filejob.h

/*
    This file is part of the KDE libraries
    SPDX-FileCopyrightText: 2006 Allan Sandfeld Jensen <kde@carewolf.com>
 
    SPDX-License-Identifier: LGPL-2.0-only
*/
 
#ifndef KIO_FILEJOB_H
#define KIO_FILEJOB_H
 
#include "kiocore_export.h"
#include "simplejob.h"
 
namespace KIO
{
class FileJobPrivate;
/**
 * @class KIO::FileJob filejob.h <KIO/FileJob>
 *
 *  The file-job is an asynchronous version of normal file handling.
 *  It allows block-wise reading and writing, and allows seeking and truncation. Results are returned through signals.
 *
 *  Should always be created using KIO::open(const QUrl&, QIODevice::OpenMode).
 */
 
class KIOCORE_EXPORT FileJob : public SimpleJob
{
    Q_OBJECT
 
public:
    ~FileJob() override;
 
    /**
     * This function attempts to read up to \p size bytes from the URL passed to
     * KIO::open() and returns the bytes received via the data() signal.
     *
     * The read operation commences at the current file offset, and the file
     * offset is incremented by the number of bytes read, but this change in the
     * offset does not result in the position() signal being emitted.
     *
     * If the current file offset is at or past the end of file (i.e. EOD), no
     * bytes are read, and the data() signal returns an empty QByteArray.
     *
     * On error the data() signal is not emitted. To catch errors please connect
     * to the result() signal.
     *
     * @param size the requested amount of data to read
     *
     */
    void read(KIO::filesize_t size);
 
    /**
     * This function attempts to write all the bytes in \p data to the URL
     * passed to KIO::open() and returns the bytes written received via the
     * written() signal.
     *
     * The write operation commences at the current file offset, and the file
     * offset is incremented by the number of bytes read, but this change in the
     * offset does not result in the position() being emitted.
     *
     * On error the written() signal is not emitted. To catch errors please
     * connect to the result() signal.
     *
     * @param data the data to write
     */
    void write(const QByteArray &data);
 
    /**
     * Closes the file KIO worker.
     *
     * The worker emits close() and result().
     */
    void close();
 
    /**
     * Seek
     *
     * The worker emits position() on successful seek to the specified \p offset.
     *
     * On error the position() signal is not emitted. To catch errors please
     * connect to the result() signal.
     *
     * @param offset the position from start to go to
     */
    void seek(KIO::filesize_t offset);
 
    /**
     * Truncate
     *
     * The worker emits truncated() on successful truncation to the specified \p length.
     *
     * On error the truncated() signal is not emitted. To catch errors please
     * connect to the result() signal.
     *
     * @param length the desired length to truncate to
     * @since 5.66
     */
    void truncate(KIO::filesize_t length);
 
    /**
     * Size
     *
     * @return the file size
     */
    KIO::filesize_t size();
 
Q_SIGNALS:
    /**
     * Data from the worker has arrived. Emitted after read().
     *
     * Unless a read() request was sent for 0 bytes, End of data (EOD) has been
     * reached if data.size() == 0
     *
     * @param job the job that emitted this signal
     * @param data data received from the worker.
     *
     */
    void data(KIO::Job *job, const QByteArray &data);
 
    /**
     * Signals the file is a redirection.
     * Follow this url manually to reach data
     * @param job the job that emitted this signal
     * @param url the new URL
     */
    void redirection(KIO::Job *job, const QUrl &url);
 
    /**
     * MIME type determined.
     * @param job the job that emitted this signal
     * @param mimeType the MIME type
     * @since 5.78
     */
    void mimeTypeFound(KIO::Job *job, const QString &mimeType);
 
    /**
     * File is open, metadata has been determined and the
     * file KIO worker is ready to receive commands.
     * @param job the job that emitted this signal
     */
    void open(KIO::Job *job);
 
    /**
     * \p written bytes were written to the file. Emitted after write().
     * @param job the job that emitted this signal
     * @param written bytes written.
     */
    void written(KIO::Job *job, KIO::filesize_t written);
 
    /**
     * Signals that the file is closed and will accept no more commands.
     *
     * @param job the job that emitted this signal
     *
     * @since 5.79
     */
    void fileClosed(KIO::Job *job);
 
    /**
     * The file has reached this position. Emitted after seek().
     * @param job the job that emitted this signal
     * @param offset the new position
     */
    void position(KIO::Job *job, KIO::filesize_t offset);
 
    /**
     * The file has been truncated to this point. Emitted after truncate().
     * @param job the job that emitted this signal
     * @param length the new length of the file
     * @since 5.66
     */
    void truncated(KIO::Job *job, KIO::filesize_t length);
 
protected:
    KIOCORE_NO_EXPORT explicit FileJob(FileJobPrivate &dd);
 
private:
    Q_DECLARE_PRIVATE(FileJob)
};
 
/**
 * Open ( random access I/O )
 *
 * The file-job emits open() when opened
 *
 * On error the open() signal is not emitted. To catch errors please
 * connect to the result() signal.
 *
 * @param url the URL of the file
 * @param mode the access privileges: see \ref OpenMode
 *
 * @return The file-handling job. It will never return 0. Errors are handled asynchronously
 * (emitted as signals).
 */
KIOCORE_EXPORT FileJob *open(const QUrl &url, QIODevice::OpenMode mode);
 
} // namespace
 
#endif