Merge pull request #6364 from 3nids/setting_enum_value

[settings] add method to get value for a setting associated to an enum

python/core/qgssettings.sip.in

@@ -9,6 +9,7 @@
 
 
 
+
 class QgsSettings : QObject
 {
 %Docstring
@@ -220,6 +221,7 @@ An optional Section argument can be used to get a value from a specific Section.
     sipIsErr = !sipRes;
 %End
 
+
     bool contains( const QString &key, const QgsSettings::Section section = QgsSettings::NoSection ) const;
 %Docstring
 Returns true if there exists a setting called key; returns false otherwise.

src/core/qgssettings.h

@@ -18,6 +18,8 @@
 #define QGSSETTINGS_H
 
 #include <QSettings>
+#include <QMetaEnum>
+
 #include "qgis_core.h"
 #include "qgis.h"
 
@@ -216,6 +218,31 @@ class CORE_EXPORT QgsSettings : public QObject
     % End
 #endif
 
+#ifndef SIP_RUN
+
+    /**
+     * Return the setting value for a setting based on an enum.
+     * This forces the output to be a valid and existing entry of the enum.
+     * Hence if the setting value is incorrect, the given default value is returned.
+     * \note The enum needs to be declared with Q_ENUM
+     */
+    template <class T>
+    T enumSettingValue( const QString &key, const T &defaultValue,
+                        const Section section = NoSection ) const
+    {
+      T v = static_cast<T>( value( key, static_cast<int>( defaultValue ), section ).toInt() );
+      QMetaEnum metaEnum = QMetaEnum::fromType<T>();
+      if ( metaEnum.isValid() )
+      {
+        if ( !metaEnum.valueToKey( static_cast<int>( v ) ) )
+        {
+          v = defaultValue;
+        }
+      }
+      return v;
+    }
+#endif
+
     /**
      * Returns true if there exists a setting called key; returns false otherwise.
      * If a group is set using beginGroup(), key is taken to be relative to that group.

tests/src/core/CMakeLists.txt

@@ -165,6 +165,7 @@ SET(TESTS
  testqgsrectangle.cpp
  testqgsrenderers.cpp
  testqgsrulebasedrenderer.cpp
+ testqgssettings.cpp
  testqgsshapeburst.cpp
  testqgssimplemarker.cpp
  testqgssnappingutils.cpp

tests/src/core/testqgssettings.cpp

@@ -0,0 +1,56 @@
+/***************************************************************************
+     testqgssettings.cpp
+     --------------------------------------
+    Date                 : 17.02.2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis.rouzaud@gmail.com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#include <QObject>
+
+
+#include "qgssettings.h"
+#include "qgsunittypes.h"
+#include "qgstest.h"
+
+
+/**
+ * \ingroup UnitTests
+ * This is a unit test for the operations on curve geometries
+ */
+class TestQgsSettings : public QObject
+{
+    Q_OBJECT
+
+  private slots:
+    void enumSettingValue();
+};
+
+
+void TestQgsSettings::enumSettingValue()
+{
+  QgsSettings settings;
+
+  // assign to inexisting value
+  settings.setValue( QStringLiteral( "qgis/testing/my_value_for_units" ), -1 );
+  // just to be sure it really doesn't exist
+  QVERIFY( static_cast<int>( QgsUnitTypes::LayoutMeters ) != -1 );
+
+  // standard method returns invalid value
+  int v1 = settings.value( QStringLiteral( "qgis/testing/my_value_for_units" ), QgsUnitTypes::LayoutMeters ).toInt();
+  QCOMPARE( v1, -1 );
+
+  // enum method returns default value if current setting is incorrect
+  QgsUnitTypes::LayoutUnit v2 = settings.enumSettingValue( QStringLiteral( "qgis/testing/my_value_for_units" ), QgsUnitTypes::LayoutMeters );
+  QCOMPARE( v2, QgsUnitTypes::LayoutMeters );
+}
+
+
+QGSTEST_MAIN( TestQgsSettings )
+#include "testqgssettings.moc"