Ensure standard expressions functions are deleted on exit

(Avoids a lot of LeakSanitiser noise)

python/core/qgsexpression.sip

@@ -299,9 +299,24 @@ class QgsExpression
     static const QList<QgsExpression::Function *>& Functions();
     static const QStringList& BuiltinFunctions();
 
+    /** Registers a function to the expression engine. This is required to allow expressions to utilise the function.
+     * @param function function to register
+     * @returns true on successful registration
+     * @see unregisterFunction
+     */
     static bool registerFunction( Function* function );
+
+    /** Unregisters a function from the expression engine. The function will no longer be usable in expressions.
+     * @param name function name
+     * @see registerFunction
+     */
     static bool unregisterFunction( QString name );
 
+    /** Deletes all registered functions whose ownership have been transferred to the expression engine.
+     * @note added in QGIS 2.12
+     */
+    static void cleanRegisteredFunctions();
+
     // tells whether the identifier is a name of existing function
     static bool isFunctionName( const QString& name );
 

src/core/qgsapplication.cpp

@@ -22,6 +22,7 @@
 #include "qgsmaplayerregistry.h"
 #include "qgsnetworkaccessmanager.h"
 #include "qgsproviderregistry.h"
+#include "qgsexpression.h"
 
 #include <QDir>
 #include <QFile>
@@ -634,6 +635,9 @@ void QgsApplication::exitQgis()
   //This isn't strictly necessary (since we're exiting anyway) but doing so prevents a lot of
   //LeakSanitiser noise which hides real issues
   QgsApplication::sendPostedEvents( 0, QEvent::DeferredDelete );
+
+  //delete all registered functions from expression engine (see above comment)
+  QgsExpression::cleanRegisteredFunctions();
 }
 
 QString QgsApplication::showSettings()

src/core/qgsexpression.cpp

@@ -1767,7 +1767,7 @@ static QVariant fcnGetLayerProperty( const QVariantList& values, const QgsExpres
   return QVariant();
 }
 
-bool QgsExpression::registerFunction( QgsExpression::Function* function )
+bool QgsExpression::registerFunction( QgsExpression::Function* function, bool transferOwnership )
 {
   int fnIdx = functionIndex( function->name() );
   if ( fnIdx != -1 )
@@ -1775,6 +1775,8 @@ bool QgsExpression::registerFunction( QgsExpression::Function* function )
     return false;
   }
   QgsExpression::gmFunctions.append( function );
+  if ( transferOwnership )
+    QgsExpression::gmOwnedFunctions.append( function );
   return true;
 }
 
@@ -1794,7 +1796,11 @@ bool QgsExpression::unregisterFunction( QString name )
   return false;
 }
 
-
+void QgsExpression::cleanRegisteredFunctions()
+{
+  qDeleteAll( QgsExpression::gmOwnedFunctions );
+  QgsExpression::gmOwnedFunctions.clear();
+}
 
 QStringList QgsExpression::gmBuiltinFunctions;
 
@@ -1842,6 +1848,7 @@ const QStringList& QgsExpression::BuiltinFunctions()
 }
 
 QList<QgsExpression::Function*> QgsExpression::gmFunctions;
+QList<QgsExpression::Function*> QgsExpression::gmOwnedFunctions;
 
 const QList<QgsExpression::Function*>& QgsExpression::Functions()
 {
@@ -1978,6 +1985,12 @@ const QList<QgsExpression::Function*>& QgsExpression::Functions()
     ;
 
     QgsExpressionContextUtils::registerContextFunctions();
+
+    //QgsExpression has ownership of all built-in functions
+    Q_FOREACH ( QgsExpression::Function* func, gmFunctions )
+    {
+      gmOwnedFunctions << func;
+    }
   }
   return gmFunctions;
 }

src/core/qgsexpression.h

@@ -490,9 +490,28 @@ class CORE_EXPORT QgsExpression
     static QStringList gmBuiltinFunctions;
     static const QStringList& BuiltinFunctions();
 
-    static bool registerFunction( Function* function );
+    /** Registers a function to the expression engine. This is required to allow expressions to utilise the function.
+     * @param function function to register
+     * @param transferOwnership set to true to transfer ownership of function to expression engine
+     * @returns true on successful registration
+     * @see unregisterFunction
+     */
+    static bool registerFunction( Function* function, bool transferOwnership = false );
+
+    /** Unregisters a function from the expression engine. The function will no longer be usable in expressions.
+     * @param name function name
+     * @see registerFunction
+     */
     static bool unregisterFunction( QString name );
 
+    //! List of functions owned by the expression engine
+    static QList<Function*> gmOwnedFunctions;
+
+    /** Deletes all registered functions whose ownership have been transferred to the expression engine.
+     * @note added in QGIS 2.12
+     */
+    static void cleanRegisteredFunctions();
+
     // tells whether the identifier is a name of existing function
     static bool isFunctionName( const QString& name );