Fix crash on QgsDataDefined copy (fix #12027)

qgis · Apr 21, 2015 · 774e5d3 · 774e5d3
1 parent 8cb8755
commit 774e5d3
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Showing 4 changed files with 103 additions and 19 deletions.
diff --git a/python/core/qgsdatadefined.sip b/python/core/qgsdatadefined.sip
@@ -30,6 +30,12 @@ class QgsDataDefined
      */
     QgsDataDefined( const QgsExpression * expression );
 
+    /**
+     * Copy constructor. Note that copies of data defined objects with expressions
+     * will not be prepared.
+     */
+    QgsDataDefined( const QgsDataDefined& other );
+
     ~QgsDataDefined();
 
     /**Returns whether the data defined container is set to all the default
@@ -54,7 +60,22 @@ class QgsDataDefined
     //void setExpressionParams( QMap<QString, QVariant> params );
     void insertExpressionParam( QString key, QVariant param );
 
+    /** Prepares the expression using a vector layer
+     * @param layer vector layer
+     * @returns true if expression was successfully prepared
+     */
     bool prepareExpression( QgsVectorLayer* layer );
+
+    /** Prepares the expression using a fields collection
+     * @param fields
+     * @returns true if expression was successfully prepared
+     * @note added in QGIS 2.9
+     */
+    bool prepareExpression( const QgsFields &fields );
+
+    /** Returns whether the data defined object's expression is prepared
+     * @returns true if expression is prepared
+     */
     bool expressionIsPrepared() const;
 
     QgsExpression* expression();

diff --git a/src/core/qgsdatadefined.cpp b/src/core/qgsdatadefined.cpp
@@ -43,9 +43,20 @@ QgsDataDefined::QgsDataDefined( const QgsExpression * expression )
   mExpressionPrepared = false;
 }
 
+QgsDataDefined::QgsDataDefined( const QgsDataDefined &other )
+    : mExpression( 0 )
+    , mActive( other.isActive() )
+    , mUseExpression( other.useExpression() )
+    , mExpressionString( other.expressionString() )
+    , mField( other.field() )
+    , mExpressionParams( other.expressionParams() )
+    , mExpressionPrepared( false )
+{
+
+}
+
 QgsDataDefined::~QgsDataDefined()
 {
-  mExpressionParams.clear();
   delete mExpression;
 }
 
@@ -61,6 +72,20 @@ void QgsDataDefined::setExpressionString( const QString &expr )
 }
 
 bool QgsDataDefined::prepareExpression( QgsVectorLayer* layer )
+{
+  if ( layer )
+  {
+    return prepareExpression( layer->pendingFields() );
+  }
+  else
+  {
+    //preparing expression without a layer set, so pass empty field list
+    QgsFields empty;
+    return prepareExpression( empty );
+  }
+}
+
+bool QgsDataDefined::prepareExpression( const QgsFields &fields )
 {
   if ( !mUseExpression || mExpressionString.isEmpty() )
   {
@@ -86,16 +111,7 @@ bool QgsDataDefined::prepareExpression( QgsVectorLayer* layer )
     }
   }
 
-  if ( layer )
-  {
-    mExpression->prepare( layer->pendingFields() );
-  }
-  else
-  {
-    //preparing expression without a layer set, so pass empty field list
-    QgsFields empty;
-    mExpression->prepare( empty );
-  }
+  mExpression->prepare( fields );
 
   if ( mExpression->hasEvalError() )
   {
@@ -104,16 +120,16 @@ bool QgsDataDefined::prepareExpression( QgsVectorLayer* layer )
   }
 
   mExpressionPrepared = true;
-  mExprRefColmuns = mExpression->referencedColumns();
+  mExprRefColumns = mExpression->referencedColumns();
 
   return true;
 }
 
 QStringList QgsDataDefined::referencedColumns( QgsVectorLayer* layer )
 {
-  if ( !mExprRefColmuns.isEmpty() )
+  if ( !mExprRefColumns.isEmpty() )
   {
-    return mExprRefColmuns;
+    return mExprRefColumns;
   }
 
   if ( mUseExpression )
@@ -125,10 +141,10 @@ QStringList QgsDataDefined::referencedColumns( QgsVectorLayer* layer )
   }
   else if ( !mField.isEmpty() )
   {
-    mExprRefColmuns << mField;
+    mExprRefColumns << mField;
   }
 
-  return mExprRefColmuns;
+  return mExprRefColumns;
 }
 
 void QgsDataDefined::insertExpressionParam( QString key, QVariant param )
@@ -181,3 +197,20 @@ bool QgsDataDefined::operator!=( const QgsDataDefined &other ) const
 {
   return !( *this == other );
 }
+
+QgsDataDefined &QgsDataDefined::operator=( const QgsDataDefined & rhs )
+{
+  if ( &rhs == this )
+    return *this;
+
+  delete mExpression;
+  mExpression = 0;
+  mActive = rhs.isActive();
+  mUseExpression = rhs.useExpression();
+  mExpressionString = rhs.expressionString();
+  mField = rhs.field();
+  mExpressionParams = rhs.expressionParams();
+  mExpressionPrepared = false;
+  mExprRefColumns.clear();
+  return *this;
+}
diff --git a/src/core/qgsdatadefined.h b/src/core/qgsdatadefined.h
@@ -21,6 +21,7 @@
 
 class QgsExpression;
 class QgsVectorLayer;
+class QgsFields;
 
 /** \ingroup core
  * \class QgsDataDefined
@@ -51,6 +52,12 @@ class CORE_EXPORT QgsDataDefined
      */
     explicit QgsDataDefined( const QgsExpression * expression );
 
+    /**
+     * Copy constructor. Note that copies of data defined objects with expressions
+     * will not be prepared.
+     */
+    QgsDataDefined( const QgsDataDefined& other );
+
     ~QgsDataDefined();
 
     /**Returns whether the data defined container is set to all the default
@@ -75,7 +82,22 @@ class CORE_EXPORT QgsDataDefined
     void setExpressionParams( QMap<QString, QVariant> params ) { mExpressionParams = params; }
     void insertExpressionParam( QString key, QVariant param );
 
+    /** Prepares the expression using a vector layer
+     * @param layer vector layer
+     * @returns true if expression was successfully prepared
+     */
     bool prepareExpression( QgsVectorLayer* layer );
+
+    /** Prepares the expression using a fields collection
+     * @param fields
+     * @returns true if expression was successfully prepared
+     * @note added in QGIS 2.9
+     */
+    bool prepareExpression( const QgsFields &fields );
+
+    /** Returns whether the data defined object's expression is prepared
+     * @returns true if expression is prepared
+     */
     bool expressionIsPrepared() const { return mExpressionPrepared; }
 
     QgsExpression* expression() { return mExpression; }
@@ -108,6 +130,11 @@ class CORE_EXPORT QgsDataDefined
     bool operator==( const QgsDataDefined &other ) const;
     bool operator!=( const QgsDataDefined &other ) const;
 
+    /** Assignment operator. Note that after assignment the data defined
+     * object's expression will not be prepared.
+     */
+    QgsDataDefined& operator=( QgsDataDefined const & rhs );
+
   private:
     QgsExpression* mExpression;
 
@@ -118,7 +145,8 @@ class CORE_EXPORT QgsDataDefined
 
     QMap<QString, QVariant> mExpressionParams;
     bool mExpressionPrepared;
-    QStringList mExprRefColmuns;
+    QStringList mExprRefColumns;
+
 };
 
 #endif // QGSDATADEFINED_H
diff --git a/tests/src/core/testqgsdatadefined.cpp b/tests/src/core/testqgsdatadefined.cpp
@@ -75,10 +75,12 @@ void TestQgsDataDefined::create()
 void TestQgsDataDefined::copy()
 {
   QgsDataDefined dd( true, true, QString( "sqrt(2)" ), QString( "field" ) );
-  dd.prepareExpression(NULL);
+  dd.prepareExpression( NULL );
   QgsDataDefined cpy( dd );
+  QVERIFY( cpy == dd );
   QgsDataDefined assigned;
-  assigned = cpy;
+  assigned = dd;
+  QVERIFY( assigned == dd );
 }
 
 void TestQgsDataDefined::gettersSetters()