// Copyright (C) 2016 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

// Qt-Security score:significant reason:default

#include "qdbusreply.h"

#include "qdbusmetatype.h"

#include "qdbusmetatype_p.h"

#include <QDebug>

#ifndef QT_NO_DBUS

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

/*!

    \class QDBusReply

    \inmodule QtDBus

    \since 4.2

    \brief The QDBusReply class stores the reply for a method call to a remote object.

    A QDBusReply object is a subset of the QDBusMessage object that represents a method call's

    reply. It contains only the first output argument or the error code and is used by

    QDBusInterface-derived classes to allow returning the error code as the function's return

    argument.

    It can be used in the following manner:

    \snippet code/src_qdbus_qdbusreply.cpp 0

    If the remote method call cannot fail, you can skip the error checking:

    \snippet code/src_qdbus_qdbusreply.cpp 1

    However, if it does fail under those conditions, the value returned by QDBusReply<T>::value() is

    a default-constructed value. It may be indistinguishable from a valid return value.

    QDBusReply objects are used for remote calls that have no output

    arguments or return values (i.e., they have a "void" return

    type). Use the isValid() function to test if the reply succeeded.

    \sa QDBusMessage, QDBusInterface

*/

/*!

    \fn template<typename T> QDBusReply<T>::QDBusReply(const QDBusMessage &reply)

    Automatically construct a QDBusReply object from the reply message \a reply, extracting the

    first return value from it if it is a success reply.

*/

/*!

    \fn template<typename T> QDBusReply<T>::QDBusReply(const QDBusPendingReply<T> &reply)

    Constructs a QDBusReply object from the pending reply message, \a reply.

*/

/*!

    \fn template <typename T> QDBusReply<T>::QDBusReply(const QDBusPendingCall &pcall)

    Automatically construct a QDBusReply object from the asynchronous

    pending call \a pcall. If the call isn't finished yet, QDBusReply

    will call QDBusPendingCall::waitForFinished(), which is a blocking

    operation.

    If the return types patch, QDBusReply will extract the first

    return argument from the reply.

*/

/*!

    \fn template <typename T> QDBusReply<T>::QDBusReply(const QDBusError &error)

    Constructs an error reply from the D-Bus error code given by \a error.

*/

/*!

    \fn template <typename T> QDBusReply<T>::operator=(const QDBusError &dbusError)

    Sets this object to contain the error code given by \a dbusError. You

    can later access it with error().

*/

/*!

    \fn template <typename T> QDBusReply<T>::operator=(const QDBusMessage &reply)

    Makes this object contain the \a reply message. If \a reply

    is an error message, this function will

    copy the error code and message into this object

    If \a reply is a standard reply message and contains at least

    one parameter, it will be copied into this object, as long as it

    is of the correct type. If it's not of the same type as this

    QDBusError object, this function will instead set an error code

    indicating a type mismatch.

*/

/*!

    \fn template <typename T> QDBusReply<T>::operator=(const QDBusPendingCall &pcall)

    Makes this object contain the reply specified by the pending

    asynchronous call \a pcall. If the call is not finished yet, this

    function will call QDBusPendingCall::waitForFinished() to block

    until the reply arrives.

    If \a pcall finishes with an error message, this function will

    copy the error code and message into this object

    If \a pcall finished with a standard reply message and contains at

    least one parameter, it will be copied into this object, as long

    as it is of the correct type. If it's not of the same type as this

    QDBusError object, this function will instead set an error code

    indicating a type mismatch.

*/

/*!

    \fn template <typename T> bool QDBusReply<T>::isValid() const

    Returns \c true if no error occurred; otherwise, returns \c false.

    \sa error()

*/

/*!

    \fn template<typename T> const QDBusError& QDBusReply<T>::error() const

    Returns the error code that was returned from the remote function call. If the remote call did

    not return an error (i.e., if it succeeded), then the QDBusError object that is returned will

    not be a valid error code (QDBusError::isValid() will return false).

    \sa isValid()

*/

/*!

    \fn template <typename T> Type QDBusReply<T>::value() const

    Returns the remote function's calls return value. If the remote call returned with an error,

    the return value of this function is undefined and may be undistinguishable from a valid return

    value.

    This function is not available if the remote call returns \c void.

*/

/*!

    \fn template <typename T> QDBusReply<T>::operator Type() const

    Returns the same as value().

    This function is not available if the remote call returns \c void.

*/

/*!

    \internal

    Fills in the QDBusReply data \a error and \a data from the reply message \a reply.

*/

void qDBusReplyFill(const QDBusMessage &reply, QDBusError &error, QVariant &data)

{

    error = QDBusError(reply);

    if (error.isValid()) {

        data = QVariant();      // clear it

        return;

    }

    if (reply.arguments().size() >= 1 && reply.arguments().at(0).metaType() == data.metaType()) {

        data = reply.arguments().at(0);

        return;

    }

    const char *expectedSignature = QDBusMetaType::typeToSignature(data.metaType());

    const char *receivedType = nullptr;

    QByteArray receivedSignature;

    if (reply.arguments().size() >= 1) {

        if (reply.arguments().at(0).metaType() == QDBusMetaTypeId::argument()) {

            // compare signatures instead

            QDBusArgument arg = qvariant_cast<QDBusArgument>(reply.arguments().at(0));

            receivedSignature = arg.currentSignature().toLatin1();

            if (receivedSignature == expectedSignature) {

                // matched. Demarshall it

                QDBusMetaType::demarshall(arg, data.metaType(), data.data());

                return;

            }

        } else {

            // not an argument and doesn't match?

            QMetaType type = reply.arguments().at(0).metaType();

            receivedType = type.name();

            receivedSignature = QDBusMetaType::typeToSignature(type);

        }

    }

    // error

    if (receivedSignature.isEmpty())

        receivedSignature = "<empty signature>";

    QString errorMsg;

    if (receivedType) {

        errorMsg = "Unexpected reply signature: got \"%1\" (%4), expected \"%2\" (%3)"_L1

                   .arg(QLatin1StringView(receivedSignature),

                        QLatin1StringView(expectedSignature),

                        QLatin1StringView(data.typeName()),

                        QLatin1StringView(receivedType));

    } else {

        errorMsg = "Unexpected reply signature: got \"%1\", expected \"%2\" (%3)"_L1

                   .arg(QLatin1StringView(receivedSignature),

                        QLatin1StringView(expectedSignature),

                        QLatin1StringView(data.typeName()));

    }

    error = QDBusError(QDBusError::InvalidSignature, errorMsg);

    data = QVariant();      // clear it

}

QT_END_NAMESPACE

#endif // QT_NO_DBUS