qgssettings.h

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/***************************************************************************
  qgssettings.h
  --------------------------------------
  Date                 : January 2017
  Copyright            : (C) 2017 by Alessandro Pasotti
  Email                : apasotti at boundlessgeo 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 QGSSETTINGS_H
#define QGSSETTINGS_H

#include <QSettings>
#include <QMetaEnum>

#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgslogger.h"

class CORE_EXPORT QgsSettings : public QObject
{
    Q_OBJECT
  public:

    enum Section
    {
      NoSection,
      Core,
      Gui,
      Server,
      Plugins,
      Auth,
      App,
      Providers,
      Expressions,
      Misc
    };

    explicit QgsSettings( const QString &organization,
                          const QString &application = QString(), QObject *parent = nullptr );

    QgsSettings( QSettings::Scope scope, const QString &organization,
                 const QString &application = QString(), QObject *parent = nullptr );

    QgsSettings( QSettings::Format format, QSettings::Scope scope, const QString &organization,
                 const QString &application = QString(), QObject *parent = nullptr );

    QgsSettings( const QString &fileName, QSettings::Format format, QObject *parent = nullptr );

    explicit QgsSettings( QObject *parent = nullptr );
    ~QgsSettings() override;

    void beginGroup( const QString &prefix, QgsSettings::Section section = QgsSettings::NoSection );
    void endGroup();

    QString group() const;

    QStringList allKeys() const;
    QStringList childKeys() const;
    QStringList childGroups() const;
    QStringList globalChildGroups() const;
    static QString globalSettingsPath();
    static bool setGlobalSettingsPath( const QString &path );
    int beginReadArray( const QString &prefix );

    void beginWriteArray( const QString &prefix, int size = -1 );
    void endArray();

    void setArrayIndex( int i );

    void setValue( const QString &key, const QVariant &value, QgsSettings::Section section = QgsSettings::NoSection );

#ifndef SIP_RUN
    QVariant value( const QString &key, const QVariant &defaultValue = QVariant(),
                    Section section = NoSection ) const;
#else
    SIP_PYOBJECT value( const QString &key, const QVariant &defaultValue = QVariant(),
                        SIP_PYOBJECT type = 0,
                        QgsSettings::Section section = QgsSettings::NoSection ) const / ReleaseGIL /;
    % MethodCode
    typedef PyObject *( *pyqt5_from_qvariant_by_type )( QVariant &value, PyObject *type );
    QVariant value;

    // QSettings has an internal mutex so release the GIL to avoid the possibility of deadlocks.
    Py_BEGIN_ALLOW_THREADS
    value = sipCpp->value( *a0, *a1, a3 );
    Py_END_ALLOW_THREADS

    pyqt5_from_qvariant_by_type f = ( pyqt5_from_qvariant_by_type ) sipImportSymbol( "pyqt5_from_qvariant_by_type" );
    sipRes = f( value, a2 );

    sipIsErr = !sipRes;
    % End
#endif

#ifndef SIP_RUN

    template <class T>
    T enumValue( const QString &key, const T &defaultValue,
                 const Section section = NoSection )
    {
      QMetaEnum metaEnum = QMetaEnum::fromType<T>();
      Q_ASSERT( metaEnum.isValid() );
      if ( !metaEnum.isValid() )
      {
        QgsDebugMsg( QStringLiteral( "Invalid metaenum. Enum probably misses Q_ENUM or Q_FLAG declaration." ) );
      }

      T v;
      bool ok = false;

      if ( metaEnum.isValid() )
      {
        // read as string
        QByteArray ba = value( key, metaEnum.valueToKey( static_cast<int>( defaultValue ) ), section ).toString().toUtf8();
        const char *vs = ba.data();
        v = static_cast<T>( metaEnum.keyToValue( vs, &ok ) );
        if ( ok )
          return v;
      }

      // if failed, try to read as int (old behavior)
      // this code shall be removed later (probably after QGIS 3.4 LTR for 3.6)
      // then the method could be marked as const
      v = static_cast<T>( value( key, static_cast<int>( defaultValue ), section ).toInt( &ok ) );
      if ( metaEnum.isValid() )
      {
        if ( !ok || !metaEnum.valueToKey( static_cast<int>( v ) ) )
        {
          v = defaultValue;
        }
        else
        {
          // found setting as an integer
          // convert the setting to the new form (string)
          setEnumValue( key, v, section );
        }
      }

      return v;
    }

    template <class T>
    void setEnumValue( const QString &key, const T &value,
                       const Section section = NoSection )
    {
      QMetaEnum metaEnum = QMetaEnum::fromType<T>();
      Q_ASSERT( metaEnum.isValid() );
      if ( metaEnum.isValid() )
      {
        setValue( key, metaEnum.valueToKey( static_cast<int>( value ) ), section );
      }
      else
      {
        QgsDebugMsg( QStringLiteral( "Invalid metaenum. Enum probably misses Q_ENUM or Q_FLAG declaration." ) );
      }
    }

    template <class T>
    T flagValue( const QString &key, const T &defaultValue,
                 const Section section = NoSection )
    {
      QMetaEnum metaEnum = QMetaEnum::fromType<T>();
      Q_ASSERT( metaEnum.isValid() );
      if ( !metaEnum.isValid() )
      {
        QgsDebugMsg( QStringLiteral( "Invalid metaenum. Enum probably misses Q_ENUM or Q_FLAG declaration." ) );
      }

      T v = defaultValue;
      bool ok = false;

      if ( metaEnum.isValid() )
      {
        // read as string
        QByteArray ba = value( key, metaEnum.valueToKeys( defaultValue ) ).toString().toUtf8();
        const char *vs = ba.data();
        v = static_cast<T>( metaEnum.keysToValue( vs, &ok ) );
      }
      if ( !ok )
      {
        // if failed, try to read as int (old behavior)
        // this code shall be removed later (probably after QGIS 3.4 LTR for 3.6)
        // then the method could be marked as const
        v = T( value( key, static_cast<int>( defaultValue ), section ).toInt( &ok ) );
        if ( metaEnum.isValid() )
        {
          if ( !ok || metaEnum.valueToKeys( static_cast<int>( v ) ).isEmpty() )
          {
            v = defaultValue;
          }
          else
          {
            // found setting as an integer
            // convert the setting to the new form (string)
            setFlagValue( key, v, section );
          }
        }
      }

      return v;
    }

    template <class T>
    void setFlagValue( const QString &key, const T &value,
                       const Section section = NoSection )
    {
      QMetaEnum metaEnum = QMetaEnum::fromType<T>();
      Q_ASSERT( metaEnum.isValid() );
      if ( metaEnum.isValid() )
      {
        setValue( key, metaEnum.valueToKeys( value ), section );
      }
      else
      {
        QgsDebugMsg( QStringLiteral( "Invalid metaenum. Enum probably misses Q_ENUM or Q_FLAG declaration." ) );
      }
    }
#endif

    bool contains( const QString &key, QgsSettings::Section section = QgsSettings::NoSection ) const;
    QString fileName() const;

    void sync();
    void remove( const QString &key, QgsSettings::Section section = QgsSettings::NoSection );
    QString prefixedKey( const QString &key, QgsSettings::Section section ) const;
    void clear();

  private:
    void init();
    QString sanitizeKey( const QString &key ) const;
    QSettings *mUserSettings = nullptr;
    QSettings *mGlobalSettings = nullptr;
    bool mUsingGlobalArray = false;
    Q_DISABLE_COPY( QgsSettings )

};

#endif // QGSSETTINGS_H