Store settings in SqliteTableModel

Store the relevant settings in SqliteTableModel and only update them
when they have changed. This avoids a lot of querying and converting of
variables in the data() function which is called very often and
therefore is somewhat critical for the overall performance.

src/ExtendedTableWidget.cpp

@@ -150,7 +150,7 @@ QWidget* ExtendedTableWidgetEditorDelegate::createEditor(QWidget* parent, const
         if (!currentTable->fields.at(static_cast<size_t>(index.column())-1).notnull())
             query.append (" UNION SELECT NULL");
 
-        SqliteTableModel* fkModel = new SqliteTableModel(m->db(), parent, m->chunkSize(), m->encoding());
+        SqliteTableModel* fkModel = new SqliteTableModel(m->db(), parent, m->encoding());
         fkModel->setQuery(query);
 
         QComboBox* combo = new QComboBox(parent);

src/SqlExecutionArea.cpp

@@ -22,7 +22,7 @@ SqlExecutionArea::SqlExecutionArea(DBBrowserDB& _db, QWidget* parent) :
     ui->setupUi(this);
 
     // Create model
-    model = new SqliteTableModel(db, this, static_cast<std::size_t>(Settings::getValue("db", "prefetchsize").toUInt()));
+    model = new SqliteTableModel(db, this);
     ui->tableResult->setModel(model);
     connect(model, &SqliteTableModel::finishedFetch, this, &SqlExecutionArea::fetchedData);
 
@@ -149,8 +149,8 @@ void SqlExecutionArea::reloadSettings()
     ui->splitter->restoreState(Settings::getValue("editor", "splitter1_sizes").toByteArray());
     ui->splitter_2->restoreState(Settings::getValue("editor", "splitter2_sizes").toByteArray());
 
-    // Set prefetch settings
-    model->setChunkSize(static_cast<std::size_t>(Settings::getValue("db", "prefetchsize").toUInt()));
+    // Reload model settings
+    model->reloadSettings();
 
     // Check if error indicators are enabled for the not-ok background clue
     showErrorIndicators = Settings::getValue("editor", "error_indicators").toBool();

src/TableBrowser.cpp

@@ -287,7 +287,7 @@ void TableBrowser::init(DBBrowserDB* _db)
 
     if(m_model)
         delete m_model;
-    m_model = new SqliteTableModel(*db, this, static_cast<std::size_t>(Settings::getValue("db", "prefetchsize").toUInt()));
+    m_model = new SqliteTableModel(*db, this);
 
     connect(m_model, &SqliteTableModel::finishedFetch, this, &TableBrowser::updateRecordsetLabel);
 }
@@ -537,7 +537,7 @@ void TableBrowser::reloadSettings()
     ui->dataTable->reloadSettings();
 
     ui->browseToolbar->setToolButtonStyle(static_cast<Qt::ToolButtonStyle>(Settings::getValue("General", "toolbarStyleBrowse").toInt()));
-    m_model->setChunkSize(static_cast<std::size_t>(Settings::getValue("db", "prefetchsize").toUInt()));
+    m_model->reloadSettings();
 }
 
 void TableBrowser::setCurrentTable(const sqlb::ObjectIdentifier& name)

src/sqlitetablemodel.cpp

@@ -20,14 +20,16 @@
 
 using json = nlohmann::json;
 
-SqliteTableModel::SqliteTableModel(DBBrowserDB& db, QObject* parent, size_t chunkSize, const QString& encoding)
+SqliteTableModel::SqliteTableModel(DBBrowserDB& db, QObject* parent, const QString& encoding)
     : QAbstractTableModel(parent)
     , m_db(db)
     , m_lifeCounter(0)
     , m_currentRowCount(0)
-    , m_chunkSize(chunkSize)
     , m_encoding(encoding)
 {
+    // Load initial settings first
+    reloadSettings();
+
     worker = new RowLoader(
         [this](){ return m_db.get(tr("reading rows")); },
         [this](QString stmt){ return m_db.logSQL(stmt, kLogMsg_App); },
@@ -114,11 +116,6 @@ void SqliteTableModel::reset()
     endResetModel();
 }
 
-void SqliteTableModel::setChunkSize(size_t chunksize)
-{
-    m_chunkSize = chunksize;
-}
-
 void SqliteTableModel::setQuery(const sqlb::Query& query)
 {
     // Unset all previous settings. When setting a table all information on the previously browsed data set is removed first.
@@ -341,15 +338,14 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
             return tr("loading...");
         if(role == Qt::DisplayRole && cached_row->at(column).isNull())
         {
-            return Settings::getValue("databrowser", "null_text").toString();
+            return m_nullText;
         } else if(role == Qt::DisplayRole && nosync_isBinary(index)) {
-            return Settings::getValue("databrowser", "blob_text").toString();
+            return m_blobText;
         } else if(role == Qt::DisplayRole) {
-            int limit = Settings::getValue("databrowser", "symbol_limit").toInt();
             QByteArray displayText = cached_row->at(column);
-            if (displayText.length() > limit) {
+            if (displayText.length() > m_symbolLimit) {
                 // Add "..." to the end of truncated strings
-                return decode(displayText.left(limit).append(" ..."));
+                return decode(displayText.left(m_symbolLimit).append(" ..."));
             } else {
                 return decode(displayText);
             }
@@ -373,9 +369,9 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
         if(!row_available)
             return QColor(100, 100, 100);
         if(cached_row->at(column).isNull())
-            return QColor(Settings::getValue("databrowser", "null_fg_colour").toString());
+            return m_nullFgColour;
         else if (nosync_isBinary(index))
-            return QColor(Settings::getValue("databrowser", "bin_fg_colour").toString());
+            return m_binFgColour;
         else if (m_mCondFormats.find(column) != m_mCondFormats.end()) {
             QString value = cached_row->at(column);
             // Unlock before querying from DB
@@ -385,14 +381,14 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
                 return condFormatColor;
             }
         // Regular case (not null, not binary and no matching conditional format)
-        return QColor(Settings::getValue("databrowser", "reg_fg_colour").toString());
+        return m_regFgColour;
     } else if (role == Qt::BackgroundRole) {
         if(!row_available)
             return QColor(255, 200, 200);
         if(cached_row->at(column).isNull())
-            return QColor(Settings::getValue("databrowser", "null_bg_colour").toString());
+            return m_nullBgColour;
         else if (nosync_isBinary(index))
-            return QColor(Settings::getValue("databrowser", "bin_bg_colour").toString());
+            return m_binBgColour;
         else if (m_mCondFormats.find(column) != m_mCondFormats.end()) {
             QString value = cached_row->at(column);
             // Unlock before querying from DB
@@ -402,7 +398,7 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
                 return condFormatColor;
         }
         // Regular case (not null, not binary and no matching conditional format)
-        return QColor(Settings::getValue("databrowser", "reg_bg_colour").toString());
+        return m_regBgColour;
     } else if(role == Qt::ToolTipRole) {
         sqlb::ForeignKeyClause fk = getForeignKeyClause(column-1);
         if(fk.isSet())
@@ -427,7 +423,7 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
         if(!row_available)
             return QVariant();
 
-        if(Settings::getValue("databrowser", "image_preview").toBool() && !isImageData(cached_row->at(column)).isNull())
+        if(m_imagePreviewEnabled && !isImageData(cached_row->at(column)).isNull())
         {
             QImage img;
             img.loadFromData(cached_row->at(column));
@@ -1151,3 +1147,18 @@ QModelIndex SqliteTableModel::nextMatch(const QModelIndex& start, const std::vec
             return pos;
     }
 }
+
+void SqliteTableModel::reloadSettings()
+{
+    m_nullText = Settings::getValue("databrowser", "null_text").toString();
+    m_blobText = Settings::getValue("databrowser", "blob_text").toString();
+    m_regFgColour = QColor(Settings::getValue("databrowser", "reg_fg_colour").toString());
+    m_regBgColour = QColor(Settings::getValue("databrowser", "reg_bg_colour").toString());
+    m_nullFgColour = QColor(Settings::getValue("databrowser", "null_fg_colour").toString());
+    m_nullBgColour = QColor(Settings::getValue("databrowser", "null_bg_colour").toString());
+    m_binFgColour = QColor(Settings::getValue("databrowser", "bin_fg_colour").toString());
+    m_binBgColour = QColor(Settings::getValue("databrowser", "bin_bg_colour").toString());
+    m_symbolLimit = Settings::getValue("databrowser", "symbol_limit").toInt();
+    m_imagePreviewEnabled = Settings::getValue("databrowser", "image_preview").toBool();
+    m_chunkSize = static_cast<std::size_t>(Settings::getValue("db", "prefetchsize").toUInt());
+}

src/sqlitetablemodel.h

@@ -2,6 +2,7 @@
 #define SQLITETABLEMODEL_H
 
 #include <QAbstractTableModel>
+#include <QColor>
 #include <QMutex>
 
 #include <memory>
@@ -25,7 +26,7 @@ class SqliteTableModel : public QAbstractTableModel
 #endif
 
 public:
-    explicit SqliteTableModel(DBBrowserDB& db, QObject *parent = nullptr, size_t chunkSize = 50000, const QString& encoding = QString());
+    explicit SqliteTableModel(DBBrowserDB& db, QObject *parent = nullptr, const QString& encoding = QString());
     ~SqliteTableModel() override;
 
     /// reset to state after construction
@@ -86,8 +87,6 @@ public:
     /// configure for browsing specified table
     void setQuery(const sqlb::Query& query);
 
-    void setChunkSize(size_t chunksize);
-    size_t chunkSize() { return m_chunkSize; }
     void sort(int column, Qt::SortOrder order = Qt::AscendingOrder) override;
     void sort(const std::vector<sqlb::SortedColumn>& columns);
     sqlb::ObjectIdentifier currentTableName() const { return m_query.table(); }
@@ -132,6 +131,8 @@ public:
 
     DBBrowserDB& db() { return m_db; }
 
+    void reloadSettings();
+
 public slots:
     void updateFilter(size_t column, const QString& value);
     void updateGlobalFilter(const std::vector<QString>& values);
@@ -200,6 +201,31 @@ private:
     std::map<size_t, std::vector<CondFormat>> m_mCondFormats;
     sqlb::Query m_query;
 
+    QString m_encoding;
+
+    /**
+     * These are used for multi-threaded population of the table
+     */
+    mutable QMutex m_mutexDataCache;
+
+private:
+    /**
+     * Settings. These are stored here to avoid fetching and converting them every time we need them. Because this class
+     * uses a lot of settings and because some of its functions are called very often, this should speed things up noticeable.
+     * Call reloadSettings() to update these.
+     */
+
+    QString m_nullText;
+    QString m_blobText;
+    QColor m_regFgColour;
+    QColor m_regBgColour;
+    QColor m_nullFgColour;
+    QColor m_nullBgColour;
+    QColor m_binFgColour;
+    QColor m_binBgColour;
+    int m_symbolLimit;
+    bool m_imagePreviewEnabled;
+
     /**
      * @brief m_chunkSize Size of the next chunk fetch more will try to fetch.
      * This value should be rather high, because our query
@@ -209,13 +235,6 @@ private:
      * to that row count.
      */
     size_t m_chunkSize;
-
-    QString m_encoding;
-
-    /**
-     * These are used for multi-threaded population of the table
-     */
-    mutable QMutex m_mutexDataCache;
 };
 
 #endif