Changeset 39784 in webkit for trunk/JavaScriptCore/runtime

Timestamp:

Jan 11, 2009, 12:14:58 AM (16 years ago)

Author:

[email protected]

Message:

Reviewed by Darin Adler.

​https://bugs.webkit.org/show_bug.cgi?id=23207
Moved currentTime() to from WebCore to WTF.

File:

• trunk/JavaScriptCore/runtime/DateMath.cpp (modified) (2 diffs)

trunk/JavaScriptCore/runtime/DateMath.cpp

@@ -49 +49 @@
 #include <wtf/ASCIICType.h>
 #include <wtf/Assertions.h>
+#include <wtf/CurrentTime.h>
 #include <wtf/MathExtras.h>
 #include <wtf/StringExtras.h>
@@ -292 +293 @@
 }
 
-#if PLATFORM(WIN_OS)
-
-static LARGE_INTEGER qpcFrequency;
-static bool syncedTime;
-
-static double highResUpTime()
-{
-    // We use QPC, but only after sanity checking its result, due to bugs:
-    // http://support.microsoft.com/kb/274323
-    // http://support.microsoft.com/kb/895980
-    // http://msdn.microsoft.com/en-us/library/ms644904.aspx ("...you can get different results on different processors due to bugs in the basic input/output system (BIOS) or the hardware abstraction layer (HAL)."
-
-    static LARGE_INTEGER qpcLast;
-    static DWORD tickCountLast;
-    static bool inited;
-
-    LARGE_INTEGER qpc;
-    QueryPerformanceCounter(&qpc);
-    DWORD tickCount = GetTickCount();
-
-    if (inited) {
-        __int64 qpcElapsed = ((qpc.QuadPart - qpcLast.QuadPart) * 1000) / qpcFrequency.QuadPart;
-        __int64 tickCountElapsed;
-        if (tickCount >= tickCountLast)
-            tickCountElapsed = (tickCount - tickCountLast);
-        else {
-#if COMPILER(MINGW)
-            __int64 tickCountLarge = tickCount + 0x100000000ULL;
-#else
-            __int64 tickCountLarge = tickCount + 0x100000000I64;
-#endif
-            tickCountElapsed = tickCountLarge - tickCountLast;
-        }
-
-        // force a re-sync if QueryPerformanceCounter differs from GetTickCount by more than 500ms.
-        // (500ms value is from http://support.microsoft.com/kb/274323)
-        __int64 diff = tickCountElapsed - qpcElapsed;
-        if (diff > 500 || diff < -500)
-            syncedTime = false;
-    } else
-        inited = true;
-
-    qpcLast = qpc;
-    tickCountLast = tickCount;
-
-    return (1000.0 * qpc.QuadPart) / static_cast<double>(qpcFrequency.QuadPart);;
-}
-
-static double lowResUTCTime()
-{
-#if PLATFORM(WIN_CE)
-    SYSTEMTIME systemTime;
-    GetSystemTime(&systemTime);
-    struct tm tmtime;
-    tmtime.tm_year = systemTime.wYear - 1900;
-    tmtime.tm_mon = systemTime.wMonth - 1;
-    tmtime.tm_mday = systemTime.wDay;
-    tmtime.tm_wday = systemTime.wDayOfWeek;
-    tmtime.tm_hour = systemTime.wHour;
-    tmtime.tm_min = systemTime.wMinute;
-    tmtime.tm_sec = systemTime.wSecond;
-    time_t timet = mktime(&tmtime);
-    return timet * msPerSecond + systemTime.wMilliseconds;
-#else
-    struct _timeb timebuffer;
-    _ftime(&timebuffer);
-    return timebuffer.time * msPerSecond + timebuffer.millitm;
-#endif
-}
-
-static bool qpcAvailable()
-{
-    static bool available;
-    static bool checked;
-
-    if (checked)
-        return available;
-
-    available = QueryPerformanceFrequency(&qpcFrequency);
-    checked = true;
-    return available;
-}
-
-#endif
-
+// Returns current time in milliseconds since 1 Jan 1970.
 double getCurrentUTCTimeWithMicroseconds()
 {
-#if PLATFORM(WIN_OS)
-    // Use a combination of ftime and QueryPerformanceCounter.
-    // ftime returns the information we want, but doesn't have sufficient resolution.
-    // QueryPerformanceCounter has high resolution, but is only usable to measure time intervals.
-    // To combine them, we call ftime and QueryPerformanceCounter initially. Later calls will use QueryPerformanceCounter
-    // by itself, adding the delta to the saved ftime.  We periodically re-sync to correct for drift.
-    static bool started;
-    static double syncLowResUTCTime;
-    static double syncHighResUpTime;
-    static double lastUTCTime;
-
-    double lowResTime = lowResUTCTime();
-
-    if (!qpcAvailable())
-        return lowResTime;
-
-    double highResTime = highResUpTime();
-
-    if (!syncedTime) {
-        timeBeginPeriod(1); // increase time resolution around low-res time getter
-        syncLowResUTCTime = lowResTime = lowResUTCTime();
-        timeEndPeriod(1); // restore time resolution
-        syncHighResUpTime = highResTime;
-        syncedTime = true;
-    }
-
-    double highResElapsed = highResTime - syncHighResUpTime;
-    double utc = syncLowResUTCTime + highResElapsed;
-
-    // force a clock re-sync if we've drifted
-    double lowResElapsed = lowResTime - syncLowResUTCTime;
-    const double maximumAllowedDriftMsec = 15.625 * 2.0; // 2x the typical low-res accuracy
-    if (fabs(highResElapsed - lowResElapsed) > maximumAllowedDriftMsec)
-        syncedTime = false;
-
-    // make sure time doesn't run backwards (only correct if difference is < 2 seconds, since DST or clock changes could occur)
-    const double backwardTimeLimit = 2000.0;
-    if (utc < lastUTCTime && (lastUTCTime - utc) < backwardTimeLimit)
-        return lastUTCTime;
-    lastUTCTime = utc;
-#else
-    struct timeval tv;
-    gettimeofday(&tv, 0);
-    double utc = tv.tv_sec * msPerSecond + tv.tv_usec / 1000.0;
-#endif
-    return utc;
+    return currentTime() * 1000.0; 
 }