src/dbus/qdbusreply.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/dbus/qdbusreply.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,244 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDBus module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qdbusreply.h"
+#include "qdbusmetatype.h"
+#include "qdbusmetatype_p.h"
+#include <QDebug>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \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 doc/src/snippets/code/src_qdbus_qdbusreply.cpp 0
+
+    If the remote method call cannot fail, you can skip the error checking:
+    \snippet doc/src/snippets/code/src_qdbus_qdbusreply.cpp 1
+
+    However, if it does fail under those conditions, the value returned by QDBusReply::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 QDBusReply::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 QDBusReply::QDBusReply(const QDBusPendingReply<T> &reply)
+    Constructs a QDBusReply object from the pending reply message, \a reply.
+*/
+
+/*!
+    \fn QDBusReply::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 QDBusReply::QDBusReply(const QDBusError &error)
+    Constructs an error reply from the D-Bus error code given by \a error.
+*/
+
+/*!
+    \fn QDBusReply::operator=(const QDBusReply &other)
+    Makes this object be a copy of the object \a other.
+*/
+
+/*!
+    \fn QDBusReply::operator=(const QDBusError &error)
+    Sets this object to contain the error code given by \a error. You
+    can later access it with error().
+*/
+
+/*!
+    \fn QDBusReply::operator=(const QDBusMessage &message)
+
+    Makes this object contain the reply specified by message \a
+    message. If \a message is an error message, this function will
+    copy the error code and message into this object
+
+    If \a message 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 QDBusReply::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 bool QDBusReply::isValid() const
+
+    Returns true if no error occurred; otherwise, returns false.
+
+    \sa error()
+*/
+
+/*!
+    \fn QDBusReply::error()
+
+    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 QDBusReply::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 QDBusReply::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 = reply;
+
+    if (error.isValid()) {
+        data = QVariant();      // clear it
+        return;
+    }
+
+    if (reply.arguments().count() >= 1 && reply.arguments().at(0).userType() == data.userType()) {
+        data = reply.arguments().at(0);
+        return;
+    }
+
+    const char *expectedSignature = QDBusMetaType::typeToSignature(data.userType());
+    const char *receivedType = 0;
+    QByteArray receivedSignature;
+
+    if (reply.arguments().count() >= 1) {
+        if (reply.arguments().at(0).userType() == 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.userType(), data.data());
+                return;
+            }
+        } else {
+            // not an argument and doesn't match?
+            int type = reply.arguments().at(0).userType();
+            receivedType = QVariant::typeToName(QVariant::Type(type));
+            receivedSignature = QDBusMetaType::typeToSignature(type);
+        }
+    }
+
+    // error
+    if (receivedSignature.isEmpty())
+        receivedSignature = "no signature";
+    QString errorMsg;
+    if (receivedType) {
+        errorMsg = QString::fromLatin1("Unexpected reply signature: got \"%1\" (%4), "
+                                         "expected \"%2\" (%3)")
+                   .arg(QLatin1String(receivedSignature),
+                        QLatin1String(expectedSignature),
+                        QLatin1String(data.typeName()),
+                        QLatin1String(receivedType));
+    } else {
+        errorMsg = QString::fromLatin1("Unexpected reply signature: got \"%1\", "
+                                         "expected \"%2\" (%3)")
+                   .arg(QLatin1String(receivedSignature),
+                        QLatin1String(expectedSignature),
+                        QLatin1String(data.typeName()));
+    }
+
+    error = QDBusError(QDBusError::InvalidSignature, errorMsg);
+    data = QVariant();      // clear it
+}
+
+QT_END_NAMESPACE