The QPacketProtocol class encapsulates communicating discrete packets across fragmented IO channels, such as TCP sockets. More...

#include <qpacketprotocol_p.h>

Inheritance diagram for QPacketProtocol:

Signals
void	invalidPacket ()
	A packet larger than the maximum allowable packet size was received. More...

void	packetWritten ()
	Emitted each time a packet is completing written to the device. More...

void	readyRead ()
	Emitted whenever a new packet is received. More...

Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...

Public Functions
void	clear ()
	Discard any unread packets. More...

QIODevice *	device ()
	Return the QIODevice passed to the QPacketProtocol constructor. More...

qint32	maximumPacketSize () const
	Returns the maximum packet size allowed. More...

qint64	packetsAvailable () const
	Returns the number of received packets yet to be read. More...

	QPacketProtocol (QIODevice dev, QObject parent=0)
	Construct a QPacketProtocol instance that works on dev with the specified parent. More...

QPacket	read ()
	Return the next unread packet, or an invalid QPacket instance if no packets are available. More...

QPacketAutoSend	send ()
	Returns a streamable object that is transmitted on destruction. More...

void	send (const QPacket &)
	Transmit the packet. More...

qint32	setMaximumPacketSize (qint32)
	Sets the maximum allowable packet size to max. More...

bool	waitForReadyRead (int msecs=3000)
	This function locks until a new packet is available for reading and the QIODevice::readyRead() signal has been emitted. More...

virtual	~QPacketProtocol ()
	Destroys the QPacketProtocol instance. More...

Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...

const QObjectList &	children () const
	Returns a list of child objects. More...

bool	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=0, const QObject receiver=0, const char *member=0)

bool	disconnect (const QObject receiver, const char member=0)

void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...

void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...

QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...

virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...

virtual bool	eventFilter (QObject , QEvent )
	Filters events if this object has been installed as an event filter for the watched object. More...

template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...

template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...

template<typename T >
QList< T >	findChildren (const QRegExp &re) const

bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...

void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...

bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...

void	killTimer (int id)
	Kills the timer with timer identifier, id. More...

virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...

QString	objectName () const

QObject *	parent () const
	Returns a pointer to the parent object. More...

QVariant	property (const char *name) const
	Returns the value of the object's name property. More...

Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...

void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...

void	setObjectName (const QString &name)

void	setParent (QObject *)
	Makes the object a child of parent. More...

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...

void	setUserData (uint id, QObjectUserData *data)

bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...

int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...

QThread *	thread () const
	Returns the thread in which the object lives. More...

QObjectUserData *	userData (uint id) const

virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Properties
QPacketProtocolPrivate *	d

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...

Static Public Functions inherited from QObject
static bool	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...

static bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	Disconnects signal in object sender from method in object receiver. More...

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static uint	registerUserData ()

static QString	tr (const char sourceText, const char comment=0, int n=-1)

static QString	trUtf8 (const char sourceText, const char comment=0, int n=-1)

Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...

Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...

virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...

virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...

virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...

	QObject (QObjectPrivate &dd, QObject *parent=0)

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...

QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...

Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject

Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()

T *	qobject_cast (QObject *object)

	QObjectList

void *	qt_find_obj_child (QObject parent, const char type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

The QPacketProtocol class encapsulates communicating discrete packets across fragmented IO channels, such as TCP sockets.

Warning: This function is not part of the public interface.

QPacketProtocol makes it simple to send arbitrary sized data "packets" across fragmented transports such as TCP and UDP.

As transmission boundaries are not respected, sending packets over protocols like TCP frequently involves "stitching" them back together at the receiver. QPacketProtocol makes this easier by performing this task for you. Packet data sent using QPacketProtocol is prepended with a 4-byte size header allowing the receiving QPacketProtocol to buffer the packet internally until it has all been received. QPacketProtocol does not perform any sanity checking on the size or on the data, so this class should only be used in prototyping or trusted situations where DOS attacks are unlikely.

QPacketProtocol does not perform any communications itself. Instead it can operate on any QIODevice that supports the QIODevice::readyRead() signal. A logical "packet" is encapsulated by the companion QPacket class. The following example shows two ways to send data using QPacketProtocol. The transmitted data is equivalent in both.

QTcpSocket socket;
// ... connect socket ...
QPacketProtocol protocol(&socket);
// Send packet the quick way
protocol.send() << "Hello world" << 123;
// Send packet the longer way
QPacket packet;
packet << "Hello world" << 123;
protocol.send(packet);

Likewise, the following shows how to read data from QPacketProtocol, assuming that the QPacketProtocol::readyRead() signal has been emitted.

// ... QPacketProtocol::readyRead() is emitted ...
int a;
QByteArray b;
// Receive packet the quick way
protocol.read() >> a >> b;
// Receive packet the longer way
QPacket packet = protocol.read();
p >> a >> b;

See also: QPacket

Definition at line 62 of file qpacketprotocol_p.h.

Constructors and Destructors

◆ QPacketProtocol()

QPacketProtocol::QPacketProtocol	(	QIODevice *	dev,
		QObject *	parent = `0`
	)

explicit

Construct a QPacketProtocol instance that works on dev with the specified parent.

Definition at line 234 of file qpacketprotocol.cpp.

 : QObject(parent), d(new QPacketProtocolPrivate(this, dev))
 {
     Q_ASSERT(dev);
 }

◆ ~QPacketProtocol()

QPacketProtocol::~QPacketProtocol ( )

virtual

Destroys the QPacketProtocol instance.

Definition at line 243 of file qpacketprotocol.cpp.

244 {

245 }

Functions

◆ clear()

void QPacketProtocol::clear ( )

Discard any unread packets.

Definition at line 322 of file qpacketprotocol.cpp.

 {
     d->packets.clear();
 }

◆ device()

QIODevice * QPacketProtocol::device ( )

Return the QIODevice passed to the QPacketProtocol constructor.

Definition at line 386 of file qpacketprotocol.cpp.

 {
     return d->dev;
 }

◆ invalidPacket

void QPacketProtocol::invalidPacket ( )

signal

A packet larger than the maximum allowable packet size was received.

The packet will be discarded and, as it indicates corruption in the protocol, no further packets will be received.

◆ maximumPacketSize()

qint32 QPacketProtocol::maximumPacketSize ( ) const

Returns the maximum packet size allowed.

By default this is 2,147,483,647 bytes.

If a packet claiming to be larger than the maximum packet size is received, the QPacketProtocol::invalidPacket() signal is emitted.

See also: QPacketProtocol::setMaximumPacketSize()

Definition at line 256 of file qpacketprotocol.cpp.

 {
     return d->maxPacketSize;
 }

◆ packetsAvailable()

qint64 QPacketProtocol::packetsAvailable ( ) const

Returns the number of received packets yet to be read.

Definition at line 314 of file qpacketprotocol.cpp.

Referenced by QDeclarativeDebugConnectionPrivate::readyRead().

 {
     return d->packets.count();
 }

◆ packetWritten

void QPacketProtocol::packetWritten ( )

signal

Emitted each time a packet is completing written to the device.

This signal may be used for communications flow control.

◆ read()

QPacket QPacketProtocol::read ( )

Return the next unread packet, or an invalid QPacket instance if no packets are available.

This method does NOT block.

Definition at line 331 of file qpacketprotocol.cpp.

Referenced by QDeclarativeDebugConnectionPrivate::readyRead().

 {
     if(0 == d->packets.count())
         return QPacket();
 
     QPacket rv(d->packets.at(0));
     d->packets.removeFirst();
     return rv;
 }

◆ readyRead

void QPacketProtocol::readyRead ( )

signal

Emitted whenever a new packet is received.

Applications may use QPacketProtocol::read() to retrieve this packet.

◆ send() [1/2]

QPacketAutoSend QPacketProtocol::send ( )

Returns a streamable object that is transmitted on destruction.

For example

protocol.send() << "Hello world" << 123;

will send a packet containing "Hello world" and 123. To construct more complex packets, explicitly construct a QPacket instance.

Definition at line 283 of file qpacketprotocol.cpp.

Referenced by QDeclarativeDebugConnectionPrivate::advertisePlugins(), QDeclarativeDebugConnectionPrivate::connected(), and QPacketAutoSend::~QPacketAutoSend().

 {
     return QPacketAutoSend(this);
 }

◆ send() [2/2]

void QPacketProtocol::send ( const QPacket & packet )

Transmit the packet.

Definition at line 296 of file qpacketprotocol.cpp.

 {
     if(p.b.isEmpty())
         return; // We don't send empty packets
 
     qint64 sendSize = p.b.size() + sizeof(qint32);
 
     d->sendingPackets.append(sendSize);
     qint32 sendSize32 = sendSize;
     qint64 writeBytes = d->dev->write((char *)&sendSize32, sizeof(qint32));
     Q_ASSERT(writeBytes == sizeof(qint32));
     writeBytes = d->dev->write(p.b);
     Q_ASSERT(writeBytes == p.b.size());
 }

◆ setMaximumPacketSize()

qint32 QPacketProtocol::setMaximumPacketSize ( qint32 max )

Sets the maximum allowable packet size to max.

See also: QPacketProtocol::maximumPacketSize()

Definition at line 266 of file qpacketprotocol.cpp.

 {
     if(max > (signed)sizeof(qint32))
         d->maxPacketSize = max;
     return d->maxPacketSize;
 }

◆ waitForReadyRead()

bool QPacketProtocol::waitForReadyRead ( int msecs = 3000 )

This function locks until a new packet is available for reading and the QIODevice::readyRead() signal has been emitted.

The function will timeout after msecs milliseconds; the default timeout is 30000 milliseconds.

The function returns true if the readyRead() signal is emitted and there is new data available for reading; otherwise it returns false (if an error occurred or the operation timed out).

Definition at line 365 of file qpacketprotocol.cpp.

 {
     if (!d->packets.isEmpty())
         return true;
 
     QElapsedTimer stopWatch;
     stopWatch.start();
 
     d->waitingForPacket = true;
     do {
         if (!d->dev->waitForReadyRead(msecs))
             return false;
         if (!d->waitingForPacket)
             return true;
         msecs = qt_timeout_value(msecs, stopWatch.elapsed());
     } while (true);
 }

Properties

◆ d

QPacketProtocolPrivate* QPacketProtocol::d

private

Definition at line 90 of file qpacketprotocol_p.h.

Referenced by clear(), device(), maximumPacketSize(), packetsAvailable(), read(), send(), setMaximumPacketSize(), and waitForReadyRead().

The documentation for this class was generated from the following files:

/src/declarative/debugger/qpacketprotocol_p.h
/src/declarative/debugger/qpacketprotocol.cpp

Signals

Public Functions

Properties

Additional Inherited Members

Detailed Description

Constructors and Destructors

◆ QPacketProtocol()

◆ ~QPacketProtocol()

Functions

◆ clear()

◆ device()

◆ invalidPacket

◆ maximumPacketSize()

◆ packetsAvailable()

◆ packetWritten

◆ read()

◆ readyRead

◆ send() [1/2]

◆ send() [2/2]

◆ setMaximumPacketSize()

◆ waitForReadyRead()

Properties

◆ d