Use QCache for model states

mixxxdj · Aug 6, 2021 · 17e31cb · 17e31cb
1 parent f2f72d1
commit 17e31cb
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Showing 4 changed files with 12 additions and 50 deletions.
diff --git a/src/widget/wlibrarytableview.cpp b/src/widget/wlibrarytableview.cpp
@@ -14,19 +14,15 @@
 #include "widget/wwidget.h"
 
 namespace {
-// number of items to stop purging
-constexpr int kClearModelStatesLowWatermark = 1000;
-// number of items to start purging
-constexpr int kClearModelStatesHighWatermark = 1100;
+// number of entries in the model cache
+constexpr int kModelCacheSize = 1000;
 } // namespace
 
 WLibraryTableView::WLibraryTableView(QWidget* parent,
-        UserSettingsPointer pConfig,
-        const ConfigKey& vScrollBarPosKey)
+        UserSettingsPointer pConfig)
         : QTableView(parent),
           m_pConfig(pConfig),
-          m_vScrollBarPosKey(vScrollBarPosKey) {
-
+          m_modelStateCache(kModelCacheSize) {
     // Setup properties for table
 
     // Editing starts when clicking on an already selected item.
@@ -60,8 +56,7 @@ WLibraryTableView::WLibraryTableView(QWidget* parent,
 }
 
 WLibraryTableView::~WLibraryTableView() {
-    qDeleteAll(m_vModelState);
-    m_vModelState.clear();
+    m_modelStateCache.clear();
 }
 
 
@@ -126,12 +121,10 @@ void WLibraryTableView::saveTrackModelState(
     VERIFY_OR_DEBUG_ASSERT(!key.isEmpty()) {
         return;
     }
-    ModelState* state = m_vModelState[key];
+    ModelState* state = m_modelStateCache[key];
     if (!state) {
         state = new ModelState();
     }
-
-    state->lastChange = QDateTime::currentSecsSinceEpoch();
     // qDebug() << "save: saveTrackModelState:" << key << model << verticalScrollBar()->value() << " | ";
     state->verticalScrollPosition = verticalScrollBar()->value();
     state->horizontalScrollPosition = horizontalScrollBar()->value();
@@ -142,11 +135,7 @@ void WLibraryTableView::saveTrackModelState(
         state->selectionIndex = QModelIndexList();
     }
     state->currentIndex = selectionModel()->currentIndex();
-    m_vModelState[key] = state;
-
-    if (m_vModelState.size() > kClearModelStatesHighWatermark) {
-        clearStateCache();
-    }
+    m_modelStateCache.insert(key, state, 1);
 }
 
 void WLibraryTableView::restoreTrackModelState(
@@ -157,7 +146,7 @@ void WLibraryTableView::restoreTrackModelState(
         return;
     }
 
-    ModelState* state = m_vModelState[key];
+    ModelState* state = m_modelStateCache[key];
     if (!state) {
         return;
     }
@@ -225,27 +214,6 @@ void WLibraryTableView::restoreCurrentViewState() {
     restoreTrackModelState(currentModel, key);
 }
 
-void WLibraryTableView::clearStateCache() {
-    auto lru = QMultiMap<qint64, QString>();
-
-    auto i = m_vModelState.constBegin();
-    while (i != m_vModelState.constEnd()) {
-        lru.insert(i.value()->lastChange, i.key());
-        i++;
-    }
-    QList sortKeys = lru.keys();
-    std::sort(sortKeys.begin(),
-            sortKeys.end(),
-            [](const qint64 a, const qint64 b) { return a < b; });
-
-    while (m_vModelState.size() > kClearModelStatesLowWatermark) {
-        const QStringList keys = lru.values(sortKeys.takeFirst());
-        for (const auto& key : keys) {
-            m_vModelState.take(key);
-        }
-    }
-}
-
 void WLibraryTableView::focusInEvent(QFocusEvent* event) {
     QTableView::focusInEvent(event);
 

diff --git a/src/widget/wlibrarytableview.h b/src/widget/wlibrarytableview.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <QCache>
 #include <QDateTime>
 #include <QFont>
 #include <QItemSelectionModel>
@@ -20,13 +21,11 @@ class WLibraryTableView : public QTableView, public virtual LibraryView {
         int verticalScrollPosition;
         QModelIndexList selectionIndex;
         QModelIndex currentIndex;
-        qint64 lastChange;
     };
 
   public:
     WLibraryTableView(QWidget* parent,
-            UserSettingsPointer pConfig,
-            const ConfigKey& vScrollBarPosKey);
+            UserSettingsPointer pConfig);
     ~WLibraryTableView() override;
 
     void moveSelection(int delta) override;
@@ -41,7 +40,6 @@ class WLibraryTableView : public QTableView, public virtual LibraryView {
     /// @param key unique for trackmodel
     void restoreTrackModelState(const QAbstractItemModel* model, const QString& key);
     /// @brief clears the state cache until it's size is = kClearModelStatesLowWatermark
-    void clearStateCache();
     void saveCurrentViewState() override;
     void restoreCurrentViewState() override;
 
@@ -63,8 +61,7 @@ class WLibraryTableView : public QTableView, public virtual LibraryView {
 
   private:
     const UserSettingsPointer m_pConfig;
-    const ConfigKey m_vScrollBarPosKey;
 
     // saves scrollposition/selection/etc
-    QMap<QString, ModelState*> m_vModelState;
+    QCache<QString, ModelState> m_modelStateCache;
 };
diff --git a/src/widget/wtracktableview.cpp b/src/widget/wtracktableview.cpp
@@ -38,9 +38,7 @@ WTrackTableView::WTrackTableView(QWidget* parent,
         double backgroundColorOpacity,
         bool sorting)
         : WLibraryTableView(parent,
-                  pConfig,
-                  ConfigKey(LIBRARY_CONFIGVALUE,
-                          WTRACKTABLEVIEW_VSCROLLBARPOS_KEY)),
+                  pConfig),
           m_pConfig(pConfig),
           m_pLibrary(pLibrary),
           m_backgroundColorOpacity(backgroundColorOpacity),

diff --git a/src/widget/wtracktableview.h b/src/widget/wtracktableview.h
@@ -18,7 +18,6 @@ class ExternalTrackCollection;
 class Library;
 class WTrackMenu;
 
-const QString WTRACKTABLEVIEW_VSCROLLBARPOS_KEY = "VScrollBarPos"; /** ConfigValue key for QTable vertical scrollbar position */
 const QString LIBRARY_CONFIGVALUE = "[Library]"; /** ConfigValue "value" (wtf) for library stuff */
 
 class WTrackTableView : public WLibraryTableView {