ContentManager::updateDownloads() runs in a separate thread

src/contentmanager.cpp

@@ -130,12 +130,36 @@ ContentManager::ContentManager(Library* library, kiwix::Downloader* downloader,
     setCategories();
     setLanguages();
 
-    m_downloadUpdateTimer.start(1000);
-    connect(&m_downloadUpdateTimer, &QTimer::timeout,
-            this, &ContentManager::updateDownloads);
-
     connect(this, &ContentManager::downloadUpdated,
             this, &ContentManager::updateDownload);
+
+    if ( mp_downloader ) {
+        startDownloadUpdaterThread();
+    }
+}
+
+void ContentManager::startDownloadUpdaterThread()
+{
+    // so that DownloadInfo can be copied across threads
+    qRegisterMetaType<DownloadInfo>("DownloadInfo");
+
+    mp_downloadUpdaterThread = QThread::create([=]() {
+       while ( mp_downloadUpdaterThread != nullptr ) {
+            updateDownloads();
+            QThread::msleep(1000);
+        }
+    });
+    mp_downloadUpdaterThread->start();
+}
+
+ContentManager::~ContentManager()
+{
+    if ( mp_downloadUpdaterThread )
+    {
+        QThread* t = mp_downloadUpdaterThread;
+        mp_downloadUpdaterThread = nullptr; // tell the thread to terminate
+        t->wait();
+    }
 }
 
 void ContentManager::updateModel()

src/contentmanager.h

@@ -22,7 +22,7 @@ public: // types
 
 public: // functions
     explicit ContentManager(Library* library, kiwix::Downloader *downloader, QObject *parent = nullptr);
-    virtual ~ContentManager() {}
+    virtual ~ContentManager();
 
     ContentManagerView* getView() { return mp_view; }
     void setLocal(bool local);
@@ -84,6 +84,7 @@ private: // functions
     // the remote or local library (in that order).
     const kiwix::Book& getRemoteOrLocalBook(const QString &id);
 
+    void startDownloadUpdaterThread();
     std::string startDownload(const kiwix::Book& book);
     void removeDownload(QString bookId);
     void downloadStarted(const kiwix::Book& book, const std::string& downloadId);
@@ -96,7 +97,7 @@ private: // data
     kiwix::LibraryPtr mp_remoteLibrary;
     kiwix::Downloader* mp_downloader;
     ContentManagerModel::Downloads m_downloads;
-    QTimer m_downloadUpdateTimer;
+    QThread* mp_downloadUpdaterThread = nullptr;
     OpdsRequestManager m_remoteLibraryManager;
     ContentManagerView* mp_view;
     bool m_local = true;