308 lines
10 KiB
C++
308 lines
10 KiB
C++
/****************************************************************************
|
|
**
|
|
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
|
|
** Contact: http://www.qt-project.org/legal
|
|
**
|
|
** This file is part of the QtCore 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 Digia. For licensing terms and
|
|
** conditions see http://qt.digia.com/licensing. For further information
|
|
** use the contact form at http://qt.digia.com/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 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, Digia gives you certain additional
|
|
** rights. These rights are described in the Digia Qt LGPL Exception
|
|
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
|
|
**
|
|
** GNU General Public License Usage
|
|
** Alternatively, this file may be used under the terms of the GNU
|
|
** General Public License version 3.0 as published by the Free Software
|
|
** Foundation and appearing in the file LICENSE.GPL included in the
|
|
** packaging of this file. Please review the following information to
|
|
** ensure the GNU General Public License version 3.0 requirements will be
|
|
** met: http://www.gnu.org/copyleft/gpl.html.
|
|
**
|
|
**
|
|
** $QT_END_LICENSE$
|
|
**
|
|
****************************************************************************/
|
|
|
|
#include "qsocketnotifier.h"
|
|
|
|
#include "qplatformdefs.h"
|
|
|
|
#include "qabstracteventdispatcher.h"
|
|
#include "qcoreapplication.h"
|
|
|
|
#include "qobject_p.h"
|
|
#include <private/qthread_p.h>
|
|
|
|
QT_BEGIN_NAMESPACE
|
|
|
|
class QSocketNotifierPrivate : public QObjectPrivate
|
|
{
|
|
Q_DECLARE_PUBLIC(QSocketNotifier)
|
|
public:
|
|
qintptr sockfd;
|
|
QSocketNotifier::Type sntype;
|
|
bool snenabled;
|
|
};
|
|
|
|
/*!
|
|
\class QSocketNotifier
|
|
\inmodule QtCore
|
|
\brief The QSocketNotifier class provides support for monitoring
|
|
activity on a file descriptor.
|
|
|
|
\ingroup network
|
|
\ingroup io
|
|
|
|
The QSocketNotifier makes it possible to integrate Qt's event
|
|
loop with other event loops based on file descriptors. File
|
|
descriptor action is detected in Qt's main event
|
|
loop (QCoreApplication::exec()).
|
|
|
|
\target write notifiers
|
|
|
|
Once you have opened a device using a low-level (usually
|
|
platform-specific) API, you can create a socket notifier to
|
|
monitor the file descriptor. The socket notifier is enabled by
|
|
default, i.e. it emits the activated() signal whenever a socket
|
|
event corresponding to its type occurs. Connect the activated()
|
|
signal to the slot you want to be called when an event
|
|
corresponding to your socket notifier's type occurs.
|
|
|
|
There are three types of socket notifiers: read, write, and
|
|
exception. The type is described by the \l Type enum, and must be
|
|
specified when constructing the socket notifier. After
|
|
construction it can be determined using the type() function. Note
|
|
that if you need to monitor both reads and writes for the same
|
|
file descriptor, you must create two socket notifiers. Note also
|
|
that it is not possible to install two socket notifiers of the
|
|
same type (\l Read, \l Write, \l Exception) on the same socket.
|
|
|
|
The setEnabled() function allows you to disable as well as enable
|
|
the socket notifier. It is generally advisable to explicitly
|
|
enable or disable the socket notifier, especially for write
|
|
notifiers. A disabled notifier ignores socket events (the same
|
|
effect as not creating the socket notifier). Use the isEnabled()
|
|
function to determine the notifier's current status.
|
|
|
|
Finally, you can use the socket() function to retrieve the
|
|
socket identifier. Although the class is called QSocketNotifier,
|
|
it is normally used for other types of devices than sockets.
|
|
QTcpSocket and QUdpSocket provide notification through signals, so
|
|
there is normally no need to use a QSocketNotifier on them.
|
|
|
|
\section1 Notes for Windows Users
|
|
|
|
The socket passed to QSocketNotifier will become non-blocking, even if
|
|
it was created as a blocking socket.
|
|
The activated() signal is sometimes triggered by high general activity
|
|
on the host, even if there is nothing to read. A subsequent read from
|
|
the socket can then fail, the error indicating that there is no data
|
|
available (e.g., \c{WSAEWOULDBLOCK}). This is an operating system
|
|
limitation, and not a bug in QSocketNotifier.
|
|
|
|
To ensure that the socket notifier handles read notifications correctly,
|
|
follow these steps when you receive a notification:
|
|
|
|
\list 1
|
|
\li Disable the notifier.
|
|
\li Read data from the socket.
|
|
\li Re-enable the notifier if you are interested in more data (such as after
|
|
having written a new command to a remote server).
|
|
\endlist
|
|
|
|
To ensure that the socket notifier handles write notifications correctly,
|
|
follow these steps when you receive a notification:
|
|
|
|
\list 1
|
|
\li Disable the notifier.
|
|
\li Write as much data as you can (before \c EWOULDBLOCK is returned).
|
|
\li Re-enable notifier if you have more data to write.
|
|
\endlist
|
|
|
|
\b{Further information:}
|
|
On Windows, Qt always disables the notifier after getting a notification,
|
|
and only re-enables it if more data is expected. For example, if data is
|
|
read from the socket and it can be used to read more, or if reading or
|
|
writing is not possible because the socket would block, in which case
|
|
it is necessary to wait before attempting to read or write again.
|
|
|
|
\sa QFile, QProcess, QTcpSocket, QUdpSocket
|
|
*/
|
|
|
|
/*!
|
|
\enum QSocketNotifier::Type
|
|
|
|
This enum describes the various types of events that a socket
|
|
notifier can recognize. The type must be specified when
|
|
constructing the socket notifier.
|
|
|
|
Note that if you need to monitor both reads and writes for the
|
|
same file descriptor, you must create two socket notifiers. Note
|
|
also that it is not possible to install two socket notifiers of
|
|
the same type (Read, Write, Exception) on the same socket.
|
|
|
|
\value Read There is data to be read.
|
|
\value Write Data can be written.
|
|
\value Exception An exception has occurred. We recommend against using this.
|
|
|
|
\sa QSocketNotifier(), type()
|
|
*/
|
|
|
|
/*!
|
|
Constructs a socket notifier with the given \a parent. It enables
|
|
the \a socket, and watches for events of the given \a type.
|
|
|
|
It is generally advisable to explicitly enable or disable the
|
|
socket notifier, especially for write notifiers.
|
|
|
|
\b{Note for Windows users:} The socket passed to QSocketNotifier
|
|
will become non-blocking, even if it was created as a blocking socket.
|
|
|
|
\sa setEnabled(), isEnabled()
|
|
*/
|
|
|
|
QSocketNotifier::QSocketNotifier(qintptr socket, Type type, QObject *parent)
|
|
: QObject(*new QSocketNotifierPrivate, parent)
|
|
{
|
|
Q_D(QSocketNotifier);
|
|
if (socket < 0)
|
|
qWarning("QSocketNotifier: Invalid socket specified");
|
|
d->sockfd = socket;
|
|
d->sntype = type;
|
|
d->snenabled = true;
|
|
|
|
if (!d->threadData->eventDispatcher.load()) {
|
|
qWarning("QSocketNotifier: Can only be used with threads started with QThread");
|
|
} else {
|
|
d->threadData->eventDispatcher.load()->registerSocketNotifier(this);
|
|
}
|
|
}
|
|
|
|
/*!
|
|
Destroys this socket notifier.
|
|
*/
|
|
|
|
QSocketNotifier::~QSocketNotifier()
|
|
{
|
|
setEnabled(false);
|
|
}
|
|
|
|
|
|
/*!
|
|
\fn void QSocketNotifier::activated(int socket)
|
|
|
|
This signal is emitted whenever the socket notifier is enabled and
|
|
a socket event corresponding to its \l {Type}{type} occurs.
|
|
|
|
The socket identifier is passed in the \a socket parameter.
|
|
|
|
\sa type(), socket()
|
|
*/
|
|
|
|
|
|
/*!
|
|
Returns the socket identifier specified to the constructor.
|
|
|
|
\sa type()
|
|
*/
|
|
qintptr QSocketNotifier::socket() const
|
|
{
|
|
Q_D(const QSocketNotifier);
|
|
return d->sockfd;
|
|
}
|
|
|
|
/*!
|
|
Returns the socket event type specified to the constructor.
|
|
|
|
\sa socket()
|
|
*/
|
|
QSocketNotifier::Type QSocketNotifier::type() const
|
|
{
|
|
Q_D(const QSocketNotifier);
|
|
return d->sntype;
|
|
}
|
|
|
|
/*!
|
|
Returns true if the notifier is enabled; otherwise returns false.
|
|
|
|
\sa setEnabled()
|
|
*/
|
|
bool QSocketNotifier::isEnabled() const
|
|
{
|
|
Q_D(const QSocketNotifier);
|
|
return d->snenabled;
|
|
}
|
|
|
|
/*!
|
|
If \a enable is true, the notifier is enabled; otherwise the notifier
|
|
is disabled.
|
|
|
|
The notifier is enabled by default, i.e. it emits the activated()
|
|
signal whenever a socket event corresponding to its
|
|
\l{type()}{type} occurs. If it is disabled, it ignores socket
|
|
events (the same effect as not creating the socket notifier).
|
|
|
|
Write notifiers should normally be disabled immediately after the
|
|
activated() signal has been emitted
|
|
|
|
\sa isEnabled(), activated()
|
|
*/
|
|
|
|
void QSocketNotifier::setEnabled(bool enable)
|
|
{
|
|
Q_D(QSocketNotifier);
|
|
if (d->sockfd < 0)
|
|
return;
|
|
if (d->snenabled == enable) // no change
|
|
return;
|
|
d->snenabled = enable;
|
|
|
|
if (!d->threadData->eventDispatcher.load()) // perhaps application/thread is shutting down
|
|
return;
|
|
if (d->snenabled)
|
|
d->threadData->eventDispatcher.load()->registerSocketNotifier(this);
|
|
else
|
|
d->threadData->eventDispatcher.load()->unregisterSocketNotifier(this);
|
|
}
|
|
|
|
|
|
/*!\reimp
|
|
*/
|
|
bool QSocketNotifier::event(QEvent *e)
|
|
{
|
|
Q_D(QSocketNotifier);
|
|
// Emits the activated() signal when a QEvent::SockAct or QEvent::SockClose is
|
|
// received.
|
|
if (e->type() == QEvent::ThreadChange) {
|
|
if (d->snenabled) {
|
|
QMetaObject::invokeMethod(this, "setEnabled", Qt::QueuedConnection,
|
|
Q_ARG(bool, d->snenabled));
|
|
setEnabled(false);
|
|
}
|
|
}
|
|
QObject::event(e); // will activate filters
|
|
if ((e->type() == QEvent::SockAct) || (e->type() == QEvent::SockClose)) {
|
|
emit activated(d->sockfd, QPrivateSignal());
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
QT_END_NAMESPACE
|