eeprom-programmer/eeprom_programmer_PC/src/sigwatch.cpp at main · feer9/eeprom-programmer · GitHub

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* Unix signal watcher for Qt.

* Permission is hereby granted, free of charge, to any person obtaining a copy

* of this software and associated documentation files (the "Software"), to deal

* in the Software without restriction, including without limitation the rights

* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

* copies of the Software, and to permit persons to whom the Software is

* furnished to do so, subject to the following conditions:

* The above copyright notice and this permission notice shall be included in

* all copies or substantial portions of the Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

* SOFTWARE.

#include <sys/socket.h>

#include <unistd.h>

#include <errno.h>

#include <QMap>

#include <QSocketNotifier>

#include <QDebug>

#include "sigwatch.h"

/*!

* \brief The UnixSignalWatcherPrivate class implements the back-end signal

* handling for the UnixSignalWatcher.

* \see http://qt-project.org/doc/qt-5.0/qtdoc/unix-signals.html

class UnixSignalWatcherPrivate : public QObject

{

UnixSignalWatcher * const q_ptr;

Q_DECLARE_PUBLIC(UnixSignalWatcher)

public:

UnixSignalWatcherPrivate(UnixSignalWatcher *q);

~UnixSignalWatcherPrivate();

void watchForSignal(int signal);

static void signalHandler(int signal);

void _q_onNotify(int sockfd);

private:

static int sockpair[2];

QSocketNotifier *notifier;

QList<int> watchedSignals;

};

int UnixSignalWatcherPrivate::sockpair[2];

UnixSignalWatcherPrivate::UnixSignalWatcherPrivate(UnixSignalWatcher *q) :

q_ptr(q)

{

// Create socket pair

if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair)) {

qDebug() << "UnixSignalWatcher: socketpair: " << ::strerror(errno);

return;

}

// Create a notifier for the read end of the pair

notifier = new QSocketNotifier(sockpair[1], QSocketNotifier::Read);

QObject::connect(notifier, SIGNAL(activated(int)), q, SLOT(_q_onNotify(int)));

notifier->setEnabled(true);

}

UnixSignalWatcherPrivate::~UnixSignalWatcherPrivate()

{

delete notifier;

}

/*!

* Registers a handler for the given Unix \a signal. The handler will write to

* a socket pair, the other end of which is connected to a QSocketNotifier.

* This provides a way to break out of the asynchronous context from which the

* signal handler is called and back into the Qt event loop.

void UnixSignalWatcherPrivate::watchForSignal(int signal)

{

if (watchedSignals.contains(signal)) {

qDebug() << "Already watching for signal" << signal;

return;

}

// Register a sigaction which will write to the socket pair

struct sigaction sigact;

sigact.sa_handler = UnixSignalWatcherPrivate::signalHandler;

sigact.sa_flags = 0;

::sigemptyset(&sigact.sa_mask);

sigact.sa_flags |= SA_RESTART;

if (::sigaction(signal, &sigact, NULL)) {

qDebug() << "UnixSignalWatcher: sigaction: " << ::strerror(errno);

return;

}

watchedSignals.append(signal);

}

/*!

* Called when a Unix \a signal is received. Write to the socket to wake up the

* QSocketNotifier.

void UnixSignalWatcherPrivate::signalHandler(int signal)

{

ssize_t nBytes = ::write(sockpair[0], &signal, sizeof(signal));

Q_UNUSED(nBytes);

}

/*!

* Called when the signal handler has written to the socket pair. Emits the Unix

* signal as a Qt signal.

void UnixSignalWatcherPrivate::_q_onNotify(int sockfd)

{

Q_Q(UnixSignalWatcher);

int signal;

ssize_t nBytes = ::read(sockfd, &signal, sizeof(signal));

Q_UNUSED(nBytes);

qDebug() << "Caught signal:" << ::strsignal(signal);

emit q->unixSignal(signal);

}

/*!

* Create a new UnixSignalWatcher as a child of the given \a parent.

UnixSignalWatcher::UnixSignalWatcher(QObject *parent) :

QObject(parent),

d_ptr(new UnixSignalWatcherPrivate(this))

{

}

/*!

* Destroy this UnixSignalWatcher.

UnixSignalWatcher::~UnixSignalWatcher()

{

delete d_ptr;

}

/*!

* Register a signal handler for the given \a signal.

* After calling this method you can \c connect() to the unixSignal() Qt signal

* to be notified when the Unix signal is received.

void UnixSignalWatcher::watchForSignal(int signal)

{

Q_D(UnixSignalWatcher);

d->watchForSignal(signal);

}

/*!

* \fn void UnixSignalWatcher::unixSignal(int signal)

* Emitted when the given Unix \a signal is received.

* watchForSignal() must be called for each Unix signal that you want to receive

* via the unixSignal() Qt signal. If a watcher is watching multiple signals,

* unixSignal() will be emitted whenever *any* of the watched Unix signals are

* received, and the \a signal argument can be inspected to find out which one

* was actually received.

#include "moc_sigwatch.cpp"

eeprom-programmer/eeprom_programmer_PC/src/sigwatch.cpp at main · feer9/eeprom-programmer · GitHub

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