Thumbnail field of RowNode can be data or url

Now the 0'th field of ContentManagerModel's row representation (which is
used for the book thumbnail) can hold either the favicon image data or its
url (before it held only the image data).

src/contentmanagermodel.cpp

@@ -33,8 +33,15 @@ QVariant ContentManagerModel::data(const QModelIndex& index, int role) const
     auto item = static_cast<Node*>(index.internalPointer());
     const auto displayRole = role == Qt::DisplayRole;
     const auto additionalInfoRole = role == Qt::UserRole+1;
-    if (displayRole || additionalInfoRole)
-        return item->data(index.column());
+    if (displayRole || additionalInfoRole) {
+        const QVariant r = item->data(index.column());
+        if ( index.column() == 0 && r.type() == QVariant::String ) {
+            // Thumbnail was requested but what we have is only its URL
+            return QVariant();
+        } else {
+            return r;
+        }
+    }
 
     return QVariant();
 }
@@ -111,22 +118,24 @@ void ContentManagerModel::setBooksData(const BookInfoList& data)
     emit dataChanged(QModelIndex(), QModelIndex());
 }
 
-QByteArray ContentManagerModel::getThumbnail(const BookInfo& bookItem) const
+// Returns either data of the thumbnail (as a QByteArray) or a URL (as a
+// QString) from where the actual data can be obtained.
+QVariant ContentManagerModel::getThumbnail(const BookInfo& bookItem) const
 {
     const QVariant faviconEntry = bookItem["favicon"];
     if ( faviconEntry.type() == QVariant::ByteArray )
-        return faviconEntry.toByteArray();
+        return faviconEntry;
 
     const auto faviconUrl = faviconEntry.toString();
     return m_iconMap.contains(faviconUrl)
          ? m_iconMap[faviconUrl]
-         : QByteArray();
+         : faviconEntry;
 }
 
 std::shared_ptr<RowNode> ContentManagerModel::createNode(BookInfo bookItem) const
 {
     QString id = bookItem["id"].toString();
-    const QByteArray bookIcon = getThumbnail(bookItem);
+    const QVariant bookIcon = getThumbnail(bookItem);
     std::weak_ptr<RowNode> weakRoot = rootNode;
     auto rowNodePtr = std::shared_ptr<RowNode>(new
                                     RowNode({bookIcon, bookItem["title"],
@@ -167,8 +176,9 @@ void ContentManagerModel::refreshIcons()
     td.clearQueue();
     for (auto i = 0; i < rowCount() && i < m_data.size(); i++) {
         const auto& bookItem = m_data[i];
-        if ( bookItem["favicon"].type() == QVariant::String ) {
-            const auto faviconUrl = bookItem["favicon"].toString();
+        const QVariant favicon = bookItem["favicon"];
+        if ( favicon.type() == QVariant::String ) {
+            const auto faviconUrl = favicon.toString();
             if (faviconUrl != "" && !m_iconMap.contains(faviconUrl)) {
                 td.addDownload(faviconUrl, bookItem["id"].toString());
             }

src/contentmanagermodel.h

@@ -57,7 +57,9 @@ protected: // functions
     void fetchMore(const QModelIndex &parent) override;
 
 private: // functions
-    QByteArray getThumbnail(const BookInfo& bookItem) const;
+    // Returns either data of the thumbnail (as a QByteArray) or a URL (as a
+    // QString) from where the actual data can be obtained.
+    QVariant getThumbnail(const BookInfo& bookItem) const;
 
 private: // data
     BookInfoList m_data;