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Diffstat (limited to 'src/plugins/qmltooling/packetprotocol/qpacket.cpp')
-rw-r--r-- | src/plugins/qmltooling/packetprotocol/qpacket.cpp | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/plugins/qmltooling/packetprotocol/qpacket.cpp b/src/plugins/qmltooling/packetprotocol/qpacket.cpp new file mode 100644 index 0000000000..fab0a5b189 --- /dev/null +++ b/src/plugins/qmltooling/packetprotocol/qpacket.cpp @@ -0,0 +1,141 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtQml module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qpacket_p.h" + +QT_BEGIN_NAMESPACE + +/*! + \class QPacket + \internal + + \brief The QPacket class encapsulates an unfragmentable packet of data to be + transmitted by QPacketProtocol. + + The QPacket class works together with QPacketProtocol to make it simple to + send arbitrary sized data "packets" across fragmented transports such as TCP + and UDP. + + QPacket provides a QDataStream interface to an unfragmentable packet. + Applications should construct a QPacket, propagate it with data and then + transmit it over a QPacketProtocol instance. For example: + \code + int version = QDataStream::Qt_DefaultCompiledVersion; + QPacketProtocol protocol(...); + + QPacket myPacket(version); + myPacket << "Hello world!" << 123; + protocol.send(myPacket.data()); + \endcode + + As long as both ends of the connection are using the QPacketProtocol class + and the same data stream version, the data within this packet will be + delivered unfragmented at the other end, ready for extraction. + + \code + QByteArray greeting; + int count; + + QPacket myPacket(version, protocol.read()); + + myPacket >> greeting >> count; + \endcode + + Only packets constructed from raw byte arrays may be read from. Empty QPacket + instances are for transmission only and are considered "write only". Attempting + to read data from them will result in undefined behavior. + + \ingroup io + \sa QPacketProtocol + */ + + +/*! + Constructs an empty write-only packet. + */ +QPacket::QPacket(int version) +{ + buf.open(QIODevice::WriteOnly); + setDevice(&buf); + setVersion(version); +} + +/*! + Constructs a read-only packet. + */ +QPacket::QPacket(int version, const QByteArray &data) +{ + buf.setData(data); + buf.open(QIODevice::ReadOnly); + setDevice(&buf); + setVersion(version); +} + +/*! + Returns a reference to the raw packet data. + */ +const QByteArray &QPacket::data() const +{ + return buf.data(); +} + +/*! + Returns a copy of the raw packet data, with extra reserved space removed. + Mind that this triggers a deep copy. Use it if you anticipate the data to be detached soon anyway. + */ +QByteArray QPacket::squeezedData() const +{ + QByteArray ret = buf.data(); + ret.squeeze(); + return ret; +} + +/*! + Clears the packet, discarding any data. + */ +void QPacket::clear() +{ + buf.reset(); + QByteArray &buffer = buf.buffer(); + // Keep the old size to prevent unnecessary allocations + buffer.reserve(buffer.capacity()); + buffer.truncate(0); +} + +QT_END_NAMESPACE |