fix windows build (extern "C" can returns pointers, but not C++ containers)

Author: jef-n

cmake/SIPMacros.cmake

@@ -37,7 +37,7 @@
 
 SET(SIP_INCLUDES)
 SET(SIP_TAGS)
-SET(SIP_CONCAT_PARTS 10)
+SET(SIP_CONCAT_PARTS 16)
 SET(SIP_DISABLE_FEATURES)
 SET(SIP_EXTRA_OPTIONS)
 SET(SIP_EXTRA_OBJECTS)

src/core/qgsdataitemproviderregistry.cpp

@@ -21,7 +21,7 @@
 #include "qgslogger.h"
 #include "qgsproviderregistry.h"
 
-typedef QList<QgsDataItemProvider *> dataItemProviders_t();
+typedef QList<QgsDataItemProvider *> *dataItemProviders_t();
 
 
 /**
@@ -71,8 +71,10 @@ QgsDataItemProviderRegistry::QgsDataItemProviderRegistry()
     dataItemProviders_t *dataItemProvidersFn = reinterpret_cast< dataItemProviders_t * >( cast_to_fptr( library->resolve( "dataItemProviders" ) ) );
     if ( dataItemProvidersFn )
     {
+      QList<QgsDataItemProvider *> *providerList = dataItemProvidersFn();
       // the function is a factory - we keep ownership of the returned providers
-      mProviders << dataItemProvidersFn();
+      mProviders << *providerList;
+      delete providerList;
     }
 
     // legacy support - using dataItem() and dataCapabilities() methods

src/providers/ogr/qgsogrprovider.cpp

@@ -2928,10 +2928,11 @@ QGISEXTERN bool createEmptyDataSource( const QString &uri,
 }
 
 
-QGISEXTERN QList<QgsDataItemProvider *> dataItemProviders()
+QGISEXTERN QList< QgsDataItemProvider * > *dataItemProviders()
 {
-  return QList<QgsDataItemProvider *>()
-         << new QgsGeoPackageDataItemProvider;
+  QList< QgsDataItemProvider * > *providers = new QList< QgsDataItemProvider * >();
+  *providers << new QgsGeoPackageDataItemProvider;
+  return providers;
 }
 
 QgsCoordinateReferenceSystem QgsOgrProvider::crs() const

src/providers/wms/qgswmsdataitems.cpp

@@ -469,11 +469,15 @@ QgsDataItem *QgsWmsDataItemProvider::createDataItem( const QString &path, QgsDat
   return nullptr;
 }
 
-QGISEXTERN QList<QgsDataItemProvider *> dataItemProviders()
+QGISEXTERN QList<QgsDataItemProvider *> *dataItemProviders()
 {
-  return QList<QgsDataItemProvider *>()
-         << new QgsWmsDataItemProvider
-         << new QgsXyzTileDataItemProvider;
+  QList<QgsDataItemProvider *> *providers = new QList<QgsDataItemProvider *>();
+
+  *providers
+      << new QgsWmsDataItemProvider
+      << new QgsXyzTileDataItemProvider;
+
+  return providers;
 }
 
 // ---------------------------------------------------------------------------