[FEATURE] Detect literal default values for spatialite provider

src/providers/spatialite/qgsspatialiteprovider.cpp

@@ -684,6 +684,7 @@ void QgsSpatiaLiteProvider::loadFieldsAbstractInterface( gaiaVectorLayerPtr lyr
   mAttributeFields.clear();
   mPrimaryKey.clear(); // cazzo cazzo cazzo
   mPrimaryKeyAttrs.clear();
+  mDefaultValues.clear();
 
   gaiaLayerAttributeFieldPtr fld = lyr->First;
   if ( !fld )
@@ -729,6 +730,8 @@ void QgsSpatiaLiteProvider::loadFieldsAbstractInterface( gaiaVectorLayerPtr lyr
     for ( int i = 1; i <= rows; i++ )
     {
       QString name = QString::fromUtf8( results[( i * columns ) + 1] );
+      insertDefaultValue( i - 1, QString::fromUtf8( results[( i * columns ) + 4] ) );
+
       QString pk = results[( i * columns ) + 5];
       QString type = results[( i * columns ) + 2];
       type = type.toLower();
@@ -870,6 +873,37 @@ error:
 
 }
 
+void QgsSpatiaLiteProvider::insertDefaultValue( int fieldIndex, QString defaultVal )
+{
+  if ( !defaultVal.isEmpty() )
+  {
+    QVariant defaultVariant;
+    switch ( mAttributeFields.at( fieldIndex ).type() )
+    {
+      case QVariant::LongLong:
+        defaultVariant = defaultVal.toLongLong();
+        break;
+
+      case QVariant::Double:
+        defaultVariant = defaultVal.toDouble();
+        break;
+
+      default:
+      {
+        if ( defaultVal.startsWith( '\'' ) )
+          defaultVal = defaultVal.remove( 0, 1 );
+        if ( defaultVal.endsWith( '\'' ) )
+          defaultVal.chop( 1 );
+        defaultVal.replace( "''", "'" );
+
+        defaultVariant = defaultVal;
+        break;
+      }
+    }
+    mDefaultValues.insert( fieldIndex, defaultVariant );
+  }
+}
+
 void QgsSpatiaLiteProvider::loadFields()
 {
   int ret;
@@ -884,6 +918,7 @@ void QgsSpatiaLiteProvider::loadFields()
   QString sql;
 
   mAttributeFields.clear();
+  mDefaultValues.clear();
 
   if ( !mIsQuery )
   {
@@ -921,6 +956,8 @@ void QgsSpatiaLiteProvider::loadFields()
           const TypeSubType fieldType = getVariantType( type );
           mAttributeFields.append( QgsField( name, fieldType.first, type, 0, 0, QString(), fieldType.second ) );
         }
+
+        insertDefaultValue( i - 1, QString::fromUtf8( results[( i * columns ) + 4] ) );
       }
     }
     sqlite3_free_table( results );
@@ -3820,8 +3857,10 @@ bool QgsSpatiaLiteProvider::addFeatures( QgsFeatureList & flist )
           }
           else if ( type == QVariant::String )
           {
+            QString stringVal = v.toString();
+
             // binding a TEXT value
-            QByteArray ba = v.toString().toUtf8();
+            QByteArray ba = stringVal.toUtf8();
             sqlite3_bind_text( stmt, ++ia, ba.constData(), ba.size(), SQLITE_TRANSIENT );
           }
           else if ( type == QVariant::StringList || type == QVariant::List )
@@ -4229,6 +4268,11 @@ QgsVectorDataProvider::Capabilities QgsSpatiaLiteProvider::capabilities() const
   return mEnabledCapabilities;
 }
 
+QVariant QgsSpatiaLiteProvider::defaultValue( int fieldId ) const
+{
+  return mDefaultValues.value( fieldId, QVariant() );
+}
+
 void QgsSpatiaLiteProvider::closeDb()
 {
 // trying to close the SQLite DB

src/providers/spatialite/qgsspatialiteprovider.h

@@ -165,6 +165,8 @@ class QgsSpatiaLiteProvider: public QgsVectorDataProvider
     //! Returns a bitmask containing the supported capabilities
     QgsVectorDataProvider::Capabilities capabilities() const override;
 
+    QVariant defaultValue( int fieldId ) const override;
+
     /** The SpatiaLite provider does its own transforms so we return
      * true for the following three functions to indicate that transforms
      * should not be handled by the QgsCoordinateTransform object. See the
@@ -338,6 +340,9 @@ class QgsSpatiaLiteProvider: public QgsVectorDataProvider
     //! Name of the geometry column in the table
     QString mGeometryColumn;
 
+    //! Map of field index to default value
+    QMap<int, QVariant> mDefaultValues;
+
     //! Name of the SpatialIndex table
     QString mIndexTable;
 
@@ -448,6 +453,8 @@ class QgsSpatiaLiteProvider: public QgsVectorDataProvider
 
     void fetchConstraints();
 
+    void insertDefaultValue( int fieldIndex, QString defaultVal );
+
     enum GEOS_3D
     {
       GEOS_3D_POINT              = -2147483647,

tests/src/python/test_provider_spatialite.py

@@ -139,6 +139,10 @@ class TestQgsSpatialiteProvider(unittest.TestCase, ProviderTestCase):
         sql = "CREATE TABLE test_constraints(id INTEGER PRIMARY KEY, num INTEGER NOT NULL, desc TEXT UNIQUE, desc2 TEXT, num2 INTEGER NOT NULL UNIQUE)"
         cur.execute(sql)
 
+        # simple table with defaults
+        sql = "CREATE TABLE test_defaults (id INTEGER NOT NULL PRIMARY KEY, name TEXT DEFAULT 'qgis ''is good', number INTEGER DEFAULT 5, number2 REAL DEFAULT 5.7, no_default REAL)"
+        cur.execute(sql)
+
         cur.execute("COMMIT")
         con.close()
 
@@ -461,6 +465,16 @@ class TestQgsSpatialiteProvider(unittest.TestCase, ProviderTestCase):
 
         self.assertTrue(vl.commitChanges())
 
+    def testDefaultValues(self):
+
+        l = QgsVectorLayer("dbname=%s table='test_defaults' key='id'" % self.dbname, "test_defaults", "spatialite")
+        self.assertTrue(l.isValid())
+
+        self.assertEqual(l.dataProvider().defaultValue(1), "qgis 'is good")
+        self.assertEqual(l.dataProvider().defaultValue(2), 5)
+        self.assertEqual(l.dataProvider().defaultValue(3), 5.7)
+        self.assertFalse(l.dataProvider().defaultValue(4))
+
 
 if __name__ == '__main__':
     unittest.main()