Don't reset the whole merged model when one of the submodels changes

src/mergedproxymodel.cpp

@@ -17,13 +17,17 @@
 #include "mergedproxymodel.h"
 
 #include <QStringList>
+#include <QtDebug>
+
+#include <limits>
 
 std::size_t hash_value(const QModelIndex& index) {
   return qHash(index);
 }
 
 MergedProxyModel::MergedProxyModel(QObject* parent)
-  : QAbstractProxyModel(parent)
+  : QAbstractProxyModel(parent),
+    resetting_model_(NULL)
 {
 }
 
@@ -95,12 +99,25 @@ void MergedProxyModel::SourceModelReset() {
 void MergedProxyModel::SubModelReset() {
   const QAbstractItemModel* submodel = static_cast<const QAbstractItemModel*>(sender());
 
+  // TODO: When we require Qt 4.6, use beginResetModel() and endResetModel()
+  // in LibraryModel and catch those here - that will let us do away with this
+  // std::numeric_limits<int>::max() hack.
+
+  // Remove all the children of the item that got deleted
+  QModelIndex source_parent = merge_points_.value(submodel);
+  QModelIndex proxy_parent = mapFromSource(source_parent);
+
+  // We can't know how many children it had, since it's already disappeared...
+  resetting_model_ = submodel;
+  beginRemoveRows(proxy_parent, 0, std::numeric_limits<int>::max() - 1);
+  endRemoveRows();
+  resetting_model_ = NULL;
+
   // Delete all the mappings that reference the submodel
   MappingContainer::index<tag_by_pointer>::type::iterator it =
       mappings_.get<tag_by_pointer>().begin();
   MappingContainer::index<tag_by_pointer>::type::iterator end =
       mappings_.get<tag_by_pointer>().end();
-
   while (it != end) {
     if ((*it)->source_index.model() == submodel) {
       delete *it;
@@ -110,8 +127,12 @@ void MergedProxyModel::SubModelReset() {
     }
   }
 
-  // Reset the proxy
-  reset();
+  // "Insert" items from the newly reset submodel
+  int count = submodel->rowCount();
+  if (count) {
+    beginInsertRows(proxy_parent, 0, count-1);
+    endInsertRows();
+  }
 }
 
 QModelIndex MergedProxyModel::GetActualSourceParent(const QModelIndex& source_parent,
@@ -148,12 +169,20 @@ QModelIndex MergedProxyModel::mapToSource(const QModelIndex& proxy_index) const
     return QModelIndex();
 
   Mapping* mapping = static_cast<Mapping*>(proxy_index.internalPointer());
+  if (mappings_.get<tag_by_pointer>().find(mapping) ==
+      mappings_.get<tag_by_pointer>().end())
+    return QModelIndex();
+  if (mapping->source_index.model() == resetting_model_)
+    return QModelIndex();
+
   return mapping->source_index;
 }
 
 QModelIndex MergedProxyModel::mapFromSource(const QModelIndex& source_index) const {
   if (!source_index.isValid())
     return QModelIndex();
+  if (source_index.model() == resetting_model_)
+    return QModelIndex();
 
   // Add a mapping if we don't have one already
   MappingContainer::index<tag_by_source>::type::iterator it =

src/mergedproxymodel.h

@@ -85,7 +85,9 @@ class MergedProxyModel : public QAbstractProxyModel {
   void DeleteAllMappings();
 
   struct Mapping {
-    Mapping(const QModelIndex& _source_index) : source_index(_source_index) {}
+    Mapping(const QModelIndex& _source_index)
+      : source_index(_source_index) {}
+
     QModelIndex source_index;
   };
 
@@ -103,6 +105,7 @@ class MergedProxyModel : public QAbstractProxyModel {
 
   MappingContainer mappings_;
   QMap<const QAbstractItemModel*, QModelIndex> merge_points_;
+  const QAbstractItemModel* resetting_model_;
 };
 
 #endif // MERGEDPROXYMODEL_H

src/radioviewcontainer.cpp

@@ -31,6 +31,9 @@ RadioViewContainer::RadioViewContainer(QWidget *parent)
 {
   ui_.setupUi(this);
 
+  connect(ui_.tree, SIGNAL(collapsed(QModelIndex)), SLOT(Collapsed(QModelIndex)));
+  connect(ui_.tree, SIGNAL(expanded(QModelIndex)), SLOT(Expanded(QModelIndex)));
+
   filter_animation_->setFrameRange(0, ui_.filter->sizeHint().height());
   connect(filter_animation_, SIGNAL(frameChanged(int)), SLOT(SetFilterHeight(int)));
 
@@ -47,19 +50,37 @@ void RadioViewContainer::SetModel(RadioModel* model) {
           SLOT(CurrentIndexChanged(QModelIndex)));
 }
 
-void RadioViewContainer::CurrentIndexChanged(const QModelIndex& index) {
+void RadioViewContainer::ServiceChanged(const QModelIndex& index, bool changed_away) {
   RadioItem* item = model_->IndexToItem(
       model_->merged_model()->FindSourceParent(index));
   if (!item)
     return;
 
-  RadioService* service = item->service;
-  if (!service || service == current_service_)
-    return;
+  if (changed_away) {
+    SetFilterVisible(false);
+  } else {
+    RadioService* service = item->service;
+    if (!service || service == current_service_)
+      return;
+    current_service_ = service;
 
-  qDebug() << service->name();
+    SetFilterVisible(service->SetupLibraryFilter(ui_.filter));
+  }
+}
 
-  SetFilterVisible(service->SetupLibraryFilter(ui_.filter));
+void RadioViewContainer::CurrentIndexChanged(const QModelIndex& index) {
+  ServiceChanged(index);
+}
+
+void RadioViewContainer::Collapsed(const QModelIndex& index) {
+  if (model_->merged_model()->mapToSource(index).model() == model_) {
+    SetFilterVisible(false);
+    current_service_ = NULL;
+  }
+}
+
+void RadioViewContainer::Expanded(const QModelIndex& index) {
+  ServiceChanged(index);
 }
 
 void RadioViewContainer::SetFilterVisible(bool visible) {

src/radioviewcontainer.h

@@ -38,10 +38,13 @@ class RadioViewContainer : public QWidget {
   RadioView* tree() const { return ui_.tree; }
 
  private slots:
+  void Collapsed(const QModelIndex& index);
+  void Expanded(const QModelIndex& index);
   void CurrentIndexChanged(const QModelIndex& index);
   void SetFilterHeight(int height);
 
  private:
+  void ServiceChanged(const QModelIndex& index, bool changed_away = false);
   void SetFilterVisible(bool visible);
 
  private: