From b919198e465e3556425bd51758e22b7407bf1e0e Mon Sep 17 00:00:00 2001
From: Martin Dobias <wonder.sk@gmail.com>
Date: Wed, 31 Aug 2016 18:37:46 +0800
Subject: [PATCH] Fix loading of XYZ tile layer data item provider

---
 src/core/qgsdataitemproviderregistry.cpp | 13 +++++++++++++
 src/providers/wms/qgswmsdataitems.cpp    | 16 +++++++---------
 src/providers/wms/qgswmsdataitems.h      | 13 +++++++++++++
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/src/core/qgsdataitemproviderregistry.cpp b/src/core/qgsdataitemproviderregistry.cpp
index 8e7e51645513..8608cd1c987b 100644
--- a/src/core/qgsdataitemproviderregistry.cpp
+++ b/src/core/qgsdataitemproviderregistry.cpp
@@ -21,6 +21,8 @@
 #include "qgslogger.h"
 #include "qgsproviderregistry.h"
 
+typedef QList<QgsDataItemProvider*> dataItemProviders_t();
+
 
 /**
  * \ingroup core
@@ -64,6 +66,17 @@ QgsDataItemProviderRegistry::QgsDataItemProviderRegistry()
     if ( !library )
       continue;
 
+    // new / better way of returning data items from providers
+
+    dataItemProviders_t* dataItemProvidersFn = reinterpret_cast< dataItemProviders_t * >( cast_to_fptr( library->resolve( "dataItemProviders" ) ) );
+    if ( dataItemProvidersFn )
+    {
+      // the function is a factory - we keep ownership of the returned providers
+      mProviders << dataItemProvidersFn();
+    }
+
+    // legacy support - using dataItem() and dataCapabilities() methods
+
     dataCapabilities_t * dataCapabilities = reinterpret_cast< dataCapabilities_t * >( cast_to_fptr( library->resolve( "dataCapabilities" ) ) );
     if ( !dataCapabilities )
     {
diff --git a/src/providers/wms/qgswmsdataitems.cpp b/src/providers/wms/qgswmsdataitems.cpp
index a0a1e2860b3b..e28ac7a8859f 100644
--- a/src/providers/wms/qgswmsdataitems.cpp
+++ b/src/providers/wms/qgswmsdataitems.cpp
@@ -420,10 +420,6 @@ void QgsWMSRootItem::newConnection()
 QGISEXTERN void registerGui( QMainWindow *mainWindow )
 {
   QgsTileScaleWidget::showTileScale( mainWindow );
-
-  // with dataItem(...) at provider level we can only have one root item,
-  // so we have a data item provider for XYZ tile layers
-  QgsDataItemProviderRegistry::instance()->addProvider( new QgsXyzTileDataItemProvider );
 }
 
 QGISEXTERN QgsWMSSourceSelect * selectWidget( QWidget * parent, Qt::WindowFlags fl )
@@ -431,12 +427,8 @@ QGISEXTERN QgsWMSSourceSelect * selectWidget( QWidget * parent, Qt::WindowFlags
   return new QgsWMSSourceSelect( parent, fl );
 }
 
-QGISEXTERN int dataCapabilities()
-{
-  return  QgsDataProvider::Net;
-}
 
-QGISEXTERN QgsDataItem * dataItem( QString thePath, QgsDataItem* parentItem )
+QgsDataItem* QgsWmsDataItemProvider::createDataItem( const QString& thePath, QgsDataItem *parentItem )
 {
   QgsDebugMsg( "thePath = " + thePath );
   if ( thePath.isEmpty() )
@@ -458,6 +450,12 @@ QGISEXTERN QgsDataItem * dataItem( QString thePath, QgsDataItem* parentItem )
   return nullptr;
 }
 
+QGISEXTERN QList<QgsDataItemProvider*> dataItemProviders()
+{
+  return QList<QgsDataItemProvider*>()
+         << new QgsWmsDataItemProvider
+         << new QgsXyzTileDataItemProvider;
+}
 
 // ---------------------------------------------------------------------------
 
diff --git a/src/providers/wms/qgswmsdataitems.h b/src/providers/wms/qgswmsdataitems.h
index ca7fa3683191..d6dc4b8f7bbf 100644
--- a/src/providers/wms/qgswmsdataitems.h
+++ b/src/providers/wms/qgswmsdataitems.h
@@ -106,6 +106,19 @@ class QgsWMSRootItem : public QgsDataCollectionItem
     void newConnection();
 };
 
+
+//! Provider for WMS root data item
+class QgsWmsDataItemProvider : public QgsDataItemProvider
+{
+  public:
+    virtual QString name() override { return "WMS"; }
+
+    virtual int capabilities() override { return QgsDataProvider::Net; }
+
+    virtual QgsDataItem* createDataItem( const QString& path, QgsDataItem* parentItem ) override;
+};
+
+
 //! Root item for XYZ tile layers
 class QgsXyzTileRootItem : public QgsDataCollectionItem
 {