Cache sub-menus.

Approved by Renato Araujo Oliveira Filho, PS Jenkins bot.

2 files changed, 54 insertions, 15 deletions

diff --git a/libqmenumodel/src/qmenumodel.cpp b/libqmenumodel/src/qmenumodel.cpp
index 53dc966..1326d77 100644
--- a/libqmenumodel/src/qmenumodel.cpp
+++ b/libqmenumodel/src/qmenumodel.cpp
@@ -15,6 +15,7 @@
  *
  * Authors:
  *      Renato Araujo Oliveira Filho <renato@canonical.com>
+ *      Olivier Tilloy <olivier.tilloy@canonical.com>
  */
 
 extern "C" {
@@ -24,8 +25,6 @@ extern "C" {
 #include "qmenumodel.h"
 #include "converter.h"
 
-#include <QDebug>
-
 /*!
     \qmltype QMenuModel
     \brief The QMenuModel class implements the base list model for menus
@@ -41,6 +40,7 @@ QMenuModel::QMenuModel(GMenuModel *other, QObject *parent)
       m_menuModel(0),
       m_signalChangedId(0)
 {
+    m_cache = new QHash<int, QMenuModel*>;
     setMenuModel(other);
 
     connect(this, SIGNAL(rowsInserted(const QModelIndex &, int, int)), SIGNAL(countChanged()));
@@ -52,6 +52,7 @@ QMenuModel::QMenuModel(GMenuModel *other, QObject *parent)
 QMenuModel::~QMenuModel()
 {
     clearModel();
+    delete m_cache;
 }
 
 /*!
@@ -131,10 +132,10 @@ void QMenuModel::clearModel()
         m_menuModel = NULL;
     }
 
-    QList<QMenuModel*> list = findChildren<QMenuModel*>(QString(), Qt::FindDirectChildrenOnly);
-    Q_FOREACH(QMenuModel *model, list) {
-        delete model;
+    Q_FOREACH(QMenuModel* child, *m_cache) {
+        delete child;
     }
+    m_cache->clear();
 }
 
 /*! \internal */
@@ -219,17 +220,25 @@ QVariant QMenuModel::getStringAttribute(const QModelIndex &index,
 QVariant QMenuModel::getLink(const QModelIndex &index,
                              const QString &linkName) const
 {
-    GMenuModel *link;
-
-    link = g_menu_model_get_item_link(m_menuModel,
-                                      index.row(),
-                                      linkName.toUtf8().data());
-
+    GMenuModel *link = g_menu_model_get_item_link(m_menuModel,
+                                                  index.row(),
+                                                  linkName.toUtf8().data());
     if (link) {
-        QMenuModel *other = new QMenuModel(link, const_cast<QMenuModel*>(this));
-        return QVariant::fromValue<QObject*>(other);
+        QMenuModel* child = 0;
+        int key = index.row();
+        if (m_cache->contains(key)) {
+            QMenuModel* cached = m_cache->value(key);
+            if (cached->menuModel() == link) {
+                child = cached;
+            }
+        }
+        if (child == 0) {
+            child = new QMenuModel(link);
+            m_cache->insert(key, child);
+        }
+        g_object_unref(link);
+        return QVariant::fromValue<QObject*>(child);
     }
-
     return QVariant();
 }
 
@@ -265,21 +274,47 @@ QVariant QMenuModel::getExtraProperties(const QModelIndex &index) const
 }
 
 /*! \internal */
-void QMenuModel::onItemsChanged(GMenuModel *,
+QHash<int, QMenuModel*> QMenuModel::cache() const
+{
+    return *m_cache;
+}
+
+/*! \internal */
+void QMenuModel::onItemsChanged(GMenuModel *model,
                                 gint position,
                                 gint removed,
                                 gint added,
                                 gpointer data)
 {
     QMenuModel *self = reinterpret_cast<QMenuModel*>(data);
+    QHash<int, QMenuModel*>* cache = self->m_cache;
 
+    int prevcount = g_menu_model_get_n_items(model) + removed - added;
     if (removed > 0) {
         self->beginRemoveRows(QModelIndex(), position, position + removed - 1);
+        // Remove invalidated menus from the cache
+        for (int i = position, iMax = position + removed; i < iMax; ++i) {
+            if (cache->contains(i)) {
+                delete cache->take(i);
+            }
+        }
+        // Update the indexes of other cached menus to account for the removals
+        for (int i = position + removed; i < prevcount; ++i) {
+            if (cache->contains(i)) {
+                cache->insert(i - removed, cache->take(i));
+            }
+        }
         self->endRemoveRows();
     }
 
     if (added > 0) {
         self->beginInsertRows(QModelIndex(), position, position + added - 1);
+        // Update the indexes of cached menus to account for the insertions
+        for (int i = prevcount - removed - 1; i >= position; --i) {
+            if (cache->contains(i)) {
+                cache->insert(i + added, cache->take(i));
+            }
+        }
         self->endInsertRows();
     }
 }
diff --git a/libqmenumodel/src/qmenumodel.h b/libqmenumodel/src/qmenumodel.h
index 9371bd8..54a5c42 100644
--- a/libqmenumodel/src/qmenumodel.h
+++ b/libqmenumodel/src/qmenumodel.h
@@ -60,7 +60,11 @@ protected:
     void setMenuModel(GMenuModel *model);
     GMenuModel *menuModel() const;
 
+    // helper getter intended for use in tests only
+    QHash<int, QMenuModel*> cache() const;
+
 private:
+    QHash<int, QMenuModel*>* m_cache;
     GMenuModel *m_menuModel;
     guint m_signalChangedId;