QtLocalPeer Class Reference

#include <qtlocalpeer.h>

Inheritance diagram for QtLocalPeer:

Signals
void	messageReceived (const QString &message)

Public Member Functions
QString	applicationId () const
bool	isClient ()
	QtLocalPeer (QObject *parent=0, const QString &appId=QString())
bool	sendMessage (const QString &message, int timeout)

Protected Slots
void	receiveConnection ()

Protected Attributes
QString	id
QtLP_Private::QtLockedFile	lockFile
QLocalServer *	server
QString	socketName

Static Private Attributes
static const char *	ack = "ack"

Detailed Description

Definition at line 13 of file qtlocalpeer.h.

Constructor & Destructor Documentation

QtLocalPeer()

QtLocalPeer::QtLocalPeer	(	QObject *	parent = 0,
		const QString &	appId = QString() )

Definition at line 34 of file qtlocalpeer.cpp.

    : QObject(parent), id(appId)
{
    QString prefix = id;
    if (id.isEmpty()) {
        id = QCoreApplication::applicationFilePath();
#if defined(Q_OS_WIN)
        id = id.toLower();
#endif
        prefix = id.section(QLatin1Char('/'), -1);
    }
    prefix.remove(QRegularExpression("[^a-zA-Z]"));
    prefix.truncate(6);
 
    QByteArray idc = id.toUtf8();
    quint16 idNum = qChecksum(idc.constData(), idc.size());
    socketName = QLatin1String("qtsingleapp-") + prefix
                 + QLatin1Char('-') + QString::number(idNum, 16);
 
#if defined(Q_OS_WIN)
    if (!pProcessIdToSessionId) {
        QLibrary lib("kernel32");
        pProcessIdToSessionId = (PProcessIdToSessionId)lib.resolve("ProcessIdToSessionId");
    }
    if (pProcessIdToSessionId) {
        DWORD sessionId = 0;
        pProcessIdToSessionId(GetCurrentProcessId(), &sessionId);
        socketName += QLatin1Char('-') + QString::number(sessionId, 16);
    }
#else
    socketName += QLatin1Char('-') + QString::number(::getuid(), 16);
#endif
 
    server = new QLocalServer(this);
    QString lockName = QDir(QDir::tempPath()).absolutePath()
                       + QLatin1Char('/') + socketName
                       + QLatin1String("-lockfile");
    lockFile.setFileName(lockName);
    lockFile.open(QIODevice::ReadWrite);
}

References id, lockFile, QtLP_Private::QtLockedFile::open(), server, and socketName.

Member Function Documentation

applicationId()

QString QtLocalPeer::applicationId ( ) const

inline

Definition at line 21 of file qtlocalpeer.h.

        { return id; }

References id.

isClient()

bool QtLocalPeer::isClient

(

)

Definition at line 77 of file qtlocalpeer.cpp.

{
    if (lockFile.isLocked())
        return false;
 
    if (!lockFile.lock(QtLP_Private::QtLockedFile::WriteLock, false))
        return true;
 
    bool res = server->listen(socketName);
#if defined(Q_OS_UNIX) && (QT_VERSION >= QT_VERSION_CHECK(4,5,0))
    // ### Workaround
    if (!res && server->serverError() == QAbstractSocket::AddressInUseError) {
        QFile::remove(QDir::cleanPath(QDir::tempPath())+QLatin1Char('/')+socketName);
        res = server->listen(socketName);
    }
#endif
    if (!res)
        qWarning("QtSingleCoreApplication: listen on local socket failed, %s", qPrintable(server->errorString()));
    QObject::connect(server, SIGNAL(newConnection()), SLOT(receiveConnection()));
    return false;
}

References QtLP_Private::QtLockedFile::isLocked(), QtLP_Private::QtLockedFile::lock(), lockFile, receiveConnection(), server, socketName, and QtLP_Private::QtLockedFile::WriteLock.

messageReceived

void QtLocalPeer::messageReceived ( const QString & message )

signal

receiveConnection

void QtLocalPeer::receiveConnection ( )

protectedslot

Definition at line 137 of file qtlocalpeer.cpp.

{
    QLocalSocket* socket = server->nextPendingConnection();
    if (!socket)
        return;
 
    while (true) {
        if (socket->state() == QLocalSocket::UnconnectedState) {
            qWarning("QtLocalPeer: Peer disconnected");
            delete socket;
            return;
        }
        if (socket->bytesAvailable() >= qint64(sizeof(quint32)))
            break;
        socket->waitForReadyRead();
    }
 
    QDataStream ds(socket);
    QByteArray uMsg;
    quint32 remaining;
    ds >> remaining;
    uMsg.resize(remaining);
    int got = 0;
    char* uMsgBuf = uMsg.data();
    do {
        got = ds.readRawData(uMsgBuf, remaining);
        remaining -= got;
        uMsgBuf += got;
    } while (remaining && got >= 0 && socket->waitForReadyRead(2000));
    if (got < 0) {
        qWarning("QtLocalPeer: Message reception failed %s", socket->errorString().toLatin1().constData());
        delete socket;
        return;
    }
    QString message(QString::fromUtf8(uMsg));
    socket->write(ack, qstrlen(ack));
    socket->waitForBytesWritten(1000);
    socket->waitForDisconnected(1000); // make sure client reads ack
    delete socket;
    emit messageReceived(message); //### (might take a long time to return)
}

References ack, messageReceived(), and server.

sendMessage()

bool QtLocalPeer::sendMessage	(	const QString &	message,
		int	timeout )

Definition at line 100 of file qtlocalpeer.cpp.

{
    if (!isClient())
        return false;
 
    QLocalSocket socket;
    bool connOk = false;
    for(int i = 0; i < 2; i++) {
        // Try twice, in case the other instance is just starting up
        socket.connectToServer(socketName);
        connOk = socket.waitForConnected(timeout/2);
        if (connOk || i)
            break;
        int ms = 250;
#if defined(Q_OS_WIN)
        Sleep(DWORD(ms));
#else
        struct timespec ts = { ms / 1000, (ms % 1000) * 1000 * 1000 };
        nanosleep(&ts, NULL);
#endif
    }
    if (!connOk)
        return false;
 
    QByteArray uMsg(message.toUtf8());
    QDataStream ds(&socket);
    ds.writeBytes(uMsg.constData(), uMsg.size());
    bool res = socket.waitForBytesWritten(timeout);
    if (res) {
        res &= socket.waitForReadyRead(timeout);   // wait for ack
        if (res)
            res &= (socket.read(qstrlen(ack)) == ack);
    }
    return res;
}

References ack, isClient(), and socketName.

Member Data Documentation

ack

const char * QtLocalPeer::ack = "ack"

staticprivate

Definition at line 37 of file qtlocalpeer.h.

id

QString QtLocalPeer::id

protected

Definition at line 31 of file qtlocalpeer.h.

lockFile

QtLP_Private::QtLockedFile QtLocalPeer::lockFile

protected

Definition at line 34 of file qtlocalpeer.h.

server

QLocalServer* QtLocalPeer::server

protected

Definition at line 33 of file qtlocalpeer.h.

socketName

QString QtLocalPeer::socketName

protected

Definition at line 32 of file qtlocalpeer.h.

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

• libs/ui/qtsingleapplication/qtlocalpeer.h
• libs/ui/qtsingleapplication/qtlocalpeer.cpp