File indexing completed on 2024-04-21 03:56:53

 /*
     This file is part of the KDE libraries
     SPDX-FileCopyrightText: 2008 Christian Ehrlicher <ch.ehrlicher@gmx.de>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 #ifndef KMEMFILE_H
 #define KMEMFILE_H
 
 #include <QIODevice>
 #include <kservice_export.h>
 #include <memory>
 
 #ifndef QT_NO_SHAREDMEMORY
 
 /**
  * @internal
  * Simple QIODevice for QSharedMemory to keep ksycoca cache in memory only once
  * The first call to open() loads the file into a shm segment. Every
  * subsequent call only attaches to this segment. When the file content changed,
  * you have to execute KMemFile::fileContentsChanged() to update the internal
  * structures. The next call to open() creates a new shm segment. The old one
  * is automatically destroyed when the last process closed KMemFile.
  */
 
 class KMemFile : public QIODevice
 {
     Q_OBJECT
 public:
     /**
      * ctor
      *
      * @param filename the file to load into memory
      * @param parent our parent
      */
     explicit KMemFile(const QString &filename, QObject *parent = nullptr);
     /**
      * dtor
      */
     ~KMemFile() override;
     /**
      * closes the KMemFile
      *
      * @reimp
      */
     void close() override;
     /**
      * As KMemFile is a random access device, it returns false
      *
      * @reimp
      */
     bool isSequential() const override;
     /**
      * @reimp
      * @param mode only QIODevice::ReadOnly is accepted
      */
     bool open(OpenMode mode) override;
     /**
      * Sets the current read/write position to pos
      * @reimp
      * @param pos the new read/write position
      */
     bool seek(qint64 pos) override;
     /**
      * Returns the size of the file
      * @reimp
      */
     qint64 size() const override;
     /**
      * This static function updates the internal information about the file
      * loaded into shared memory. The next time the file is opened, the file is
      * reread from the file system.
      */
     static void fileContentsChanged(const QString &filename);
 
 protected:
     /** @reimp */
     qint64 readData(char *data, qint64 maxSize) override;
     /** @reimp */
     qint64 writeData(const char *data, qint64 maxSize) override;
 
 private:
     class Private;
     friend class Private;
     std::unique_ptr<Private> const d;
 };
 
 #endif // QT_NO_SHAREDMEMORY
 
 #endif // KMEMFILE_H