Add QDateTime members that operate on 64-bit milliseconds.

This complements QDateTime::currentMsecsSinceEpoch.

Task-number: QTBUG-9017
Reviewed-by: Denis Dzyubenko

2 files changed, 105 insertions, 15 deletions

diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp
index 54a4205..7628dd2 100644
--- a/src/corelib/tools/qdatetime.cpp
+++ b/src/corelib/tools/qdatetime.cpp
@@ -2315,17 +2315,35 @@ void QDateTime::setTimeSpec(Qt::TimeSpec spec)
     }
 }
 
-static uint toTime_tHelper(const QDate &utcDate, const QTime &utcTime)
+qint64 toMsecsSinceEpoch_helper(qint64 jd, int msecs)
 {
-    int days = QDate(1970, 1, 1).daysTo(utcDate);
-    int secs = QTime().secsTo(utcTime);
-    if (days < 0 || (days == 0 && secs < 0))
-        return uint(-1);
+    int days = jd - julianDayFromGregorianDate(1970, 1, 1);
+    qint64 retval = (qlonglong(days) * MSECS_PER_DAY) + msecs;
+    return retval;
+}
 
-    qlonglong retval = (qlonglong(days) * SECS_PER_DAY) + secs;
-    if (retval >= Q_INT64_C(0xFFFFFFFF))
-        return uint(-1);
-    return uint(retval);
+/*!
+    \since 4.7
+
+    Returns the datetime as the number of milliseconds that have passed
+    since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt::UTC).
+
+    On systems that do not support time zones, this function will
+    behave as if local time were Qt::UTC.
+
+    The behavior for this function is undefined if the datetime stored in
+    this object is not valid. However, for all valid dates, this function
+    returns a unique value.
+
+    \sa toTime_t(), setMsecsSinceEpoch()
+*/
+qint64 QDateTime::toMsecsSinceEpoch() const
+{
+    QDate utcDate;
+    QTime utcTime;
+    d->getUTC(utcDate, utcTime);
+
+    return toMsecsSinceEpoch_helper(utcDate.jd, utcTime.ds());
 }
 
 /*!
@@ -2335,16 +2353,63 @@ static uint toTime_tHelper(const QDate &utcDate, const QTime &utcTime)
     On systems that do not support time zones, this function will
     behave as if local time were Qt::UTC.
 
-    \sa setTime_t()
+    \note This function returns a 32-bit unsigned integer, so it does not
+    support dates before 1970, but it does support dates after
+    2038-01-19T03:14:06, which may not be valid time_t values. Be careful
+    when passing those time_t values to system functions, which could
+    interpret them as negative dates.
+
+    If the date is outside the range 1970-01-01T00:00:00 to
+    2106-02-07T06:28:14, this function returns -1 cast to an unsigned integer
+    (i.e., 0xFFFFFFFF).
+
+    To get an extended range, use toMsecsSinceEpoch().
+
+    \sa toMsecsSinceEpoch(), setTime_t()
 */
 
 uint QDateTime::toTime_t() const
 {
-    QDate utcDate;
-    QTime utcTime;
-    d->getUTC(utcDate, utcTime);
+    qint64 retval = toMsecsSinceEpoch() / 1000;
+    if (quint64(retval) >= Q_UINT64_C(0xFFFFFFFF))
+        return uint(-1);
+    return uint(retval);
+}
 
-    return toTime_tHelper(utcDate, utcTime);
+/*!
+    \since 4.7
+
+    Sets the date and time given the number of \a mulliseconds that have
+    passed since 1970-01-01T00:00:00.000, Coordinated Universal Time
+    (Qt::UTC). On systems that do not support time zones this function
+    will behave as if local time were Qt::UTC.
+
+    Note that there are possible values for \a msecs that lie outside the
+    valid range of QDateTime, both negative and positive. The behavior of
+    this function is undefined for those values.
+
+    \sa toMsecsSinceEpoch(), setTime_t()
+*/
+void QDateTime::setMsecsSinceEpoch(qint64 msecs)
+{
+    detach();
+
+    QDateTimePrivate::Spec oldSpec = d->spec;
+
+    int ddays = msecs / MSECS_PER_DAY;
+    msecs %= MSECS_PER_DAY;
+    if (msecs < 0) {
+        // negative
+        --ddays;
+        msecs += MSECS_PER_DAY;
+    }
+
+    d->date = QDate(1970, 1, 1).addDays(ddays);
+    d->time = QTime().addMSecs(msecs);
+    d->spec = QDateTimePrivate::UTC;
+
+    if (oldSpec != QDateTimePrivate::UTC)
+        d->spec = d->getLocal(d->date, d->time);
 }
 
 /*!
@@ -3088,6 +3153,27 @@ QDateTime QDateTime::fromTime_t(uint seconds)
 }
 
 /*!
+  \since 4.7
+
+  Returns a datetime whose date and time are the number of milliseconds \a msec
+  that have passed since 1970-01-01T00:00:00.000, Coordinated Universal
+  Time (Qt::UTC). On systems that do not support time zones, the time
+  will be set as if local time were Qt::UTC.
+
+  Note that there are possible values for \a msecs that lie outside the valid
+  range of QDateTime, both negative and positive. The behavior of this
+  function is undefined for those values.
+
+  \sa toTime_t(), setTime_t()
+*/
+QDateTime QDateTime::fromMsecsSinceEpoch(qint64 msecs)
+{
+    QDateTime d;
+    d.setMsecsSinceEpoch(msecs);
+    return d;
+}
+
+/*!
  \since 4.4
  \internal
 
@@ -3841,7 +3927,8 @@ static QDateTimePrivate::Spec utcToLocal(QDate &date, QTime &time)
 {
     QDate fakeDate = adjustDate(date);
 
-    time_t secsSince1Jan1970UTC = toTime_tHelper(fakeDate, time);
+    // won't overflow because of fakeDate
+    time_t secsSince1Jan1970UTC = toMsecsSinceEpoch_helper(fakeDate.toJulianDay(), QTime().msecsTo(time)) / 1000;
     tm *brokenDown = 0;
 
 #if defined(Q_OS_WINCE)
diff --git a/src/corelib/tools/qdatetime.h b/src/corelib/tools/qdatetime.h
index ef5968e..248793b 100644
--- a/src/corelib/tools/qdatetime.h
+++ b/src/corelib/tools/qdatetime.h
@@ -230,10 +230,12 @@ public:
     QDate date() const;
     QTime time() const;
     Qt::TimeSpec timeSpec() const;
+    qint64 toMsecsSinceEpoch() const;
     uint toTime_t() const;
     void setDate(const QDate &date);
     void setTime(const QTime &time);
     void setTimeSpec(Qt::TimeSpec spec);
+    void setMsecsSinceEpoch(qint64 msecs);
     void setTime_t(uint secsSince1Jan1970UTC);
 #ifndef QT_NO_DATESTRING
     QString toString(Qt::DateFormat f = Qt::TextDate) const;
@@ -267,6 +269,7 @@ public:
     static QDateTime fromString(const QString &s, const QString &format);
 #endif
     static QDateTime fromTime_t(uint secsSince1Jan1970UTC);
+    static QDateTime fromMsecsSinceEpoch(qint64 msecs);
     static qint64 currentMsecsSinceEpoch();
 
 #ifdef QT3_SUPPORT