Check for client updates on startup (#5359)

cockatrice/src/client/network/client_update_checker.cpp

@@ -0,0 +1,35 @@
+#include "client_update_checker.h"
+
+#include "../../settings/cache_settings.h"
+#include "release_channel.h"
+
+ClientUpdateChecker::ClientUpdateChecker(QObject *parent) : QObject(parent)
+{
+}
+
+void ClientUpdateChecker::check()
+{
+    auto releaseChannel = SettingsCache::instance().getUpdateReleaseChannel();
+
+    finishedCheckConnection =
+        connect(releaseChannel, &ReleaseChannel::finishedCheck, this, &ClientUpdateChecker::actFinishedCheck);
+    errorConnection = connect(releaseChannel, &ReleaseChannel::error, this, &ClientUpdateChecker::actError);
+
+    releaseChannel->checkForUpdates();
+}
+
+void ClientUpdateChecker::actFinishedCheck(bool needToUpdate, bool isCompatible, Release *release)
+{
+    disconnect(finishedCheckConnection);
+    disconnect(errorConnection);
+
+    emit finishedCheck(needToUpdate, isCompatible, release);
+}
+
+void ClientUpdateChecker::actError(const QString &errorString)
+{
+    disconnect(finishedCheckConnection);
+    disconnect(errorConnection);
+
+    emit error(errorString);
+}

cockatrice/src/client/network/client_update_checker.h

@@ -0,0 +1,45 @@
+#ifndef CLIENT_UPDATE_CHECKER_H
+#define CLIENT_UPDATE_CHECKER_H
+#include <QObject>
+
+class Release;
+
+/**
+ * We use a singleton instance of UpdateChannel, which can cause interference and feedback loops when multiple objects
+ * connect to it.
+ *
+ * This class encapsulates the usage of that UpdateChannel to ensure that the check only happens once per connection and
+ * the connection is destroyed after it's been used.
+ */
+class ClientUpdateChecker : public QObject
+{
+    Q_OBJECT
+
+    QMetaObject::Connection finishedCheckConnection;
+    QMetaObject::Connection errorConnection;
+
+    void actFinishedCheck(bool needToUpdate, bool isCompatible, Release *release);
+    void actError(const QString &errorString);
+
+public:
+    explicit ClientUpdateChecker(QObject *parent = nullptr);
+    /**
+     * Actually performs the check, using the currently selected update channel in the settings.
+     * Any resulting signals will only be sent once.
+     * This method should only be called ONCE per instance.
+     */
+    void check();
+
+signals:
+    /**
+     * Forwarded from UpdateChannel::finishedCheck
+     */
+    void finishedCheck(bool needToUpdate, bool isCompatible, Release *release);
+
+    /**
+     * Forwarded from UpdateChannel::error
+     */
+    void error(const QString &errorString);
+};
+
+#endif // CLIENT_UPDATE_CHECKER_H

cockatrice/src/client/network/release_channel.cpp

@@ -112,7 +112,7 @@ void StableReleaseChannel::releaseListFinished()
     QVariantMap resultMap = jsonResponse.toVariant().toMap();
     if (!(resultMap.contains("name") && resultMap.contains("html_url") && resultMap.contains("tag_name") &&
           resultMap.contains("published_at"))) {
-        qWarning() << "Invalid received from the release update server.";
+        qWarning() << "Invalid received from the release update server:" << resultMap;
         emit error(tr("Invalid reply received from the release update server."));
         return;
     }