Make QOtaClient a singleton type

Having a several instances of this type does not
make sense. This also is more consistent with the
QML API where OtaClient is a singleton type.

Change-Id: I11b704691f6e08730eb898520eeaa383e8549275
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

4 files changed, 25 insertions, 13 deletions

diff --git a/examples/cpp/basic-daemon/main.cpp b/examples/cpp/basic-daemon/main.cpp
index f67d1bd..1f0657d 100644
--- a/examples/cpp/basic-daemon/main.cpp
+++ b/examples/cpp/basic-daemon/main.cpp
@@ -40,16 +40,18 @@ class UpdateChecker : public QObject
 {
     Q_OBJECT
 public:
-    UpdateChecker(const QString &guiUpdater) : m_guiUpdaterPath(guiUpdater)
+    UpdateChecker(const QString &guiUpdater) :
+        m_device(&QOtaClient::instance()),
+        m_guiUpdaterPath(guiUpdater)
     {
-        connect(&m_device, &QOtaClient::fetchRemoteInfoFinished, this, &UpdateChecker::fetchFinished);
-        connect(&m_device, &QOtaClient::statusStringChanged, this, &UpdateChecker::log);
-        connect(&m_device, &QOtaClient::errorOccurred, this, &UpdateChecker::logError);
+        connect(m_device, &QOtaClient::fetchRemoteInfoFinished, this, &UpdateChecker::fetchFinished);
+        connect(m_device, &QOtaClient::statusStringChanged, this, &UpdateChecker::log);
+        connect(m_device, &QOtaClient::errorOccurred, this, &UpdateChecker::logError);
         connect(&m_fetchTimer, &QTimer::timeout, this, &UpdateChecker::startFetch);
 
         m_repoConfig.setUrl(QStringLiteral("http://www.b2qtupdate.com/ostree-repo"));
-        if (!m_device.isRepositoryConfigSet(&m_repoConfig))
-            m_device.setRepositoryConfig(&m_repoConfig);
+        if (!m_device->isRepositoryConfigSet(&m_repoConfig))
+            m_device->setRepositoryConfig(&m_repoConfig);
 
         m_fetchTimer.setSingleShot(true);
         m_fetchTimer.start();
@@ -63,12 +65,12 @@ public:
     void startFetch()
     {
         log(QStringLiteral("verifying remote server for system updates..."));
-        m_device.fetchRemoteInfo();
+        m_device->fetchRemoteInfo();
     }
 
     void fetchFinished(bool success)
     {
-        if (success && m_device.updateAvailable()) {
+        if (success && m_device->updateAvailable()) {
             log(QStringLiteral("update available"));
             // Any inter-process communication mechanism could be used here. In this demo we
             // simply launch a GUI that can be used to execute the update commands (such as examples/qml/basic/).
@@ -91,7 +93,7 @@ public:
     }
 
 private:
-    QOtaClient m_device;
+    QOtaClient *m_device;
     QOtaRepositoryConfig m_repoConfig;
     QTimer m_fetchTimer;
     QString m_guiUpdaterPath;
diff --git a/src/imports/pluginmain.cpp b/src/imports/pluginmain.cpp
index 1355232..25f3a36 100644
--- a/src/imports/pluginmain.cpp
+++ b/src/imports/pluginmain.cpp
@@ -472,8 +472,9 @@ static QObject *otaClientSingleton(QQmlEngine *qmlEngine, QJSEngine *jsEngine)
 {
     Q_UNUSED(qmlEngine);
     Q_UNUSED(jsEngine);
-    return new QOtaClient;
+    return &QOtaClient::instance();
 }
+
 class QOTAUpdatePlugin : public QQmlExtensionPlugin
 {
     Q_OBJECT
diff --git a/src/lib/qotaclient.cpp b/src/lib/qotaclient.cpp
index 30670a1..05ab97d 100644
--- a/src/lib/qotaclient.cpp
+++ b/src/lib/qotaclient.cpp
@@ -291,8 +291,7 @@ void QOtaClientPrivate::defaultRevisionChanged(const QString &defaultRevision)
     \c nullptr value).
 */
 
-QOtaClient::QOtaClient(QObject *parent) :
-    QObject(parent),
+QOtaClient::QOtaClient() :
     d_ptr(new QOtaClientPrivate(this))
 {
     Q_D(QOtaClient);
@@ -318,6 +317,15 @@ QOtaClient::~QOtaClient()
 }
 
 /*!
+    Returns a singleton instance of QOtaClient.
+*/
+QOtaClient& QOtaClient::instance()
+{
+    static QOtaClient otaClient;
+    return otaClient;
+}
+
+/*!
 //! [fetchremoteinfo-description]
     Fetches OTA metadata from a remote server and updates the local metadata
     cache. This metadata contains information on what system version is available
diff --git a/src/lib/qotaclient.h b/src/lib/qotaclient.h
index 66fbc2f..901c1ae 100644
--- a/src/lib/qotaclient.h
+++ b/src/lib/qotaclient.h
@@ -60,7 +60,7 @@ class Q_DECL_EXPORT QOtaClient : public QObject
     Q_PROPERTY(QString rollbackRevision READ rollbackRevision NOTIFY rollbackInfoChanged)
     Q_PROPERTY(QByteArray rollbackInfo READ rollbackInfo NOTIFY rollbackInfoChanged)
 public:
-    explicit QOtaClient(QObject *parent = nullptr);
+    static QOtaClient& instance();
     virtual ~QOtaClient();
 
     bool updateAvailable() const;
@@ -113,6 +113,7 @@ Q_SIGNALS:
     void updateRemoteInfoOfflineFinished(bool success);
 
 private:
+    QOtaClient();
     Q_DISABLE_COPY(QOtaClient)
     Q_DECLARE_PRIVATE(QOtaClient)
     QOtaClientPrivate *const d_ptr;