Revert "Use another workaround to update files tree view"

This reverts commit 0f82c169362cd2e26c053725d3b8fae3889f1655.

src/gui/torrentcontentmodel.cpp

@@ -221,7 +221,11 @@ void TorrentContentModel::updateFilesProgress(const QVector<qreal> &fp)
     m_rootItem->recalculateProgress();
     m_rootItem->recalculateAvailability();
 
-    emit layoutChanged();
+    const QVector<ColumnInterval> columns =
+    {
+        {TorrentContentModelItem::COL_PROGRESS, TorrentContentModelItem::COL_PROGRESS}
+    };
+    notifySubtreeUpdated(index(0, 0), columns);
 }
 
 void TorrentContentModel::updateFilesPriorities(const QVector<BitTorrent::DownloadPriority> &fprio)
@@ -235,7 +239,12 @@ void TorrentContentModel::updateFilesPriorities(const QVector<BitTorrent::Downlo
     for (int i = 0; i < fprio.size(); ++i)
         m_filesIndex[i]->setPriority(static_cast<BitTorrent::DownloadPriority>(fprio[i]));
 
-    emit layoutChanged();
+    const QVector<ColumnInterval> columns =
+    {
+        {TorrentContentModelItem::COL_NAME, TorrentContentModelItem::COL_NAME},
+        {TorrentContentModelItem::COL_PRIO, TorrentContentModelItem::COL_PRIO}
+    };
+    notifySubtreeUpdated(index(0, 0), columns);
 }
 
 void TorrentContentModel::updateFilesAvailability(const QVector<qreal> &fa)
@@ -250,7 +259,11 @@ void TorrentContentModel::updateFilesAvailability(const QVector<qreal> &fa)
     // Update folders progress in the tree
     m_rootItem->recalculateProgress();
 
-    emit layoutChanged();
+    const QVector<ColumnInterval> columns =
+    {
+        {TorrentContentModelItem::COL_AVAILABILITY, TorrentContentModelItem::COL_AVAILABILITY}
+    };
+    notifySubtreeUpdated(index(0, 0), columns);
 }
 
 QVector<BitTorrent::DownloadPriority> TorrentContentModel::getFilePriorities() const
@@ -295,13 +308,17 @@ bool TorrentContentModel::setData(const QModelIndex &index, const QVariant &valu
 
         if (currentPrio != newPrio)
         {
-            emit layoutAboutToBeChanged();
             item->setPriority(newPrio);
             // Update folders progress in the tree
             m_rootItem->recalculateProgress();
             m_rootItem->recalculateAvailability();
 
-            emit layoutChanged();
+            const QVector<ColumnInterval> columns =
+            {
+                {TorrentContentModelItem::COL_NAME, TorrentContentModelItem::COL_NAME},
+                {TorrentContentModelItem::COL_PRIO, TorrentContentModelItem::COL_PRIO}
+            };
+            notifySubtreeUpdated(index, columns);
             emit filteredFilesChanged();
 
             return true;
@@ -333,9 +350,14 @@ bool TorrentContentModel::setData(const QModelIndex &index, const QVariant &valu
                 const auto newPrio = static_cast<BitTorrent::DownloadPriority>(value.toInt());
                 if (currentPrio != newPrio)
                 {
-                    emit layoutAboutToBeChanged();
                     item->setPriority(newPrio);
-                    emit layoutChanged();
+
+                    const QVector<ColumnInterval> columns =
+                    {
+                        {TorrentContentModelItem::COL_NAME, TorrentContentModelItem::COL_NAME},
+                        {TorrentContentModelItem::COL_PRIO, TorrentContentModelItem::COL_PRIO}
+                    };
+                    notifySubtreeUpdated(index, columns);
 
                     if ((newPrio == BitTorrent::DownloadPriority::Ignored)
                         || (currentPrio == BitTorrent::DownloadPriority::Ignored))
@@ -570,3 +592,54 @@ void TorrentContentModel::setupModelData(const BitTorrent::AbstractFileStorage &
 
     endResetModel();
 }
+
+void TorrentContentModel::notifySubtreeUpdated(const QModelIndex &index, const QVector<ColumnInterval> &columns)
+{
+    // For best performance, `columns` entries should be arranged from left to right
+
+    Q_ASSERT(index.isValid());
+
+    // emit itself
+    for (const ColumnInterval &column : columns)
+        emit dataChanged(index.siblingAtColumn(column.first()), index.siblingAtColumn(column.last()));
+
+    // propagate up the model
+    QModelIndex parentIndex = parent(index);
+    while (parentIndex.isValid())
+    {
+        for (const ColumnInterval &column : columns)
+            emit dataChanged(parentIndex.siblingAtColumn(column.first()), parentIndex.siblingAtColumn(column.last()));
+        parentIndex = parent(parentIndex);
+    }
+
+    // propagate down the model
+    QVector<QModelIndex> parentIndexes;
+
+    if (hasChildren(index))
+        parentIndexes.push_back(index);
+
+    while (!parentIndexes.isEmpty())
+    {
+        const QModelIndex parent = parentIndexes.takeLast();
+
+        const int childCount = rowCount(parent);
+        const QModelIndex child = this->index(0, 0, parent);
+
+        // emit this generation
+        for (const ColumnInterval &column : columns)
+        {
+            const QModelIndex childTopLeft = child.siblingAtColumn(column.first());
+            const QModelIndex childBottomRight = child.sibling((childCount - 1), column.last());
+            emit dataChanged(childTopLeft, childBottomRight);
+        }
+
+        // check generations further down
+        parentIndexes.reserve(childCount);
+        for (int i = 0; i < childCount; ++i)
+        {
+            const QModelIndex sibling = child.siblingAtRow(i);
+            if (hasChildren(sibling))
+                parentIndexes.push_back(sibling);
+        }
+    }
+}

src/gui/torrentcontentmodel.h

@@ -81,6 +81,10 @@ signals:
     void filteredFilesChanged();
 
 private:
+    using ColumnInterval = IndexInterval<int>;
+
+    void notifySubtreeUpdated(const QModelIndex &index, const QVector<ColumnInterval> &columns);
+
     TorrentContentModelFolder *m_rootItem = nullptr;
     QVector<TorrentContentModelFile *> m_filesIndex;
     QFileIconProvider *m_fileIconProvider = nullptr;