TreeModel: Add more item functions

canFetchMore/fetchMore, and insertChild (at given position). Make
prepend/appendChild use the latter.

Change-Id: I4162fe6e64f37d26de209aa81894c9730957694b
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>

src/libs/utils/treemodel.cpp

@@ -671,39 +671,36 @@ Qt::ItemFlags TreeItem::flags(int column) const
     return m_flags;
 }
 
+bool TreeItem::canFetchMore() const
+{
+    return false;
+}
+
 void TreeItem::prependChild(TreeItem *item)
 {
-    QTC_CHECK(!item->parent());
+    insertChild(0, item);
-
-    if (m_model && !m_lazy) {
-        QModelIndex idx = index();
-        item->propagateModel(m_model);
-        m_model->beginInsertRows(idx, 0, 0);
-        item->m_parent = this;
-        item->m_model = m_model;
-        m_children.prepend(item);
-        m_model->endInsertRows();
-    } else {
-        m_children.prepend(item);
-    }
 }
 
 void TreeItem::appendChild(TreeItem *item)
+{
+    insertChild(m_children.size(), item);
+}
+
+void TreeItem::insertChild(int pos, TreeItem *item)
 {
     QTC_CHECK(!item->parent());
+    QTC_ASSERT(0 <= pos && pos <= m_children.size(), return); // '<= size' is intentional.
 
     if (m_model && !m_lazy) {
-        const int n = rowCount();
         QModelIndex idx = index();
-        item->propagateModel(m_model);
+        m_model->beginInsertRows(idx, pos, pos);
-        m_model->beginInsertRows(idx, n, n);
         item->m_parent = this;
         item->m_model = m_model;
-        m_children.append(item);
+        m_children.insert(m_children.begin() + pos, item);
         m_model->endInsertRows();
     } else {
         item->m_parent = this;
-        m_children.append(item);
+        m_children.insert(m_children.begin() + pos, item);
     }
 }
 
@@ -910,6 +907,23 @@ Qt::ItemFlags TreeModel::flags(const QModelIndex &idx) const
                 : (Qt::ItemIsEnabled|Qt::ItemIsSelectable);
 }
 
+bool TreeModel::canFetchMore(const QModelIndex &idx) const
+{
+    if (!idx.isValid())
+        return false;
+    TreeItem *item = itemFromIndex(idx);
+    return item ? item->canFetchMore() : false;
+}
+
+void TreeModel::fetchMore(const QModelIndex &idx)
+{
+    if (!idx.isValid())
+        return;
+    TreeItem *item = itemFromIndex(idx);
+    if (item)
+        item->fetchMore();
+}
+
 TreeItem *TreeModel::rootItem() const
 {
     return m_root;

src/libs/utils/treemodel.h

@@ -62,8 +62,12 @@ public:
     virtual bool setData(int column, const QVariant &data, int role);
     virtual Qt::ItemFlags flags(int column) const;
 
+    virtual bool canFetchMore() const;
+    virtual void fetchMore() {}
+
     void prependChild(TreeItem *item);
     void appendChild(TreeItem *item);
+    void insertChild(int pos, TreeItem *item);
     void removeChildren();
     void update();
     void expand();
@@ -242,6 +246,9 @@ public:
     Qt::ItemFlags flags(const QModelIndex &idx) const;
     QVariant headerData(int section, Qt::Orientation orientation, int role) const;
 
+    bool canFetchMore(const QModelIndex &idx) const;
+    void fetchMore(const QModelIndex &idx);
+
     TreeItem *rootItem() const;
     TreeItem *itemFromIndex(const QModelIndex &) const;
     QModelIndex indexFromItem(const TreeItem *needle) const;