Revert "Streamline singleton behavior"

This reverts commit b4a8547. The template based approach was not cross-platform friendly. When cross-compiling for Android it caused a new instance of every singleton per shared library. Mostly using the magic statics pattern instead now: See http://stackoverflow.com/a/11711991/2319028 Important things to remember for crash on exit: * QgsNetworkAccessManager needs to die before QApplication * QgsMapLayerRegistry needs to be emptied before QgsProviderRegistry goes away And finally: DON'T USE SINGLETONS! They are for "one and only one" and not for "happens to be only one" situations.
qgis · Apr 28, 2015 · c2fb5e1 · c2fb5e1 · nyalldawson · Apr 28, 2015
1 parent 96560c8
commit c2fb5e1
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Showing 18 changed files with 68 additions and 99 deletions.
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -1000,8 +1000,6 @@ QgisApp::~QgisApp()
   delete QgsProject::instance();
 
   delete mPythonUtils;
-
-  QgsMapLayerStyleGuiUtils::cleanup();
 }
 
 void QgisApp::dragEnterEvent( QDragEnterEvent *event )

diff --git a/src/app/qgsmaplayerstyleguiutils.cpp b/src/app/qgsmaplayerstyleguiutils.cpp
@@ -25,6 +25,12 @@
 #include "qgsmaplayerstylemanager.h"
 
 
+QgsMapLayerStyleGuiUtils* QgsMapLayerStyleGuiUtils::instance()
+{
+  static QgsMapLayerStyleGuiUtils sInstance;
+  return &sInstance;
+}
+
 QAction* QgsMapLayerStyleGuiUtils::actionAddStyle( QgsMapLayer* layer, QObject* parent )
 {
   QAction* a = new QAction( tr( "Add" ), parent );

diff --git a/src/app/qgsmaplayerstyleguiutils.h b/src/app/qgsmaplayerstyleguiutils.h
@@ -18,19 +18,18 @@
 
 #include <QObject>
 
-#include "qgssingleton.h"
-
 class QgsMapLayer;
 
 class QAction;
 class QMenu;
 
 /** Various GUI utility functions for dealing with map layer's style manager */
-class QgsMapLayerStyleGuiUtils : public QObject, public QgsSingleton<QgsMapLayerStyleGuiUtils>
+class QgsMapLayerStyleGuiUtils : public QObject
 {
     Q_OBJECT
-  public:
 
+  public:
+    static QgsMapLayerStyleGuiUtils* instance();
     QAction* actionAddStyle( QgsMapLayer* layer, QObject* parent = 0 );
     QAction* actionRemoveStyle( QgsMapLayer* layer, QObject* parent = 0 );
     QAction* actionRenameStyle( QgsMapLayer* layer, QObject* parent = 0 );

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -548,7 +548,6 @@ SET(QGIS_CORE_HDRS
   qgsscalecalculator.h
   qgsscaleutils.h
   qgssimplifymethod.h
-  qgssingleton.h
   qgssnapper.h
   qgssnappingutils.h
   qgsspatialindex.h

diff --git a/src/core/effects/qgspainteffectregistry.cpp b/src/core/effects/qgspainteffectregistry.cpp
@@ -60,6 +60,12 @@ QgsPaintEffectRegistry::~QgsPaintEffectRegistry()
   mMetadata.clear();
 }
 
+QgsPaintEffectRegistry* QgsPaintEffectRegistry::instance()
+{
+  static QgsPaintEffectRegistry sInstance;
+  return &sInstance;
+}
+
 QgsPaintEffectAbstractMetadata *QgsPaintEffectRegistry::effectMetadata( const QString &name ) const
 {
   if ( mMetadata.contains( name ) )

diff --git a/src/core/effects/qgspainteffectregistry.h b/src/core/effects/qgspainteffectregistry.h
@@ -16,7 +16,6 @@
 #ifndef QGSPAINTEFFECTREGISTRY_H
 #define QGSPAINTEFFECTREGISTRY_H
 
-#include "qgssingleton.h"
 #include "qgis.h"
 #include <QDomElement>
 #include <QDomDocument>
@@ -152,9 +151,10 @@ class CORE_EXPORT QgsPaintEffectMetadata : public QgsPaintEffectAbstractMetadata
  *
  * \note Added in version 2.9
  */
-class CORE_EXPORT QgsPaintEffectRegistry : public QgsSingleton<QgsPaintEffectRegistry>
+class CORE_EXPORT QgsPaintEffectRegistry
 {
   public:
+    static QgsPaintEffectRegistry* instance();
 
     /** Returns the metadata for a specific effect.
      * @param name unique string name for paint effect class
@@ -194,8 +194,6 @@ class CORE_EXPORT QgsPaintEffectRegistry : public QgsSingleton<QgsPaintEffectReg
     ~QgsPaintEffectRegistry();
 
     QMap<QString, QgsPaintEffectAbstractMetadata*> mMetadata;
-
-    friend class QgsSingleton<QgsPaintEffectRegistry>; // Let QgsSingleton access private constructor
 };
 
 #endif //QGSPAINTEFFECTREGISTRY_H
diff --git a/src/core/qgsapplication.cpp b/src/core/qgsapplication.cpp
@@ -623,13 +623,6 @@ void QgsApplication::initQgis()
 
 void QgsApplication::exitQgis()
 {
-  // Cleanup known singletons
-  QgsMapLayerRegistry::cleanup();
-  QgsNetworkAccessManager::cleanup();
-  QgsCoordinateTransformCache::cleanup();
-  QgsDataItemProviderRegistry::cleanup();
-
-  // Cleanup providers
   delete QgsProviderRegistry::instance();
 }
 

diff --git a/src/core/qgscrscache.cpp b/src/core/qgscrscache.cpp
@@ -18,15 +18,20 @@
 #include "qgscrscache.h"
 #include "qgscoordinatetransform.h"
 
+
+QgsCoordinateTransformCache* QgsCoordinateTransformCache::instance()
+{
+  static QgsCoordinateTransformCache mInstance;
+  return &mInstance;
+}
+
 QgsCoordinateTransformCache::~QgsCoordinateTransformCache()
 {
   QHash< QPair< QString, QString >, QgsCoordinateTransform* >::const_iterator tIt = mTransforms.constBegin();
   for ( ; tIt != mTransforms.constEnd(); ++tIt )
   {
     delete tIt.value();
   }
-
-  mTransforms.clear();
 }
 
 const QgsCoordinateTransform* QgsCoordinateTransformCache::transform( const QString& srcAuthId, const QString& destAuthId, int srcDatumTransform, int destDatumTransform )

diff --git a/src/core/qgscrscache.h b/src/core/qgscrscache.h
@@ -19,16 +19,16 @@
 #define QGSCRSCACHE_H
 
 #include "qgscoordinatereferencesystem.h"
-#include "qgssingleton.h"
 #include <QHash>
 
 class QgsCoordinateTransform;
 
 /**Cache coordinate transform by authid of source/dest transformation to avoid the
 overhead of initialisation for each redraw*/
-class CORE_EXPORT QgsCoordinateTransformCache : public QgsSingleton<QgsCoordinateTransformCache>
+class CORE_EXPORT QgsCoordinateTransformCache
 {
   public:
+    static QgsCoordinateTransformCache* instance();
     ~QgsCoordinateTransformCache();
     /**Returns coordinate transformation. Cache keeps ownership
         @param srcAuthId auth id string of source crs
@@ -41,6 +41,7 @@ class CORE_EXPORT QgsCoordinateTransformCache : public QgsSingleton<QgsCoordinat
     void invalidateCrs( const QString& crsAuthId );
 
   private:
+    static QgsCoordinateTransformCache* mInstance;
     QMultiHash< QPair< QString, QString >, QgsCoordinateTransform* > mTransforms; //same auth_id pairs might have different datum transformations
 };
 

diff --git a/src/core/qgsdataitemproviderregistry.cpp b/src/core/qgsdataitemproviderregistry.cpp
@@ -79,6 +79,12 @@ QgsDataItemProviderRegistry::QgsDataItemProviderRegistry()
   }
 }
 
+QgsDataItemProviderRegistry* QgsDataItemProviderRegistry::instance()
+{
+  static QgsDataItemProviderRegistry sInstance;
+  return &sInstance;
+}
+
 QgsDataItemProviderRegistry::~QgsDataItemProviderRegistry()
 {
   qDeleteAll( mProviders );

diff --git a/src/core/qgsdataitemproviderregistry.h b/src/core/qgsdataitemproviderregistry.h
@@ -16,8 +16,6 @@
 #ifndef QGSDATAITEMPROVIDERREGISTRY_H
 #define QGSDATAITEMPROVIDERREGISTRY_H
 
-#include "qgssingleton.h"
-
 #include <QList>
 
 class QgsDataItemProvider;
@@ -28,9 +26,11 @@ class QgsDataItemProvider;
  *
  * @note added in 2.10
  */
-class CORE_EXPORT QgsDataItemProviderRegistry : public QgsSingleton<QgsDataItemProviderRegistry>
+class CORE_EXPORT QgsDataItemProviderRegistry
 {
   public:
+    static QgsDataItemProviderRegistry* instance();
+
     ~QgsDataItemProviderRegistry();
 
     //! Get list of available providers
@@ -45,8 +45,6 @@ class CORE_EXPORT QgsDataItemProviderRegistry : public QgsSingleton<QgsDataItemP
   private:
     QgsDataItemProviderRegistry();
 
-    friend class QgsSingleton<QgsDataItemProviderRegistry>; // Let QgsSingleton access private constructor
-
     //! available providers. this class owns the pointers
     QList<QgsDataItemProvider*> mProviders;
 };

diff --git a/src/core/qgsmaplayerregistry.cpp b/src/core/qgsmaplayerregistry.cpp
@@ -19,6 +19,15 @@
 #include "qgsmaplayer.h"
 #include "qgslogger.h"
 
+//
+// Static calls to enforce singleton behaviour
+//
+QgsMapLayerRegistry *QgsMapLayerRegistry::instance()
+{
+  static QgsMapLayerRegistry sInstance;
+  return &sInstance;
+}
+
 //
 // Main class begins now...
 //

diff --git a/src/core/qgsmaplayerregistry.h b/src/core/qgsmaplayerregistry.h
@@ -23,20 +23,21 @@
 #include <QSet>
 #include <QObject>
 #include <QStringList>
-
-#include "qgssingleton.h"
 class QString;
 class QgsMapLayer;
 
 /** \ingroup core
 * This class tracks map layers that are currently loaded and provides
 * a means to fetch a pointer to a map layer and delete it.
 */
-class CORE_EXPORT QgsMapLayerRegistry : public QObject, public QgsSingleton<QgsMapLayerRegistry>
+class CORE_EXPORT QgsMapLayerRegistry : public QObject
 {
     Q_OBJECT
 
   public:
+    //! Returns the instance pointer, creating the object on the first call
+    static QgsMapLayerRegistry * instance();
+
     //! Return the number of registered layers.
     int count();
 
@@ -242,8 +243,6 @@ class CORE_EXPORT QgsMapLayerRegistry : public QObject, public QgsSingleton<QgsM
 
     QMap<QString, QgsMapLayer*> mMapLayers;
     QSet<QgsMapLayer*> mOwnedLayers;
-
-    friend class QgsSingleton<QgsMapLayerRegistry>; // Let QgsSingleton access private constructor
 }; // class QgsMapLayerRegistry
 
 #endif //QgsMapLayerRegistry_H

diff --git a/src/core/qgsnetworkaccessmanager.cpp b/src/core/qgsnetworkaccessmanager.cpp
@@ -86,6 +86,15 @@ class QgsNetworkProxyFactory : public QNetworkProxyFactory
     }
 };
 
+//
+// Static calls to enforce singleton behaviour
+//
+QgsNetworkAccessManager* QgsNetworkAccessManager::instance()
+{
+  static QgsNetworkAccessManager* sInstance( new QgsNetworkAccessManager( QApplication::instance() ) );
+  return sInstance;
+}
+
 QgsNetworkAccessManager::QgsNetworkAccessManager( QObject *parent )
     : QNetworkAccessManager( parent )
     , mUseSystemProxy( false )

diff --git a/src/core/qgsnetworkaccessmanager.h b/src/core/qgsnetworkaccessmanager.h
@@ -24,8 +24,6 @@
 #include <QNetworkProxy>
 #include <QNetworkRequest>
 
-#include "qgssingleton.h"
-
 /*
  * \class QgsNetworkAccessManager
  * \brief network access manager for QGIS
@@ -43,11 +41,15 @@
  * that the fallback proxy should not be used for, then no proxy will be used.
  *
  */
-class CORE_EXPORT QgsNetworkAccessManager : public QNetworkAccessManager, public QgsSingleton<QgsNetworkAccessManager>
+class CORE_EXPORT QgsNetworkAccessManager : public QNetworkAccessManager
 {
     Q_OBJECT
 
   public:
+    //! returns a pointer to the single instance
+    // and creates that instance on the first call.
+    static QgsNetworkAccessManager* instance();
+
     QgsNetworkAccessManager( QObject *parent = 0 );
 
     //! destructor

diff --git a/src/core/qgsproviderregistry.cpp b/src/core/qgsproviderregistry.cpp
@@ -29,6 +29,7 @@
 #include "qgsmessagelog.h"
 #include "qgsprovidermetadata.h"
 #include "qgsvectorlayer.h"
+#include "qgsmaplayerregistry.h"
 
 
 // typedefs for provider plugin functions of interest
@@ -204,11 +205,13 @@ typedef void cleanupProviderFunction_t();
 
 QgsProviderRegistry::~QgsProviderRegistry()
 {
+  QgsMapLayerRegistry::instance()->removeAllMapLayers();
+
   Providers::const_iterator it = mProviders.begin();
 
   while ( it != mProviders.end() )
   {
-    QgsDebugMsg( QString( "cleanup: %1" ).arg( it->first ) );
+    QgsDebugMsg( QString( "cleanup:%1" ).arg( it->first ) );
     QString lib = it->second->library();
     QLibrary myLib( lib );
     if ( myLib.isLoaded() )
@@ -405,7 +408,7 @@ QWidget* QgsProviderRegistry::selectWidget( const QString & providerKey,
 
 #if QT_VERSION >= 0x050000
 QFunctionPointer QgsProviderRegistry::function( QString const & providerKey,
-    QString const & functionName )
+                                                QString const & functionName )
 {
   QLibrary myLib( library( providerKey ) );
 

diff --git a/src/core/qgssingleton.h b/src/core/qgssingleton.h