--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/corelib/kernel/qcore_unix.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,163 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qcore_unix_p.h"
+
+#ifndef Q_OS_VXWORKS
+#  include <sys/select.h>
+#  include <sys/time.h>
+#else
+#  include <selectLib.h>
+#endif
+
+#include <stdlib.h>
+
+#ifdef Q_OS_MAC
+#include <mach/mach_time.h>
+#endif
+
+#if !defined(QT_NO_CLOCK_MONOTONIC)
+# if defined(QT_BOOTSTRAPPED)
+#  define QT_NO_CLOCK_MONOTONIC
+# endif
+#endif
+
+QT_BEGIN_NAMESPACE
+
+bool qt_gettime_is_monotonic()
+{
+#if (_POSIX_MONOTONIC_CLOCK-0 > 0) || defined(Q_OS_MAC)
+    return true;
+#else
+    static int returnValue = 0;
+
+    if (returnValue == 0) {
+#  if (_POSIX_MONOTONIC_CLOCK-0 < 0)
+        returnValue = -1;
+#  elif (_POSIX_MONOTONIC_CLOCK == 0)
+        // detect if the system support monotonic timers
+        long x = sysconf(_SC_MONOTONIC_CLOCK);
+        returnValue = (x >= 200112L) ? 1 : -1;
+#  endif
+    }
+
+    return returnValue != -1;
+#endif
+}
+
+timeval qt_gettime()
+{
+    timeval tv;
+#if defined(Q_OS_MAC)
+    static mach_timebase_info_data_t info = {0,0};
+    if (info.denom == 0)
+        mach_timebase_info(&info);
+
+    uint64_t cpu_time = mach_absolute_time();
+    uint64_t nsecs = cpu_time * (info.numer / info.denom);
+    tv.tv_sec = nsecs / 1000000000ull;
+    tv.tv_usec = (nsecs / 1000) - (tv.tv_sec * 1000000);
+    return tv;
+#elif (_POSIX_MONOTONIC_CLOCK-0 > 0)
+    timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    tv.tv_sec = ts.tv_sec;
+    tv.tv_usec = ts.tv_nsec / 1000;
+    return tv;
+#else
+#  if !defined(QT_NO_CLOCK_MONOTONIC) && !defined(QT_BOOTSTRAPPED)
+    if (qt_gettime_is_monotonic()) {
+        timespec ts;
+        clock_gettime(CLOCK_MONOTONIC, &ts);
+        tv.tv_sec = ts.tv_sec;
+        tv.tv_usec = ts.tv_nsec / 1000;
+        return tv;
+    }
+#  endif
+    // use gettimeofday
+    ::gettimeofday(&tv, 0);
+    return tv;
+#endif
+}
+
+static inline bool time_update(struct timeval *tv, const struct timeval &start,
+                               const struct timeval &timeout)
+{
+    if (!qt_gettime_is_monotonic()) {
+        // we cannot recalculate the timeout without a monotonic clock as the time may have changed
+        return false;
+    }
+
+    // clock source is monotonic, so we can recalculate how much timeout is left
+    struct timeval now = qt_gettime();
+    *tv = timeout + start - now;
+    return true;
+}
+
+int qt_safe_select(int nfds, fd_set *fdread, fd_set *fdwrite, fd_set *fdexcept,
+                   const struct timeval *orig_timeout)
+{
+    if (!orig_timeout) {
+        // no timeout -> block forever
+        register int ret;
+        EINTR_LOOP(ret, select(nfds, fdread, fdwrite, fdexcept, 0));
+        return ret;
+    }
+
+    timeval start = qt_gettime();
+    timeval timeout = *orig_timeout;
+
+    // loop and recalculate the timeout as needed
+    int ret;
+    forever {
+        ret = ::select(nfds, fdread, fdwrite, fdexcept, &timeout);
+        if (ret != -1 || errno != EINTR)
+            return ret;
+
+        // recalculate the timeout
+        if (!time_update(&timeout, start, *orig_timeout)) {
+            // clock reset, fake timeout error
+            return 0;
+        }
+    }
+}
+
+QT_END_NAMESPACE