Hello,

I have the following code:

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qDebug() << root->entries();
const KArchiveFile* packageFile = static_cast<const KArchiveFile*>(root->entry("package.xml"));
qDebug() << packageFile->data();

The file package.xml exists, as it is outputed by the first line, but the third line generates this error:

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QIODevice::read: Called with maxSize < 0
QIODevice::seek: Invalid pos: -1024
test_archive(14744) KArchiveFile::data: Failed to sync to 2048 to read "package.xml"

I've also tried packageFile->createDevice()->readAll(), but I still got the first two errors.

Any ideas?

I'm on Ubuntu 12.04 (64 bit)

Jan

Can you please post as much of your complete code as possible, and upload the archive you are trying to read somewhere so people can look into this?

Ok, here is a very simple code that compiles and creates the errors:

KArchiveTest.pro:

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QT       += core
QT       -= gui

LIBS += -lkdecore

TARGET = KArchiveTest
TEMPLATE = app
SOURCES += main.cpp

main.cpp:

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#include <karchive.h>
#include <kfilterdev.h>
#include <ktar.h>
#include <QBuffer>
#include <QFile>
#include <QDebug>

int main(int argc, char *argv[])
{
    QFile f("test.tar.gz");
    f.open(QFile::ReadOnly);

    KArchive* archive = new KTar(KFilterDev::device(&f, "application/x-gzip"));
    archive->open(QIODevice::ReadOnly);

    const KArchiveDirectory* root = archive->directory();
    qDebug() << root->entries(); //returns test.txt

    const KArchiveFile* file = static_cast<const KArchiveFile*>(root->entry("test.txt"));

    /*
     * The following line creates these errors:
QIODevice::read: Called with maxSize < 0
QIODevice::seek: Invalid pos: -1024
unnamed app(14317) KArchiveFile::data: Failed to sync to 512 to read "test.txt"
     */
    qDebug() << file->data();

    delete file;
    delete root;
    delete archive;
}


Jan

Edit: Here is the archive I used for testing: https://www.dropbox.com/s/zoaby1ksrhdy5v5/test.tar.gz

I can confirm this using your test suite.
I got this backtrace:

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#0  0x0000000000000021 in ?? ()
#1  0x00007ffff79ff117 in qDeleteAll<QHash<QString, KArchiveEntry*>::const_iterator> (end=<optimized out>, begin=<optimized out>) at /opt/trunk-kde/qt/include/QtCore/qalgorithms.h:322
#2  qDeleteAll<QHash<QString, KArchiveEntry*> > (c=...) at /opt/trunk-kde/qt/include/QtCore/qalgorithms.h:330
#3  ~KArchiveDirectoryPrivate (this=0x629b70, __in_chrg=<optimized out>) at /home/ben/kdesvn/kde/kdelibs/kdecore/io/karchive.cpp:697
#4  KArchiveDirectory::~KArchiveDirectory (this=0x629b50, __in_chrg=<optimized out>) at /home/ben/kdesvn/kde/kdelibs/kdecore/io/karchive.cpp:713
#5  0x00007ffff79ff179 in KArchiveDirectory::~KArchiveDirectory (this=0x629b50, __in_chrg=<optimized out>) at /home/ben/kdesvn/kde/kdelibs/kdecore/io/karchive.cpp:714
#6  0x00000000004015bc in main (argc=1, argv=0x7fffffffd7b8) at main.cpp:30

I'll pass this information on to the appropriate person(s) to see if they may know what the issue is.

Ok, thank you!

Jan

The maintainer of the KArchive code has let me know they will look into finding a solution to this issue this week (spare time permitting).
I'll update this topic when that happens.

There are two issues with this testcase:
1) Your .tar.gz file is actually not gzipped, it's a wrongly named uncompressed tar file. See "file test.tar.gz" for proof.
2) The code, on the other hand, forces the use of a KFilterDev for gunzipping as input device. This is unnecessary -- even if the input file was really gzipped -- because KTar is perfectly capable of handling real .tar.gz files as input.
3) (Yeah I can't count). Deleting "file" and "root" is wrong, these are owned by KTar.

This leads to the following working code:

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#include <ktar.h>
#include <QFile>
#include <QDebug>

int main(int argc, char *argv[])
{
    // QCoreApplication app(argc, argv); missing here

    QFile f("test.tar.gz");
    if (!f.open(QFile::ReadOnly)) {
        return 1;
    }

    KArchive* archive = new KTar(&f);
    archive->open(QIODevice::ReadOnly);

    const KArchiveDirectory* root = archive->directory();
    qDebug() << root->entries(); //returns test.txt

    const KArchiveFile* file = static_cast<const KArchiveFile*>(root->entry("test.txt"));
    qDebug() << file->data(); // shows "some test text\n"

    delete archive;
}