Better responsive to provider removal

python/gui/auto_generated/processing/qgsprocessingtoolboxmodel.sip.in

@@ -67,6 +67,12 @@ Returns a list of children belonging to the node.
 %End
 
 
+    QgsProcessingToolboxModelNode *takeChild( QgsProcessingToolboxModelNode *node );
+%Docstring
+Removes the specified ``node`` from this node's children, and gives
+ownership back to the caller.
+%End
+
     QgsProcessingToolboxModelGroupNode *getChildGroupNode( const QString &id );
 %Docstring
 Tries to find a child node belonging to this node, which corresponds to
@@ -115,6 +121,11 @@ specified ``provider``.
     QgsProcessingProvider *provider();
 %Docstring
 Returns the provider associated with this node.
+%End
+
+    QString providerId() const;
+%Docstring
+Returns the provider ID.
 %End
 
 };
@@ -258,6 +269,16 @@ a None if the index does not represent a provider.
 
 .. seealso:: :py:func:`algorithmForIndex`
 
+.. seealso:: :py:func:`indexForProvider`
+%End
+
+    QString providerIdForIndex( const QModelIndex &index ) const;
+%Docstring
+Returns the provider ID which corresponds to a given ``index``, or
+an empty string if the index does not represent a provider.
+
+.. seealso:: :py:func:`algorithmForIndex`
+
 .. seealso:: :py:func:`indexForProvider`
 %End
 
@@ -278,9 +299,9 @@ Returns true if ``index`` corresponds to an algorithm.
 .. seealso:: :py:func:`algorithmForIndex`
 %End
 
-    QModelIndex indexForProvider( QgsProcessingProvider *provider ) const;
+    QModelIndex indexForProvider( const QString &providerId ) const;
 %Docstring
-Returns the index corresponding to the specified ``provider``.
+Returns the index corresponding to the specified ``providerId``.
 
 .. seealso:: :py:func:`providerForIndex`
 %End

python/gui/processing/qgsprocessingtoolboxmodel.sip.in

@@ -67,6 +67,12 @@ Returns a list of children belonging to the node.
 %End
 
 
+    QgsProcessingToolboxModelNode* takeChild( QgsProcessingToolboxModelNode* node );
+%Docstring
+Removes the specified ``node`` from this node's children, and gives
+ownership back to the caller.
+%End
+
     QgsProcessingToolboxModelGroupNode *getChildGroupNode( const QString &id );
 %Docstring
 Tries to find a child node belonging to this node, which corresponds to
@@ -115,6 +121,11 @@ specified ``provider``.
     QgsProcessingProvider *provider();
 %Docstring
 Returns the provider associated with this node.
+%End
+
+    QString providerId() const;
+%Docstring
+Returns the provider ID.
 %End
 
 };
@@ -258,6 +269,16 @@ a None if the index does not represent a provider.
 
 .. seealso:: :py:func:`algorithmForIndex`
 
+.. seealso:: :py:func:`indexForProvider`
+%End
+
+    QString providerIdForIndex( const QModelIndex &index ) const;
+%Docstring
+Returns the provider ID which corresponds to a given ``index``, or
+an empty string if the index does not represent a provider.
+
+.. seealso:: :py:func:`algorithmForIndex`
+
 .. seealso:: :py:func:`indexForProvider`
 %End
 
@@ -278,9 +299,9 @@ Returns true if ``index`` corresponds to an algorithm.
 .. seealso:: :py:func:`algorithmForIndex`
 %End
 
-    QModelIndex indexForProvider( QgsProcessingProvider *provider ) const;
+    QModelIndex indexForProvider(const QString &providerId ) const;
 %Docstring
-Returns the index corresponding to the specified ``provider``.
+Returns the index corresponding to the specified ``providerId``.
 
 .. seealso:: :py:func:`providerForIndex`
 %End

src/gui/processing/qgsprocessingtoolboxmodel.cpp

@@ -31,6 +31,11 @@ QgsProcessingToolboxModelNode::~QgsProcessingToolboxModelNode()
   deleteChildren();
 }
 
+QgsProcessingToolboxModelNode *QgsProcessingToolboxModelNode::takeChild( QgsProcessingToolboxModelNode *node )
+{
+  return mChildren.takeAt( mChildren.indexOf( node ) );
+}
+
 QgsProcessingToolboxModelGroupNode *QgsProcessingToolboxModelNode::getChildGroupNode( const QString &groupId )
 {
   for ( QgsProcessingToolboxModelNode *node : qgis::as_const( mChildren ) )
@@ -67,7 +72,8 @@ void QgsProcessingToolboxModelNode::deleteChildren()
 //
 
 QgsProcessingToolboxModelProviderNode::QgsProcessingToolboxModelProviderNode( QgsProcessingProvider *provider )
-  : mProvider( provider )
+  : mProviderId( provider->id() )
+  , mProvider( provider )
 {}
 
 QgsProcessingProvider *QgsProcessingToolboxModelProviderNode::provider()
@@ -109,7 +115,7 @@ QgsProcessingToolboxModel::QgsProcessingToolboxModel( QObject *parent, QgsProces
   rebuild();
 
   connect( mRegistry, &QgsProcessingRegistry::providerAdded, this, &QgsProcessingToolboxModel::providerAdded );
-  connect( mRegistry, &QgsProcessingRegistry::providerRemoved, this, &QgsProcessingToolboxModel::rebuild );
+  connect( mRegistry, &QgsProcessingRegistry::providerRemoved, this, &QgsProcessingToolboxModel::providerRemoved );
 }
 
 void QgsProcessingToolboxModel::rebuild()
@@ -132,9 +138,44 @@ void QgsProcessingToolboxModel::providerAdded( const QString &id )
   if ( !provider )
     return;
 
-  beginResetModel();
-  addProvider( provider );
-  endResetModel();
+  if ( !isTopLevelProvider( id ) )
+  {
+    int previousRowCount = rowCount();
+    beginInsertRows( QModelIndex(), previousRowCount + 1, previousRowCount + 1 );
+    addProvider( provider );
+    endInsertRows();
+  }
+  else
+  {
+    //native providers use top level groups - that's too hard for us to
+    //work out exactly what's going to change, so just reset the model
+    beginResetModel();
+    addProvider( provider );
+    endResetModel();
+  }
+}
+
+void QgsProcessingToolboxModel::providerRemoved( const QString &id )
+{
+  if ( isTopLevelProvider( id ) )
+  {
+    // native providers use top level groups - so we can't
+    // work out what to remove. Just rebuild the whole model instead.
+    rebuild();
+  }
+  else
+  {
+    // can't retrieve the provider - it's been deleted!
+    // so find node by id
+    QModelIndex index = indexForProvider( id );
+    QgsProcessingToolboxModelNode *node = index2node( index );
+    if ( !node )
+      return;
+
+    beginRemoveRows( QModelIndex(), index.row(), index.row() );
+    delete mRootNode->takeChild( node );
+    endRemoveRows();
+  }
 }
 
 QgsProcessingToolboxModelNode *QgsProcessingToolboxModel::index2node( const QModelIndex &index ) const
@@ -163,7 +204,7 @@ void QgsProcessingToolboxModel::addProvider( QgsProcessingProvider *provider )
   connect( provider, &QgsProcessingProvider::algorithmsLoaded, this, &QgsProcessingToolboxModel::rebuild, Qt::UniqueConnection );
 
   QgsProcessingToolboxModelNode *parentNode = nullptr;
-  if ( !isTopLevelProvider( provider ) )
+  if ( !isTopLevelProvider( provider->id() ) )
   {
     std::unique_ptr< QgsProcessingToolboxModelProviderNode > node = qgis::make_unique< QgsProcessingToolboxModelProviderNode >( provider );
     parentNode = node.get();
@@ -198,11 +239,11 @@ void QgsProcessingToolboxModel::addProvider( QgsProcessingProvider *provider )
   }
 }
 
-bool QgsProcessingToolboxModel::isTopLevelProvider( QgsProcessingProvider *provider )
+bool QgsProcessingToolboxModel::isTopLevelProvider( const QString &providerId )
 {
-  return provider->id() == QLatin1String( "qgis" ) ||
-         provider->id() == QLatin1String( "native" ) ||
-         provider->id() == QLatin1String( "3d" );
+  return providerId == QLatin1String( "qgis" ) ||
+         providerId == QLatin1String( "native" ) ||
+         providerId == QLatin1String( "3d" );
 }
 
 QString QgsProcessingToolboxModel::toolTipForAlgorithm( const QgsProcessingAlgorithm *algorithm )
@@ -368,6 +409,15 @@ QgsProcessingProvider *QgsProcessingToolboxModel::providerForIndex( const QModel
   return qobject_cast< QgsProcessingToolboxModelProviderNode * >( n )->provider();
 }
 
+QString QgsProcessingToolboxModel::providerIdForIndex( const QModelIndex &index ) const
+{
+  QgsProcessingToolboxModelNode *n = index2node( index );
+  if ( !n || n->nodeType() != QgsProcessingToolboxModelNode::NodeProvider )
+    return nullptr;
+
+  return qobject_cast< QgsProcessingToolboxModelProviderNode * >( n )->providerId();
+}
+
 const QgsProcessingAlgorithm *QgsProcessingToolboxModel::algorithmForIndex( const QModelIndex &index ) const
 {
   QgsProcessingToolboxModelNode *n = index2node( index );
@@ -383,27 +433,24 @@ bool QgsProcessingToolboxModel::isAlgorithm( const QModelIndex &index ) const
   return ( n && n->nodeType() == QgsProcessingToolboxModelNode::NodeAlgorithm );
 }
 
-QModelIndex QgsProcessingToolboxModel::indexForProvider( QgsProcessingProvider *provider ) const
+QModelIndex QgsProcessingToolboxModel::indexForProvider( const QString &providerId ) const
 {
-  if ( !provider )
-    return QModelIndex();
-
-  std::function< QModelIndex( const QModelIndex &parent, QgsProcessingProvider *provider ) > findIndex = [&]( const QModelIndex & parent, QgsProcessingProvider * provider )->QModelIndex
+  std::function< QModelIndex( const QModelIndex &parent, const QString &providerId ) > findIndex = [&]( const QModelIndex & parent, const QString & providerId )->QModelIndex
   {
     for ( int row = 0; row < rowCount( parent ); ++row )
     {
       QModelIndex current = index( row, 0, parent );
-      if ( providerForIndex( current ) == provider )
+      if ( providerIdForIndex( current ) == providerId )
         return current;
 
-      QModelIndex checkChildren = findIndex( current, provider );
+      QModelIndex checkChildren = findIndex( current, providerId );
       if ( checkChildren.isValid() )
         return checkChildren;
     }
     return QModelIndex();
   };
 
-  return findIndex( QModelIndex(), provider );
+  return findIndex( QModelIndex(), providerId );
 }
 
 QModelIndex QgsProcessingToolboxModel::indexOfParentTreeNode( QgsProcessingToolboxModelNode *parentNode ) const

src/gui/processing/qgsprocessingtoolboxmodel.h

@@ -89,6 +89,12 @@ class GUI_EXPORT QgsProcessingToolboxModelNode : public QObject
      */
     QList<QgsProcessingToolboxModelNode *> children() const { return mChildren; } SIP_SKIP
 
+    /**
+     * Removes the specified \a node from this node's children, and gives
+     * ownership back to the caller.
+     */
+    QgsProcessingToolboxModelNode *takeChild( QgsProcessingToolboxModelNode *node );
+
     /**
      * Tries to find a child node belonging to this node, which corresponds to
      * a group node with the given group \a id. Returns nullptr if no matching
@@ -140,8 +146,14 @@ class GUI_EXPORT QgsProcessingToolboxModelProviderNode : public QgsProcessingToo
      */
     QgsProcessingProvider *provider();
 
+    /**
+     * Returns the provider ID.
+     */
+    QString providerId() const { return mProviderId; }
+
   private:
 
+    QString mProviderId;
     QgsProcessingProvider *mProvider = nullptr;
 
 };
@@ -278,6 +290,15 @@ class GUI_EXPORT QgsProcessingToolboxModel : public QAbstractItemModel
      */
     QgsProcessingProvider *providerForIndex( const QModelIndex &index ) const;
 
+    /**
+     * Returns the provider ID which corresponds to a given \a index, or
+     * an empty string if the index does not represent a provider.
+     *
+     * \see algorithmForIndex()
+     * \see indexForProvider()
+     */
+    QString providerIdForIndex( const QModelIndex &index ) const;
+
     /**
      * Returns the algorithm which corresponds to a given \a index, or
      * a nullptr if the index does not represent an algorithm.
@@ -295,10 +316,10 @@ class GUI_EXPORT QgsProcessingToolboxModel : public QAbstractItemModel
     bool isAlgorithm( const QModelIndex &index ) const;
 
     /**
-     * Returns the index corresponding to the specified \a provider.
+     * Returns the index corresponding to the specified \a providerId.
      * \see providerForIndex()
      */
-    QModelIndex indexForProvider( QgsProcessingProvider *provider ) const;
+    QModelIndex indexForProvider( const QString &providerId ) const;
 
     /**
      * Returns the index corresponding to the parent of a given node.
@@ -309,6 +330,7 @@ class GUI_EXPORT QgsProcessingToolboxModel : public QAbstractItemModel
 
     void rebuild();
     void providerAdded( const QString &id );
+    void providerRemoved( const QString &id );
 
   private:
 
@@ -319,10 +341,10 @@ class GUI_EXPORT QgsProcessingToolboxModel : public QAbstractItemModel
     void addProvider( QgsProcessingProvider *provider );
 
     /**
-     * Returns true if \a provider is a "top-level" provider, which shows
+     * Returns true if \a providerId is a "top-level" provider, which shows
      * groups directly under the root node and not under a provider child node.
      */
-    static bool isTopLevelProvider( QgsProcessingProvider *provider );
+    static bool isTopLevelProvider( const QString &providerId );
 
     /**
      * Returns a formatted tooltip for an \a algorithm.