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#include "setpluginpathonqtcoreoperation.h"

#include "qtpatch.h"

#include <QtCore/QByteArrayMatcher>
#include <QtCore/QDir>
#include <QtCore/QDebug>

using namespace QInstaller;

namespace {
    QByteArray getOldValue(const QString &binaryPath)
    {
        QFileInfo fileInfo(binaryPath);

        if (!fileInfo.exists()) {
            qDebug() << QString::fromLatin1("qpatch: warning: file '%1' not found").arg(binaryPath);
            return QByteArray();
        }

        QFile file(binaryPath);
        int readOpenCount = 0;
        while (!file.open(QFile::ReadOnly) && readOpenCount < 20000) {
            ++readOpenCount;
            qApp->processEvents();
        }
        Q_ASSERT(file.isOpen());
        if (!file.isOpen()) {
            qDebug() << QString::fromLatin1("qpatch: warning: file '%1' can not be opened as ReadOnly.").arg(
                binaryPath);
            qDebug() << file.errorString();
            return QByteArray();
        }

        const QByteArray source = file.readAll();
        file.close();

        int offset = 0;
        QByteArray searchValue("qt_plugpath=");
        QByteArrayMatcher byteArrayMatcher(searchValue);
        offset = byteArrayMatcher.indexIn(source, offset);
        Q_ASSERT(offset > 0);
        if (offset == -1)
            return QByteArray();

        int stringEndPosition = offset;
        while(source.at(stringEndPosition++) != '\0') {}
        // between the search string and the first \0 is the QByteArray we are looking for
        return source.mid(offset + searchValue.size(), stringEndPosition - offset);
    }
}

SetPluginPathOnQtCoreOperation::SetPluginPathOnQtCoreOperation()
{
    setName(QLatin1String("SetPluginPathOnQtCore"));
}

void SetPluginPathOnQtCoreOperation::backup()
{
}

bool SetPluginPathOnQtCoreOperation::performOperation()
{
    const QStringList args = arguments();

    if (args.count() != 2) {
        setError(InvalidArguments);
        setErrorString(tr("Invalid arguments in %0: %1 arguments given, %2 expected%3.")
            .arg(name()).arg(arguments().count()).arg(tr("exactly 2"), QLatin1String("")));
        return false;
    }

    const QString qtCoreLibraryDir = args.at(0);
    const QByteArray newValue = QDir::toNativeSeparators(args.at(1)).toUtf8();

    if (newValue.size() >= 255) {
        setError(UserDefinedError);
        setErrorString(tr("Qt patch error: new Qt plugin path '%1'\nneeds to be less than 255 characters.")
            .arg(QString::fromLocal8Bit(newValue)));
        return false;
    }
    QStringList libraryFiles;
#ifdef Q_OS_WIN
    libraryFiles << QString::fromLatin1("%1/QtCore4.dll").arg(qtCoreLibraryDir);
    libraryFiles << QString::fromLatin1("%1/QtCore4d.dll").arg(qtCoreLibraryDir);
#else
    libraryFiles << qtCoreLibraryDir + QLatin1String("/libQtCore.so");
#endif
    foreach (const QString &coreLibrary, libraryFiles) {
        if (QFile::exists(coreLibrary)) {
            QByteArray oldValue(getOldValue(coreLibrary));
            Q_ASSERT(!oldValue.isEmpty());
            oldValue = QByteArray("qt_plugpath=%1").replace("%1", oldValue);
            QByteArray adjutedNewValue = QByteArray("qt_plugpath=%1").replace("%1", newValue);

            bool isPatched = QtPatch::patchBinaryFile(coreLibrary, oldValue, adjutedNewValue);
            if (!isPatched)
                qDebug() << "qpatch: warning: could not patch the plugin path in" << coreLibrary;
        }
    }

    return true;
}

bool SetPluginPathOnQtCoreOperation::undoOperation()
{
    return true;
}

bool SetPluginPathOnQtCoreOperation::testOperation()
{
    return true;
}

Operation *SetPluginPathOnQtCoreOperation::clone() const
{
    return new SetPluginPathOnQtCoreOperation();
}