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       1                 :            : /***************************************************************************
       2                 :            :   qgslayertreenode.h
       3                 :            :   --------------------------------------
       4                 :            :   Date                 : May 2014
       5                 :            :   Copyright            : (C) 2014 by Martin Dobias
       6                 :            :   Email                : wonder dot sk at gmail dot com
       7                 :            :  ***************************************************************************
       8                 :            :  *                                                                         *
       9                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      10                 :            :  *   it under the terms of the GNU General Public License as published by  *
      11                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      12                 :            :  *   (at your option) any later version.                                   *
      13                 :            :  *                                                                         *
      14                 :            :  ***************************************************************************/
      15                 :            : 
      16                 :            : #ifndef QGSLAYERTREENODE_H
      17                 :            : #define QGSLAYERTREENODE_H
      18                 :            : 
      19                 :            : #include "qgis_core.h"
      20                 :            : #include <QObject>
      21                 :            : 
      22                 :            : #include "qgsobjectcustomproperties.h"
      23                 :            : #include "qgsreadwritecontext.h"
      24                 :            : #include "qgis_sip.h"
      25                 :            : 
      26                 :            : class QDomElement;
      27                 :            : 
      28                 :            : class QgsProject;
      29                 :            : class QgsMapLayer;
      30                 :            : 
      31                 :            : /**
      32                 :            :  * \ingroup core
      33                 :            :  * \brief This class is a base class for nodes in a layer tree.
      34                 :            :  *
      35                 :            :  * Layer tree is a hierarchical structure consisting of group and layer nodes:
      36                 :            :  *
      37                 :            :  * - group nodes are containers and may contain children (layer and group nodes)
      38                 :            :  * - layer nodes point to map layers, they do not contain further children
      39                 :            :  *
      40                 :            :  * Layer trees may be used for organization of layers, typically a layer tree
      41                 :            :  * is exposed to the user using QgsLayerTreeView widget which shows the tree
      42                 :            :  * and allows manipulation with the tree.
      43                 :            :  *
      44                 :            :  * Ownership of nodes: every node is owned by its parent. Therefore once node
      45                 :            :  * is added to a layer tree, it is the responsibility of the parent to delete it
      46                 :            :  * when the node is not needed anymore. Deletion of root node of a tree will
      47                 :            :  * delete all nodes of the tree.
      48                 :            :  *
      49                 :            :  * Signals: signals are propagated from children to parent. That means it is
      50                 :            :  * sufficient to connect to root node in order to get signals about updates
      51                 :            :  * in the whole layer tree. When adding or removing a node that contains further
      52                 :            :  * children (i.e. a whole subtree), the addition/removal signals are emitted
      53                 :            :  * only for the root node of the subtree that is being added or removed.
      54                 :            :  *
      55                 :            :  * Custom properties: Every node may have some custom properties assigned to it.
      56                 :            :  * This mechanism allows third parties store additional data with the nodes.
      57                 :            :  * The properties are used within QGIS code (whether to show layer in overview,
      58                 :            :  * whether the node is embedded from another project etc), but may be also
      59                 :            :  * used by third party plugins. Custom properties are stored also in the project
      60                 :            :  * file. The storage is not efficient for large amount of data.
      61                 :            :  *
      62                 :            :  * Custom properties that have already been used within QGIS:
      63                 :            :  *
      64                 :            :  * - "loading" - whether the project is being currently loaded (root node only)
      65                 :            :  * - "overview" - whether to show a layer in overview
      66                 :            :  * - "showFeatureCount" - whether to show feature counts in layer tree (vector only)
      67                 :            :  * - "embedded" - whether the node comes from an external project
      68                 :            :  * - "embedded_project" - path to the external project (embedded root node only)
      69                 :            :  * - "legend/..." - properties for legend appearance customization
      70                 :            :  * - "expandedLegendNodes" - list of layer's legend nodes' rules in expanded state
      71                 :            :  *
      72                 :            :  * \see also QgsLayerTree, QgsLayerTreeLayer, QgsLayerTreeGroup
      73                 :            :  * \since QGIS 2.4
      74                 :            :  */
      75                 :            : class CORE_EXPORT QgsLayerTreeNode : public QObject
      76                 :            : {
      77                 :            :     Q_OBJECT
      78                 :            : 
      79                 :            : #ifdef SIP_RUN
      80                 :            :     SIP_CONVERT_TO_SUBCLASS_CODE
      81                 :            :     if ( sipCpp->inherits( "QgsLayerTreeNode" ) )
      82                 :            :     {
      83                 :            :       sipType = sipType_QgsLayerTreeNode;
      84                 :            :       QgsLayerTreeNode *node = qobject_cast<QgsLayerTreeNode *>( sipCpp );
      85                 :            :       if ( QgsLayerTree::isLayer( node ) )
      86                 :            :         sipType = sipType_QgsLayerTreeLayer;
      87                 :            :       else if ( qobject_cast<QgsLayerTree *>( sipCpp ) )
      88                 :            :         sipType = sipType_QgsLayerTree;
      89                 :            :       else if ( QgsLayerTree::isGroup( node ) )
      90                 :            :         sipType = sipType_QgsLayerTreeGroup;
      91                 :            :     }
      92                 :            :     else
      93                 :            :       sipType = 0;
      94                 :            :     SIP_END
      95                 :            : #endif
      96                 :            : 
      97                 :            :   public:
      98                 :            : 
      99                 :            :     //! Enumeration of possible tree node types
     100                 :            :     enum NodeType
     101                 :            :     {
     102                 :            :       NodeGroup,   //!< Container of other groups and layers
     103                 :            :       NodeLayer    //!< Leaf node pointing to a layer
     104                 :            :     };
     105                 :            : 
     106                 :            :     ~QgsLayerTreeNode() override;
     107                 :            : 
     108                 :            :     //! Find out about type of the node. It is usually shorter to use convenience functions from QgsLayerTree namespace for that
     109                 :          2 :     NodeType nodeType() const { return mNodeType; }
     110                 :            :     //! Gets pointer to the parent. If parent is NULLPTR, the node is a root node
     111                 :          0 :     QgsLayerTreeNode *parent() { return mParent; }
     112                 :            :     //! Gets list of children of the node. Children are owned by the parent
     113                 :          3 :     QList<QgsLayerTreeNode *> children() { return mChildren; }
     114                 :            :     //! Gets list of children of the node. Children are owned by the parent
     115                 :          0 :     QList<QgsLayerTreeNode *> children() const { return mChildren; } SIP_SKIP
     116                 :            : 
     117                 :            :     /**
     118                 :            :      * Removes the childrens, disconnect all the forwarded and external signals and sets their parent to NULLPTR
     119                 :            :      * \return the removed children
     120                 :            :      * \since QGIS 3.16
     121                 :            :      */
     122                 :            :     QList<QgsLayerTreeNode *> abandonChildren() SIP_SKIP;
     123                 :            : 
     124                 :            :     /**
     125                 :            :      * Returns name of the node
     126                 :            :      * \since QGIS 3.0
     127                 :            :      */
     128                 :            :     virtual QString name() const = 0;
     129                 :            : 
     130                 :            :     /**
     131                 :            :      * Set name of the node. Emits nameChanged signal.
     132                 :            :      * \since QGIS 3.0
     133                 :            :      */
     134                 :            :     virtual void setName( const QString &name ) = 0;
     135                 :            : 
     136                 :            :     /**
     137                 :            :      * Read layer tree from XML. Returns new instance.
     138                 :            :      * Does not resolve textual references to layers. Call resolveReferences() afterwards to do it.
     139                 :            :      */
     140                 :            :     static QgsLayerTreeNode *readXml( QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;
     141                 :            : 
     142                 :            :     /**
     143                 :            :      * Read layer tree from XML. Returns new instance.
     144                 :            :      * Also resolves textual references to layers from the project (calls resolveReferences() internally).
     145                 :            :      * \since QGIS 3.0
     146                 :            :      */
     147                 :            :     static QgsLayerTreeNode *readXml( QDomElement &element, const QgsProject *project ) SIP_FACTORY;
     148                 :            : 
     149                 :            :     //! Write layer tree to XML
     150                 :            :     virtual void writeXml( QDomElement &parentElement, const QgsReadWriteContext &context ) = 0;
     151                 :            : 
     152                 :            :     //! Returns string with layer tree structure. For debug purposes only
     153                 :            :     virtual QString dump() const = 0;
     154                 :            : 
     155                 :            :     //! Create a copy of the node. Returns new instance
     156                 :            :     virtual QgsLayerTreeNode *clone() const = 0 SIP_FACTORY;
     157                 :            : 
     158                 :            :     /**
     159                 :            :      * Turn textual references to layers into map layer object from project.
     160                 :            :      * This method should be called after readXml()
     161                 :            :      * If \a looseMatching is TRUE then a looser match will be used, where a layer
     162                 :            :      * will match if the name, public source, and data provider match. This can be
     163                 :            :      * used to match legend customization from different projects where layers
     164                 :            :      * will have different layer IDs.
     165                 :            :      * \since QGIS 3.0
     166                 :            :      */
     167                 :            :     virtual void resolveReferences( const QgsProject *project, bool looseMatching = false ) = 0;
     168                 :            : 
     169                 :            :     /**
     170                 :            :      * Returns whether a node is really visible (ie checked and all its ancestors checked as well)
     171                 :            :      * \since QGIS 3.0
     172                 :            :      */
     173                 :            :     bool isVisible() const;
     174                 :            : 
     175                 :            :     /**
     176                 :            :      * Returns whether a node is checked (independently of its ancestors or children)
     177                 :            :      * \since QGIS 3.0
     178                 :            :      */
     179                 :          0 :     bool itemVisibilityChecked() const { return mChecked; }
     180                 :            : 
     181                 :            :     /**
     182                 :            :      * Check or uncheck a node (independently of its ancestors or children)
     183                 :            :      *
     184                 :            :      * \see QgsLayerTreeView::setLayerVisible()
     185                 :            :      *
     186                 :            :      * \since QGIS 3.0
     187                 :            :      */
     188                 :            :     void setItemVisibilityChecked( bool checked );
     189                 :            : 
     190                 :            :     /**
     191                 :            :      * Check or uncheck a node and all its children (taking into account exclusion rules)
     192                 :            :      * \since QGIS 3.0
     193                 :            :      */
     194                 :            :     virtual void setItemVisibilityCheckedRecursive( bool checked );
     195                 :            : 
     196                 :            :     /**
     197                 :            :      * Check or uncheck a node and all its parents
     198                 :            :      * \since QGIS 3.0
     199                 :            :      */
     200                 :            :     void setItemVisibilityCheckedParentRecursive( bool checked );
     201                 :            : 
     202                 :            :     /**
     203                 :            :      * Returns whether this node is checked and all its children.
     204                 :            :      * \since QGIS 3.0
     205                 :            :      */
     206                 :            :     bool isItemVisibilityCheckedRecursive() const;
     207                 :            : 
     208                 :            :     /**
     209                 :            :      * Returns whether this node is unchecked and all its children.
     210                 :            :      * \since QGIS 3.0
     211                 :            :      */
     212                 :            :     bool isItemVisibilityUncheckedRecursive() const;
     213                 :            : 
     214                 :            :     /**
     215                 :            :      * Returns a list of any checked layers which belong to this node or its
     216                 :            :      * children.
     217                 :            :      * \since QGIS 3.0
     218                 :            :      */
     219                 :            :     QList< QgsMapLayer * > checkedLayers() const;
     220                 :            : 
     221                 :            :     /**
     222                 :            :      * Returns the depth of this node, i.e. the number of its ancestors
     223                 :            :      * \since QGIS 3.14
     224                 :            :      */
     225                 :            :     int depth() const;
     226                 :            : 
     227                 :            :     //! Returns whether the node should be shown as expanded or collapsed in GUI
     228                 :            :     bool isExpanded() const;
     229                 :            :     //! Sets whether the node should be shown as expanded or collapsed in GUI
     230                 :            :     void setExpanded( bool expanded );
     231                 :            : 
     232                 :            :     //! Sets a custom property for the node. Properties are stored in a map and saved in project file.
     233                 :            :     void setCustomProperty( const QString &key, const QVariant &value );
     234                 :            :     //! Read a custom property from layer. Properties are stored in a map and saved in project file.
     235                 :            :     QVariant customProperty( const QString &key, const QVariant &defaultValue = QVariant() ) const;
     236                 :            :     //! Remove a custom property from layer. Properties are stored in a map and saved in project file.
     237                 :            :     void removeCustomProperty( const QString &key );
     238                 :            :     //! Returns list of keys stored in custom properties
     239                 :            :     QStringList customProperties() const;
     240                 :            :     //! Remove a child from a node
     241                 :            :     bool takeChild( QgsLayerTreeNode *node );
     242                 :            : 
     243                 :            :   signals:
     244                 :            : 
     245                 :            :     //! Emitted when one or more nodes will be added to a node within the tree
     246                 :            :     void willAddChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
     247                 :            :     //! Emitted when one or more nodes have been added to a node within the tree
     248                 :            :     void addedChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
     249                 :            :     //! Emitted when one or more nodes will be removed from a node within the tree
     250                 :            :     void willRemoveChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
     251                 :            :     //! Emitted when one or more nodes has been removed from a node within the tree
     252                 :            :     void removedChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
     253                 :            :     //! Emitted when check state of a node within the tree has been changed
     254                 :            :     void visibilityChanged( QgsLayerTreeNode *node );
     255                 :            :     //! Emitted when a custom property of a node within the tree has been changed or removed
     256                 :            :     void customPropertyChanged( QgsLayerTreeNode *node, const QString &key );
     257                 :            :     //! Emitted when the collapsed/expanded state of a node within the tree has been changed
     258                 :            :     void expandedChanged( QgsLayerTreeNode *node, bool expanded );
     259                 :            : 
     260                 :            :     /**
     261                 :            :      * Emitted when the name of the node is changed
     262                 :            :      * \since QGIS 3.0
     263                 :            :      */
     264                 :            :     void nameChanged( QgsLayerTreeNode *node, QString name );
     265                 :            : 
     266                 :            :   protected:
     267                 :            : 
     268                 :            :     //! Constructor
     269                 :            :     QgsLayerTreeNode( NodeType t, bool checked = true );
     270                 :            :     QgsLayerTreeNode( const QgsLayerTreeNode &other );
     271                 :            : 
     272                 :            :     // low-level utility functions
     273                 :            : 
     274                 :            :     //! Read common XML elements.
     275                 :            :     void readCommonXml( QDomElement &element );
     276                 :            :     //! Write common XML elements.
     277                 :            :     void writeCommonXml( QDomElement &element );
     278                 :            : 
     279                 :            :     //! Low-level insertion of children to the node. The children must not have any parent yet!
     280                 :            :     void insertChildrenPrivate( int index, QList<QgsLayerTreeNode *> nodes );
     281                 :            :     //! Low-level removal of children from the node.
     282                 :            :     void removeChildrenPrivate( int from, int count, bool destroy = true );
     283                 :            : 
     284                 :            :   protected:
     285                 :            :     //! type of the node - determines which subclass is used
     286                 :            :     NodeType mNodeType;
     287                 :            :     bool mChecked;
     288                 :            :     //! pointer to the parent node - NULLPTR in case of root node
     289                 :            :     QgsLayerTreeNode *mParent = nullptr;
     290                 :            :     //! list of children - node is responsible for their deletion
     291                 :            :     QList<QgsLayerTreeNode *> mChildren;
     292                 :            :     //! whether the node should be shown in GUI as expanded
     293                 :            :     bool mExpanded;
     294                 :            :     //! custom properties attached to the node
     295                 :            :     QgsObjectCustomProperties mProperties;
     296                 :            : 
     297                 :            :     //! Sets parent to NULLPTR and disconnects all external and forwarded signals
     298                 :            :     virtual void makeOrphan() SIP_SKIP;
     299                 :            : 
     300                 :            :   private:
     301                 :            :     QgsLayerTreeNode &operator=( const QgsLayerTreeNode & ) = delete;
     302                 :            : 
     303                 :            : };
     304                 :            : 
     305                 :            : 
     306                 :            : 
     307                 :            : 
     308                 :            : #endif // QGSLAYERTREENODE_H