Preserve spoiler files and serialize update reloads

cockatrice/src/client/network/update/card_spoiler/spoiler_background_updater.cpp

@@ -3,252 +3,385 @@
 #include "../../../../main.h"
 #include "../../../settings/cache_settings.h"
 
-#include <QChar>
+#include <QCoreApplication>
 #include <QCryptographicHash>
-#include <QDateTime>
 #include <QDebug>
 #include <QDir>
 #include <QFile>
 #include <QFileInfo>
 #include <QFutureWatcher>
-#include <QIODevice>
-#include <QList>
-#include <QLocale>
-#include <QMessageLogger>
 #include <QNetworkAccessManager>
 #include <QNetworkReply>
 #include <QNetworkRequest>
-#include <QSharedPointer>
+#include <QSaveFile>
 #include <QSystemTrayIcon>
-#include <QTimeZone>
+#include <QTimer>
 #include <QUrl>
+#include <QXmlStreamReader>
 #include <QtConcurrentRun>
-#include <QtGlobal>
+#include <exception>
-#include <functional>
 #include <libcockatrice/card/database/card_database.h>
 #include <libcockatrice/card/database/card_database_manager.h>
 #include <libcockatrice/network/network_manager.h>
 #include <libcockatrice/settings/download_settings.h>
 #include <libcockatrice/settings/paths_settings.h>
-#include <tuple>
-#include <utility>
 #include <version_string.h>
 
-#define SPOILERS_STATUS_URL "https://raw.githubusercontent.com/Cockatrice/Magic-Spoiler/files/SpoilerSeasonEnabled"
+namespace
-#define SPOILERS_URL "https://raw.githubusercontent.com/Cockatrice/Magic-Spoiler/files/spoiler.xml"
-
-SpoilerBackgroundUpdater::SpoilerBackgroundUpdater(QObject *apParent) : QObject(apParent), cardUpdateProcess(nullptr)
 {
-    isSpoilerDownloadEnabled = SettingsCache::instance().downloads().getDownloadSpoilersStatus();
+const QUrl SPOILERS_STATUS_URL(
-    if (isSpoilerDownloadEnabled) {
+    QStringLiteral("https://raw.githubusercontent.com/Cockatrice/Magic-Spoiler/files/SpoilerSeasonEnabled"));
-        // Start the process of checking if we're in spoiler season
+const QUrl SPOILERS_URL(QStringLiteral("https://raw.githubusercontent.com/Cockatrice/Magic-Spoiler/files/spoiler.xml"));
-        // File exists means we're in spoiler season
+// Request coordination stays on the GUI thread; reload workers never access it.
-        startSpoilerDownloadProcess(SPOILERS_STATUS_URL, false);
+QPointer<SpoilerBackgroundUpdater> currentUpdater;
+QPointer<QFutureWatcher<bool>> activeReload;
+quint64 newestOperation = 0;
+
+bool removeSpoilerFile(const QString &path)
+{
+    QFile file(path);
+    if (!file.exists()) {
+        return false;
+    }
+    if (!file.remove()) {
+        qCWarning(SpoilerBackgroundUpdaterLog) << "Could not remove spoiler database" << path << file.errorString();
+        return false;
+    }
+    return true;
+}
+} // namespace
+
+SpoilerBackgroundUpdater::SpoilerBackgroundUpdater(QObject *parent, bool forceReload)
+    : QObject(parent), enabledAtStart(SettingsCache::instance().downloads().getDownloadSpoilersStatus()),
+      forceReload(forceReload), targetPath(SettingsCache::instance().paths().getSpoilerCardDatabasePath()),
+      operationId(++newestOperation), manager(NetworkManagerFactory::create(this)), notificationIcon(trayIcon)
+{
+    connect(&SettingsCache::instance().downloads(), &DownloadSettings::downloadSpoilerStatusChanged, this,
+            &SpoilerBackgroundUpdater::cancelIfSettingsChanged);
+    connect(&SettingsCache::instance().paths(), &PathsSettings::cardDatabasePathChanged, this,
+            &SpoilerBackgroundUpdater::cancelIfSettingsChanged);
+    // Even a disabled/no-op operation completes after its caller can connect signals.
+    QTimer::singleShot(0, this, &SpoilerBackgroundUpdater::begin);
+}
+
+void SpoilerBackgroundUpdater::begin()
+{
+    if (completed) {
+        return;
+    }
+    if (cancelled || operationId != newestOperation ||
+        (!reloadOnly && (!enabledAtStart || !SettingsCache::instance().downloads().getDownloadSpoilersStatus())) ||
+        targetPath != SettingsCache::instance().paths().getSpoilerCardDatabasePath()) {
+        finish();
+        return;
+    }
+    const auto previous = currentUpdater;
+    if (activeReload) {
+        // The existing database API stores its final load status after its parser
+        // mutex is released. Do not overlap updater-owned calls to that API.
+        connect(activeReload, &QFutureWatcher<bool>::finished, this, &SpoilerBackgroundUpdater::begin,
+                static_cast<Qt::ConnectionType>(Qt::QueuedConnection | Qt::SingleShotConnection));
+        if (previous && previous != this) {
+            previous->cancel();
+        }
+        return;
+    }
+    currentUpdater = this;
+    QPointer<SpoilerBackgroundUpdater> guard(this);
+    if (previous && previous != this) {
+        previous->cancel();
+    }
+    if (!guard) {
+        return;
+    }
+    if (!isCurrent()) {
+        finish();
+    } else if (reloadOnly) {
+        reloadDatabase(false);
     } else {
-        qCInfo(SpoilerBackgroundUpdaterLog) << "Spoilers Disabled";
+        downloadFromURL(SPOILERS_STATUS_URL, false);
     }
 }
 
-void SpoilerBackgroundUpdater::startSpoilerDownloadProcess(QString url, bool saveResults)
+bool SpoilerBackgroundUpdater::isCurrent() const
 {
-    auto spoilerURL = QUrl(url);
+    return !completed && !cancelled && currentUpdater == this && operationId == newestOperation &&
-    downloadFromURL(spoilerURL, saveResults);
+           (reloadOnly || SettingsCache::instance().downloads().getDownloadSpoilersStatus()) &&
+           targetPath == SettingsCache::instance().paths().getSpoilerCardDatabasePath();
 }
 
-void SpoilerBackgroundUpdater::downloadFromURL(QUrl url, bool saveResults)
+void SpoilerBackgroundUpdater::cancelIfSettingsChanged()
 {
-    auto *nam = NetworkManagerFactory::create(this);
+    if ((!reloadOnly && !SettingsCache::instance().downloads().getDownloadSpoilersStatus()) ||
-    auto request = QNetworkRequest(url);
+        targetPath != SettingsCache::instance().paths().getSpoilerCardDatabasePath()) {
-    request.setHeader(QNetworkRequest::UserAgentHeader, QString("Cockatrice %1").arg(VERSION_STRING));
+        cancel();
-    QNetworkReply *reply = nam->get(request);
+    }
+}
 
+void SpoilerBackgroundUpdater::cancel()
+{
+    if (completed) {
+        return;
+    }
+    cancelled = true;
+    const auto reply = activeReply;
+    activeReply.clear();
+    QPointer<SpoilerBackgroundUpdater> guard(this);
+    if (reply) {
+        reply->abort();
+        if (reply) {
+            reply->deleteLater();
+        }
+    }
+    // A running reload owns no updater state. Allow its completion to retire its
+    // watcher before a heap-owned updater is released by the caller.
+    if (guard && !reloading) {
+        finish();
+    }
+}
+
+void SpoilerBackgroundUpdater::downloadFromURL(const QUrl &url, bool saveResults)
+{
+    QNetworkRequest request(url);
+    request.setHeader(QNetworkRequest::UserAgentHeader, QString("Cockatrice %1").arg(VERSION_STRING));
+    request.setTransferTimeout(60000);
+    activeReply = manager->get(request);
     if (saveResults) {
-        // This will write out to the file (used for spoiler.xml)
+        connect(activeReply, &QNetworkReply::finished, this,
-        connect(reply, &QNetworkReply::finished, this, &SpoilerBackgroundUpdater::actDownloadFinishedSpoilersFile);
+                &SpoilerBackgroundUpdater::actDownloadFinishedSpoilersFile);
     } else {
-        // This will check the status (used to see if we're in spoiler season or not)
+        connect(activeReply, &QNetworkReply::finished, this,
-        connect(reply, &QNetworkReply::finished, this, &SpoilerBackgroundUpdater::actCheckIfSpoilerSeasonEnabled);
+                &SpoilerBackgroundUpdater::actCheckIfSpoilerSeasonEnabled);
+    }
+}
+
+void SpoilerBackgroundUpdater::actCheckIfSpoilerSeasonEnabled()
+{
+    auto *reply = qobject_cast<QNetworkReply *>(sender());
+    if (!reply || reply != activeReply) {
+        return;
+    }
+    activeReply.clear();
+    reply->deleteLater();
+    if (!isCurrent()) {
+        finish();
+        return;
+    }
+    if (reply->error() == QNetworkReply::NoError) {
+        downloadFromURL(SPOILERS_URL, true);
+    } else if (reply->error() == QNetworkReply::ContentNotFoundError) {
+        const bool existed = QFileInfo::exists(targetPath);
+        seasonEnded = existed;
+        if (existed && !removeSpoilerFile(targetPath)) {
+            finish(tr("The spoiler season has ended, but the old spoiler database could not be removed."));
+            return;
+        }
+        if (existed || forceReload) {
+            reloadDatabase(false);
+        } else {
+            finish();
+        }
+    } else {
+        finish(tr("Could not check spoiler availability: %1").arg(reply->errorString()));
     }
 }
 
 void SpoilerBackgroundUpdater::actDownloadFinishedSpoilersFile()
 {
-    // Check for server reply
+    auto *reply = qobject_cast<QNetworkReply *>(sender());
-    auto *reply = dynamic_cast<QNetworkReply *>(sender());
+    if (!reply || reply != activeReply) {
-    QNetworkReply::NetworkError errorCode = reply->error();
+        return;
-
+    }
-    if (errorCode == QNetworkReply::NoError) {
+    activeReply.clear();
-        spoilerData = reply->readAll();
+    reply->deleteLater();
-
+    if (!isCurrent()) {
-        // Save the spoiler.xml file to the disk
+        finish();
-        saveDownloadedFile(spoilerData);
+        return;
-
+    }
-        reply->deleteLater();
+    if (reply->error() != QNetworkReply::NoError) {
-        emit spoilerCheckerDone();
+        finish(tr("Could not download spoilers: %1").arg(reply->errorString()));
+        return;
+    }
+    spoilerData = reply->readAll();
+    QString error;
+    const SaveResult result = saveDownloadedFile(spoilerData, error);
+    if (result == SaveResult::Failed) {
+        finish(isCurrent() ? error : QString());
+    } else if (result == SaveResult::Written || forceReload) {
+        reloadDatabase(result == SaveResult::Written);
     } else {
-        qCWarning(SpoilerBackgroundUpdaterLog) << "Error downloading spoilers file" << errorCode;
+        finish();
+    }
+}
+
+QString SpoilerBackgroundUpdater::validateDownloadedFile(const QByteArray &data) const
+{
+    QXmlStreamReader xml(data);
+    if (!xml.readNextStartElement() || xml.name() != QStringLiteral("cockatrice_carddatabase")) {
+        return tr("The download is not a Cockatrice card database. The previous spoiler file was preserved.");
+    }
+    bool versionOk = false;
+    const int version = xml.attributes().value(QStringLiteral("version")).toInt(&versionOk);
+    if (!versionOk || (version != 3 && version != 4)) {
+        return tr("The spoiler database uses an unsupported format. The previous spoiler file was preserved.");
+    }
+    bool hasCards = false;
+    int depth = 1;
+    while (!xml.atEnd()) {
+        const auto token = xml.readNext();
+        if (token == QXmlStreamReader::StartElement) {
+            ++depth;
+            if (depth == 2 && xml.name() == QStringLiteral("cards")) {
+                hasCards = true;
+            }
+        } else if (token == QXmlStreamReader::EndElement) {
+            --depth;
+        }
+    }
+    if (xml.hasError() || !hasCards) {
+        return tr("The spoiler database is incomplete or invalid. The previous spoiler file was preserved.");
+    }
+    return {};
+}
+
+SpoilerBackgroundUpdater::SaveResult SpoilerBackgroundUpdater::saveDownloadedFile(const QByteArray &data,
+                                                                                 QString &error)
+{
+    error = validateDownloadedFile(data);
+    if (!error.isEmpty()) {
+        return SaveResult::Failed;
+    }
+    if (!isCurrent()) {
+        error = tr("The spoiler update was cancelled because its settings changed.");
+        return SaveResult::Failed;
+    }
+    if (getHash(targetPath) == getHash(data)) {
+        return SaveResult::Unchanged;
+    }
+    const QDir directory = QFileInfo(targetPath).dir();
+    if (!directory.exists() && !directory.mkpath(QStringLiteral("."))) {
+        error = tr("Could not create the spoiler database directory: %1").arg(directory.absolutePath());
+        return SaveResult::Failed;
+    }
+    QSaveFile file(targetPath);
+    file.setDirectWriteFallback(false);
+    if (!file.open(QIODevice::WriteOnly) || file.write(data) != data.size() || !file.flush()) {
+        error = tr("Could not save the spoiler database to %1: %2. The previous file was preserved.")
+                    .arg(targetPath, file.errorString());
+        return SaveResult::Failed;
+    }
+    if (!isCurrent()) {
+        file.cancelWriting();
+        return SaveResult::Failed;
+    }
+    if (!file.commit()) {
+        error = tr("Could not replace the spoiler database at %1: %2. The previous file was preserved.")
+                    .arg(targetPath, file.errorString());
+        return SaveResult::Failed;
+    }
+    return SaveResult::Written;
+}
+
+void SpoilerBackgroundUpdater::reloadDatabase(bool updated)
+{
+    reloading = true;
+    auto *database = CardDatabaseManager::getInstance();
+    // The job outlives an individual request, so destroying that request cannot
+    // let a newer updater overlap the worker that is still completing.
+    auto *watcher = new QFutureWatcher<bool>(QCoreApplication::instance());
+    activeReload = watcher;
+    connect(watcher, &QFutureWatcher<bool>::finished, watcher, [watcher] {
+        if (activeReload == watcher) {
+            activeReload.clear();
+        }
+        watcher->deleteLater();
+    });
+    connect(watcher, &QFutureWatcher<bool>::finished, this, [this, watcher, database, updated] {
+        bool loaded = false;
+        try {
+            loaded = watcher->result() && database->getLoadStatus() == Ok;
+        } catch (const std::exception &error) {
+            qCWarning(SpoilerBackgroundUpdaterLog) << "Spoiler database reload failed:" << error.what();
+        }
+        reloading = false;
+        if (!isCurrent()) {
+            finish();
+        } else if (!loaded) {
+            finish(tr("Could not reload card data after updating spoilers. Use Update Spoilers to retry the reload."));
+        } else {
+            finish({}, updated);
+        }
+    });
+    watcher->setFuture(QtConcurrent::run([database] {
+        database->reloadCardDatabasesAndNotify();
+        return true;
+    }));
+}
+
+void SpoilerBackgroundUpdater::finish(const QString &error, bool updated)
+{
+    if (completed) {
+        return;
+    }
+    completed = true;
+    spoilerData = QByteArray();
+    if (currentUpdater == this) {
+        currentUpdater.clear();
+    }
+    QPointer<SpoilerBackgroundUpdater> guard(this);
+    if (!error.isEmpty() && !cancelled) {
+        qCWarning(SpoilerBackgroundUpdaterLog) << error;
+        if (notificationIcon) {
+            notificationIcon->showMessage(tr("Spoiler update failed"), error);
+        }
+        if (!guard) {
+            return;
+        }
+        emit spoilerUpdateFailed(error);
+    } else if (updated && !cancelled) {
+        if (notificationIcon) {
+            notificationIcon->showMessage(tr("Spoilers have been updated!"),
+                                          tr("The card database now includes the downloaded spoilers."));
+        }
+        if (!guard) {
+            return;
+        }
+        emit spoilersUpdatedSuccessfully();
+    } else if (seasonEnded && !cancelled && notificationIcon) {
+        notificationIcon->showMessage(tr("Spoiler season has ended"),
+                                      tr("The spoiler database was removed. Please run Oracle to get released cards."));
+    }
+    if (guard) {
         emit spoilerCheckerDone();
     }
 }
 
 bool SpoilerBackgroundUpdater::deleteSpoilerFile()
 {
-    QString fileName = SettingsCache::instance().paths().getSpoilerCardDatabasePath();
+    const QString path = SettingsCache::instance().paths().getSpoilerCardDatabasePath();
-    QFileInfo fi(fileName);
+    if (QFileInfo::exists(path) && !removeSpoilerFile(path)) {
-    QDir fileDir(fi.path());
-    QFile file(fileName);
-
-    // Delete the spoiler.xml file
-    if (file.exists() && file.remove()) {
-        qCInfo(SpoilerBackgroundUpdaterLog) << "Deleting spoiler.xml";
-        return true;
-    }
-
-    qCInfo(SpoilerBackgroundUpdaterLog) << "Error: Spoiler.xml not found or not deleted";
-    return false;
-}
-
-void SpoilerBackgroundUpdater::actCheckIfSpoilerSeasonEnabled()
-{
-    auto *response = dynamic_cast<QNetworkReply *>(sender());
-    QNetworkReply::NetworkError errorCode = response->error();
-
-    if (errorCode == QNetworkReply::ContentNotFoundError) {
-        // Spoiler season is offline at this point, so the spoiler.xml file can be safely deleted
-        // The user should run Oracle to get the latest card information
-        if (deleteSpoilerFile() && trayIcon) {
-            trayIcon->showMessage(tr("Spoilers season has ended"), tr("Deleting spoiler.xml. Please run Oracle"));
-        }
-
-        qCInfo(SpoilerBackgroundUpdaterLog) << "Spoiler Season Offline";
-        emit spoilerCheckerDone();
-    } else if (errorCode == QNetworkReply::NoError) {
-        qCInfo(SpoilerBackgroundUpdaterLog) << "Spoiler Service Online";
-        startSpoilerDownloadProcess(SPOILERS_URL, true);
-    } else if (errorCode == QNetworkReply::HostNotFoundError) {
-        if (trayIcon) {
-            trayIcon->showMessage(tr("Spoilers download failed"), tr("No internet connection"));
-        }
-
-        qCWarning(SpoilerBackgroundUpdaterLog) << "Spoiler download failed due to no internet connection";
-        emit spoilerCheckerDone();
-    } else {
-        if (trayIcon) {
-            trayIcon->showMessage(tr("Spoilers download failed"), tr("Error") + " " + (short)errorCode);
-        }
-
-        qCWarning(SpoilerBackgroundUpdaterLog) << "Spoiler download failed with reason" << errorCode;
-        emit spoilerCheckerDone();
-    }
-}
-
-bool SpoilerBackgroundUpdater::saveDownloadedFile(QByteArray data)
-{
-    QString fileName = SettingsCache::instance().paths().getSpoilerCardDatabasePath();
-    QFileInfo fi(fileName);
-    QDir fileDir(fi.path());
-
-    if (!fileDir.exists() && !fileDir.mkpath(fileDir.absolutePath())) {
         return false;
     }
-
+    // Explicit disable must clear the in-memory view even when another actor has
-    // Check if the data matches. If it does, then spoilers are up to date.
+    // already removed the file. Queue behind an older reload through the same
-    if (getHash(fileName) == getHash(data)) {
+    // updater lifecycle, so its final snapshot cannot restore disabled spoilers.
-        if (trayIcon) {
+    auto *updater = new SpoilerBackgroundUpdater(QCoreApplication::instance(), true);
-            trayIcon->showMessage(tr("Spoilers already up to date"), tr("No new spoilers added"));
+    updater->reloadOnly = true;
-        }
+    connect(updater, &SpoilerBackgroundUpdater::spoilerCheckerDone, updater, &QObject::deleteLater);
-
-        qCInfo(SpoilerBackgroundUpdaterLog) << "Spoilers Up to Date";
-        return false;
-    }
-
-    QFile file(fileName);
-    if (!file.open(QIODevice::WriteOnly)) {
-        qCWarning(SpoilerBackgroundUpdaterLog) << "Spoiler Service Error: File open (w) failed for" << fileName;
-        file.close();
-        return false;
-    }
-
-    if (file.write(data) == -1) {
-        qCWarning(SpoilerBackgroundUpdaterLog) << "Spoiler Service Error: File write (w) failed for" << fileName;
-        file.close();
-        return false;
-    }
-
-    file.close();
-
-    // Data written, so reload the card database
-    qCInfo(SpoilerBackgroundUpdaterLog) << "Spoiler Service Data Written";
-    // Spoilers can introduce sets the config has never seen; the loader never
-    // runs checkUnknownSets() itself, so run it once the finished snapshot has
-    // been swapped in.
-    auto *watcher = new QFutureWatcher<void>(this);
-    connect(watcher, &QFutureWatcher<void>::finished, this, [watcher] {
-        watcher->deleteLater();
-        CardDatabaseManager::getInstance()->checkUnknownSets();
-    });
-    watcher->setFuture(QtConcurrent::run([] { CardDatabaseManager::getInstance()->loadCardDatabases(); }));
-
-    // If the user has notifications enabled, let them know
-    // when the database was last updated
-    if (trayIcon) {
-        QList<QByteArray> lines = data.split('\n');
-
-        for (const QByteArray &line : lines) {
-            if (line.contains("Created At:")) {
-                QString timeStamp = QString(line).replace("Created At:", "").trimmed();
-                timeStamp.chop(6); // Remove " (UTC)"
-
-                auto utcTime = QLocale().toDateTime(timeStamp, "ddd, MMM dd yyyy, hh:mm:ss");
-#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
-                utcTime.setTimeZone(QTimeZone::UTC);
-#else
-                utcTime.setTimeSpec(Qt::UTC);
-#endif
-
-                QString localTime = utcTime.toLocalTime().toString("MMM d, hh:mm");
-
-                trayIcon->showMessage(tr("Spoilers have been updated!"), tr("Last change:") + " " + localTime);
-                emit spoilersUpdatedSuccessfully();
-                return true;
-            }
-        }
-    }
-
     return true;
 }
 
 QByteArray SpoilerBackgroundUpdater::getHash(const QString fileName)
 {
     QFile file(fileName);
-
+    if (!file.open(QIODevice::ReadOnly)) {
-    if (file.open(QFile::ReadOnly)) {
+        return {};
-        // Only read the first 512 bytes (enough to get the "created" tag)
-        const QByteArray bytes = file.read(512);
-
-        QCryptographicHash hash(QCryptographicHash::Algorithm::Md5);
-        hash.addData(bytes);
-
-        qCInfo(SpoilerBackgroundUpdaterLog) << "File Hash =" << hash.result();
-
-        file.close();
-        return hash.result();
-    } else {
-        qCWarning(SpoilerBackgroundUpdaterLog) << "getHash ReadOnly failed!";
-        file.close();
-        return QByteArray();
     }
+    QCryptographicHash hash(QCryptographicHash::Sha256);
+    return hash.addData(&file) ? hash.result() : QByteArray();
 }
 
 QByteArray SpoilerBackgroundUpdater::getHash(QByteArray data)
 {
-    // Only read the first 512 bytes (enough to get the "created" tag)
+    return QCryptographicHash::hash(data, QCryptographicHash::Sha256);
-    const QByteArray bytes = data.left(512);
-
-    QCryptographicHash hash(QCryptographicHash::Algorithm::Md5);
-    hash.addData(bytes);
-
-    qCInfo(SpoilerBackgroundUpdaterLog) << "Data Hash =" << hash.result();
-
-    return hash.result();
 }

cockatrice/src/client/network/update/card_spoiler/spoiler_background_updater.h

@@ -2,7 +2,6 @@
  * @file spoiler_background_updater.h
  * @ingroup Client
  */
-//! \todo Document this file.
 
 #ifndef COCKATRICE_SPOILER_DOWNLOADER_H
 #define COCKATRICE_SPOILER_DOWNLOADER_H
@@ -10,10 +9,13 @@
 #include <QByteArray>
 #include <QLoggingCategory>
 #include <QObject>
+#include <QPointer>
 #include <QString>
 #include <qtmetamacros.h>
 
-class QProcess;
+class QNetworkAccessManager;
+class QNetworkReply;
+class QSystemTrayIcon;
 class QUrl;
 
 inline Q_LOGGING_CATEGORY(SpoilerBackgroundUpdaterLog, "spoiler_background_updater");
@@ -22,7 +24,7 @@ class SpoilerBackgroundUpdater : public QObject
 {
     Q_OBJECT
 public:
-    explicit SpoilerBackgroundUpdater(QObject *apParent = nullptr);
+    explicit SpoilerBackgroundUpdater(QObject *parent = nullptr, bool forceReload = false);
     inline QString getCardUpdaterBinaryName()
     {
         return "oracle";
@@ -32,20 +34,45 @@ public:
     static bool deleteSpoilerFile();
 
 private slots:
+    void begin();
     void actDownloadFinishedSpoilersFile();
     void actCheckIfSpoilerSeasonEnabled();
+    void cancelIfSettingsChanged();
 
 private:
-    bool isSpoilerDownloadEnabled;
+    enum class SaveResult
-    QProcess *cardUpdateProcess;
+    {
+        Failed,
+        Unchanged,
+        Written
+    };
+
+    const bool enabledAtStart;
+    const bool forceReload;
+    const QString targetPath;
+    const quint64 operationId;
+    QNetworkAccessManager *manager;
+    QPointer<QNetworkReply> activeReply;
+    QPointer<QSystemTrayIcon> notificationIcon;
     QByteArray spoilerData;
-    void startSpoilerDownloadProcess(QString url, bool saveResults);
+    bool completed = false;
-    void downloadFromURL(QUrl url, bool saveResults);
+    bool cancelled = false;
-    bool saveDownloadedFile(QByteArray data);
+    bool reloading = false;
+    bool seasonEnded = false;
+    bool reloadOnly = false;
+
+    bool isCurrent() const;
+    void cancel();
+    void finish(const QString &error = {}, bool updated = false);
+    void downloadFromURL(const QUrl &url, bool saveResults);
+    void reloadDatabase(bool updated);
+    QString validateDownloadedFile(const QByteArray &data) const;
+    SaveResult saveDownloadedFile(const QByteArray &data, QString &error);
 
 signals:
     void spoilersUpdatedSuccessfully();
     void spoilerCheckerDone();
+    void spoilerUpdateFailed(const QString &message);
 };
 
-#endif // COCKATRICE_SPOILER_DOWNLOADER_H
+#endif // COCKATRICE_SPOILER_DOWNLOADER_H

cockatrice/src/interface/widgets/settings_page/deck_editor_settings_page.cpp

@@ -8,6 +8,7 @@
 #include <QAbstractItemModel>
 #include <QAbstractItemView>
 #include <QAction>
+#include <QCoreApplication>
 #include <QDateTime>
 #include <QDebug>
 #include <QDir>
@@ -332,16 +333,33 @@ void DeckEditorSettingsPage::updateSpoilers()
     updateNowButton->setDisabled(true);
     updateNowButton->setText(tr("Updating..."));
 
-    // Create a new SBU that will act as if the client was just reloaded
+    // The explicit update also retries a previous reload of an unchanged file.
-    auto *sbu = new SpoilerBackgroundUpdater();
+    // Application ownership lets it finish if the settings page is closed.
-    connect(sbu, &SpoilerBackgroundUpdater::spoilerCheckerDone, this, &DeckEditorSettingsPage::unlockSettings);
+    auto *sbu = new SpoilerBackgroundUpdater(QCoreApplication::instance(), true);
-    connect(sbu, &SpoilerBackgroundUpdater::spoilersUpdatedSuccessfully, this, &DeckEditorSettingsPage::unlockSettings);
+    spoilerUpdater = sbu;
+    connect(sbu, &SpoilerBackgroundUpdater::spoilerCheckerDone, this, [this, sbu] {
+        if (spoilerUpdater == sbu) {
+            spoilerUpdater.clear();
+            unlockSettings();
+        }
+    });
+    connect(sbu, &SpoilerBackgroundUpdater::spoilerCheckerDone, sbu, &QObject::deleteLater);
+    connect(sbu, &SpoilerBackgroundUpdater::spoilerUpdateFailed, this, [this, sbu](const QString &message) {
+        if (spoilerUpdater != sbu) {
+            return;
+        }
+        auto *notice = new QMessageBox(QMessageBox::Warning, tr("Spoiler update"), message, QMessageBox::Ok, this);
+        notice->setTextFormat(Qt::PlainText);
+        notice->setAttribute(Qt::WA_DeleteOnClose);
+        notice->open();
+    });
 }
 
 void DeckEditorSettingsPage::unlockSettings()
 {
-    updateNowButton->setDisabled(false);
+    updateNowButton->setEnabled(SettingsCache::instance().downloads().getDownloadSpoilersStatus());
     updateNowButton->setText(tr("Update Spoilers"));
+    lastUpdatedLabel.setText(tr("Last Change") + ": " + getLastUpdateTime());
 }
 
 QString DeckEditorSettingsPage::getLastUpdateTime()
@@ -379,12 +397,22 @@ void DeckEditorSettingsPage::setSpoilersEnabled(bool anInput)
     mpSpoilerSavePathLineEdit->setEnabled(anInput);
     mpSpoilerPathButton->setEnabled(anInput);
     lastUpdatedLabel.setEnabled(anInput);
-    updateNowButton->setEnabled(anInput);
+    updateNowButton->setEnabled(anInput && !spoilerUpdater);
     infoOnSpoilersLabel.setEnabled(anInput);
 
-    if (!anInput) {
+    if (!anInput && (sender() == &mcDownloadSpoilersCheckBox ||
-        SpoilerBackgroundUpdater::deleteSpoilerFile();
+                     QFileInfo::exists(SettingsCache::instance().paths().getSpoilerCardDatabasePath()))) {
+        if (!SpoilerBackgroundUpdater::deleteSpoilerFile()) {
+            auto *notice = new QMessageBox(QMessageBox::Warning, tr("Spoiler update"),
+                                          tr("The spoiler database could not be removed. Check its file permissions "
+                                             "and try disabling spoilers again."),
+                                          QMessageBox::Ok, this);
+            notice->setTextFormat(Qt::PlainText);
+            notice->setAttribute(Qt::WA_DeleteOnClose);
+            notice->open();
+        }
     }
+    lastUpdatedLabel.setText(tr("Last Change") + ": " + getLastUpdateTime());
 }
 
 void DeckEditorSettingsPage::retranslateUi()
@@ -396,7 +424,7 @@ void DeckEditorSettingsPage::retranslateUi()
     lastUpdatedLabel.setText(tr("Last Change") + ": " + getLastUpdateTime());
     infoOnSpoilersLabel.setText(tr("Spoilers download automatically on launch") + "\n" +
                                 tr("Press the button to manually update without relaunching") + "\n\n" +
-                                tr("Do not close settings until manual update is complete"));
+                                tr("Updates continue if you close settings"));
     picDownloadCheckBox.setText(tr("Download card pictures on the fly"));
     urlLinkLabel.setText(QString("<a href='%1'>%2</a>").arg(WIKI_CUSTOM_PIC_URL).arg(tr("How to add a custom URL")));
     resetDownloadURLs.setText(tr("Reset Download URLs"));

cockatrice/src/interface/widgets/settings_page/deck_editor_settings_page.h

@@ -5,6 +5,7 @@
 
 #include <QCheckBox>
 #include <QLabel>
+#include <QPointer>
 #include <QPushButton>
 #include <QString>
 #include <qtmetamacros.h>
@@ -15,6 +16,7 @@ class QLineEdit;
 class QListWidget;
 class QListWidgetItem;
 class QModelIndex;
+class SpoilerBackgroundUpdater;
 
 class DeckEditorSettingsPage : public AbstractSettingsPage
 {
@@ -54,6 +56,7 @@ private:
     QLabel infoOnSpoilersLabel;
     QPushButton *mpSpoilerPathButton;
     QPushButton *updateNowButton;
+    QPointer<SpoilerBackgroundUpdater> spoilerUpdater;
 
     /** @brief Adds a list item for the given URL, storing the raw URL alongside its displayed label. */
     QListWidgetItem *addUrlItem(const QString &url);