Move all settings logic to the preferences dialog

Read and write the settings only from the preferences dialog.

Remove all the copies of some settings which were stored in nearly every
dialog class individually.

Simplify the settings dialog code by removing all those not really
needed slots.

src/PreferencesDialog.cpp

@@ -5,6 +5,8 @@
 #include <QFileDialog>
 #include "sqlitedb.h"
 
+QHash<QString, QVariant> PreferencesDialog::m_hCache;
+
 PreferencesDialog::PreferencesDialog(QWidget* parent)
     : QDialog(parent),
       ui(new Ui::PreferencesDialog)
@@ -22,108 +24,105 @@ PreferencesDialog::~PreferencesDialog()
     delete ui;
 }
 
-void PreferencesDialog::defaultDataChanged( int which )
-{
-    if (which==2) {
-        defaultnewdata = QString("\'\'");
-    } else if (which==1) {
-        defaultnewdata = QString("0");
-    } else {
-        defaultnewdata = QString("NULL");
-    }
-}
-
-void PreferencesDialog::defaultTextChanged( int which )
-{
-    if (which==1) {
-        defaulttext = QString("Auto");
-    } else {
-        defaulttext = QString("Plain");
-    }
-
-}
-
-void PreferencesDialog::encodingChanged( int which )
-{
-    if (which == 0) {
-        defaultencoding = QString("UTF-8");
-    } else {
-        defaultencoding = QString("UTF-16");
-    }
-}
-
-void PreferencesDialog::foreignkeysStateChanged(int state)
-{
-    foreignkeys = state > 0;
-}
-
 void PreferencesDialog::chooseLocation()
 {
     QString s = QFileDialog::getExistingDirectory(
                 this,
                 tr("Choose a directory"),
-                defaultlocation,
+                getSettingsValue("db", "defaultlocation").toString(),
                 QFileDialog::ShowDirsOnly | QFileDialog::DontResolveSymlinks);
 
     if(!s.isEmpty())
-    {
-        defaultlocation = s;
-        ui->locationEdit->setText(defaultlocation);
-    }
+        ui->locationEdit->setText(s);
 }
 
 void PreferencesDialog::loadSettings()
 {
-    QSettings settings(QApplication::organizationName(), QApplication::organizationName());
-    settings.sync();
-
-    defaultencoding = settings.value( "/db/defaultencoding", "UTF-8" ).toString();
-    defaultnewdata = settings.value( "/db/defaultnewdata", "NULL" ).toString();
-    defaultlocation = settings.value( "/db/defaultlocation", QDir::homePath() ).toString();
-    defaulttext = settings.value( "/db/defaulttext", "Plain" ).toString();
-    foreignkeys = settings.value( "/db/foreignkeys", true ).toBool();
-
-    if (defaultencoding=="Latin1" || defaultencoding == "UTF-8")
-    {
-        ui->encodingComboBox->setCurrentIndex(0);
-    } else {
-        ui->encodingComboBox->setCurrentIndex(1);
-        defaultencoding = QString("UTF-16");
-    }
-    
-    if (defaultnewdata=="\'\'")
-    {
-	ui->defaultdataComboBox->setCurrentIndex(2) ;
-    } else if (defaultnewdata=="0")
-    {
-	ui->defaultdataComboBox->setCurrentIndex(1) ;
-    } else {
-	ui->defaultdataComboBox->setCurrentIndex(0) ;
-        defaultnewdata = QString("NULL");
-    }
-
-    if (defaulttext=="Auto")
-    {
-	ui->defaultTextComboBox->setCurrentIndex(1) ;
-    } else {
-	ui->defaultTextComboBox->setCurrentIndex(0) ;
-        defaulttext = QString("Plain");
-    }
-
-    ui->foreignKeysCheckBox->setChecked(foreignkeys);
-    
-    ui->locationEdit->setText(defaultlocation);
+    ui->encodingComboBox->setCurrentIndex(ui->encodingComboBox->findText(getSettingsValue("db", "defaultencoding").toString(), Qt::MatchFixedString));
+    ui->defaultdataComboBox->setCurrentIndex(ui->defaultdataComboBox->findText(getSettingsValue("db", "defaultnewdata").toString(), Qt::MatchFixedString));
+    ui->locationEdit->setText(getSettingsValue("db", "defaultlocation").toString());
+    ui->defaultTextComboBox->setCurrentIndex(ui->defaultTextComboBox->findText(getSettingsValue("db", "defaulttext").toString(), Qt::MatchFixedString));
+    ui->foreignKeysCheckBox->setChecked(getSettingsValue("db", "foreignkeys").toBool());
 }
 
 void PreferencesDialog::saveSettings()
 {
-    QSettings settings(QApplication::organizationName(), QApplication::organizationName());
-
-    settings.setValue( "/db/defaultencoding", defaultencoding  );
-    settings.setValue( "/db/defaultnewdata", defaultnewdata );
-    settings.setValue( "/db/defaultlocation", defaultlocation  );
-    settings.setValue( "/db/defaulttext", defaulttext  );
-    settings.setValue( "/db/foreignkeys", foreignkeys );
-    settings.sync();
+    setSettingsValue("db", "defaultencoding", ui->encodingComboBox->currentText());
+    setSettingsValue("db", "defaultnewdata", ui->defaultdataComboBox->currentText());
+    setSettingsValue("db", "defaultlocation", ui->locationEdit->text());
+    setSettingsValue("db", "defaulttext", ui->defaultTextComboBox->currentText());
+    setSettingsValue("db", "foreignkeys", ui->foreignKeysCheckBox->isChecked());
     accept();
 }
+
+QVariant PreferencesDialog::getSettingsValue(const QString& group, const QString& name)
+{
+    // Have a look in the cache first
+    QHash<QString, QVariant>::iterator cacheIndex = m_hCache.find(group + name);
+    if(cacheIndex != m_hCache.end())
+    {
+        return cacheIndex.value();
+    } else {
+        // Nothing found in the cache, so get the value from the settings file or get the default value if there is no value set yet
+        QSettings settings(QApplication::organizationName(), QApplication::organizationName());
+        QVariant value = settings.value(group + "/" + name, getSettingsDefaultValue(group, name));
+
+        // Store this value in the cache for further usage and return it afterwards
+        m_hCache.insert(group + name, value);
+        return value;
+    }
+}
+
+void PreferencesDialog::setSettingsValue(const QString& group, const QString& name, const QVariant& value)
+{
+    // Set the group and save the given value
+    QSettings settings(QApplication::organizationName(), QApplication::organizationName());
+    settings.beginGroup(group);
+    settings.setValue(name, value);
+    settings.endGroup();
+
+    // Also change it in the cache
+    m_hCache[group + name] = value;
+}
+
+QVariant PreferencesDialog::getSettingsDefaultValue(const QString& group, const QString& name)
+{
+    // db/defaultencoding?
+    if(group == "db" && name == "defaultencoding")
+        return "UTF-8";
+
+    // db/defaultnewdata?
+    if(group == "db" && name == "defaultnewdata")
+        return "NULL";
+
+    // db/defaultlocation?
+    if(group == "db" && name == "defaultlocation")
+        return QDir::homePath();
+
+    // db/defaulttext?
+    if(group == "db" && name == "defaulttext")
+        return "Plain";
+
+    // db/foreignkeys?
+    if(group == "db" && name == "foreignkeys")
+        return true;
+
+    // MainWindow/geometry?
+    if(group == "MainWindow" && name == "geometry")
+        return "";
+
+    // MainWindow/windowState?
+    if(group == "MainWindow" && name == "windowState")
+        return "";
+
+    // SQLLogDock/Log?
+    if(group == "SQLLogDock" && name == "Log")
+        return "Application";
+
+    // General/recentFileList?
+    if(group == "General" && name == "recentFileList")
+        return QStringList();
+
+    // Unknown combination of group and name? Return an invalid QVariant!
+    return QVariant();
+}