qt-creator/src/libs/utils/processutils.cpp

/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Creator.
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** GNU General Public License Usage
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** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
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#include "processutils.h"

#ifdef Q_OS_WIN
#include <qt_windows.h>
#else
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#endif

namespace Utils {

QIODevice::OpenMode ProcessStartHandler::openMode() const
{
    if (m_processMode == ProcessMode::Writer)
        return QIODevice::ReadWrite; // some writers also read data
    if (m_writeData.isEmpty())
        return QIODevice::ReadOnly; // only reading
    return QIODevice::ReadWrite; // initial write and then reading (close the write channel)
}

void ProcessStartHandler::handleProcessStart(QProcess *process)
{
    if (m_processMode == ProcessMode::Writer)
        return;
    if (m_writeData.isEmpty())
        process->closeWriteChannel();
}

void ProcessStartHandler::handleProcessStarted(QProcess *process)
{
    if (!m_writeData.isEmpty()) {
        process->write(m_writeData);
        m_writeData = {};
        if (m_processMode == ProcessMode::Reader)
            process->closeWriteChannel();
    }
}


void ProcessStartHandler::setBelowNormalPriority(QProcess *process)
{
#ifdef Q_OS_WIN
    process->setCreateProcessArgumentsModifier(
        [](QProcess::CreateProcessArguments *args) {
            args->flags |= BELOW_NORMAL_PRIORITY_CLASS;
    });
#else
    Q_UNUSED(process)
#endif // Q_OS_WIN
}

void ProcessStartHandler::setNativeArguments(QProcess *process, const QString &arguments)
{
#ifdef Q_OS_WIN
    if (!arguments.isEmpty())
        process->setNativeArguments(arguments);
#else
    Q_UNUSED(process)
    Q_UNUSED(arguments)
#endif // Q_OS_WIN
}


void ProcessHelper::setupChildProcess_impl()
{
#if defined Q_OS_UNIX
    // nice value range is -20 to +19 where -20 is highest, 0 default and +19 is lowest
    if (m_lowPriority) {
        errno = 0;
        if (::nice(5) == -1 && errno != 0)
            perror("Failed to set nice value");
    }

    // Disable terminal by becoming a session leader.
    if (m_unixTerminalDisabled)
        setsid();
#endif
}

} // namespace Utils