DocumentsTree: Allow rearranging items by DND

BUG: 267508

addons/filetree/katefiletree.cpp

@@ -92,16 +92,21 @@ private:
 KateFileTree::KateFileTree(QWidget *parent)
     : QTreeView(parent)
 {
-    setAcceptDrops(false);
     setIndentation(12);
     setAllColumnsShowFocus(true);
     setFocusPolicy(Qt::NoFocus);
-    setDragEnabled(true);
-    setDragDropMode(QAbstractItemView::DragOnly);
     setSelectionBehavior(QAbstractItemView::SelectRows);
     // for hover close button
     viewport()->setAttribute(Qt::WA_Hover);
 
+    // DND
+    setDefaultDropAction(Qt::MoveAction);
+    setDragDropMode(QAbstractItemView::InternalMove);
+    setDragDropOverwriteMode(false);
+    setAcceptDrops(true);
+    setDropIndicatorShown(true);
+    setDragEnabled(true);
+
     setItemDelegate(new StyleDelegate(this));
 
     // handle activated (e.g. for pressing enter) + clicked (to avoid to need to do double-click e.g. on Windows)
@@ -246,6 +251,13 @@ void KateFileTree::setupContextMenuActionGroups()
                                        i18nc("@action:inmenu sorting option", "Opening Order"),
                                        i18n("Sort by Opening Order"),
                                        &KateFileTree::slotSortOpeningOrder);
+
+    m_customSorting = new QAction(QIcon(), i18n("Custom Sorting"), this);
+    m_customSorting->setCheckable(true);
+    m_customSorting->setActionGroup(sortGroup);
+    connect(m_customSorting, &QAction::triggered, this, [this] {
+        Q_EMIT sortRoleChanged(CustomSorting);
+    });
 }
 
 QAction *KateFileTree::setupOption(QActionGroup *group,
@@ -337,6 +349,7 @@ void KateFileTree::contextMenuEvent(QContextMenuEvent *event)
     m_sortByFile->setChecked(sortRole == Qt::DisplayRole);
     m_sortByPath->setChecked(sortRole == KateFileTreeModel::PathRole);
     m_sortByOpeningOrder->setChecked(sortRole == KateFileTreeModel::OpeningOrderRole);
+    m_customSorting->setChecked(sortRole == CustomSorting);
 
     KTextEditor::Document *doc = docFromIndex(m_indexContextMenu);
     const bool isFile = (nullptr != doc);
@@ -392,6 +405,7 @@ void KateFileTree::contextMenuEvent(QContextMenuEvent *event)
     sort_menu->addAction(m_sortByFile);
     sort_menu->addAction(m_sortByPath);
     sort_menu->addAction(m_sortByOpeningOrder);
+    sort_menu->addAction(m_customSorting);
 
     menu.addAction(m_resetHistory);
 
@@ -448,8 +462,6 @@ void KateFileTree::slotOpenWithMenuAction(QAction *a)
     job->start();
 }
 
-Q_DECLARE_METATYPE(QList<KTextEditor::Document *>)
-
 void KateFileTree::slotDocumentClose()
 {
     m_previouslySelected = QModelIndex();

addons/filetree/katefiletree.h

@@ -108,6 +108,7 @@ private:
     QAction *m_sortByFile;
     QAction *m_sortByPath;
     QAction *m_sortByOpeningOrder;
+    QAction *m_customSorting;
     QAction *m_resetHistory;
 
     KateFileTreeProxyModel *m_proxyModel = nullptr;

addons/filetree/katefiletreeconfigpage.cpp

@@ -71,6 +71,7 @@ KateFileTreeConfigPage::KateFileTreeConfigPage(QWidget *parent, KateFileTreePlug
     cmbSort->addItem(i18n("Opening Order"), static_cast<int>(KateFileTreeModel::OpeningOrderRole));
     cmbSort->addItem(i18n("Document Name"), static_cast<int>(Qt::DisplayRole));
     cmbSort->addItem(i18n("Url"), static_cast<int>(KateFileTreeModel::PathRole));
+    cmbSort->addItem(i18n("Custom Sorting"), static_cast<int>(CustomSorting));
 
     // view mode
     QHBoxLayout *lo3 = new QHBoxLayout;

addons/filetree/katefiletreemodel.cpp

@@ -29,6 +29,24 @@
 
 static constexpr int MaxHistoryItems = 10;
 
+class FileTreeMimeData : public QMimeData
+{
+    Q_OBJECT
+public:
+    FileTreeMimeData(const QModelIndex &index)
+        : m_index(index)
+    {
+    }
+
+    QModelIndex index() const
+    {
+        return m_index;
+    }
+
+private:
+    QPersistentModelIndex m_index;
+};
+
 class ProxyItemDir;
 class ProxyItem
 {
@@ -485,7 +503,7 @@ Qt::ItemFlags KateFileTreeModel::flags(const QModelIndex &index) const
     Qt::ItemFlags flags = Qt::ItemIsEnabled;
 
     if (!index.isValid()) {
-        return Qt::NoItemFlags;
+        return Qt::NoItemFlags | Qt::ItemIsDropEnabled;
     }
 
     const ProxyItem *item = static_cast<ProxyItem *>(index.internalPointer());
@@ -494,6 +512,10 @@ Qt::ItemFlags KateFileTreeModel::flags(const QModelIndex &index) const
             flags |= Qt::ItemIsSelectable;
         }
 
+        if (item->childCount() > 0) {
+            flags |= Qt::ItemIsDropEnabled;
+        }
+
         if (item->doc() && item->doc()->url().isValid()) {
             flags |= Qt::ItemIsDragEnabled;
         }
@@ -502,8 +524,6 @@ Qt::ItemFlags KateFileTreeModel::flags(const QModelIndex &index) const
     return flags;
 }
 
-Q_DECLARE_METATYPE(QList<KTextEditor::Document *>)
-
 QVariant KateFileTreeModel::data(const QModelIndex &index, int role) const
 {
     if (!index.isValid()) {
@@ -572,28 +592,66 @@ QVariant KateFileTreeModel::data(const QModelIndex &index, int role) const
     return QVariant();
 }
 
-QMimeData *KateFileTreeModel::mimeData(const QModelIndexList &indexes) const
+Qt::DropActions KateFileTreeModel::supportedDropActions() const
 {
-    QList<QUrl> urls;
-
-    for (const auto &index : indexes) {
-        ProxyItem *item = static_cast<ProxyItem *>(index.internalPointer());
-        if (!item || !item->doc() || !item->doc()->url().isValid()) {
-            continue;
-        }
+    Qt::DropActions a = QAbstractItemModel::supportedDropActions();
+    a |= Qt::MoveAction;
+    return a;
+}
 
-        urls.append(item->doc()->url());
+QMimeData *KateFileTreeModel::mimeData(const QModelIndexList &indexes) const
+{
+    if (indexes.size() != columnCount()) {
+        return nullptr;
     }
 
-    if (urls.isEmpty()) {
+    ProxyItem *item = static_cast<ProxyItem *>(indexes.at(0).internalPointer());
+    QList<QUrl> urls;
+    if (!item || !item->doc() || !item->doc()->url().isValid()) {
         return nullptr;
     }
+    urls.append(item->doc()->url());
 
-    QMimeData *mimeData = new QMimeData();
+    FileTreeMimeData *mimeData = new FileTreeMimeData(indexes.at(0));
     mimeData->setUrls(urls);
     return mimeData;
 }
 
+bool KateFileTreeModel::canDropMimeData(const QMimeData *data, Qt::DropAction action, int, int, const QModelIndex &parent) const
+{
+    if (auto md = qobject_cast<const FileTreeMimeData *>(data)) {
+        return action == Qt::MoveAction && md->index().parent() == parent;
+    }
+    return false;
+}
+
+bool KateFileTreeModel::dropMimeData(const QMimeData *data, Qt::DropAction, int row, int, const QModelIndex &parent)
+{
+    auto md = qobject_cast<const FileTreeMimeData *>(data);
+    if (!md) {
+        return false;
+    }
+
+    const auto index = md->index();
+    Q_ASSERT(parent == index.parent());
+    if (!index.isValid() || index.row() > rowCount(parent) || index.row() == row) {
+        return false;
+    }
+
+    auto parentItem = parent.isValid() ? static_cast<ProxyItemDir *>(parent.internalPointer()) : m_root;
+    auto &childs = parentItem->children();
+    int sourceRow = index.row();
+
+    beginMoveRows(index.parent(), index.row(), index.row(), parent, row);
+    childs.insert(row, childs.at(index.row()));
+    if (sourceRow > row) {
+        sourceRow++;
+    }
+    childs.takeAt(sourceRow);
+    endMoveRows();
+    return true;
+}
+
 QVariant KateFileTreeModel::headerData(int section, Qt::Orientation orientation, int role) const
 {
     Q_UNUSED(orientation);
@@ -1328,3 +1386,5 @@ void KateFileTreeModel::resetHistory()
         dataChanged(idx, idx, QVector<int>(1, Qt::BackgroundRole));
     }
 }
+
+#include "katefiletreemodel.moc"

addons/filetree/katefiletreemodel.h

@@ -48,6 +48,8 @@ public:
 
     QMimeData *mimeData(const QModelIndexList &indexes) const override;
 
+    Qt::DropActions supportedDropActions() const override;
+
     /* extra api for view */
     QModelIndex docIndex(const KTextEditor::Document *) const;
 
@@ -71,6 +73,9 @@ public:
     void documentEdited(const KTextEditor::Document *);
     void resetHistory();
 
+    bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) override;
+    bool canDropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) const override;
+
 public Q_SLOTS:
     void documentOpened(KTextEditor::Document *);
     void documentClosed(KTextEditor::Document *);
@@ -115,4 +120,6 @@ private:
     bool m_listMode;
 };
 
+Q_DECLARE_METATYPE(QList<KTextEditor::Document *>)
+
 #endif /* KATEFILETREEMODEL_H */

addons/filetree/katefiletreeplugin.cpp

@@ -195,11 +195,6 @@ KateFileTreePluginView::KateFileTreePluginView(KTextEditor::MainWindow *mainWind
     });
 
     m_fileTree->setModel(m_proxyModel);
-
-    m_fileTree->setDragEnabled(false);
-    m_fileTree->setDragDropMode(QAbstractItemView::InternalMove);
-    m_fileTree->setDropIndicatorShown(false);
-
     m_fileTree->setSelectionMode(QAbstractItemView::SingleSelection);
 
     connect(m_fileTree->selectionModel(), &QItemSelectionModel::currentChanged, m_fileTree, &KateFileTree::slotCurrentChanged);

addons/filetree/katefiletreeproxymodel.cpp

@@ -65,6 +65,7 @@ bool KateFileTreeProxyModel::lessThan(const QModelIndex &left, const QModelIndex
     }
 
     case KateFileTreeModel::OpeningOrderRole:
+    case CustomSorting:
         return (left.row() - right.row()) < 0;
     }
 

addons/filetree/katefiletreeproxymodel.h

@@ -14,6 +14,8 @@ namespace KTextEditor
 class Document;
 }
 
+enum { CustomSorting = 1000 };
+
 class KateFileTreeProxyModel : public QSortFilterProxyModel
 {
     Q_OBJECT