qt-everywhere-src-5.14.1/qtbase/src/corelib/io/qlockfile_p.h

/****************************************************************************
**
** Copyright (C) 2013 David Faure <faure+bluesystems@kde.org>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
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** $QT_BEGIN_LICENSE:LGPL$
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#ifndef QLOCKFILE_P_H
#define QLOCKFILE_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QtCore/private/qglobal_p.h>
#include <QtCore/qlockfile.h>
#include <QtCore/qfile.h>

#include <qplatformdefs.h>

#ifdef Q_OS_WIN
#include <io.h>
#include <qt_windows.h>
#endif

QT_BEGIN_NAMESPACE

class QLockFilePrivate
{
public:
    QLockFilePrivate(const QString &fn)
        : fileName(fn),
#ifdef Q_OS_WIN
          fileHandle(INVALID_HANDLE_VALUE),
#else
          fileHandle(-1),
#endif
          staleLockTime(30 * 1000), // 30 seconds
          lockError(QLockFile::NoError),
          isLocked(false)
    {
    }
    QLockFile::LockError tryLock_sys();
    bool removeStaleLock();
    QByteArray lockFileContents() const;
    // Returns \c true if the lock belongs to dead PID, or is old.
    // The attempt to delete it will tell us if it was really stale or not, though.
    bool isApparentlyStale() const;

    // used in dbusmenu
    Q_CORE_EXPORT static QString processNameByPid(qint64 pid);
    static bool isProcessRunning(qint64 pid, const QString &appname);

    QString fileName;
#ifdef Q_OS_WIN
    Qt::HANDLE fileHandle;
#else
    int fileHandle;
#endif
    int staleLockTime; // "int milliseconds" is big enough for 24 days
    QLockFile::LockError lockError;
    bool isLocked;

    static int getLockFileHandle(QLockFile *f)
    {
        int fd;
#ifdef Q_OS_WIN
        // Use of this function on Windows WILL leak a file descriptor.
        fd = _open_osfhandle(intptr_t(f->d_func()->fileHandle), 0);
#else
        fd = f->d_func()->fileHandle;
#endif
        QT_LSEEK(fd, 0, SEEK_SET);
        return fd;
    }
};

QT_END_NAMESPACE

#endif /* QLOCKFILE_P_H */