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#include "qprelaunchprocessbackend.h"

#include <qjsondocument.h>
#include <QUuid>
#include <QDebug>

QT_BEGIN_NAMESPACE_PROCESSMANAGER

/*!
  \class QPrelaunchProcessBackend
  \brief The QPrelaunchProcessBackend class encapsulates a process that is started and later told what to run.
  \inmodule QtProcessManager

  The QPrelaunchProcessBackend class contains an internal QProcess object that is
  "prelaunched" by the QPrelaunchProcessBackendFactory object.  When the factory
  is asked to create a new process, the prelaunched backend is returned.  When start() is
  called, the prelaunched process is passed a QProcessInfo record encoded in QBinaryJson
  document format (a serialized JSON object).  This record should be used by the
  prelaunched process to transform itself into the correctly running application.
 */

/*!
  Construct a QPrelaunchProcessBackend with QProcessInfo \a info and optional \a parent.
  The \a info QProcessInfo is used to start the internal QProcess.  This is different
  from the final QProcessInfo which will be directly passed to the running QProcess.
 */

QPrelaunchProcessBackend::QPrelaunchProcessBackend(const QProcessInfo &info, QObject *parent)
    : QUnixProcessBackend(info, parent)
    , m_started(false)
{
}

/*!
  Destroy this and child objects
*/

QPrelaunchProcessBackend::~QPrelaunchProcessBackend()
{
}

/*!
  Starts the internal QProcess with the prelaunch information.
 */

void QPrelaunchProcessBackend::prestart()
{
    if (createProcess())
        startProcess();
}

/*!
  Switch the stored QProcessInfo to the final \a info object.
  This function also updates the identifier of the process.
 */

void QPrelaunchProcessBackend::setInfo(const QProcessInfo& info)
{
    m_info = info;
    setDesiredPriority(m_info.priority());
    setDesiredOomAdjustment(m_info.oomAdjustment());
    createName();
}

/*!
  Check to see if this prelaunched process is ready to be used.
  Return true if the process has been created and is running.
 */

bool QPrelaunchProcessBackend::isReady() const
{
    return m_process && m_process->state() == QProcess::Running;
}

/*!
  Pretend to start the prelaunched process.
  The stored QProcessInfo record is written to the internal QProcess as a serialized
  JSON object (the internal QProcess receives it from stdin).
  Then emit all queued signals that were captured from the QProcess.
 */

void QPrelaunchProcessBackend::start()
{
    if (m_started) {
        qWarning() << "Can't restart prelaunched process";
        return;
    }

    m_started = true;
    // Pass the actual process info to the child process
    QByteArray byteArray = QJsonDocument::fromVariant(m_info.toMap()).toBinaryData();
    write(byteArray.data(), byteArray.size());

    while (m_queue.size()) {
        QueuedSignal s = m_queue.takeFirst();
        switch (s.name) {
        case QueuedSignal::StateChanged:
            emit stateChanged(s.n.state);
            break;
        case QueuedSignal::Started:
            emit started();
            break;
        case QueuedSignal::Error:
            emit error(s.n.error);
            break;
        case QueuedSignal::Finished:
            emit finished(s.n.f.exitCode, s.n.f.exitStatus);
            break;
        }
    }
}

/*!
  Return the current process state.  Until the process has been
  officially "started", the state has to be NotRunning.
 */

QProcess::ProcessState QPrelaunchProcessBackend::state() const
{
    if (m_started)
        return QUnixProcessBackend::state();
    else
        return QProcess::NotRunning;
}

/*!
    \internal
*/
void QPrelaunchProcessBackend::handleProcessStarted()
{
    QUnixProcessBackend::handleProcessStarted();
    if (!m_started) {
        QueuedSignal s;
        s.name = QueuedSignal::Started;
        m_queue << s;
    }
    emit started();
}

/*!
    \internal
*/
void QPrelaunchProcessBackend::handleProcessError(QProcess::ProcessError processError)
{
    QUnixProcessBackend::handleProcessError(processError);
    if (!m_started) {
        QueuedSignal s;
        s.name = QueuedSignal::Error;
        s.n.error = processError;
        m_queue << s;
    }
    emit error(processError);
}

/*!
    \internal
*/
void QPrelaunchProcessBackend::handleProcessFinished(int exitCode, QProcess::ExitStatus status)
{
    QUnixProcessBackend::handleProcessFinished(exitCode, status);
    if (!m_started) {
        QueuedSignal s;
        s.name = QueuedSignal::Finished;
        s.n.f.exitCode = exitCode;
        s.n.f.exitStatus = status;
        m_queue << s;
    }
    emit finished(exitCode, status);
}

/*!
    \internal
*/
void QPrelaunchProcessBackend::handleProcessStateChanged(QProcess::ProcessState state)
{
    QUnixProcessBackend::handleProcessStateChanged(state);
    if (!m_started) {
        QueuedSignal s;
        s.name = QueuedSignal::StateChanged;
        s.n.state = state;
        m_queue << s;
    }
    emit stateChanged(state);
}

/*!
  \class QueuedSignal
  \internal
 */

/*!
  \enum QueuedSignal::SignalName
  \internal
 */

#include "moc_qprelaunchprocessbackend.cpp"

QT_END_NAMESPACE_PROCESSMANAGER