Preview task-group selections until Meta is released

plasma-task-group-shortcuts/pendingselection.cpp

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: MIT
+
+#include "pendingselection.h"
+
+PendingSelection::PendingSelection(QAbstractItemModel &model)
+{
+    connect(&model, &QAbstractItemModel::modelReset, this, &PendingSelection::cancel);
+    connect(&model, &QAbstractItemModel::rowsRemoved, this, [this] {
+        if (!m_task.isValid()) {
+            cancel();
+        }
+    });
+}
+
+void PendingSelection::select(const QModelIndex &task, bool defer)
+{
+    m_task = task;
+    if (defer && task.isValid()) {
+        Q_EMIT previewRequested(task);
+    } else {
+        finish();
+    }
+}
+
+void PendingSelection::finish()
+{
+    const QPersistentModelIndex task = m_task;
+    cancel();
+    if (task.isValid()) {
+        Q_EMIT activationRequested(task);
+    }
+}
+
+void PendingSelection::cancel()
+{
+    m_task = QPersistentModelIndex();
+    Q_EMIT previewHidden();
+}