurchaseBackend *backend = reinterpret_cast<AndroidInAppPurchaseBackend *>(nativePointer);
+    QMetaObject::invokeMethod(backend,
+                              "registerPurchased",
+                              Qt::AutoConnection,
+                              Q_ARG(QString, QJniObject(identifier).toString()),
+                              Q_ARG(QString, QJniObject(signature).toString()),
+                              Q_ARG(QString, QJniObject(data).toString()),
+                              Q_ARG(QString, QJniObject(purchaseToken).toString()),
+                              Q_ARG(QString, QJniObject(orderId).toString()),
+                              Q_ARG(QDateTime, dateTime));
+}
+
+static void purchaseSucceeded(JNIEnv *, jclass, jlong nativePointer, jint requestCode,
+                              jstring signature, jstring data, jstring purchaseToken, jstring orderId, jlong timestamp)
+{
+    QDateTime dateTime = QDateTime::fromMSecsSinceEpoch(qint64(timestamp));
+    dateTime.setTimeSpec(Qt::LocalTime);
+
+    AndroidInAppPurchaseBackend *backend = reinterpret_cast<AndroidInAppPurchaseBackend *>(nativePointer);
+    QMetaObject::invokeMethod(backend,
+                              "purchaseSucceeded",
+                              Qt::AutoConnection,
+                              Q_ARG(int, int(requestCode)),
+                              Q_ARG(QString, QJniObject(signature).toString()),
+                              Q_ARG(QString, QJniObject(data).toString()),
+                              Q_ARG(QString, QJniObject(purchaseToken).toString()),
+                              Q_ARG(QString, QJniObject(orderId).toString()),
+                              Q_ARG(QDateTime, dateTime));
+}
+
+static void purchaseFailed(JNIEnv *, jclass, jlong nativePointer, jint requestCode, jint failureReason, jstring errorString)
+{
+    AndroidInAppPurchaseBackend *backend = reinterpret_cast<AndroidInAppPurchaseBackend *>(nativePointer);
+    QMetaObject::invokeMethod(backend,
+                              "purchaseFailed",
+                              Qt::AutoConnection,
+                              Q_ARG(int, int(requestCode)),
+                              Q_ARG(int, int(failureReason)),
+                              Q_ARG(QString, QJniObject(errorString).toString()));
+}
+
+static JNINativeMethod methods[] = {
+    {"purchasedProductsQueried", "(J)V", (void *)purchasedProductsQueried},
+    {"registerProduct", "(JLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V", (void *)registerProduct},
+    {"registerPurchased", "(JLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;J)V", (void *)registerPurchased},
+    {"purchaseSucceeded", "(JILjava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;J)V", (void *)purchaseSucceeded},
+    {"purchaseFailed", "(JIILjava/lang/String;)V", (void *)purchaseFailed}
+};
+
+JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *)
+{
+    static bool initialized = false;
+    if (initialized){
+        return JNI_VERSION_1_6;}
+    initialized = true;
+
+    JNIEnv *env;
+    if (vm->GetEnv((void **)&env, JNI_VERSION_1_6) != JNI_OK){
+        return JNI_ERR;}
+
+    jclass clazz = env->FindClass("org/qtproject/qt/android/purchasing/InAppPurchase");
+    if (!clazz){
+        return JNI_ERR;}
+
+    if (env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0])) < 0){
+        return JNI_ERR;}
+
+    return JNI_VERSION_1_6;
+}
diff --git a/examples/demos/hangman/purchasing/android/build.gradle b/examples/demos/hangman/purchasing/android/build.gradle
new file mode 100644
index 000000000..b33486e1c
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/build.gradle
@@ -0,0 +1,79 @@
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:4.1.3'
+    }
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+apply plugin: 'com.android.application'
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
+    implementation "com.android.billingclient:billing:4.0.0"
+}
+
+android {
+    /*******************************************************
+     * The following variables:
+     * - androidBuildToolsVersion,
+     * - androidCompileSdkVersion
+     * - qtAndroidDir - holds the path to qt android files
+     *                   needed to build any Qt application
+     *                   on Android.
+     *
+     * are defined in gradle.properties file. This file is
+     * updated by QtCreator and androiddeployqt tools.
+     * Changing them manually might break the compilation!
+     *******************************************************/
+
+    compileSdkVersion androidCompileSdkVersion.toInteger()
+
+    buildToolsVersion androidBuildToolsVersion
+
+    sourceSets {
+        main {
+            manifest.srcFile 'AndroidManifest.xml'
+            java.srcDirs = [qtAndroidDir + '/src', 'src', 'java']
+            aidl.srcDirs = [qtAndroidDir + '/src', 'src', 'aidl']
+            res.srcDirs = [qtAndroidDir + '/res', 'res']
+            resources.srcDirs = ['resources']
+            renderscript.srcDirs = ['src']
+            assets.srcDirs = ['assets']
+            jniLibs.srcDirs = ['libs']
+       }
+    }
+
+    tasks.withType(JavaCompile) {
+        options.incremental = true
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    lintOptions {
+        abortOnError false
+    }
+
+    // Do not compress Qt binary resources file
+    aaptOptions {
+        noCompress 'rcc'
+    }
+
+    defaultConfig {
+        resConfig "en"
+        minSdkVersion qtMinSdkVersion
+        targetSdkVersion qtTargetSdkVersion
+        ndk.abiFilters = qtTargetAbiList.split(",")
+    }
+}
diff --git a/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64.java b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64.java
new file mode 100644
index 000000000..fb0605fa8
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64.java
@@ -0,0 +1,572 @@
+/* Copyright (c) 2012 Google Inc.
+ * Copyright (c) 2015 The Qt Company Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.qtproject.qt.android.purchasing;
+
+// This code was converted from code at http://iharder.sourceforge.net/base64/
+// Lots of extraneous features were removed.
+/* The original code said:
+ * <p>
+ * I am placing this code in the Public Domain. Do with it as you will.
+ * This software comes with no guarantees or warranties but with
+ * plenty of well-wishing instead!
+ * Please visit
+ * <a href="http://iharder.net/xmlizable">http://iharder.net/xmlizable</a>
+ * periodically to check for updates or to contribute improvements.
+ * </p>
+ *
+ * @author Robert Harder
+ * @author rharder@usa.net
+ * @version 1.3
+ */
+
+/**
+ * Base64 converter class. This code is not a complete MIME encoder;
+ * it simply converts binary data to base64 data and back.
+ *
+ * <p>Note {@link CharBase64} is a GWT-compatible implementation of this
+ * class.
+ */
+public class Base64 {
+    /** Specify encoding (value is {@code true}). */
+    public final static boolean ENCODE = true;
+
+    /** Specify decoding (value is {@code false}). */
+    public final static boolean DECODE = false;
+
+    /** The equals sign (=) as a byte. */
+    private final static byte EQUALS_SIGN = (byte) '=';
+
+    /** The new line character (\n) as a byte. */
+    private final static byte NEW_LINE = (byte) '\n';
+
+    /**
+     * The 64 valid Base64 values.
+     */
+    private final static byte[] ALPHABET =
+        {(byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F',
+        (byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K',
+        (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P',
+        (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U',
+        (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
+        (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e',
+        (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j',
+        (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o',
+        (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't',
+        (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y',
+        (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3',
+        (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8',
+        (byte) '9', (byte) '+', (byte) '/'};
+
+    /**
+     * The 64 valid web safe Base64 values.
+     */
+    private final static byte[] WEBSAFE_ALPHABET =
+        {(byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F',
+        (byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K',
+        (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P',
+        (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U',
+        (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
+        (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e',
+        (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j',
+        (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o',
+        (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't',
+        (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y',
+        (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3',
+        (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8',
+        (byte) '9', (byte) '-', (byte) '_'};
+
+    /**
+     * Translates a Base64 value to either its 6-bit reconstruction value
+     * or a negative number indicating some other meaning.
+     **/
+    private final static byte[] DECODABET = {-9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal  0 -  8
+        -5, -5, // Whitespace: Tab and Linefeed
+        -9, -9, // Decimal 11 - 12
+        -5, // Whitespace: Carriage Return
+        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
+        -9, -9, -9, -9, -9, // Decimal 27 - 31
+        -5, // Whitespace: Space
+        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
+        62, // Plus sign at decimal 43
+        -9, -9, -9, // Decimal 44 - 46
+        63, // Slash at decimal 47
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
+        -9, -9, -9, // Decimal 58 - 60
+        -1, // Equals sign at decimal 61
+        -9, -9, -9, // Decimal 62 - 64
+        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
+        14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
+        -9, -9, -9, -9, -9, -9, // Decimal 91 - 96
+        26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
+        39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
+        -9, -9, -9, -9, -9 // Decimal 123 - 127
+        /*  ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 */
+    };
+
+    /** The web safe decodabet */
+    private final static byte[] WEBSAFE_DECODABET =
+        {-9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal  0 -  8
+        -5, -5, // Whitespace: Tab and Linefeed
+        -9, -9, // Decimal 11 - 12
+        -5, // Whitespace: Carriage Return
+        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
+        -9, -9, -9, -9, -9, // Decimal 27 - 31
+        -5, // Whitespace: Space
+        -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 44
+        62, // Dash '-' sign at decimal 45
+        -9, -9, // Decimal 46-47
+        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
+        -9, -9, -9, // Decimal 58 - 60
+        -1, // Equals sign at decimal 61
+        -9, -9, -9, // Decimal 62 - 64
+        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
+        14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
+        -9, -9, -9, -9, // Decimal 91-94
+        63, // Underscore '_' at decimal 95
+        -9, // Decimal 96
+        26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
+        39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
+        -9, -9, -9, -9, -9 // Decimal 123 - 127
+        /*  ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 128 - 139
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
+        -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 */
+        };
+
+    // Indicates white space in encoding
+    private final static byte WHITE_SPACE_ENC = -5;
+    // Indicates equals sign in encoding
+    private final static byte EQUALS_SIGN_ENC = -1;
+
+    /** Defeats instantiation. */
+    private Base64() {
+    }
+
+    /* ********  E N C O D I N G   M E T H O D S  ******** */
+
+    /**
+     * Encodes up to three bytes of the array <var>source</var>
+     * and writes the resulting four Base64 bytes to <var>destination</var>.
+     * The source and destination arrays can be manipulated
+     * anywhere along their length by specifying
+     * <var>srcOffset</var> and <var>destOffset</var>.
+     * This method does not check to make sure your arrays
+     * are large enough to accommodate <var>srcOffset</var> + 3 for
+     * the <var>source</var> array or <var>destOffset</var> + 4 for
+     * the <var>destination</var> array.
+     * The actual number of significant bytes in your array is
+     * given by <var>numSigBytes</var>.
+     *
+     * @param source the array to convert
+     * @param srcOffset the index where conversion begins
+     * @param numSigBytes the number of significant bytes in your array
+     * @param destination the array to hold the conversion
+     * @param destOffset the index where output will be put
+     * @param alphabet is the encoding alphabet
+     * @return the <var>destination</var> array
+     * @since 1.3
+     */
+    private static byte[] encode3to4(byte[] source, int srcOffset,
+            int numSigBytes, byte[] destination, int destOffset, byte[] alphabet) {
+        //           1         2         3
+        // 01234567890123456789012345678901 Bit position
+        // --------000000001111111122222222 Array position from threeBytes
+        // --------|    ||    ||    ||    | Six bit groups to index alphabet
+        //          >>18  >>12  >> 6  >> 0  Right shift necessary
+        //                0x3f  0x3f  0x3f  Additional AND
+
+        // Create buffer with zero-padding if there are only one or two
+        // significant bytes passed in the array.
+        // We have to shift left 24 in order to flush out the 1's that appear
+        // when Java treats a value as negative that is cast from a byte to an int.
+        int inBuff =
+                (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
+                | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
+                | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
+
+        switch (numSigBytes) {
+            case 3:
+                destination[destOffset] = alphabet[(inBuff >>> 18)];
+                destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+                destination[destOffset + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+                destination[destOffset + 3] = alphabet[(inBuff) & 0x3f];
+                return destination;
+            case 2:
+                destination[destOffset] = alphabet[(inBuff >>> 18)];
+                destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+                destination[destOffset + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+                destination[destOffset + 3] = EQUALS_SIGN;
+                return destination;
+            case 1:
+                destination[destOffset] = alphabet[(inBuff >>> 18)];
+                destination[destOffset + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+                destination[destOffset + 2] = EQUALS_SIGN;
+                destination[destOffset + 3] = EQUALS_SIGN;
+                return destination;
+            default:
+                return destination;
+        } // end switch
+    } // end encode3to4
+
+    /**
+     * Encodes a byte array into Base64 notation.
+     * Equivalent to calling
+     * {@code encodeBytes(source, 0, source.length)}
+     *
+     * @param source The data to convert
+     * @since 1.4
+     */
+    public static String encode(byte[] source) {
+        return encode(source, 0, source.length, ALPHABET, true);
+    }
+
+    /**
+     * Encodes a byte array into web safe Base64 notation.
+     *
+     * @param source The data to convert
+     * @param doPadding is {@code true} to pad result with '=' chars
+     *        if it does not fall on 3 byte boundaries
+     */
+    public static String encodeWebSafe(byte[] source, boolean doPadding) {
+        return encode(source, 0, source.length, WEBSAFE_ALPHABET, doPadding);
+    }
+
+    /**
+     * Encodes a byte array into Base64 notation.
+     *
+     * @param source the data to convert
+     * @param off offset in array where conversion should begin
+     * @param len length of data to convert
+     * @param alphabet the encoding alphabet
+     * @param doPadding is {@code true} to pad result with '=' chars
+     * if it does not fall on 3 byte boundaries
+     * @since 1.4
+     */
+    public static String encode(byte[] source, int off, int len, byte[] alphabet,
+            boolean doPadding) {
+        byte[] outBuff = encode(source, off, len, alphabet, Integer.MAX_VALUE);
+        int outLen = outBuff.length;
+
+        // If doPadding is false, set length to truncate '='
+        // padding characters
+        while (doPadding == false && outLen > 0) {
+            if (outBuff[outLen - 1] != '=') {
+                break;
+            }
+            outLen -= 1;
+        }
+
+        return new String(outBuff, 0, outLen);
+    }
+
+    /**
+     * Encodes a byte array into Base64 notation.
+     *
+     * @param source the data to convert
+     * @param off offset in array where conversion should begin
+     * @param len length of data to convert
+     * @param alphabet is the encoding alphabet
+     * @param maxLineLength maximum length of one line.
+     * @return the BASE64-encoded byte array
+     */
+    public static byte[] encode(byte[] source, int off, int len, byte[] alphabet,
+            int maxLineLength) {
+        int lenDiv3 = (len + 2) / 3; // ceil(len / 3)
+        int len43 = lenDiv3 * 4;
+        byte[] outBuff = new byte[len43 // Main 4:3
+                                  + (len43 / maxLineLength)]; // New lines
+
+        int d = 0;
+        int e = 0;
+        int len2 = len - 2;
+        int lineLength = 0;
+        for (; d < len2; d += 3, e += 4) {
+
+            // The following block of code is the same as
+            // encode3to4( source, d + off, 3, outBuff, e, alphabet );
+            // but inlined for faster encoding (~20% improvement)
+            int inBuff =
+                    ((source[d + off] << 24) >>> 8)
+                    | ((source[d + 1 + off] << 24) >>> 16)
+                    | ((source[d + 2 + off] << 24) >>> 24);
+            outBuff[e] = alphabet[(inBuff >>> 18)];
+            outBuff[e + 1] = alphabet[(inBuff >>> 12) & 0x3f];
+            outBuff[e + 2] = alphabet[(inBuff >>> 6) & 0x3f];
+            outBuff[e + 3] = alphabet[(inBuff) & 0x3f];
+
+            lineLength += 4;
+            if (lineLength == maxLineLength) {
+                outBuff[e + 4] = NEW_LINE;
+                e++;
+                lineLength = 0;
+            } // end if: end of line
+        } // end for: each piece of array
+
+        if (d < len) {
+            encode3to4(source, d + off, len - d, outBuff, e, alphabet);
+
+            lineLength += 4;
+            if (lineLength == maxLineLength) {
+                // Add a last newline
+                outBuff[e + 4] = NEW_LINE;
+                e++;
+            }
+            e += 4;
+        }
+
+        assert (e == outBuff.length);
+        return outBuff;
+    }
+
+
+    /* ********  D E C O D I N G   M E T H O D S  ******** */
+
+
+    /**
+     * Decodes four bytes from array <var>source</var>
+     * and writes the resulting bytes (up to three of them)
+     * to <var>destination</var>.
+     * The source and destination arrays can be manipulated
+     * anywhere along their length by specifying
+     * <var>srcOffset</var> and <var>destOffset</var>.
+     * This method does not check to make sure your arrays
+     * are large enough to accommodate <var>srcOffset</var> + 4 for
+     * the <var>source</var> array or <var>destOffset</var> + 3 for
+     * the <var>destination</var> array.
+     * This method returns the actual number of bytes that
+     * were converted from the Base64 encoding.
+     *
+     *
+     * @param source the array to convert
+     * @param srcOffset the index where conversion begins
+     * @param destination the array to hold the conversion
+     * @param destOffset the index where output will be put
+     * @param decodabet the decodabet for decoding Base64 content
+     * @return the number of decoded bytes converted
+     * @since 1.3
+     */
+    private static int decode4to3(byte[] source, int srcOffset,
+            byte[] destination, int destOffset, byte[] decodabet) {
+        // Example: Dk==
+        if (source[srcOffset + 2] == EQUALS_SIGN) {
+            int outBuff =
+                    ((decodabet[source[srcOffset]] << 24) >>> 6)
+                    | ((decodabet[source[srcOffset + 1]] << 24) >>> 12);
+
+            destination[destOffset] = (byte) (outBuff >>> 16);
+            return 1;
+        } else if (source[srcOffset + 3] == EQUALS_SIGN) {
+            // Example: DkL=
+            int outBuff =
+                    ((decodabet[source[srcOffset]] << 24) >>> 6)
+                    | ((decodabet[source[srcOffset + 1]] << 24) >>> 12)
+                    | ((decodabet[source[srcOffset + 2]] << 24) >>> 18);
+
+            destination[destOffset] = (byte) (outBuff >>> 16);
+            destination[destOffset + 1] = (byte) (outBuff >>> 8);
+            return 2;
+        } else {
+            // Example: DkLE
+            int outBuff =
+                    ((decodabet[source[srcOffset]] << 24) >>> 6)
+                    | ((decodabet[source[srcOffset + 1]] << 24) >>> 12)
+                    | ((decodabet[source[srcOffset + 2]] << 24) >>> 18)
+                    | ((decodabet[source[srcOffset + 3]] << 24) >>> 24);
+
+            destination[destOffset] = (byte) (outBuff >> 16);
+            destination[destOffset + 1] = (byte) (outBuff >> 8);
+            destination[destOffset + 2] = (byte) (outBuff);
+            return 3;
+        }
+    } // end decodeToBytes
+
+
+    /**
+     * Decodes data from Base64 notation.
+     *
+     * @param s the string to decode (decoded in default encoding)
+     * @return the decoded data
+     * @since 1.4
+     */
+    public static byte[] decode(String s) throws Base64DecoderException {
+        byte[] bytes = s.getBytes();
+        return decode(bytes, 0, bytes.length);
+    }
+
+    /**
+     * Decodes data from web safe Base64 notation.
+     * Web safe encoding uses '-' instead of '+', '_' instead of '/'
+     *
+     * @param s the string to decode (decoded in default encoding)
+     * @return the decoded data
+     */
+    public static byte[] decodeWebSafe(String s) throws Base64DecoderException {
+        byte[] bytes = s.getBytes();
+        return decodeWebSafe(bytes, 0, bytes.length);
+    }
+
+    /**
+     * Decodes Base64 content in byte array format and returns
+     * the decoded byte array.
+     *
+     * @param source The Base64 encoded data
+     * @return decoded data
+     * @since 1.3
+     * @throws Base64DecoderException
+     */
+    public static byte[] decode(byte[] source) throws Base64DecoderException {
+        return decode(source, 0, source.length);
+    }
+
+    /**
+     * Decodes web safe Base64 content in byte array format and returns
+     * the decoded data.
+     * Web safe encoding uses '-' instead of '+', '_' instead of '/'
+     *
+     * @param source the string to decode (decoded in default encoding)
+     * @return the decoded data
+     */
+    public static byte[] decodeWebSafe(byte[] source)
+            throws Base64DecoderException {
+        return decodeWebSafe(source, 0, source.length);
+    }
+
+    /**
+     * Decodes Base64 content in byte array format and returns
+     * the decoded byte array.
+     *
+     * @param source the Base64 encoded data
+     * @param off    the offset of where to begin decoding
+     * @param len    the length of characters to decode
+     * @return decoded data
+     * @since 1.3
+     * @throws Base64DecoderException
+     */
+    public static byte[] decode(byte[] source, int off, int len)
+            throws Base64DecoderException {
+        return decode(source, off, len, DECODABET);
+    }
+
+    /**
+     * Decodes web safe Base64 content in byte array format and returns
+     * the decoded byte array.
+     * Web safe encoding uses '-' instead of '+', '_' instead of '/'
+     *
+     * @param source the Base64 encoded data
+     * @param off    the offset of where to begin decoding
+     * @param len    the length of characters to decode
+     * @return decoded data
+     */
+    public static byte[] decodeWebSafe(byte[] source, int off, int len)
+            throws Base64DecoderException {
+        return decode(source, off, len, WEBSAFE_DECODABET);
+    }
+
+    /**
+     * Decodes Base64 content using the supplied decodabet and returns
+     * the decoded byte array.
+     *
+     * @param source the Base64 encoded data
+     * @param off the offset of where to begin decoding
+     * @param len the length of characters to decode
+     * @param decodabet the decodabet for decoding Base64 content
+     * @return decoded data
+     */
+    public static byte[] decode(byte[] source, int off, int len, byte[] decodabet)
+            throws Base64DecoderException {
+        int len34 = len * 3 / 4;
+        byte[] outBuff = new byte[2 + len34]; // Upper limit on size of output
+        int outBuffPosn = 0;
+
+        byte[] b4 = new byte[4];
+        int b4Posn = 0;
+        int i = 0;
+        byte sbiCrop = 0;
+        byte sbiDecode = 0;
+        for (i = 0; i < len; i++) {
+            sbiCrop = (byte) (source[i + off] & 0x7f); // Only the low seven bits
+            sbiDecode = decodabet[sbiCrop];
+
+            if (sbiDecode >= WHITE_SPACE_ENC) { // White space Equals sign or better
+                if (sbiDecode >= EQUALS_SIGN_ENC) {
+                    // An equals sign (for padding) must not occur at position 0 or 1
+                    // and must be the last byte[s] in the encoded value
+                    if (sbiCrop == EQUALS_SIGN) {
+                        int bytesLeft = len - i;
+                        byte lastByte = (byte) (source[len - 1 + off] & 0x7f);
+                        if (b4Posn == 0 || b4Posn == 1) {
+                            throw new Base64DecoderException(
+                                    "invalid padding byte '=' at byte offset " + i);
+                        } else if ((b4Posn == 3 && bytesLeft > 2)
+                                || (b4Posn == 4 && bytesLeft > 1)) {
+                            throw new Base64DecoderException(
+                                    "padding byte '=' falsely signals end of encoded value "
+                                            + "at offset " + i);
+                        } else if (lastByte != EQUALS_SIGN && lastByte != NEW_LINE) {
+                            throw new Base64DecoderException(
+                                    "encoded value has invalid trailing byte");
+                        }
+                        break;
+                    }
+
+                    b4[b4Posn++] = sbiCrop;
+                    if (b4Posn == 4) {
+                        outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet);
+                        b4Posn = 0;
+                    }
+                }
+            } else {
+                throw new Base64DecoderException("Bad Base64 input character at " + i
+                        + ": " + source[i + off] + "(decimal)");
+            }
+        }
+
+        // Because web safe encoding allows non padding base64 encodes, we
+        // need to pad the rest of the b4 buffer with equal signs when
+        // b4Posn != 0.  There can be at most 2 equal signs at the end of
+        // four characters, so the b4 buffer must have two or three
+        // characters.  This also catches the case where the input is
+        // padded with EQUALS_SIGN
+        if (b4Posn != 0) {
+            if (b4Posn == 1) {
+                throw new Base64DecoderException("single trailing character at offset "
+                        + (len - 1));
+            }
+            b4[b4Posn++] = EQUALS_SIGN;
+            outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, decodabet);
+        }
+
+        byte[] out = new byte[outBuffPosn];
+        System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
+        return out;
+    }
+}
diff --git a/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64DecoderException.java b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64DecoderException.java
new file mode 100644
index 000000000..884294712
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Base64DecoderException.java
@@ -0,0 +1,34 @@
+/* Copyright (c) 2012 Google Inc.
+ * Copyright (c) 2015 The Qt Company Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.qtproject.qt.android.purchasing;
+
+/**
+ * Exception thrown when encountering an invalid Base64 input character.
+ *
+ * @author nelson
+ */
+public class Base64DecoderException extends Exception {
+    public Base64DecoderException() {
+        super();
+    }
+
+    public Base64DecoderException(String s) {
+        super(s);
+    }
+
+    private static final long serialVersionUID = 1L;
+}
diff --git a/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/InAppPurchase.java b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/InAppPurchase.java
new file mode 100644
index 000000000..1930840a3
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/InAppPurchase.java
@@ -0,0 +1,375 @@
+/****************************************************************************
+ **
+ ** 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."
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+package org.qtproject.qt.android.purchasing;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import android.app.Activity;
+import android.content.Context;
+import android.util.Log;
+
+import com.android.billingclient.api.AcknowledgePurchaseParams;
+import com.android.billingclient.api.AcknowledgePurchaseResponseListener;
+import com.android.billingclient.api.BillingClient;
+import com.android.billingclient.api.BillingClientStateListener;
+import com.android.billingclient.api.BillingFlowParams;
+import com.android.billingclient.api.BillingResult;
+import com.android.billingclient.api.ConsumeParams;
+import com.android.billingclient.api.ConsumeResponseListener;
+import com.android.billingclient.api.Purchase;
+import com.android.billingclient.api.Purchase.PurchaseState;
+import com.android.billingclient.api.PurchasesResponseListener;
+import com.android.billingclient.api.PurchasesUpdatedListener;
+import com.android.billingclient.api.SkuDetails;
+import com.android.billingclient.api.SkuDetailsParams;
+import com.android.billingclient.api.SkuDetailsResponseListener;
+
+
+/***********************************************************************
+ ** More info: https://developer.android.com/google/play/billing
+ ** Add Dependencies below to build.gradle file:
+
+dependencies {
+    def billing_version = "4.0.0"
+    implementation "com.android.billingclient:billing:$billing_version"
+}
+
+***********************************************************************/
+
+public class InAppPurchase implements PurchasesUpdatedListener
+{
+    private Context m_context = null;
+    private long m_nativePointer;
+    private String m_publicKey = null;
+    private int purchaseRequestCode;
+
+
+    private BillingClient billingClient;
+
+    public static final int RESULT_OK = BillingClient.BillingResponseCode.OK;
+    public static final int RESULT_USER_CANCELED = BillingClient.BillingResponseCode.USER_CANCELED;
+    public static final String TYPE_INAPP = BillingClient.SkuType.INAPP;
+    public static final String TAG = "InAppPurchase";
+
+    // Should be in sync with InAppTransaction::FailureReason
+    public static final int FAILUREREASON_NOFAILURE    = 0;
+    public static final int FAILUREREASON_USERCANCELED = 1;
+    public static final int FAILUREREASON_ERROR        = 2;
+
+    public InAppPurchase(Context context, long nativePointer)
+    {
+        m_context = context;
+        m_nativePointer = nativePointer;
+    }
+
+    public void initializeConnection(){
+        billingClient = BillingClient.newBuilder(m_context)
+                .enablePendingPurchases()
+                .setListener(this)
+                .build();
+        billingClient.startConnection(new BillingClientStateListener() {
+            @Override
+            public void onBillingSetupFinished(BillingResult billingResult) {
+                if (billingResult.getResponseCode() == RESULT_OK) {
+                    purchasedProductsQueried(m_nativePointer);
+                }
+            }
+
+            @Override
+            public void onBillingServiceDisconnected() {
+                Log.w(TAG, "Billing service disconnected");
+            }
+        });
+    }
+
+    @Override
+    public void onPurchasesUpdated(BillingResult billingResult, List<Purchase> purchases) {
+
+        int responseCode = billingResult.getResponseCode();
+
+        if (purchases == null) {
+            purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, "Data missing from result");
+            return;
+        }
+
+        if (billingResult.getResponseCode() == RESULT_OK) {
+            handlePurchase(purchases);
+        } else if (responseCode == RESULT_USER_CANCELED) {
+            purchaseFailed(purchaseRequestCode, FAILUREREASON_USERCANCELED, "");
+        } else {
+            String errorString = getErrorString(responseCode);
+            purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, errorString);
+        }
+    }
+
+    //Get list of purchases from onPurchasesUpdated
+    private void handlePurchase(List<Purchase> purchases) {
+
+        for (Purchase purchase : purchases) {
+            try {
+                if (m_publicKey != null && !Security.verifyPurchase(m_publicKey, TYPE_INAPP, purchase.getSignature())) {
+                    purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, "Signature could not be verified");
+                    return;
+                }
+                int purchaseState = purchase.getPurchaseState();
+                if (purchaseState != PurchaseState.PURCHASED) {
+                    purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, "Unexpected purchase state in result");
+                    return;
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+                purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, e.getMessage());
+            }
+            purchaseSucceeded(purchaseRequestCode, purchase.getSignature(), TYPE_INAPP, purchase.getPurchaseToken(), purchase.getOrderId(), purchase.getPurchaseTime());
+        }
+    }
+
+    public void queryDetails(final String[] productIds) {
+
+        int index = 0;
+        while (index < productIds.length) {
+            List<String> productIdList = new ArrayList<>();
+            for (int i = index; i < Math.min(index + 20, productIds.length); ++i) {
+                productIdList.add(productIds[i]);
+            }
+            index += productIdList.size();
+
+            SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();
+            params.setSkusList(productIdList).setType(BillingClient.SkuType.INAPP);
+            billingClient.querySkuDetailsAsync(params.build(),
+                    new SkuDetailsResponseListener() {
+                        @Override
+                        public void onSkuDetailsResponse(BillingResult billingResult, List<SkuDetails> skuDetailsList) {
+                            int responseCode = billingResult.getResponseCode();
+
+                            if (responseCode != RESULT_OK) {
+                                Log.e(TAG, "queryDetails: Couldn't retrieve sku details.");
+                                return;
+                            }
+                            if (skuDetailsList == null) {
+                                Log.e(TAG, "queryDetails: No details list in response.");
+                                return;
+                            }
+
+                            for (SkuDetails skuDetails : skuDetailsList) {
+                                try {
+                                    String queriedProductId = skuDetails.getSku();
+                                    String queriedPrice = skuDetails.getPrice();
+                                    String queriedTitle = skuDetails.getTitle();
+                                    String queriedDescription = skuDetails.getDescription();
+                                    registerProduct(m_nativePointer,
+                                            queriedProductId,
+                                            queriedPrice,
+                                            queriedTitle,
+                                            queriedDescription);
+                                } catch (Exception e) {
+                                    e.printStackTrace();
+                                }
+                            }
+                        }
+                    });
+
+
+            queryPurchasedProducts(productIdList);
+        }
+    }
+
+    //Launch Google purchasing screen
+    public void launchBillingFlow(String identifier, int requestCode){
+
+        purchaseRequestCode = requestCode;
+        List<String> skuList = new ArrayList<>();
+        skuList.add(identifier);
+        SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();
+        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP);
+        billingClient.querySkuDetailsAsync(params.build(),
+                new SkuDetailsResponseListener() {
+                    @Override
+                    public void onSkuDetailsResponse(BillingResult billingResult, List<SkuDetails> skuDetailsList) {
+
+                        if (billingResult.getResponseCode() != RESULT_OK) {
+                            Log.e(TAG, "Unable to launch Google Play purchase screen");
+                            String errorString = getErrorString(requestCode);
+                            purchaseFailed(requestCode, FAILUREREASON_ERROR, errorString);
+                            return;
+                        }
+                        else if (skuDetailsList == null){
+                            purchaseFailed(purchaseRequestCode, FAILUREREASON_ERROR, "Data missing from result");
+                            return;
+                        }
+
+                        BillingFlowParams purchaseParams = BillingFlowParams.newBuilder()
+                                .setSkuDetails(skuDetailsList.get(0))
+                                .build();
+
+                        //Results will be delivered to onPurchasesUpdated
+                        billingClient.launchBillingFlow((Activity) m_context, purchaseParams);
+                    }
+                });
+    }
+
+    public void consumePurchase(String purchaseToken){
+
+        ConsumeResponseListener listener = new ConsumeResponseListener() {
+            @Override
+            public void onConsumeResponse(BillingResult billingResult, String purchaseToken) {
+                if (billingResult.getResponseCode() != RESULT_OK) {
+                    Log.e(TAG, "Unable to consume purchase. Response code: " + billingResult.getResponseCode());
+                }
+            }
+        };
+        ConsumeParams consumeParams =
+                ConsumeParams.newBuilder()
+                        .setPurchaseToken(purchaseToken)
+                        .build();
+        billingClient.consumeAsync(consumeParams, listener);
+    }
+
+    public void acknowledgeUnlockablePurchase(String purchaseToken){
+
+        AcknowledgePurchaseParams acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
+                .setPurchaseToken(purchaseToken)
+                .build();
+
+        AcknowledgePurchaseResponseListener acknowledgePurchaseResponseListener = new AcknowledgePurchaseResponseListener() {
+            @Override
+            public void onAcknowledgePurchaseResponse(BillingResult billingResult) {
+                if (billingResult.getResponseCode() != RESULT_OK){
+                    Log.e(TAG, "Unable to acknowledge purchase. Response code: " + billingResult.getResponseCode());
+                }
+            }
+        };
+        billingClient.acknowledgePurchase(acknowledgePurchaseParams, acknowledgePurchaseResponseListener);
+    }
+
+    public void queryPurchasedProducts(List<String> productIdList) {
+
+        billingClient.queryPurchasesAsync(TYPE_INAPP, new PurchasesResponseListener() {
+            @Override
+            public void onQueryPurchasesResponse(BillingResult billingResult, List<Purchase> list) {
+                for (Purchase purchase : list) {
+
+                    if (productIdList.contains(purchase.getSkus().get(0))) {
+                        registerPurchased(m_nativePointer,
+                                purchase.getSkus().get(0),
+                                purchase.getSignature(),
+                                TYPE_INAPP,
+                                purchase.getPurchaseToken(),
+                                purchase.getDeveloperPayload(),
+                                purchase.getPurchaseTime());
+                    }
+                }
+            }
+        });
+    }
+
+    private String getErrorString(int responseCode){
+        String errorString;
+        switch (responseCode) {
+            case BillingClient.BillingResponseCode.BILLING_UNAVAILABLE: errorString = "Billing unavailable"; break;
+            case BillingClient.BillingResponseCode.ITEM_UNAVAILABLE: errorString = "Item unavailable"; break;
+            case BillingClient.BillingResponseCode.DEVELOPER_ERROR: errorString = "Developer error"; break;
+            case BillingClient.BillingResponseCode.ERROR: errorString = "Fatal error occurred"; break;
+            case BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED: errorString = "Item already owned"; break;
+            case BillingClient.BillingResponseCode.ITEM_NOT_OWNED: errorString = "Item not owned"; break;
+            default: errorString = "Unknown billing error " + responseCode; break;
+        };
+        return errorString;
+    }
+
+    public void setPublicKey(String publicKey)
+    {
+        m_publicKey = publicKey;
+    }
+
+    private void purchaseFailed(int requestCode, int failureReason, String errorString)
+    {
+        purchaseFailed(m_nativePointer, requestCode, failureReason, errorString);
+    }
+
+
+    private void purchaseSucceeded(int requestCode,
+                                   String signature,
+                                   String purchaseData,
+                                   String purchaseToken,
+                                   String orderId,
+                                   long timestamp)
+    {
+        purchaseSucceeded(m_nativePointer, requestCode, signature, purchaseData, purchaseToken, orderId, timestamp);
+    }
+
+    private native static void queryFailed(long nativePointer, String productId);
+    private native static void purchasedProductsQueried(long nativePointer);
+    private native static void registerProduct(long nativePointer,
+                                               String productId,
+                                               String price,
+                                               String title,
+                                               String description);
+    private native static void purchaseFailed(long nativePointer,
+                                              int requestCode,
+                                              int failureReason,
+                                              String errorString);
+    private native static void purchaseSucceeded(long nativePointer,
+                                                 int requestCode,
+                                                 String signature,
+                                                 String data,
+                                                 String purchaseToken,
+                                                 String orderId,
+                                                 long timestamp);
+    private native static void registerPurchased(long nativePointer,
+                                                 String identifier,
+                                                 String signature,
+                                                 String data,
+                                                 String purchaseToken,
+                                                 String orderId,
+                                                 long timestamp);
+}
diff --git a/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Security.java b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Security.java
new file mode 100644
index 000000000..5ce0ab681
--- /dev/null
+++ b/examples/demos/hangman/purchasing/android/src/org/qtproject/qt/android/purchasing/Security.java
@@ -0,0 +1,131 @@
+/* Copyright (c) 2012 Google Inc.
+ * Copyright (c) 2015 The Qt Company Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.qtproject.qt.android.purchasing;
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.SignatureException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.X509EncodedKeySpec;
+
+/**
+ * Security-related methods. For a secure implementation, all of this code
+ * should be implemented on a server that communicates with the
+ * application on the device. For the sake of simplicity and clarity of this
+ * example, this code is included here and is executed on the device. If you
+ * must verify the purchases on the phone, you should obfuscate this code to
+ * make it harder for an attacker to replace the code with stubs that treat all
+ * purchases as verified.
+ */
+public class Security {
+    private static final String TAG = "IABUtil/Security";
+
+    private static final String KEY_FACTORY_ALGORITHM = "RSA";
+    private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
+
+    /**
+     * Verifies that the data was signed with the given signature, and returns
+     * the verified purchase. The data is in JSON format and signed
+     * with a private key. The data also contains the {@link PurchaseState}
+     * and product ID of the purchase.
+     * @param base64PublicKey the base64-encoded public key to use for verifying.
+     * @param signedData the signed JSON string (signed, not encrypted)
+     * @param signature the signature for the data, signed with the private key
+     */
+    public static boolean verifyPurchase(String base64PublicKey, String signedData, String signature) {
+        if (signedData == null) {
+            Log.e(TAG, "data is null");
+            return false;
+        }
+
+        boolean verified = false;
+        if (!TextUtils.isEmpty(signature)) {
+            PublicKey key = Security.generatePublicKey(base64PublicKey);
+            verified = Security.verify(key, signedData, signature);
+            if (!verified) {
+                Log.w(TAG, "signature does not match data.");
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Generates a PublicKey instance from a string containing the
+     * Base64-encoded public key.
+     *
+     * @param encodedPublicKey Base64-encoded public key
+     * @throws IllegalArgumentException if encodedPublicKey is invalid
+     */
+    public static PublicKey generatePublicKey(String encodedPublicKey) {
+        try {
+            byte[] decodedKey = Base64.decode(encodedPublicKey);
+            KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
+            return keyFactory.generatePublic(new X509EncodedKeySpec(decodedKey));
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);
+        } catch (InvalidKeySpecException e) {
+            Log.e(TAG, "Invalid key specification.");
+            throw new IllegalArgumentException(e);
+        } catch (Base64DecoderException e) {
+            Log.e(TAG, "Base64 decoding failed.");
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+    /**
+     * Verifies that the signature from the server matches the computed
+     * signature on the data.  Returns true if the data is correctly signed.
+     *
+     * @param publicKey public key associated with the developer account
+     * @param signedData signed data from server
+     * @param signature server signature
+     * @return true if the data and signature match
+     */
+    public static boolean verify(PublicKey publicKey, String signedData, String signature) {
+        Signature sig;
+        try {
+            sig = Signature.getInstance(SIGNATURE_ALGORITHM);
+            sig.initVerify(publicKey);
+            sig.update(signedData.getBytes());
+            if (!sig.verify(Base64.decode(signature))) {
+                Log.e(TAG, "Signature verification failed.");
+                return false;
+            }
+            return true;
+        } catch (NoSuchAlgorithmException e) {
+            Log.e(TAG, "NoSuchAlgorithmException.");
+        } catch (InvalidKeyException e) {
+            Log.e(TAG, "Invalid key specification.");
+        } catch (SignatureException e) {
+            Log.e(TAG, "Signature exception.");
+        } catch (Base64DecoderException e) {
+            Log.e(TAG, "Base64 decoding failed.");
+        }
+        return false;
+    }
+}