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#include "filetime.h"

#include <QtCore/qstring.h>

#ifdef Q_OS_WIN
#include <QtCore/qt_windows.h>
#else
#include <QtCore/qdatetime.h>
#endif

namespace qbs {
namespace Internal {

#ifdef Q_OS_WIN
template<bool> struct CompileTimeAssert;
template<> struct CompileTimeAssert<true> {};
#endif

#ifdef APPLE_CUSTOM_CLOCK_GETTIME
#include <sys/time.h>

#ifndef CLOCK_REALTIME
#define CLOCK_REALTIME 0
#endif

// clk_id isn't used, only the CLOCK_REALTIME case is implemented.
int clock_gettime(int /*clk_id*/, struct timespec *t)
{
    struct timeval tv;
    // Resolution of gettimeofday is 1000nsecs = 1 microsecond.
    int ret = gettimeofday(&tv, NULL);
    t->tv_sec  = tv.tv_sec;
    t->tv_nsec = tv.tv_usec * 1000;
    return ret;
}
#endif

FileTime::FileTime()
{
#ifdef Q_OS_WIN
    static CompileTimeAssert<sizeof(FileTime::InternalType) == sizeof(FILETIME)> internal_type_has_wrong_size;
    Q_UNUSED(internal_type_has_wrong_size);
    m_fileTime = 0;
#elif HAS_CLOCK_GETTIME
    m_fileTime = {0, 0};
#else
    m_fileTime = 0;
#endif
}

FileTime::FileTime(const FileTime::InternalType &ft) : m_fileTime(ft)
{
#if HAS_CLOCK_GETTIME
    if (m_fileTime.tv_sec == 0)
        m_fileTime.tv_nsec = 0; // stat() sets only the first member to 0 for non-existing files.
#endif
}

int FileTime::compare(const FileTime &other) const
{
#ifdef Q_OS_WIN
    const FILETIME *const t1 = reinterpret_cast<const FILETIME *>(&m_fileTime);
    const FILETIME *const t2 = reinterpret_cast<const FILETIME *>(&other.m_fileTime);
    return CompareFileTime(t1, t2);
#elif HAS_CLOCK_GETTIME
    if (m_fileTime.tv_sec < other.m_fileTime.tv_sec)
        return -1;
    if (m_fileTime.tv_sec > other.m_fileTime.tv_sec)
        return 1;
    if (m_fileTime.tv_nsec < other.m_fileTime.tv_nsec)
        return -1;
    if (m_fileTime.tv_nsec > other.m_fileTime.tv_nsec)
        return 1;
    return 0;
#else
    if (m_fileTime < other.m_fileTime)
        return -1;
    if (m_fileTime > other.m_fileTime)
        return 1;
    return 0;
#endif
}

void FileTime::clear()
{
#if HAS_CLOCK_GETTIME
    m_fileTime = { 0, 0 };
#else
    m_fileTime = 0;
#endif
}

bool FileTime::isValid() const
{
    return *this != FileTime();
}

FileTime FileTime::currentTime()
{
#ifdef Q_OS_WIN
    FileTime result;
    SYSTEMTIME st;
    GetSystemTime(&st);
    FILETIME *const ft = reinterpret_cast<FILETIME *>(&result.m_fileTime);
    SystemTimeToFileTime(&st, ft);
    return result;
#elif defined APPLE_CUSTOM_CLOCK_GETTIME
    InternalType t;
    // Explicitly use our custom version, so that we don't get an additional unresolved symbol on a
    // system that actually provides one, but isn't used due to the minimium deployment target
    // being lower.
    qbs::Internal::clock_gettime(CLOCK_REALTIME, &t);
    return t;
#elif HAS_CLOCK_GETTIME
    InternalType t;
    clock_gettime(CLOCK_REALTIME, &t);
    return t;
#else
    return time(nullptr);
#endif
}

FileTime FileTime::oldestTime()
{
#ifdef Q_OS_WIN
    SYSTEMTIME st = {
        1601,
        1,
        5,
        2,
        0,
        0,
        0,
        0
    };
    FileTime result;
    FILETIME *const ft = reinterpret_cast<FILETIME *>(&result.m_fileTime);
    SystemTimeToFileTime(&st, ft);
    return result;
#elif HAS_CLOCK_GETTIME
    return FileTime({1, 0});
#else
    return 1;
#endif
}

double FileTime::asDouble() const
{
#if HAS_CLOCK_GETTIME
    return static_cast<double>(m_fileTime.tv_sec);
#else
    return static_cast<double>(m_fileTime);
#endif
}

QString FileTime::toString() const
{
#ifdef Q_OS_WIN
    const FILETIME *const ft = reinterpret_cast<const FILETIME *>(&m_fileTime);
    SYSTEMTIME stUTC, stLocal;
    FileTimeToSystemTime(ft, &stUTC);
    SystemTimeToTzSpecificLocalTime(NULL, &stUTC, &stLocal);
    const QString result = QString::fromLatin1("%1.%2.%3 %4:%5:%6")
            .arg(stLocal.wDay, 2, 10, QLatin1Char('0')).arg(stLocal.wMonth, 2, 10, QLatin1Char('0')).arg(stLocal.wYear)
            .arg(stLocal.wHour, 2, 10, QLatin1Char('0')).arg(stLocal.wMinute, 2, 10, QLatin1Char('0')).arg(stLocal.wSecond, 2, 10, QLatin1Char('0'));
    return result;
#else
    QDateTime dt;
#if HAS_CLOCK_GETTIME
   dt.setMSecsSinceEpoch(m_fileTime.tv_sec * 1000 + m_fileTime.tv_nsec / 1000000);
#else
    dt.setTime_t(m_fileTime);
#endif
    return dt.toString(Qt::ISODateWithMs);
#endif
}

} // namespace Internal
} // namespace qbs
