Browser: Abstract creation of custom data items into QgsDataItemProvider

python/core/core.sip

@@ -26,6 +26,8 @@
 %Include qgscrscache.sip
 %Include qgsdatadefined.sip
 %Include qgsdataitem.sip
+%Include qgsdataitemprovider.sip
+%Include qgsdataitemproviderregistry.sip
 %Include qgsdataprovider.sip
 %Include qgsdatasourceuri.sip
 %Include qgsdatumtransformstore.sip

python/core/qgsdataitemprovider.sip

@@ -0,0 +1,20 @@
+
+class QgsDataItemProvider
+{
+%TypeHeaderCode
+#include <qgsdataitemprovider.h>
+%End
+  public:
+    virtual ~QgsDataItemProvider();
+
+    //! Human-readable name of the provider name
+    virtual QString name() = 0;
+
+    //! Return combination of flags from QgsDataProvider::DataCapabilities
+    virtual int capabilities() = 0;
+
+    //! Create a new instance of QgsDataItem (or null) for given path and parent item.
+    //! Caller takes responsibility of deleting created items.
+    virtual QgsDataItem* createDataItem( const QString& path, QgsDataItem* parentItem ) = 0 /Factory/;
+
+};

python/core/qgsdataitemproviderregistry.sip

@@ -0,0 +1,19 @@
+
+class QgsDataItemProviderRegistry
+{
+%TypeHeaderCode
+#include <qgsdataitemproviderregistry.h>
+%End
+  public:
+    //! Returns the instance pointer, creating the object on the first call
+    static QgsDataItemProviderRegistry * instance();
+      
+    ~QgsDataItemProviderRegistry();
+
+    //! Get list of available providers
+    QList<QgsDataItemProvider*> providers() const;
+
+  private:
+    QgsDataItemProviderRegistry();
+
+};

src/core/CMakeLists.txt

@@ -77,6 +77,8 @@ SET(QGIS_CORE_SRCS
   qgsdatadefined.cpp
   qgsdatasourceuri.cpp
   qgsdataitem.cpp
+  qgsdataitemprovider.cpp
+  qgsdataitemproviderregistry.cpp
   qgsdatumtransformstore.cpp
   qgsdbfilterproxymodel.cpp
   qgsdiagramrendererv2.cpp
@@ -475,6 +477,9 @@ SET(QGIS_CORE_HDRS
   qgscsexception.h
   qgsdartmeasurement.h
   qgsdatadefined.h
+  qgsdataitem.h
+  qgsdataitemprovider.h
+  qgsdataitemproviderregistry.h
   qgsdatasourceuri.h
   qgsdatumtransformstore.h
   qgsdbfilterproxymodel.h

src/core/qgsapplication.cpp

@@ -15,6 +15,7 @@
 
 #include "qgsapplication.h"
 #include "qgscrscache.h"
+#include "qgsdataitemproviderregistry.h"
 #include "qgsexception.h"
 #include "qgsgeometry.h"
 #include "qgslogger.h"
@@ -626,6 +627,7 @@ void QgsApplication::exitQgis()
   QgsMapLayerRegistry::cleanup();
   QgsNetworkAccessManager::cleanup();
   QgsCoordinateTransformCache::cleanup();
+  QgsDataItemProviderRegistry::cleanup();
 
   // Cleanup providers
   delete QgsProviderRegistry::instance();

src/core/qgsbrowsermodel.cpp

@@ -19,6 +19,8 @@
 
 #include "qgis.h"
 #include "qgsapplication.h"
+#include "qgsdataitemprovider.h"
+#include "qgsdataitemproviderregistry.h"
 #include "qgsdataprovider.h"
 #include "qgsmimedatautils.h"
 #include "qgslogger.h"
@@ -123,40 +125,19 @@ void QgsBrowserModel::addRootItems()
   mRootItems << vols;
 #endif
 
-  // Add non file top level items
-  QStringList providersList = QgsProviderRegistry::instance()->providerList();
-
   // container for displaying providers as sorted groups (by QgsDataProvider::DataCapability enum)
   QMap<int, QgsDataItem *> providerMap;
 
-  foreach ( QString key, providersList )
+  foreach ( QgsDataItemProvider* pr, QgsDataItemProviderRegistry::instance()->providers() )
   {
-    QLibrary *library = QgsProviderRegistry::instance()->providerLibrary( key );
-    if ( !library )
-      continue;
-
-    dataCapabilities_t * dataCapabilities = ( dataCapabilities_t * ) cast_to_fptr( library->resolve( "dataCapabilities" ) );
-    if ( !dataCapabilities )
-    {
-      QgsDebugMsg( library->fileName() + " does not have dataCapabilities" );
-      continue;
-    }
-
-    int capabilities = dataCapabilities();
+    int capabilities = pr->capabilities();
     if ( capabilities == QgsDataProvider::NoDataCapabilities )
     {
-      QgsDebugMsg( library->fileName() + " does not have any dataCapabilities" );
+      QgsDebugMsg( pr->name() + " does not have any dataCapabilities" );
       continue;
     }
 
-    dataItem_t *dataItem = ( dataItem_t * ) cast_to_fptr( library->resolve( "dataItem" ) );
-    if ( !dataItem )
-    {
-      QgsDebugMsg( library->fileName() + " does not have dataItem" );
-      continue;
-    }
-
-    QgsDataItem *item = dataItem( "", NULL );  // empty path -> top level
+    QgsDataItem *item = pr->createDataItem( "", NULL );  // empty path -> top level
     if ( item )
     {
       QgsDebugMsg( "Add new top level item : " + item->name() );

src/core/qgsdataitem.cpp

@@ -32,6 +32,8 @@
 #include "qgis.h"
 #include "qgsdataitem.h"
 
+#include "qgsdataitemprovider.h"
+#include "qgsdataitemproviderregistry.h"
 #include "qgsdataprovider.h"
 #include "qgslogger.h"
 #include "qgsproviderregistry.h"
@@ -715,39 +717,6 @@ QgsDirectoryItem::QgsDirectoryItem( QgsDataItem* parent, QString name, QString d
 
 void QgsDirectoryItem::init()
 {
-  if ( mLibraries.size() > 0 )
-    return;
-
-  QStringList keys = QgsProviderRegistry::instance()->providerList();
-  QStringList::const_iterator i;
-  for ( i = keys.begin(); i != keys.end(); ++i )
-  {
-    QString k( *i );
-    // some providers hangs with empty uri (Postgis) etc...
-    // -> using libraries directly
-    QLibrary *library = QgsProviderRegistry::instance()->providerLibrary( k );
-    if ( library )
-    {
-      dataCapabilities_t * dataCapabilities = ( dataCapabilities_t * ) cast_to_fptr( library->resolve( "dataCapabilities" ) );
-      if ( !dataCapabilities )
-      {
-        QgsDebugMsg( library->fileName() + " does not have dataCapabilities" );
-        continue;
-      }
-      if ( dataCapabilities() == QgsDataProvider::NoDataCapabilities )
-      {
-        QgsDebugMsg( library->fileName() + " has NoDataCapabilities" );
-        continue;
-      }
-
-      QgsDebugMsg( QString( "%1 dataCapabilities : %2" ).arg( library->fileName() ).arg( dataCapabilities() ) );
-      mLibraries.append( library );
-    }
-    else
-    {
-      //QgsDebugMsg ( "Cannot get provider " + k );
-    }
-  }
 }
 
 QgsDirectoryItem::~QgsDirectoryItem()
@@ -761,6 +730,7 @@ QIcon QgsDirectoryItem::icon()
   return iconDir();
 }
 
+
 QVector<QgsDataItem*> QgsDirectoryItem::createChildren()
 {
   QVector<QgsDataItem*> children;
@@ -808,18 +778,9 @@ QVector<QgsDataItem*> QgsDirectoryItem::createChildren()
       }
     }
 
-    foreach ( QLibrary *library, mLibraries )
+    foreach ( QgsDataItemProvider* provider, QgsDataItemProviderRegistry::instance()->providers() )
     {
-      // we could/should create separate list of providers for each purpose
-
-      // TODO: use existing fileVectorFilters(),directoryDrivers() ?
-      dataCapabilities_t * dataCapabilities = ( dataCapabilities_t * ) cast_to_fptr( library->resolve( "dataCapabilities" ) );
-      if ( !dataCapabilities )
-      {
-        continue;
-      }
-
-      int capabilities = dataCapabilities();
+      int capabilities = provider->capabilities();
 
       if ( !(( fileInfo.isFile() && ( capabilities & QgsDataProvider::File ) ) ||
              ( fileInfo.isDir() && ( capabilities & QgsDataProvider::Dir ) ) ) )
@@ -827,19 +788,13 @@ QVector<QgsDataItem*> QgsDirectoryItem::createChildren()
         continue;
       }
 
-      dataItem_t * dataItem = ( dataItem_t * ) cast_to_fptr( library->resolve( "dataItem" ) );
-      if ( ! dataItem )
-      {
-        QgsDebugMsg( library->fileName() + " does not have dataItem" );
-        continue;
-      }
-
-      QgsDataItem * item = dataItem( path, this );
+      QgsDataItem * item = provider->createDataItem( path, this );
       if ( item )
       {
         children.append( item );
       }
     }
+
   }
 
   return children;

src/core/qgsdataitem.h

@@ -362,7 +362,8 @@ class CORE_EXPORT QgsDirectoryItem : public QgsDataCollectionItem
 
     /* static QVector<QgsDataProvider*> mProviders; */
     //! @note not available via python bindings
-    static QVector<QLibrary*> mLibraries;
+    //! @note deprecated since 2.10 - use QgsDataItemProviderRegistry
+    Q_DECL_DEPRECATED static QVector<QLibrary*> mLibraries;
 
   public slots:
     virtual void childrenCreated() override;

src/core/qgsdataitemprovider.cpp

@@ -0,0 +1,18 @@
+/***************************************************************************
+  qgsdataitemprovider.cpp
+  --------------------------------------
+  Date                 : March 2015
+  Copyright            : (C) 2015 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsdataitemprovider.h"
+
+// no implementation currently

src/core/qgsdataitemprovider.h

@@ -0,0 +1,52 @@
+/***************************************************************************
+  qgsdataitemprovider.h
+  --------------------------------------
+  Date                 : March 2015
+  Copyright            : (C) 2015 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSDATAITEMPROVIDER_H
+#define QGSDATAITEMPROVIDER_H
+
+class QgsDataItem;
+
+class QString;
+
+/**
+ * This is the interface for those who want to add custom data items to the browser tree.
+ *
+ * The method createDataItem() is ever called only if capabilities() return non-zero value.
+ * There are two occasions when createDataItem() is called:
+ * 1. to create root items (passed path is empty, parent item is null).
+ * 2. to create items in directory structure. For this capabilities have to return at least
+ *    of the following: QgsDataProider::Dir or QgsDataProvider::File. Passed path is the file
+ *    or directory being inspected, parent item is a valid QgsDirectoryItem
+ *
+ * @note added in 2.10
+ */
+class CORE_EXPORT QgsDataItemProvider
+{
+  public:
+    virtual ~QgsDataItemProvider() {}
+
+    //! Human-readable name of the provider name
+    virtual QString name() = 0;
+
+    //! Return combination of flags from QgsDataProvider::DataCapabilities
+    virtual int capabilities() = 0;
+
+    //! Create a new instance of QgsDataItem (or null) for given path and parent item.
+    //! Caller takes responsibility of deleting created items.
+    virtual QgsDataItem* createDataItem( const QString& path, QgsDataItem* parentItem ) = 0;
+
+};
+
+#endif // QGSDATAITEMPROVIDER_H

src/core/qgsdataitemproviderregistry.cpp

@@ -0,0 +1,86 @@
+/***************************************************************************
+  qgsdataitemproviderregistry.cpp
+  --------------------------------------
+  Date                 : March 2015
+  Copyright            : (C) 2015 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsdataitemproviderregistry.h"
+
+#include "qgsdataitem.h"
+#include "qgsdataitemprovider.h"
+#include "qgsdataprovider.h"
+#include "qgslogger.h"
+#include "qgsproviderregistry.h"
+
+
+/** Simple data item provider implementation that handles the support for provider plugins (which may contain
+ * dataCapabilities() and dataItem() functions).
+ *
+ * Ideally the provider plugins should directly provide implementation of QgsDataItemProvider, for the time being
+ * this is a wrapper for the legacy interface.
+ */
+class QgsDataItemProviderFromPlugin : public QgsDataItemProvider
+{
+  public:
+    QgsDataItemProviderFromPlugin( const QString& name, dataCapabilities_t* capabilitiesFunc, dataItem_t* dataItemFunc )
+        : mName( name )
+        , mCapabilitiesFunc( capabilitiesFunc )
+        , mDataItemFunc( dataItemFunc )
+    {
+    }
+
+    virtual QString name() { return mName; }
+
+    virtual int capabilities() { return mCapabilitiesFunc(); }
+
+    virtual QgsDataItem* createDataItem( const QString& path, QgsDataItem* parentItem ) { return mDataItemFunc( path, parentItem ); }
+
+  protected:
+    QString mName;
+    dataCapabilities_t* mCapabilitiesFunc;
+    dataItem_t* mDataItemFunc;
+};
+
+
+QgsDataItemProviderRegistry::QgsDataItemProviderRegistry()
+{
+  QStringList providersList = QgsProviderRegistry::instance()->providerList();
+
+  foreach ( QString key, providersList )
+  {
+    QLibrary *library = QgsProviderRegistry::instance()->providerLibrary( key );
+    if ( !library )
+      continue;
+
+    dataCapabilities_t * dataCapabilities = ( dataCapabilities_t * ) cast_to_fptr( library->resolve( "dataCapabilities" ) );
+    if ( !dataCapabilities )
+    {
+      QgsDebugMsg( library->fileName() + " does not have dataCapabilities" );
+      continue;
+    }
+
+    dataItem_t *dataItem = ( dataItem_t * ) cast_to_fptr( library->resolve( "dataItem" ) );
+    if ( !dataItem )
+    {
+      QgsDebugMsg( library->fileName() + " does not have dataItem" );
+      continue;
+    }
+
+    mProviders.append( new QgsDataItemProviderFromPlugin( library->fileName(), dataCapabilities, dataItem ) );
+  }
+}
+
+QgsDataItemProviderRegistry::~QgsDataItemProviderRegistry()
+{
+  qDeleteAll( mProviders );
+}
+

src/core/qgsdataitemproviderregistry.h

@@ -0,0 +1,48 @@
+/***************************************************************************
+  qgsdataitemproviderregistry.h
+  --------------------------------------
+  Date                 : March 2015
+  Copyright            : (C) 2015 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSDATAITEMPROVIDERREGISTRY_H
+#define QGSDATAITEMPROVIDERREGISTRY_H
+
+#include "qgssingleton.h"
+
+#include <QList>
+
+class QgsDataItemProvider;
+
+/**
+ * This singleton class keeps a list of data item providers that may add items to the browser tree.
+ * When created, it automatically adds providers from provider plugins (e.g. PostGIS, WMS, ...)
+ *
+ * @note added in 2.10
+ */
+class CORE_EXPORT QgsDataItemProviderRegistry : public QgsSingleton<QgsDataItemProviderRegistry>
+{
+  public:
+    ~QgsDataItemProviderRegistry();
+
+    //! Get list of available providers
+    QList<QgsDataItemProvider*> providers() const { return mProviders; }
+
+  private:
+    QgsDataItemProviderRegistry();
+
+    friend class QgsSingleton<QgsDataItemProviderRegistry>; // Let QgsSingleton access private constructor
+
+    //! available providers. this class owns the pointers
+    QList<QgsDataItemProvider*> mProviders;
+};
+
+#endif // QGSDATAITEMPROVIDERREGISTRY_H