qgsexpressionbuilderwidget.h

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/***************************************************************************
    qgisexpressionbuilderwidget.h - A generic expression string builder widget.
     --------------------------------------
    Date                 :  29-May-2011
    Copyright            : (C) 2011 by Nathan Woodrow
    Email                : woodrow.nathan 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 QGSEXPRESSIONBUILDER_H
#define QGSEXPRESSIONBUILDER_H

#include <QWidget>
#include "qgis_sip.h"
#include "ui_qgsexpressionbuilder.h"
#include "qgsdistancearea.h"
#include "qgsexpressioncontext.h"
#include "qgsexpression.h"

#include "QStandardItemModel"
#include "QStandardItem"
#include "QSortFilterProxyModel"
#include "QStringListModel"
#include "qgis_gui.h"

class QgsFields;
class QgsExpressionHighlighter;
class QgsRelation;

class GUI_EXPORT QgsExpressionItem : public QStandardItem
{
  public:
    enum ItemType
    {
      Header,
      Field,
      ExpressionNode
    };

    QgsExpressionItem( const QString &label,
                       const QString &expressionText,
                       const QString &helpText,
                       QgsExpressionItem::ItemType itemType = ExpressionNode )
      : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mHelpText = helpText;
      mType = itemType;
      setData( itemType, ITEM_TYPE_ROLE );
    }

    QgsExpressionItem( const QString &label,
                       const QString &expressionText,
                       QgsExpressionItem::ItemType itemType = ExpressionNode )
      : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mType = itemType;
      setData( itemType, ITEM_TYPE_ROLE );
    }

    QString getExpressionText() const { return mExpressionText; }

    QString getHelpText() const { return mHelpText; }

    void setHelpText( const QString &helpText ) { mHelpText = helpText; }

    QgsExpressionItem::ItemType getItemType() const { return mType; }

    static const int CUSTOM_SORT_ROLE = Qt::UserRole + 1;
    static const int ITEM_TYPE_ROLE = Qt::UserRole + 2;
    static const int SEARCH_TAGS_ROLE = Qt::UserRole + 3;

  private:
    QString mExpressionText;
    QString mHelpText;
    QgsExpressionItem::ItemType mType;

};

class GUI_EXPORT QgsExpressionItemSearchProxy : public QSortFilterProxyModel
{
    Q_OBJECT

  public:
    QgsExpressionItemSearchProxy();

    bool filterAcceptsRow( int source_row, const QModelIndex &source_parent ) const override;

  protected:

    bool lessThan( const QModelIndex &left, const QModelIndex &right ) const override;
};


class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExpressionBuilderWidgetBase
{
    Q_OBJECT
  public:

    QgsExpressionBuilderWidget( QWidget *parent SIP_TRANSFERTHIS = nullptr );
    ~QgsExpressionBuilderWidget() override;

    void setLayer( QgsVectorLayer *layer );

    void loadFieldNames();

    void loadFieldNames( const QgsFields &fields );

    void loadFieldsAndValues( const QMap<QString, QStringList> &fieldValues );

    void setGeomCalculator( const QgsDistanceArea &da );

    QString expressionText();

    void setExpressionText( const QString &expression );

    QString expectedOutputFormat();

    void setExpectedOutputFormat( const QString &expected );

    QgsExpressionContext expressionContext() const { return mExpressionContext; }

    void setExpressionContext( const QgsExpressionContext &context );

    void registerItem( const QString &group, const QString &label, const QString &expressionText,
                       const QString &helpText = QString(),
                       QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode,
                       bool highlightedItem = false, int sortOrder = 1,
                       QIcon icon = QIcon(),
                       const QStringList &tags = QStringList() );

    bool isExpressionValid();

    void saveToRecent( const QString &collection = "generic" );

    void loadRecent( const QString &collection = QStringLiteral( "generic" ) );

    void loadUserExpressions( );

    void saveToUserExpressions( const QString &label, const QString expression, const QString &helpText );

    void removeFromUserExpressions( const QString &label );

    void newFunctionFile( const QString &fileName = "scratch" );

    void saveFunctionFile( QString fileName );

    void loadCodeFromFile( QString path );

    void loadFunctionCode( const QString &code );

    void updateFunctionFileList( const QString &path );

    QStandardItemModel *model();

    QgsProject *project();

    void setProject( QgsProject *project );

    bool evalError() const;

    bool parserError() const;

  public slots:

    void loadSampleValues();

    void loadAllValues();

    void loadSampleUsedValues();

    void loadAllUsedValues();

    void autosave();

    void setAutoSave( bool enabled ) { mAutoSave = enabled; }

    void storeCurrentUserExpression( );

    void removeSelectedUserExpression( );

    const QList<QgsExpressionItem *> findExpressions( const QString &label );


  private slots:
    void indicatorClicked( int line, int index, Qt::KeyboardModifiers state );
    void showContextMenu( QPoint );
    void setExpressionState( bool state );
    void currentChanged( const QModelIndex &index, const QModelIndex & );
    void operatorButtonClicked();
    void btnRun_pressed();
    void btnNewFile_pressed();
    void cmbFileNames_currentItemChanged( QListWidgetItem *item, QListWidgetItem *lastitem );
    void expressionTree_doubleClicked( const QModelIndex &index );
    void txtExpressionString_textChanged();
    void txtSearchEdit_textChanged();
    void txtSearchEditValues_textChanged();
    void lblPreview_linkActivated( const QString &link );
    void mValuesListView_doubleClicked( const QModelIndex &index );
    void txtPython_textChanged();

  signals:

    void expressionParsed( bool isValid );

    void evalErrorChanged();

    void parserErrorChanged();

  protected:
    void showEvent( QShowEvent *e ) override;

  private:
    int FUNCTION_MARKER_ID = 25;
    void createErrorMarkers( QList<QgsExpression::ParserError> errors );
    void createMarkers( const QgsExpressionNode *node );
    void clearFunctionMarkers();
    void clearErrors();
    void runPythonCode( const QString &code );
    void updateFunctionTree();
    void fillFieldValues( const QString &fieldName, int countLimit, bool forceUsedValues = false );
    bool formatterCanProvideAvailableValues( const QString &fieldName );
    QString getFunctionHelp( QgsExpressionFunction *function );
    QString loadFunctionHelp( QgsExpressionItem *functionName );
    QString helpStylesheet() const;

    void loadExpressionContext();

    void loadRelations();

    void loadLayers();

    void registerItemForAllGroups( const QStringList &groups, const QString &label, const QString &expressionText,
                                   const QString &helpText = QString(),
                                   QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode,
                                   bool highlightedItem = false, int sortOrder = 1, const QStringList &tags = QStringList() );

    QString formatRelationHelp( const QgsRelation &relation ) const;

    QString formatLayerHelp( const QgsMapLayer *layer ) const;

    void setEvalError( bool evalError );

    void setParserError( bool parserError );

    void loadFieldValues( const QVariantMap &values );

    void loadFieldsAndValues( const QMap<QString, QVariantMap> &fieldValues );

    bool mAutoSave = true;
    QString mFunctionsPath;
    QgsVectorLayer *mLayer = nullptr;
    std::unique_ptr<QStandardItemModel> mModel;
    // Will hold items with
    // * a display string that matches the represented field values
    // * custom data in Qt::UserRole + 1 that contains a ready to use expression literal ('quoted string' or NULL or a plain number )
    std::unique_ptr<QStandardItemModel> mValuesModel;
    std::unique_ptr<QSortFilterProxyModel> mProxyValues;
    std::unique_ptr<QgsExpressionItemSearchProxy> mProxyModel;
    QMap<QString, QgsExpressionItem *> mExpressionGroups;
    QgsExpressionHighlighter *highlighter = nullptr;
    bool mExpressionValid = false;
    QgsDistanceArea mDa;
    QString mRecentKey;
    QMap<QString, QVariantMap>  mFieldValues;
    QgsExpressionContext mExpressionContext;
    QPointer< QgsProject > mProject;
    bool mEvalError = true;
    bool mParserError = true;
    // Translated name of the user expressions group
    QString mUserExpressionsGroupName;
    QStringList mUserExpressionLabels;
};

// clazy:excludeall=qstring-allocations

#endif // QGSEXPRESSIONBUILDER_H