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#include "qtlocalpeer.h"

#include <QtCore/QCoreApplication>

#include <QtCore/QTime>



#if defined(Q_OS_WIN)

#include <QtCore/QLibrary>

#include <QtCore/qt_windows.h>

typedef BOOL(WINAPI*PProcessIdToSessionId)(DWORD,DWORD*);

static PProcessIdToSessionId pProcessIdToSessionId = 0;

#endif

#if defined(Q_OS_UNIX)

#include <time.h>

#endif



namespace QtLP_Private {

#include "qtlockedfile.cpp"

#if defined(Q_OS_WIN)

#include "qtlockedfile_win.cpp"

#else

#include "qtlockedfile_unix.cpp"

#endif

}



const char* QtLocalPeer::ack = "ack";



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

    : 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(QRegExp("[^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);

}







bool QtLocalPeer::isClient()

{

    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;

}





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

{

    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);

    res &= socket.waitForReadyRead(timeout);   // wait for ack

    res &= (socket.read(qstrlen(ack)) == ack);

    return res;

}





void QtLocalPeer::receiveConnection()

{

    QLocalSocket* socket = server->nextPendingConnection();

    if (!socket)

        return;



    while (socket->bytesAvailable() < (int)sizeof(quint32))

        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" << socket->errorString();

        delete socket;

        return;

    }

    QString message(QString::fromUtf8(uMsg));

    socket->write(ack, qstrlen(ack));

    socket->waitForBytesWritten(1000);

    delete socket;

    emit messageReceived(message); //### (might take a long time to return)

}