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** Copyright (C) 2013 Klaralvdalens Datakonsult AB (KDAB)
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#include "kdupdaterupdateoperation.h"

#include "kdupdaterapplication.h"

#include <QDebug>
#include <QDir>
#include <QFileInfo>
#include <QTemporaryFile>

using namespace KDUpdater;

/*!
   \inmodule kdupdater
   \class KDUpdater::UpdateOperation
   \brief The UpdateOperation class is an abstract base class for update operations.

   The KDUpdater::UpdateOperation is an abstract class that specifies an interface for
   update operations. Concrete implementations of this class must perform a single update
   operation like copy, move, delete.

   \note Two separate threads cannot be using a single instance of KDUpdater::UpdateOperation
   at the same time.
*/

/*!
    \enum UpdateOperation::Error
    Error codes related to operation arguments and operation runtime failures.

    NoError             No error occurred.
    InvalidArguments    Number of arguments does not match or an invalid argument was set.
    UserDefinedError    An error occurred during operation run. Use UpdateOperation::errorString()
                        to get the human-readable description of the error that occurred.
*/

/*
    \internal
    Returns a filename for a temporary file based on \a templateName.
*/
static QString backupFileName(const QString &templateName)
{
    const QFileInfo templ(templateName);
    QTemporaryFile file( QDir::temp().absoluteFilePath(templ.fileName()));
    file.open();
    const QString name = file.fileName();
    file.close();
    file.remove();
    return name;
}

/*!
    \internal
*/
UpdateOperation::UpdateOperation()
    : m_error(0)
{}

/*!
    \internal
*/
UpdateOperation::~UpdateOperation()
{
    if (Application *app = Application::instance())
        app->addFilesForDelayedDeletion(filesForDelayedDeletion());
}

/*!
    Returns the update operation name.

    \sa setName()
*/
QString UpdateOperation::name() const
{
    return m_name;
}

/*!
    Returns a command line string that describes the update operation. The returned string will be
    of the form:

    \c{<name> <arg1> <arg2> <arg3> ....}
*/
QString UpdateOperation::operationCommand() const
{
    QString argsStr = m_arguments.join(QLatin1String( " " ));
    return QString::fromLatin1( "%1 %2" ).arg(m_name, argsStr);
}

/*!
    Returns \c true if there exists a value called \a name, otherwise returns \c false.
*/
bool UpdateOperation::hasValue(const QString &name) const
{
    return m_values.contains(name);
}

/*!
    Clears the value of \a name and removes it.
*/
void UpdateOperation::clearValue(const QString &name)
{
    m_values.remove(name);
}

/*!
    Returns the value of \a name. If the value does not exists, this returns an empty QVariant.
*/
QVariant UpdateOperation::value(const QString &name) const
{
    return m_values.value(name);
}

/*!
    Sets the value of \a name to \a value.
*/
void UpdateOperation::setValue(const QString &name, const QVariant &value)
{
    m_values[name] = value;
}

/*!
    Sets the name of the operation to \a name. Subclasses will have to provide a unique name to
    describe the operation.
*/
void UpdateOperation::setName(const QString &name)
{
    m_name = name;
}

/*!
   Sets the arguments for the update operation to \a args.
*/
void UpdateOperation::setArguments(const QStringList &args)
{
    m_arguments = args;
}

/*!
    Returns the arguments of the update operation.
*/
QStringList UpdateOperation::arguments() const
{
    return m_arguments;
}

struct StartsWith
{
    StartsWith(const QString &searchTerm)
        : m_searchTerm(searchTerm) {}

    bool operator()(const QString &searchString)
    {
        return searchString.startsWith(m_searchTerm);
    }

    QString m_searchTerm;
};


QString UpdateOperation::argumentKeyValue(const QString &key, const QString &defaultValue) const
{
    const QString keySeparater(key + QLatin1String("="));
    const QStringList tArguments(arguments());
    QStringList::const_iterator it = std::find_if(tArguments.begin(), tArguments.end(),
        StartsWith(keySeparater));
    if (it == tArguments.end())
        return defaultValue;

    const QString value = it->mid(keySeparater.size());

    it = std::find_if(++it, tArguments.end(), StartsWith(keySeparater));
    if (it != tArguments.end()) {
        qWarning() << QString::fromLatin1("There are multiple keys in the arguments calling"
            " '%1'. Only the first found '%2' is used: '%3'").arg(name(), key, arguments().join(
            QLatin1String("; ")));
    }
    return value;
}

/*!
    Returns a human-readable description of the last error that occurred.
*/
QString UpdateOperation::errorString() const
{
    return m_errorString;
}

/*!
    Returns the error that was found during the processing of the operation. If no
    error was found, returns NoError. Subclasses can set more detailed error codes (optional).

    \note To check if an operation was successful, use the return value of performOperation(),
    undoOperation(), or testOperation().
*/
int UpdateOperation::error() const
{
    return m_error;
}

/*!
    Sets the human-readable description of the last error that occurred to \a str.
*/
void UpdateOperation::setErrorString(const QString &str)
{
    m_errorString = str;
}

/*!
    Sets the error condition to be \a error. The human-readable message is set to \a errorString.

    \sa UpdateOperation::error()
    \sa UpdateOperation::errorString()
*/
void UpdateOperation::setError(int error, const QString &errorString)
{
    m_error = error;
    if (!errorString.isNull())
        m_errorString = errorString;
}

/*!
    Clears the previously set arguments.
*/
void UpdateOperation::clear()
{
    m_arguments.clear();
}

/*!
    Returns the list of files that are scheduled for later deletion.
*/
QStringList UpdateOperation::filesForDelayedDeletion() const
{
    return m_delayedDeletionFiles;
}

/*!
     Registers a list of \a files to be deleted later once the application was restarted and the
     file or files are not used anymore.
*/
void UpdateOperation::registerForDelayedDeletion(const QStringList &files)
{
    m_delayedDeletionFiles << files;
}

/*!
    Tries to delete \a file. If \a file cannot be deleted, it is registered for delayed deletion.
*/
bool UpdateOperation::deleteFileNowOrLater(const QString &file, QString *errorString)
{
    if (file.isEmpty() || QFile::remove(file))
        return true;

    if (!QFile::exists(file))
        return true;

    const QString backup = backupFileName(file);
    QFile f(file);
    if (!f.rename(backup)) {
        if (errorString)
            *errorString = tr("Renaming %1 into %2 failed with %3.").arg(file, backup, f.errorString());
        return false;
    }
    registerForDelayedDeletion(QStringList(backup));
    return true;
}

/*!
    \fn virtual void KDUpdater::UpdateOperation::backup() = 0;

    Subclasses must implement this function to back up any data before performing the action.
*/

/*!
    \fn virtual bool KDUpdater::UpdateOperation::performOperation() = 0;

    Subclasses must implement this function to perform the update operation.
*/

/*!
    \fn virtual bool KDUpdater::UpdateOperation::undoOperation() = 0;

    Subclasses must implement this function to perform the undo of the update operation.
*/

/*!
    \fn virtual bool KDUpdater::UpdateOperation::testOperation() = 0;

    Subclasses must implement this function to perform the test operation.
*/

/*!
    \fn virtual bool KDUpdater::UpdateOperation::clone() const = 0;

    Subclasses must implement this function to clone the current operation.
*/

/*!
    Saves operation arguments and values as XML. You can override this method to store your
    own extra-data. Extra-data can be any data that you need to store to perform or undo the
    operation. The default implementation is taking care of arguments and values set via
    UpdateOperation::setValue().
*/
QDomDocument UpdateOperation::toXml() const
{
    QDomDocument doc;
    QDomElement root = doc.createElement(QLatin1String("operation"));
    doc.appendChild(root);
    QDomElement args = doc.createElement(QLatin1String("arguments"));
    Q_FOREACH (const QString &s, arguments()) {
        QDomElement arg = doc.createElement(QLatin1String("argument"));
        arg.appendChild(doc.createTextNode(s));
        args.appendChild(arg);
    }
    root.appendChild(args);
    if (m_values.isEmpty())
        return doc;

    // append all values set with setValue
    QDomElement values = doc.createElement(QLatin1String("values"));
    for (QVariantMap::const_iterator it = m_values.begin(); it != m_values.end(); ++it) {
        QDomElement value = doc.createElement(QLatin1String("value"));
        const QVariant& variant = it.value();
        value.setAttribute(QLatin1String("name"), it.key());
        value.setAttribute(QLatin1String("type"), QLatin1String( QVariant::typeToName( variant.type())));

        if (variant.type() != QVariant::List && variant.type() != QVariant::StringList
            && variant.canConvert(QVariant::String)) {
            // it can convert to string? great!
            value.appendChild( doc.createTextNode(variant.toString()));
        } else {
            // no? then we have to go the hard way...
            QByteArray data;
            QDataStream stream(&data, QIODevice::WriteOnly);
            stream << variant;
            value.appendChild(doc.createTextNode(QLatin1String( data.toBase64().data())));
        }
        values.appendChild(value);
    }
    root.appendChild(values);
    return doc;
}

/*!
    Restores operation arguments and values from the XML document \a doc. Returns \c true on
    success, otherwise \c false.
*/
bool UpdateOperation::fromXml(const QDomDocument &doc)
{
    QStringList args;
    const QDomElement root = doc.documentElement();
    const QDomElement argsElem = root.firstChildElement(QLatin1String("arguments"));
    Q_ASSERT(! argsElem.isNull());
    for (QDomNode n = argsElem.firstChild(); ! n.isNull(); n = n.nextSibling()) {
        const QDomElement e = n.toElement();
        if (!e.isNull() && e.tagName() == QLatin1String("argument"))
            args << e.text();
    }
    setArguments(args);

    m_values.clear();
    const QDomElement values = root.firstChildElement(QLatin1String("values"));
    for (QDomNode n = values.firstChild(); !n.isNull(); n = n.nextSibling()) {
        const QDomElement v = n.toElement();
        if (v.isNull() || v.tagName() != QLatin1String("value"))
            continue;

        const QString name = v.attribute(QLatin1String("name"));
        const QString type = v.attribute(QLatin1String("type"));
        const QString value = v.text();

        const QVariant::Type t = QVariant::nameToType(type.toLatin1().data());
        QVariant var = qVariantFromValue(value);
        if (t == QVariant::List || t == QVariant::StringList || !var.convert(t)) {
            QDataStream stream(QByteArray::fromBase64( value.toLatin1()));
            stream >> var;
        }

        m_values[name] = var;
    }

    return true;
}

/*!
    \overload

    Restores operation arguments and values from the XML file at path \a xml. Returns \c true on
    success, otherwise \c false.
*/
bool UpdateOperation::fromXml(const QString &xml)
{
    QDomDocument doc;
    QString errorMsg;
    int errorLine;
    int errorColumn;
    if (!doc.setContent( xml, &errorMsg, &errorLine, &errorColumn)) {
        qWarning() << "Error parsing xml error=" << errorMsg << "line=" << errorLine << "column=" << errorColumn;
        return false;
    }
    return fromXml(doc);
}