In-App purchasing demo

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 #include <QDebug>

 #include <QJniEnvironment>
 #include <QtCore>

 #include "androidinapppurchasebackend.h"
 #include "androidinappproduct.h"
 #include "androidinapptransaction.h"
 #include "../inapp/inappstore.h"

 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);
 }